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/* Alias analysis for GNU C
/* Alias analysis for GNU C
   Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
   Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
   2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   2007, 2008, 2009, 2010 Free Software Foundation, Inc.
   Contributed by John Carr (jfc@mit.edu).
   Contributed by John Carr (jfc@mit.edu).
 
 
This file is part of GCC.
This file is part of GCC.
 
 
GCC is free software; you can redistribute it and/or modify it under
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
Software Foundation; either version 3, or (at your option) any later
version.
version.
 
 
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.
for more details.
 
 
You should have received a copy of the GNU General Public License
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */
<http://www.gnu.org/licenses/>.  */
 
 
#include "config.h"
#include "config.h"
#include "system.h"
#include "system.h"
#include "coretypes.h"
#include "coretypes.h"
#include "tm.h"
#include "tm.h"
#include "rtl.h"
#include "rtl.h"
#include "tree.h"
#include "tree.h"
#include "tm_p.h"
#include "tm_p.h"
#include "function.h"
#include "function.h"
#include "alias.h"
#include "alias.h"
#include "emit-rtl.h"
#include "emit-rtl.h"
#include "regs.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "hard-reg-set.h"
#include "basic-block.h"
#include "basic-block.h"
#include "flags.h"
#include "flags.h"
#include "output.h"
#include "output.h"
#include "toplev.h"
#include "toplev.h"
#include "cselib.h"
#include "cselib.h"
#include "splay-tree.h"
#include "splay-tree.h"
#include "ggc.h"
#include "ggc.h"
#include "langhooks.h"
#include "langhooks.h"
#include "timevar.h"
#include "timevar.h"
#include "target.h"
#include "target.h"
#include "cgraph.h"
#include "cgraph.h"
#include "varray.h"
#include "varray.h"
#include "tree-pass.h"
#include "tree-pass.h"
#include "ipa-type-escape.h"
#include "ipa-type-escape.h"
#include "df.h"
#include "df.h"
#include "tree-ssa-alias.h"
#include "tree-ssa-alias.h"
#include "pointer-set.h"
#include "pointer-set.h"
#include "tree-flow.h"
#include "tree-flow.h"
 
 
/* The aliasing API provided here solves related but different problems:
/* The aliasing API provided here solves related but different problems:
 
 
   Say there exists (in c)
   Say there exists (in c)
 
 
   struct X {
   struct X {
     struct Y y1;
     struct Y y1;
     struct Z z2;
     struct Z z2;
   } x1, *px1,  *px2;
   } x1, *px1,  *px2;
 
 
   struct Y y2, *py;
   struct Y y2, *py;
   struct Z z2, *pz;
   struct Z z2, *pz;
 
 
 
 
   py = &px1.y1;
   py = &px1.y1;
   px2 = &x1;
   px2 = &x1;
 
 
   Consider the four questions:
   Consider the four questions:
 
 
   Can a store to x1 interfere with px2->y1?
   Can a store to x1 interfere with px2->y1?
   Can a store to x1 interfere with px2->z2?
   Can a store to x1 interfere with px2->z2?
   (*px2).z2
   (*px2).z2
   Can a store to x1 change the value pointed to by with py?
   Can a store to x1 change the value pointed to by with py?
   Can a store to x1 change the value pointed to by with pz?
   Can a store to x1 change the value pointed to by with pz?
 
 
   The answer to these questions can be yes, yes, yes, and maybe.
   The answer to these questions can be yes, yes, yes, and maybe.
 
 
   The first two questions can be answered with a simple examination
   The first two questions can be answered with a simple examination
   of the type system.  If structure X contains a field of type Y then
   of the type system.  If structure X contains a field of type Y then
   a store thru a pointer to an X can overwrite any field that is
   a store thru a pointer to an X can overwrite any field that is
   contained (recursively) in an X (unless we know that px1 != px2).
   contained (recursively) in an X (unless we know that px1 != px2).
 
 
   The last two of the questions can be solved in the same way as the
   The last two of the questions can be solved in the same way as the
   first two questions but this is too conservative.  The observation
   first two questions but this is too conservative.  The observation
   is that in some cases analysis we can know if which (if any) fields
   is that in some cases analysis we can know if which (if any) fields
   are addressed and if those addresses are used in bad ways.  This
   are addressed and if those addresses are used in bad ways.  This
   analysis may be language specific.  In C, arbitrary operations may
   analysis may be language specific.  In C, arbitrary operations may
   be applied to pointers.  However, there is some indication that
   be applied to pointers.  However, there is some indication that
   this may be too conservative for some C++ types.
   this may be too conservative for some C++ types.
 
 
   The pass ipa-type-escape does this analysis for the types whose
   The pass ipa-type-escape does this analysis for the types whose
   instances do not escape across the compilation boundary.
   instances do not escape across the compilation boundary.
 
 
   Historically in GCC, these two problems were combined and a single
   Historically in GCC, these two problems were combined and a single
   data structure was used to represent the solution to these
   data structure was used to represent the solution to these
   problems.  We now have two similar but different data structures,
   problems.  We now have two similar but different data structures,
   The data structure to solve the last two question is similar to the
   The data structure to solve the last two question is similar to the
   first, but does not contain have the fields in it whose address are
   first, but does not contain have the fields in it whose address are
   never taken.  For types that do escape the compilation unit, the
   never taken.  For types that do escape the compilation unit, the
   data structures will have identical information.
   data structures will have identical information.
*/
*/
 
 
/* The alias sets assigned to MEMs assist the back-end in determining
/* The alias sets assigned to MEMs assist the back-end in determining
   which MEMs can alias which other MEMs.  In general, two MEMs in
   which MEMs can alias which other MEMs.  In general, two MEMs in
   different alias sets cannot alias each other, with one important
   different alias sets cannot alias each other, with one important
   exception.  Consider something like:
   exception.  Consider something like:
 
 
     struct S { int i; double d; };
     struct S { int i; double d; };
 
 
   a store to an `S' can alias something of either type `int' or type
   a store to an `S' can alias something of either type `int' or type
   `double'.  (However, a store to an `int' cannot alias a `double'
   `double'.  (However, a store to an `int' cannot alias a `double'
   and vice versa.)  We indicate this via a tree structure that looks
   and vice versa.)  We indicate this via a tree structure that looks
   like:
   like:
           struct S
           struct S
            /   \
            /   \
           /     \
           /     \
         |/_     _\|
         |/_     _\|
         int    double
         int    double
 
 
   (The arrows are directed and point downwards.)
   (The arrows are directed and point downwards.)
    In this situation we say the alias set for `struct S' is the
    In this situation we say the alias set for `struct S' is the
   `superset' and that those for `int' and `double' are `subsets'.
   `superset' and that those for `int' and `double' are `subsets'.
 
 
   To see whether two alias sets can point to the same memory, we must
   To see whether two alias sets can point to the same memory, we must
   see if either alias set is a subset of the other. We need not trace
   see if either alias set is a subset of the other. We need not trace
   past immediate descendants, however, since we propagate all
   past immediate descendants, however, since we propagate all
   grandchildren up one level.
   grandchildren up one level.
 
 
   Alias set zero is implicitly a superset of all other alias sets.
   Alias set zero is implicitly a superset of all other alias sets.
   However, this is no actual entry for alias set zero.  It is an
   However, this is no actual entry for alias set zero.  It is an
   error to attempt to explicitly construct a subset of zero.  */
   error to attempt to explicitly construct a subset of zero.  */
 
 
struct GTY(()) alias_set_entry_d {
struct GTY(()) alias_set_entry_d {
  /* The alias set number, as stored in MEM_ALIAS_SET.  */
  /* The alias set number, as stored in MEM_ALIAS_SET.  */
  alias_set_type alias_set;
  alias_set_type alias_set;
 
 
  /* Nonzero if would have a child of zero: this effectively makes this
  /* Nonzero if would have a child of zero: this effectively makes this
     alias set the same as alias set zero.  */
     alias set the same as alias set zero.  */
  int has_zero_child;
  int has_zero_child;
 
 
  /* The children of the alias set.  These are not just the immediate
  /* The children of the alias set.  These are not just the immediate
     children, but, in fact, all descendants.  So, if we have:
     children, but, in fact, all descendants.  So, if we have:
 
 
       struct T { struct S s; float f; }
       struct T { struct S s; float f; }
 
 
     continuing our example above, the children here will be all of
     continuing our example above, the children here will be all of
     `int', `double', `float', and `struct S'.  */
     `int', `double', `float', and `struct S'.  */
  splay_tree GTY((param1_is (int), param2_is (int))) children;
  splay_tree GTY((param1_is (int), param2_is (int))) children;
};
};
typedef struct alias_set_entry_d *alias_set_entry;
typedef struct alias_set_entry_d *alias_set_entry;
 
 
static int rtx_equal_for_memref_p (const_rtx, const_rtx);
static int rtx_equal_for_memref_p (const_rtx, const_rtx);
static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT);
static int memrefs_conflict_p (int, rtx, int, rtx, HOST_WIDE_INT);
static void record_set (rtx, const_rtx, void *);
static void record_set (rtx, const_rtx, void *);
static int base_alias_check (rtx, rtx, enum machine_mode,
static int base_alias_check (rtx, rtx, enum machine_mode,
                             enum machine_mode);
                             enum machine_mode);
static rtx find_base_value (rtx);
static rtx find_base_value (rtx);
static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx);
static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx);
static int insert_subset_children (splay_tree_node, void*);
static int insert_subset_children (splay_tree_node, void*);
static alias_set_entry get_alias_set_entry (alias_set_type);
static alias_set_entry get_alias_set_entry (alias_set_type);
static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx,
static const_rtx fixed_scalar_and_varying_struct_p (const_rtx, const_rtx, rtx, rtx,
                                                    bool (*) (const_rtx, bool));
                                                    bool (*) (const_rtx, bool));
static int aliases_everything_p (const_rtx);
static int aliases_everything_p (const_rtx);
static bool nonoverlapping_component_refs_p (const_tree, const_tree);
static bool nonoverlapping_component_refs_p (const_tree, const_tree);
static tree decl_for_component_ref (tree);
static tree decl_for_component_ref (tree);
static rtx adjust_offset_for_component_ref (tree, rtx);
static rtx adjust_offset_for_component_ref (tree, rtx);
static int write_dependence_p (const_rtx, const_rtx, int);
static int write_dependence_p (const_rtx, const_rtx, int);
 
 
static void memory_modified_1 (rtx, const_rtx, void *);
static void memory_modified_1 (rtx, const_rtx, void *);
 
 
/* Set up all info needed to perform alias analysis on memory references.  */
/* Set up all info needed to perform alias analysis on memory references.  */
 
 
/* Returns the size in bytes of the mode of X.  */
/* Returns the size in bytes of the mode of X.  */
#define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
#define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
 
 
/* Returns nonzero if MEM1 and MEM2 do not alias because they are in
/* Returns nonzero if MEM1 and MEM2 do not alias because they are in
   different alias sets.  We ignore alias sets in functions making use
   different alias sets.  We ignore alias sets in functions making use
   of variable arguments because the va_arg macros on some systems are
   of variable arguments because the va_arg macros on some systems are
   not legal ANSI C.  */
   not legal ANSI C.  */
#define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2)                      \
#define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2)                      \
  mems_in_disjoint_alias_sets_p (MEM1, MEM2)
  mems_in_disjoint_alias_sets_p (MEM1, MEM2)
 
 
/* Cap the number of passes we make over the insns propagating alias
/* Cap the number of passes we make over the insns propagating alias
   information through set chains.   10 is a completely arbitrary choice.  */
   information through set chains.   10 is a completely arbitrary choice.  */
#define MAX_ALIAS_LOOP_PASSES 10
#define MAX_ALIAS_LOOP_PASSES 10
 
 
/* reg_base_value[N] gives an address to which register N is related.
/* reg_base_value[N] gives an address to which register N is related.
   If all sets after the first add or subtract to the current value
   If all sets after the first add or subtract to the current value
   or otherwise modify it so it does not point to a different top level
   or otherwise modify it so it does not point to a different top level
   object, reg_base_value[N] is equal to the address part of the source
   object, reg_base_value[N] is equal to the address part of the source
   of the first set.
   of the first set.
 
 
   A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF.  ADDRESS
   A base address can be an ADDRESS, SYMBOL_REF, or LABEL_REF.  ADDRESS
   expressions represent certain special values: function arguments and
   expressions represent certain special values: function arguments and
   the stack, frame, and argument pointers.
   the stack, frame, and argument pointers.
 
 
   The contents of an ADDRESS is not normally used, the mode of the
   The contents of an ADDRESS is not normally used, the mode of the
   ADDRESS determines whether the ADDRESS is a function argument or some
   ADDRESS determines whether the ADDRESS is a function argument or some
   other special value.  Pointer equality, not rtx_equal_p, determines whether
   other special value.  Pointer equality, not rtx_equal_p, determines whether
   two ADDRESS expressions refer to the same base address.
   two ADDRESS expressions refer to the same base address.
 
 
   The only use of the contents of an ADDRESS is for determining if the
   The only use of the contents of an ADDRESS is for determining if the
   current function performs nonlocal memory memory references for the
   current function performs nonlocal memory memory references for the
   purposes of marking the function as a constant function.  */
   purposes of marking the function as a constant function.  */
 
 
static GTY(()) VEC(rtx,gc) *reg_base_value;
static GTY(()) VEC(rtx,gc) *reg_base_value;
static rtx *new_reg_base_value;
static rtx *new_reg_base_value;
 
 
/* We preserve the copy of old array around to avoid amount of garbage
/* We preserve the copy of old array around to avoid amount of garbage
   produced.  About 8% of garbage produced were attributed to this
   produced.  About 8% of garbage produced were attributed to this
   array.  */
   array.  */
static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value;
static GTY((deletable)) VEC(rtx,gc) *old_reg_base_value;
 
 
/* Static hunks of RTL used by the aliasing code; these are initialized
/* Static hunks of RTL used by the aliasing code; these are initialized
   once per function to avoid unnecessary RTL allocations.  */
   once per function to avoid unnecessary RTL allocations.  */
static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER];
static GTY (()) rtx static_reg_base_value[FIRST_PSEUDO_REGISTER];
 
 
#define REG_BASE_VALUE(X)                               \
#define REG_BASE_VALUE(X)                               \
  (REGNO (X) < VEC_length (rtx, reg_base_value)         \
  (REGNO (X) < VEC_length (rtx, reg_base_value)         \
   ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0)
   ? VEC_index (rtx, reg_base_value, REGNO (X)) : 0)
 
 
/* Vector indexed by N giving the initial (unchanging) value known for
/* Vector indexed by N giving the initial (unchanging) value known for
   pseudo-register N.  This array is initialized in init_alias_analysis,
   pseudo-register N.  This array is initialized in init_alias_analysis,
   and does not change until end_alias_analysis is called.  */
   and does not change until end_alias_analysis is called.  */
static GTY((length("reg_known_value_size"))) rtx *reg_known_value;
static GTY((length("reg_known_value_size"))) rtx *reg_known_value;
 
 
/* Indicates number of valid entries in reg_known_value.  */
/* Indicates number of valid entries in reg_known_value.  */
static GTY(()) unsigned int reg_known_value_size;
static GTY(()) unsigned int reg_known_value_size;
 
 
/* Vector recording for each reg_known_value whether it is due to a
/* Vector recording for each reg_known_value whether it is due to a
   REG_EQUIV note.  Future passes (viz., reload) may replace the
   REG_EQUIV note.  Future passes (viz., reload) may replace the
   pseudo with the equivalent expression and so we account for the
   pseudo with the equivalent expression and so we account for the
   dependences that would be introduced if that happens.
   dependences that would be introduced if that happens.
 
 
   The REG_EQUIV notes created in assign_parms may mention the arg
   The REG_EQUIV notes created in assign_parms may mention the arg
   pointer, and there are explicit insns in the RTL that modify the
   pointer, and there are explicit insns in the RTL that modify the
   arg pointer.  Thus we must ensure that such insns don't get
   arg pointer.  Thus we must ensure that such insns don't get
   scheduled across each other because that would invalidate the
   scheduled across each other because that would invalidate the
   REG_EQUIV notes.  One could argue that the REG_EQUIV notes are
   REG_EQUIV notes.  One could argue that the REG_EQUIV notes are
   wrong, but solving the problem in the scheduler will likely give
   wrong, but solving the problem in the scheduler will likely give
   better code, so we do it here.  */
   better code, so we do it here.  */
static bool *reg_known_equiv_p;
static bool *reg_known_equiv_p;
 
 
/* True when scanning insns from the start of the rtl to the
/* True when scanning insns from the start of the rtl to the
   NOTE_INSN_FUNCTION_BEG note.  */
   NOTE_INSN_FUNCTION_BEG note.  */
static bool copying_arguments;
static bool copying_arguments;
 
 
DEF_VEC_P(alias_set_entry);
DEF_VEC_P(alias_set_entry);
DEF_VEC_ALLOC_P(alias_set_entry,gc);
DEF_VEC_ALLOC_P(alias_set_entry,gc);
 
 
/* The splay-tree used to store the various alias set entries.  */
/* The splay-tree used to store the various alias set entries.  */
static GTY (()) VEC(alias_set_entry,gc) *alias_sets;
static GTY (()) VEC(alias_set_entry,gc) *alias_sets;


/* Build a decomposed reference object for querying the alias-oracle
/* Build a decomposed reference object for querying the alias-oracle
   from the MEM rtx and store it in *REF.
   from the MEM rtx and store it in *REF.
   Returns false if MEM is not suitable for the alias-oracle.  */
   Returns false if MEM is not suitable for the alias-oracle.  */
 
 
static bool
static bool
ao_ref_from_mem (ao_ref *ref, const_rtx mem)
ao_ref_from_mem (ao_ref *ref, const_rtx mem)
{
{
  tree expr = MEM_EXPR (mem);
  tree expr = MEM_EXPR (mem);
  tree base;
  tree base;
 
 
  if (!expr)
  if (!expr)
    return false;
    return false;
 
 
  /* If MEM_OFFSET or MEM_SIZE are NULL punt.  */
  /* If MEM_OFFSET or MEM_SIZE are NULL punt.  */
  if (!MEM_OFFSET (mem)
  if (!MEM_OFFSET (mem)
      || !MEM_SIZE (mem))
      || !MEM_SIZE (mem))
    return false;
    return false;
 
 
  ao_ref_init (ref, expr);
  ao_ref_init (ref, expr);
 
 
  /* Get the base of the reference and see if we have to reject or
  /* Get the base of the reference and see if we have to reject or
     adjust it.  */
     adjust it.  */
  base = ao_ref_base (ref);
  base = ao_ref_base (ref);
  if (base == NULL_TREE)
  if (base == NULL_TREE)
    return false;
    return false;
 
 
  /* If this is a pointer dereference of a non-SSA_NAME punt.
  /* If this is a pointer dereference of a non-SSA_NAME punt.
     ???  We could replace it with a pointer to anything.  */
     ???  We could replace it with a pointer to anything.  */
  if (INDIRECT_REF_P (base)
  if (INDIRECT_REF_P (base)
      && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME)
      && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME)
    return false;
    return false;
 
 
  /* The tree oracle doesn't like to have these.  */
  /* The tree oracle doesn't like to have these.  */
  if (TREE_CODE (base) == FUNCTION_DECL
  if (TREE_CODE (base) == FUNCTION_DECL
      || TREE_CODE (base) == LABEL_DECL)
      || TREE_CODE (base) == LABEL_DECL)
    return false;
    return false;
 
 
  /* If this is a reference based on a partitioned decl replace the
  /* If this is a reference based on a partitioned decl replace the
     base with an INDIRECT_REF of the pointer representative we
     base with an INDIRECT_REF of the pointer representative we
     created during stack slot partitioning.  */
     created during stack slot partitioning.  */
  if (TREE_CODE (base) == VAR_DECL
  if (TREE_CODE (base) == VAR_DECL
      && ! TREE_STATIC (base)
      && ! TREE_STATIC (base)
      && cfun->gimple_df->decls_to_pointers != NULL)
      && cfun->gimple_df->decls_to_pointers != NULL)
    {
    {
      void *namep;
      void *namep;
      namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base);
      namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base);
      if (namep)
      if (namep)
        {
        {
          ref->base_alias_set = get_alias_set (base);
          ref->base_alias_set = get_alias_set (base);
          ref->base = build1 (INDIRECT_REF, TREE_TYPE (base), *(tree *)namep);
          ref->base = build1 (INDIRECT_REF, TREE_TYPE (base), *(tree *)namep);
        }
        }
    }
    }
 
 
  ref->ref_alias_set = MEM_ALIAS_SET (mem);
  ref->ref_alias_set = MEM_ALIAS_SET (mem);
 
 
  /* If the base decl is a parameter we can have negative MEM_OFFSET in
  /* If the base decl is a parameter we can have negative MEM_OFFSET in
     case of promoted subregs on bigendian targets.  Trust the MEM_EXPR
     case of promoted subregs on bigendian targets.  Trust the MEM_EXPR
     here.  */
     here.  */
  if (INTVAL (MEM_OFFSET (mem)) < 0
  if (INTVAL (MEM_OFFSET (mem)) < 0
      && ((INTVAL (MEM_SIZE (mem)) + INTVAL (MEM_OFFSET (mem)))
      && ((INTVAL (MEM_SIZE (mem)) + INTVAL (MEM_OFFSET (mem)))
          * BITS_PER_UNIT) == ref->size)
          * BITS_PER_UNIT) == ref->size)
    return true;
    return true;
 
 
  ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT;
  ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT;
  ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT;
  ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT;
 
 
  /* The MEM may extend into adjacent fields, so adjust max_size if
  /* The MEM may extend into adjacent fields, so adjust max_size if
     necessary.  */
     necessary.  */
  if (ref->max_size != -1
  if (ref->max_size != -1
      && ref->size > ref->max_size)
      && ref->size > ref->max_size)
    ref->max_size = ref->size;
    ref->max_size = ref->size;
 
 
  /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of
  /* If MEM_OFFSET and MEM_SIZE get us outside of the base object of
     the MEM_EXPR punt.  This happens for STRICT_ALIGNMENT targets a lot.  */
     the MEM_EXPR punt.  This happens for STRICT_ALIGNMENT targets a lot.  */
  if (MEM_EXPR (mem) != get_spill_slot_decl (false)
  if (MEM_EXPR (mem) != get_spill_slot_decl (false)
      && (ref->offset < 0
      && (ref->offset < 0
          || (DECL_P (ref->base)
          || (DECL_P (ref->base)
              && (!host_integerp (DECL_SIZE (ref->base), 1)
              && (!host_integerp (DECL_SIZE (ref->base), 1)
                  || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base)))
                  || (TREE_INT_CST_LOW (DECL_SIZE ((ref->base)))
                      < (unsigned HOST_WIDE_INT)(ref->offset + ref->size))))))
                      < (unsigned HOST_WIDE_INT)(ref->offset + ref->size))))))
    return false;
    return false;
 
 
  return true;
  return true;
}
}
 
 
/* Query the alias-oracle on whether the two memory rtx X and MEM may
/* Query the alias-oracle on whether the two memory rtx X and MEM may
   alias.  If TBAA_P is set also apply TBAA.  Returns true if the
   alias.  If TBAA_P is set also apply TBAA.  Returns true if the
   two rtxen may alias, false otherwise.  */
   two rtxen may alias, false otherwise.  */
 
 
static bool
static bool
rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p)
rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p)
{
{
  ao_ref ref1, ref2;
  ao_ref ref1, ref2;
 
 
  if (!ao_ref_from_mem (&ref1, x)
  if (!ao_ref_from_mem (&ref1, x)
      || !ao_ref_from_mem (&ref2, mem))
      || !ao_ref_from_mem (&ref2, mem))
    return true;
    return true;
 
 
  return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p);
  return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p);
}
}
 
 
/* Returns a pointer to the alias set entry for ALIAS_SET, if there is
/* Returns a pointer to the alias set entry for ALIAS_SET, if there is
   such an entry, or NULL otherwise.  */
   such an entry, or NULL otherwise.  */
 
 
static inline alias_set_entry
static inline alias_set_entry
get_alias_set_entry (alias_set_type alias_set)
get_alias_set_entry (alias_set_type alias_set)
{
{
  return VEC_index (alias_set_entry, alias_sets, alias_set);
  return VEC_index (alias_set_entry, alias_sets, alias_set);
}
}
 
 
/* Returns nonzero if the alias sets for MEM1 and MEM2 are such that
/* Returns nonzero if the alias sets for MEM1 and MEM2 are such that
   the two MEMs cannot alias each other.  */
   the two MEMs cannot alias each other.  */
 
 
static inline int
static inline int
mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2)
mems_in_disjoint_alias_sets_p (const_rtx mem1, const_rtx mem2)
{
{
/* Perform a basic sanity check.  Namely, that there are no alias sets
/* Perform a basic sanity check.  Namely, that there are no alias sets
   if we're not using strict aliasing.  This helps to catch bugs
   if we're not using strict aliasing.  This helps to catch bugs
   whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or
   whereby someone uses PUT_CODE, but doesn't clear MEM_ALIAS_SET, or
   where a MEM is allocated in some way other than by the use of
   where a MEM is allocated in some way other than by the use of
   gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared.  If we begin to
   gen_rtx_MEM, and the MEM_ALIAS_SET is not cleared.  If we begin to
   use alias sets to indicate that spilled registers cannot alias each
   use alias sets to indicate that spilled registers cannot alias each
   other, we might need to remove this check.  */
   other, we might need to remove this check.  */
  gcc_assert (flag_strict_aliasing
  gcc_assert (flag_strict_aliasing
              || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2)));
              || (!MEM_ALIAS_SET (mem1) && !MEM_ALIAS_SET (mem2)));
 
 
  return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2));
  return ! alias_sets_conflict_p (MEM_ALIAS_SET (mem1), MEM_ALIAS_SET (mem2));
}
}
 
 
/* Insert the NODE into the splay tree given by DATA.  Used by
/* Insert the NODE into the splay tree given by DATA.  Used by
   record_alias_subset via splay_tree_foreach.  */
   record_alias_subset via splay_tree_foreach.  */
 
 
static int
static int
insert_subset_children (splay_tree_node node, void *data)
insert_subset_children (splay_tree_node node, void *data)
{
{
  splay_tree_insert ((splay_tree) data, node->key, node->value);
  splay_tree_insert ((splay_tree) data, node->key, node->value);
 
 
  return 0;
  return 0;
}
}
 
 
/* Return true if the first alias set is a subset of the second.  */
/* Return true if the first alias set is a subset of the second.  */
 
 
bool
bool
alias_set_subset_of (alias_set_type set1, alias_set_type set2)
alias_set_subset_of (alias_set_type set1, alias_set_type set2)
{
{
  alias_set_entry ase;
  alias_set_entry ase;
 
 
  /* Everything is a subset of the "aliases everything" set.  */
  /* Everything is a subset of the "aliases everything" set.  */
  if (set2 == 0)
  if (set2 == 0)
    return true;
    return true;
 
 
  /* Otherwise, check if set1 is a subset of set2.  */
  /* Otherwise, check if set1 is a subset of set2.  */
  ase = get_alias_set_entry (set2);
  ase = get_alias_set_entry (set2);
  if (ase != 0
  if (ase != 0
      && (ase->has_zero_child
      && (ase->has_zero_child
          || splay_tree_lookup (ase->children,
          || splay_tree_lookup (ase->children,
                                (splay_tree_key) set1)))
                                (splay_tree_key) set1)))
    return true;
    return true;
  return false;
  return false;
}
}
 
 
/* Return 1 if the two specified alias sets may conflict.  */
/* Return 1 if the two specified alias sets may conflict.  */
 
 
int
int
alias_sets_conflict_p (alias_set_type set1, alias_set_type set2)
alias_sets_conflict_p (alias_set_type set1, alias_set_type set2)
{
{
  alias_set_entry ase;
  alias_set_entry ase;
 
 
  /* The easy case.  */
  /* The easy case.  */
  if (alias_sets_must_conflict_p (set1, set2))
  if (alias_sets_must_conflict_p (set1, set2))
    return 1;
    return 1;
 
 
  /* See if the first alias set is a subset of the second.  */
  /* See if the first alias set is a subset of the second.  */
  ase = get_alias_set_entry (set1);
  ase = get_alias_set_entry (set1);
  if (ase != 0
  if (ase != 0
      && (ase->has_zero_child
      && (ase->has_zero_child
          || splay_tree_lookup (ase->children,
          || splay_tree_lookup (ase->children,
                                (splay_tree_key) set2)))
                                (splay_tree_key) set2)))
    return 1;
    return 1;
 
 
  /* Now do the same, but with the alias sets reversed.  */
  /* Now do the same, but with the alias sets reversed.  */
  ase = get_alias_set_entry (set2);
  ase = get_alias_set_entry (set2);
  if (ase != 0
  if (ase != 0
      && (ase->has_zero_child
      && (ase->has_zero_child
          || splay_tree_lookup (ase->children,
          || splay_tree_lookup (ase->children,
                                (splay_tree_key) set1)))
                                (splay_tree_key) set1)))
    return 1;
    return 1;
 
 
  /* The two alias sets are distinct and neither one is the
  /* The two alias sets are distinct and neither one is the
     child of the other.  Therefore, they cannot conflict.  */
     child of the other.  Therefore, they cannot conflict.  */
  return 0;
  return 0;
}
}
 
 
static int
static int
walk_mems_2 (rtx *x, rtx mem)
walk_mems_2 (rtx *x, rtx mem)
{
{
  if (MEM_P (*x))
  if (MEM_P (*x))
    {
    {
      if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem)))
      if (alias_sets_conflict_p (MEM_ALIAS_SET(*x), MEM_ALIAS_SET(mem)))
        return 1;
        return 1;
 
 
      return -1;
      return -1;
    }
    }
  return 0;
  return 0;
}
}
 
 
static int
static int
walk_mems_1 (rtx *x, rtx *pat)
walk_mems_1 (rtx *x, rtx *pat)
{
{
  if (MEM_P (*x))
  if (MEM_P (*x))
    {
    {
      /* Visit all MEMs in *PAT and check indepedence.  */
      /* Visit all MEMs in *PAT and check indepedence.  */
      if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x))
      if (for_each_rtx (pat, (rtx_function) walk_mems_2, *x))
        /* Indicate that dependence was determined and stop traversal.  */
        /* Indicate that dependence was determined and stop traversal.  */
        return 1;
        return 1;
 
 
      return -1;
      return -1;
    }
    }
  return 0;
  return 0;
}
}
 
 
/* Return 1 if two specified instructions have mem expr with conflict alias sets*/
/* Return 1 if two specified instructions have mem expr with conflict alias sets*/
bool
bool
insn_alias_sets_conflict_p (rtx insn1, rtx insn2)
insn_alias_sets_conflict_p (rtx insn1, rtx insn2)
{
{
  /* For each pair of MEMs in INSN1 and INSN2 check their independence.  */
  /* For each pair of MEMs in INSN1 and INSN2 check their independence.  */
  return  for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1,
  return  for_each_rtx (&PATTERN (insn1), (rtx_function) walk_mems_1,
                         &PATTERN (insn2));
                         &PATTERN (insn2));
}
}
 
 
/* Return 1 if the two specified alias sets will always conflict.  */
/* Return 1 if the two specified alias sets will always conflict.  */
 
 
int
int
alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2)
alias_sets_must_conflict_p (alias_set_type set1, alias_set_type set2)
{
{
  if (set1 == 0 || set2 == 0 || set1 == set2)
  if (set1 == 0 || set2 == 0 || set1 == set2)
    return 1;
    return 1;
 
 
  return 0;
  return 0;
}
}
 
 
/* Return 1 if any MEM object of type T1 will always conflict (using the
/* Return 1 if any MEM object of type T1 will always conflict (using the
   dependency routines in this file) with any MEM object of type T2.
   dependency routines in this file) with any MEM object of type T2.
   This is used when allocating temporary storage.  If T1 and/or T2 are
   This is used when allocating temporary storage.  If T1 and/or T2 are
   NULL_TREE, it means we know nothing about the storage.  */
   NULL_TREE, it means we know nothing about the storage.  */
 
 
int
int
objects_must_conflict_p (tree t1, tree t2)
objects_must_conflict_p (tree t1, tree t2)
{
{
  alias_set_type set1, set2;
  alias_set_type set1, set2;
 
 
  /* If neither has a type specified, we don't know if they'll conflict
  /* If neither has a type specified, we don't know if they'll conflict
     because we may be using them to store objects of various types, for
     because we may be using them to store objects of various types, for
     example the argument and local variables areas of inlined functions.  */
     example the argument and local variables areas of inlined functions.  */
  if (t1 == 0 && t2 == 0)
  if (t1 == 0 && t2 == 0)
    return 0;
    return 0;
 
 
  /* If they are the same type, they must conflict.  */
  /* If they are the same type, they must conflict.  */
  if (t1 == t2
  if (t1 == t2
      /* Likewise if both are volatile.  */
      /* Likewise if both are volatile.  */
      || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)))
      || (t1 != 0 && TYPE_VOLATILE (t1) && t2 != 0 && TYPE_VOLATILE (t2)))
    return 1;
    return 1;
 
 
  set1 = t1 ? get_alias_set (t1) : 0;
  set1 = t1 ? get_alias_set (t1) : 0;
  set2 = t2 ? get_alias_set (t2) : 0;
  set2 = t2 ? get_alias_set (t2) : 0;
 
 
  /* We can't use alias_sets_conflict_p because we must make sure
  /* We can't use alias_sets_conflict_p because we must make sure
     that every subtype of t1 will conflict with every subtype of
     that every subtype of t1 will conflict with every subtype of
     t2 for which a pair of subobjects of these respective subtypes
     t2 for which a pair of subobjects of these respective subtypes
     overlaps on the stack.  */
     overlaps on the stack.  */
  return alias_sets_must_conflict_p (set1, set2);
  return alias_sets_must_conflict_p (set1, set2);
}
}


/* Return true if all nested component references handled by
/* Return true if all nested component references handled by
   get_inner_reference in T are such that we should use the alias set
   get_inner_reference in T are such that we should use the alias set
   provided by the object at the heart of T.
   provided by the object at the heart of T.
 
 
   This is true for non-addressable components (which don't have their
   This is true for non-addressable components (which don't have their
   own alias set), as well as components of objects in alias set zero.
   own alias set), as well as components of objects in alias set zero.
   This later point is a special case wherein we wish to override the
   This later point is a special case wherein we wish to override the
   alias set used by the component, but we don't have per-FIELD_DECL
   alias set used by the component, but we don't have per-FIELD_DECL
   assignable alias sets.  */
   assignable alias sets.  */
 
 
bool
bool
component_uses_parent_alias_set (const_tree t)
component_uses_parent_alias_set (const_tree t)
{
{
  while (1)
  while (1)
    {
    {
      /* If we're at the end, it vacuously uses its own alias set.  */
      /* If we're at the end, it vacuously uses its own alias set.  */
      if (!handled_component_p (t))
      if (!handled_component_p (t))
        return false;
        return false;
 
 
      switch (TREE_CODE (t))
      switch (TREE_CODE (t))
        {
        {
        case COMPONENT_REF:
        case COMPONENT_REF:
          if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
          if (DECL_NONADDRESSABLE_P (TREE_OPERAND (t, 1)))
            return true;
            return true;
          break;
          break;
 
 
        case ARRAY_REF:
        case ARRAY_REF:
        case ARRAY_RANGE_REF:
        case ARRAY_RANGE_REF:
          if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
          if (TYPE_NONALIASED_COMPONENT (TREE_TYPE (TREE_OPERAND (t, 0))))
            return true;
            return true;
          break;
          break;
 
 
        case REALPART_EXPR:
        case REALPART_EXPR:
        case IMAGPART_EXPR:
        case IMAGPART_EXPR:
          break;
          break;
 
 
        default:
        default:
          /* Bitfields and casts are never addressable.  */
          /* Bitfields and casts are never addressable.  */
          return true;
          return true;
        }
        }
 
 
      t = TREE_OPERAND (t, 0);
      t = TREE_OPERAND (t, 0);
      if (get_alias_set (TREE_TYPE (t)) == 0)
      if (get_alias_set (TREE_TYPE (t)) == 0)
        return true;
        return true;
    }
    }
}
}
 
 
/* Return the alias set for the memory pointed to by T, which may be
/* Return the alias set for the memory pointed to by T, which may be
   either a type or an expression.  Return -1 if there is nothing
   either a type or an expression.  Return -1 if there is nothing
   special about dereferencing T.  */
   special about dereferencing T.  */
 
 
static alias_set_type
static alias_set_type
get_deref_alias_set_1 (tree t)
get_deref_alias_set_1 (tree t)
{
{
  /* If we're not doing any alias analysis, just assume everything
  /* If we're not doing any alias analysis, just assume everything
     aliases everything else.  */
     aliases everything else.  */
  if (!flag_strict_aliasing)
  if (!flag_strict_aliasing)
    return 0;
    return 0;
 
 
  /* All we care about is the type.  */
  /* All we care about is the type.  */
  if (! TYPE_P (t))
  if (! TYPE_P (t))
    t = TREE_TYPE (t);
    t = TREE_TYPE (t);
 
 
  /* If we have an INDIRECT_REF via a void pointer, we don't
  /* If we have an INDIRECT_REF via a void pointer, we don't
     know anything about what that might alias.  Likewise if the
     know anything about what that might alias.  Likewise if the
     pointer is marked that way.  */
     pointer is marked that way.  */
  if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE
  if (TREE_CODE (TREE_TYPE (t)) == VOID_TYPE
      || TYPE_REF_CAN_ALIAS_ALL (t))
      || TYPE_REF_CAN_ALIAS_ALL (t))
    return 0;
    return 0;
 
 
  return -1;
  return -1;
}
}
 
 
/* Return the alias set for the memory pointed to by T, which may be
/* Return the alias set for the memory pointed to by T, which may be
   either a type or an expression.  */
   either a type or an expression.  */
 
 
alias_set_type
alias_set_type
get_deref_alias_set (tree t)
get_deref_alias_set (tree t)
{
{
  alias_set_type set = get_deref_alias_set_1 (t);
  alias_set_type set = get_deref_alias_set_1 (t);
 
 
  /* Fall back to the alias-set of the pointed-to type.  */
  /* Fall back to the alias-set of the pointed-to type.  */
  if (set == -1)
  if (set == -1)
    {
    {
      if (! TYPE_P (t))
      if (! TYPE_P (t))
        t = TREE_TYPE (t);
        t = TREE_TYPE (t);
      set = get_alias_set (TREE_TYPE (t));
      set = get_alias_set (TREE_TYPE (t));
    }
    }
 
 
  return set;
  return set;
}
}
 
 
/* Return the alias set for T, which may be either a type or an
/* Return the alias set for T, which may be either a type or an
   expression.  Call language-specific routine for help, if needed.  */
   expression.  Call language-specific routine for help, if needed.  */
 
 
alias_set_type
alias_set_type
get_alias_set (tree t)
get_alias_set (tree t)
{
{
  alias_set_type set;
  alias_set_type set;
 
 
  /* If we're not doing any alias analysis, just assume everything
  /* If we're not doing any alias analysis, just assume everything
     aliases everything else.  Also return 0 if this or its type is
     aliases everything else.  Also return 0 if this or its type is
     an error.  */
     an error.  */
  if (! flag_strict_aliasing || t == error_mark_node
  if (! flag_strict_aliasing || t == error_mark_node
      || (! TYPE_P (t)
      || (! TYPE_P (t)
          && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node)))
          && (TREE_TYPE (t) == 0 || TREE_TYPE (t) == error_mark_node)))
    return 0;
    return 0;
 
 
  /* We can be passed either an expression or a type.  This and the
  /* We can be passed either an expression or a type.  This and the
     language-specific routine may make mutually-recursive calls to each other
     language-specific routine may make mutually-recursive calls to each other
     to figure out what to do.  At each juncture, we see if this is a tree
     to figure out what to do.  At each juncture, we see if this is a tree
     that the language may need to handle specially.  First handle things that
     that the language may need to handle specially.  First handle things that
     aren't types.  */
     aren't types.  */
  if (! TYPE_P (t))
  if (! TYPE_P (t))
    {
    {
      tree inner;
      tree inner;
 
 
      /* Remove any nops, then give the language a chance to do
      /* Remove any nops, then give the language a chance to do
         something with this tree before we look at it.  */
         something with this tree before we look at it.  */
      STRIP_NOPS (t);
      STRIP_NOPS (t);
      set = lang_hooks.get_alias_set (t);
      set = lang_hooks.get_alias_set (t);
      if (set != -1)
      if (set != -1)
        return set;
        return set;
 
 
      /* Retrieve the original memory reference if needed.  */
      /* Retrieve the original memory reference if needed.  */
      if (TREE_CODE (t) == TARGET_MEM_REF)
      if (TREE_CODE (t) == TARGET_MEM_REF)
        t = TMR_ORIGINAL (t);
        t = TMR_ORIGINAL (t);
 
 
      /* First see if the actual object referenced is an INDIRECT_REF from a
      /* First see if the actual object referenced is an INDIRECT_REF from a
         restrict-qualified pointer or a "void *".  */
         restrict-qualified pointer or a "void *".  */
      inner = t;
      inner = t;
      while (handled_component_p (inner))
      while (handled_component_p (inner))
        {
        {
          inner = TREE_OPERAND (inner, 0);
          inner = TREE_OPERAND (inner, 0);
          STRIP_NOPS (inner);
          STRIP_NOPS (inner);
        }
        }
 
 
      if (INDIRECT_REF_P (inner))
      if (INDIRECT_REF_P (inner))
        {
        {
          set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0));
          set = get_deref_alias_set_1 (TREE_OPERAND (inner, 0));
          if (set != -1)
          if (set != -1)
            return set;
            return set;
        }
        }
 
 
      /* Otherwise, pick up the outermost object that we could have a pointer
      /* Otherwise, pick up the outermost object that we could have a pointer
         to, processing conversions as above.  */
         to, processing conversions as above.  */
      while (component_uses_parent_alias_set (t))
      while (component_uses_parent_alias_set (t))
        {
        {
          t = TREE_OPERAND (t, 0);
          t = TREE_OPERAND (t, 0);
          STRIP_NOPS (t);
          STRIP_NOPS (t);
        }
        }
 
 
      /* If we've already determined the alias set for a decl, just return
      /* If we've already determined the alias set for a decl, just return
         it.  This is necessary for C++ anonymous unions, whose component
         it.  This is necessary for C++ anonymous unions, whose component
         variables don't look like union members (boo!).  */
         variables don't look like union members (boo!).  */
      if (TREE_CODE (t) == VAR_DECL
      if (TREE_CODE (t) == VAR_DECL
          && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t)))
          && DECL_RTL_SET_P (t) && MEM_P (DECL_RTL (t)))
        return MEM_ALIAS_SET (DECL_RTL (t));
        return MEM_ALIAS_SET (DECL_RTL (t));
 
 
      /* Now all we care about is the type.  */
      /* Now all we care about is the type.  */
      t = TREE_TYPE (t);
      t = TREE_TYPE (t);
    }
    }
 
 
  /* Variant qualifiers don't affect the alias set, so get the main
  /* Variant qualifiers don't affect the alias set, so get the main
     variant.  */
     variant.  */
  t = TYPE_MAIN_VARIANT (t);
  t = TYPE_MAIN_VARIANT (t);
 
 
  /* Always use the canonical type as well.  If this is a type that
  /* Always use the canonical type as well.  If this is a type that
     requires structural comparisons to identify compatible types
     requires structural comparisons to identify compatible types
     use alias set zero.  */
     use alias set zero.  */
  if (TYPE_STRUCTURAL_EQUALITY_P (t))
  if (TYPE_STRUCTURAL_EQUALITY_P (t))
    {
    {
      /* Allow the language to specify another alias set for this
      /* Allow the language to specify another alias set for this
         type.  */
         type.  */
      set = lang_hooks.get_alias_set (t);
      set = lang_hooks.get_alias_set (t);
      if (set != -1)
      if (set != -1)
        return set;
        return set;
      return 0;
      return 0;
    }
    }
  t = TYPE_CANONICAL (t);
  t = TYPE_CANONICAL (t);
  /* Canonical types shouldn't form a tree nor should the canonical
  /* Canonical types shouldn't form a tree nor should the canonical
     type require structural equality checks.  */
     type require structural equality checks.  */
  gcc_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t);
  gcc_assert (!TYPE_STRUCTURAL_EQUALITY_P (t) && TYPE_CANONICAL (t) == t);
 
 
  /* If this is a type with a known alias set, return it.  */
  /* If this is a type with a known alias set, return it.  */
  if (TYPE_ALIAS_SET_KNOWN_P (t))
  if (TYPE_ALIAS_SET_KNOWN_P (t))
    return TYPE_ALIAS_SET (t);
    return TYPE_ALIAS_SET (t);
 
 
  /* We don't want to set TYPE_ALIAS_SET for incomplete types.  */
  /* We don't want to set TYPE_ALIAS_SET for incomplete types.  */
  if (!COMPLETE_TYPE_P (t))
  if (!COMPLETE_TYPE_P (t))
    {
    {
      /* For arrays with unknown size the conservative answer is the
      /* For arrays with unknown size the conservative answer is the
         alias set of the element type.  */
         alias set of the element type.  */
      if (TREE_CODE (t) == ARRAY_TYPE)
      if (TREE_CODE (t) == ARRAY_TYPE)
        return get_alias_set (TREE_TYPE (t));
        return get_alias_set (TREE_TYPE (t));
 
 
      /* But return zero as a conservative answer for incomplete types.  */
      /* But return zero as a conservative answer for incomplete types.  */
      return 0;
      return 0;
    }
    }
 
 
  /* See if the language has special handling for this type.  */
  /* See if the language has special handling for this type.  */
  set = lang_hooks.get_alias_set (t);
  set = lang_hooks.get_alias_set (t);
  if (set != -1)
  if (set != -1)
    return set;
    return set;
 
 
  /* There are no objects of FUNCTION_TYPE, so there's no point in
  /* There are no objects of FUNCTION_TYPE, so there's no point in
     using up an alias set for them.  (There are, of course, pointers
     using up an alias set for them.  (There are, of course, pointers
     and references to functions, but that's different.)  */
     and references to functions, but that's different.)  */
  else if (TREE_CODE (t) == FUNCTION_TYPE
  else if (TREE_CODE (t) == FUNCTION_TYPE
           || TREE_CODE (t) == METHOD_TYPE)
           || TREE_CODE (t) == METHOD_TYPE)
    set = 0;
    set = 0;
 
 
  /* Unless the language specifies otherwise, let vector types alias
  /* Unless the language specifies otherwise, let vector types alias
     their components.  This avoids some nasty type punning issues in
     their components.  This avoids some nasty type punning issues in
     normal usage.  And indeed lets vectors be treated more like an
     normal usage.  And indeed lets vectors be treated more like an
     array slice.  */
     array slice.  */
  else if (TREE_CODE (t) == VECTOR_TYPE)
  else if (TREE_CODE (t) == VECTOR_TYPE)
    set = get_alias_set (TREE_TYPE (t));
    set = get_alias_set (TREE_TYPE (t));
 
 
  /* Unless the language specifies otherwise, treat array types the
  /* Unless the language specifies otherwise, treat array types the
     same as their components.  This avoids the asymmetry we get
     same as their components.  This avoids the asymmetry we get
     through recording the components.  Consider accessing a
     through recording the components.  Consider accessing a
     character(kind=1) through a reference to a character(kind=1)[1:1].
     character(kind=1) through a reference to a character(kind=1)[1:1].
     Or consider if we want to assign integer(kind=4)[0:D.1387] and
     Or consider if we want to assign integer(kind=4)[0:D.1387] and
     integer(kind=4)[4] the same alias set or not.
     integer(kind=4)[4] the same alias set or not.
     Just be pragmatic here and make sure the array and its element
     Just be pragmatic here and make sure the array and its element
     type get the same alias set assigned.  */
     type get the same alias set assigned.  */
  else if (TREE_CODE (t) == ARRAY_TYPE
  else if (TREE_CODE (t) == ARRAY_TYPE
           && !TYPE_NONALIASED_COMPONENT (t))
           && !TYPE_NONALIASED_COMPONENT (t))
    set = get_alias_set (TREE_TYPE (t));
    set = get_alias_set (TREE_TYPE (t));
 
 
  else
  else
    /* Otherwise make a new alias set for this type.  */
    /* Otherwise make a new alias set for this type.  */
    set = new_alias_set ();
    set = new_alias_set ();
 
 
  TYPE_ALIAS_SET (t) = set;
  TYPE_ALIAS_SET (t) = set;
 
 
  /* If this is an aggregate type, we must record any component aliasing
  /* If this is an aggregate type, we must record any component aliasing
     information.  */
     information.  */
  if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE)
  if (AGGREGATE_TYPE_P (t) || TREE_CODE (t) == COMPLEX_TYPE)
    record_component_aliases (t);
    record_component_aliases (t);
 
 
  return set;
  return set;
}
}
 
 
/* Return a brand-new alias set.  */
/* Return a brand-new alias set.  */
 
 
alias_set_type
alias_set_type
new_alias_set (void)
new_alias_set (void)
{
{
  if (flag_strict_aliasing)
  if (flag_strict_aliasing)
    {
    {
      if (alias_sets == 0)
      if (alias_sets == 0)
        VEC_safe_push (alias_set_entry, gc, alias_sets, 0);
        VEC_safe_push (alias_set_entry, gc, alias_sets, 0);
      VEC_safe_push (alias_set_entry, gc, alias_sets, 0);
      VEC_safe_push (alias_set_entry, gc, alias_sets, 0);
      return VEC_length (alias_set_entry, alias_sets) - 1;
      return VEC_length (alias_set_entry, alias_sets) - 1;
    }
    }
  else
  else
    return 0;
    return 0;
}
}
 
 
/* Indicate that things in SUBSET can alias things in SUPERSET, but that
/* Indicate that things in SUBSET can alias things in SUPERSET, but that
   not everything that aliases SUPERSET also aliases SUBSET.  For example,
   not everything that aliases SUPERSET also aliases SUBSET.  For example,
   in C, a store to an `int' can alias a load of a structure containing an
   in C, a store to an `int' can alias a load of a structure containing an
   `int', and vice versa.  But it can't alias a load of a 'double' member
   `int', and vice versa.  But it can't alias a load of a 'double' member
   of the same structure.  Here, the structure would be the SUPERSET and
   of the same structure.  Here, the structure would be the SUPERSET and
   `int' the SUBSET.  This relationship is also described in the comment at
   `int' the SUBSET.  This relationship is also described in the comment at
   the beginning of this file.
   the beginning of this file.
 
 
   This function should be called only once per SUPERSET/SUBSET pair.
   This function should be called only once per SUPERSET/SUBSET pair.
 
 
   It is illegal for SUPERSET to be zero; everything is implicitly a
   It is illegal for SUPERSET to be zero; everything is implicitly a
   subset of alias set zero.  */
   subset of alias set zero.  */
 
 
void
void
record_alias_subset (alias_set_type superset, alias_set_type subset)
record_alias_subset (alias_set_type superset, alias_set_type subset)
{
{
  alias_set_entry superset_entry;
  alias_set_entry superset_entry;
  alias_set_entry subset_entry;
  alias_set_entry subset_entry;
 
 
  /* It is possible in complex type situations for both sets to be the same,
  /* It is possible in complex type situations for both sets to be the same,
     in which case we can ignore this operation.  */
     in which case we can ignore this operation.  */
  if (superset == subset)
  if (superset == subset)
    return;
    return;
 
 
  gcc_assert (superset);
  gcc_assert (superset);
 
 
  superset_entry = get_alias_set_entry (superset);
  superset_entry = get_alias_set_entry (superset);
  if (superset_entry == 0)
  if (superset_entry == 0)
    {
    {
      /* Create an entry for the SUPERSET, so that we have a place to
      /* Create an entry for the SUPERSET, so that we have a place to
         attach the SUBSET.  */
         attach the SUBSET.  */
      superset_entry = GGC_NEW (struct alias_set_entry_d);
      superset_entry = GGC_NEW (struct alias_set_entry_d);
      superset_entry->alias_set = superset;
      superset_entry->alias_set = superset;
      superset_entry->children
      superset_entry->children
        = splay_tree_new_ggc (splay_tree_compare_ints);
        = splay_tree_new_ggc (splay_tree_compare_ints);
      superset_entry->has_zero_child = 0;
      superset_entry->has_zero_child = 0;
      VEC_replace (alias_set_entry, alias_sets, superset, superset_entry);
      VEC_replace (alias_set_entry, alias_sets, superset, superset_entry);
    }
    }
 
 
  if (subset == 0)
  if (subset == 0)
    superset_entry->has_zero_child = 1;
    superset_entry->has_zero_child = 1;
  else
  else
    {
    {
      subset_entry = get_alias_set_entry (subset);
      subset_entry = get_alias_set_entry (subset);
      /* If there is an entry for the subset, enter all of its children
      /* If there is an entry for the subset, enter all of its children
         (if they are not already present) as children of the SUPERSET.  */
         (if they are not already present) as children of the SUPERSET.  */
      if (subset_entry)
      if (subset_entry)
        {
        {
          if (subset_entry->has_zero_child)
          if (subset_entry->has_zero_child)
            superset_entry->has_zero_child = 1;
            superset_entry->has_zero_child = 1;
 
 
          splay_tree_foreach (subset_entry->children, insert_subset_children,
          splay_tree_foreach (subset_entry->children, insert_subset_children,
                              superset_entry->children);
                              superset_entry->children);
        }
        }
 
 
      /* Enter the SUBSET itself as a child of the SUPERSET.  */
      /* Enter the SUBSET itself as a child of the SUPERSET.  */
      splay_tree_insert (superset_entry->children,
      splay_tree_insert (superset_entry->children,
                         (splay_tree_key) subset, 0);
                         (splay_tree_key) subset, 0);
    }
    }
}
}
 
 
/* Record that component types of TYPE, if any, are part of that type for
/* Record that component types of TYPE, if any, are part of that type for
   aliasing purposes.  For record types, we only record component types
   aliasing purposes.  For record types, we only record component types
   for fields that are not marked non-addressable.  For array types, we
   for fields that are not marked non-addressable.  For array types, we
   only record the component type if it is not marked non-aliased.  */
   only record the component type if it is not marked non-aliased.  */
 
 
void
void
record_component_aliases (tree type)
record_component_aliases (tree type)
{
{
  alias_set_type superset = get_alias_set (type);
  alias_set_type superset = get_alias_set (type);
  tree field;
  tree field;
 
 
  if (superset == 0)
  if (superset == 0)
    return;
    return;
 
 
  switch (TREE_CODE (type))
  switch (TREE_CODE (type))
    {
    {
    case RECORD_TYPE:
    case RECORD_TYPE:
    case UNION_TYPE:
    case UNION_TYPE:
    case QUAL_UNION_TYPE:
    case QUAL_UNION_TYPE:
      /* Recursively record aliases for the base classes, if there are any.  */
      /* Recursively record aliases for the base classes, if there are any.  */
      if (TYPE_BINFO (type))
      if (TYPE_BINFO (type))
        {
        {
          int i;
          int i;
          tree binfo, base_binfo;
          tree binfo, base_binfo;
 
 
          for (binfo = TYPE_BINFO (type), i = 0;
          for (binfo = TYPE_BINFO (type), i = 0;
               BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
               BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
            record_alias_subset (superset,
            record_alias_subset (superset,
                                 get_alias_set (BINFO_TYPE (base_binfo)));
                                 get_alias_set (BINFO_TYPE (base_binfo)));
        }
        }
      for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
      for (field = TYPE_FIELDS (type); field != 0; field = TREE_CHAIN (field))
        if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field))
        if (TREE_CODE (field) == FIELD_DECL && !DECL_NONADDRESSABLE_P (field))
          record_alias_subset (superset, get_alias_set (TREE_TYPE (field)));
          record_alias_subset (superset, get_alias_set (TREE_TYPE (field)));
      break;
      break;
 
 
    case COMPLEX_TYPE:
    case COMPLEX_TYPE:
      record_alias_subset (superset, get_alias_set (TREE_TYPE (type)));
      record_alias_subset (superset, get_alias_set (TREE_TYPE (type)));
      break;
      break;
 
 
    /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their
    /* VECTOR_TYPE and ARRAY_TYPE share the alias set with their
       element type.  */
       element type.  */
 
 
    default:
    default:
      break;
      break;
    }
    }
}
}
 
 
/* Allocate an alias set for use in storing and reading from the varargs
/* Allocate an alias set for use in storing and reading from the varargs
   spill area.  */
   spill area.  */
 
 
static GTY(()) alias_set_type varargs_set = -1;
static GTY(()) alias_set_type varargs_set = -1;
 
 
alias_set_type
alias_set_type
get_varargs_alias_set (void)
get_varargs_alias_set (void)
{
{
#if 1
#if 1
  /* We now lower VA_ARG_EXPR, and there's currently no way to attach the
  /* We now lower VA_ARG_EXPR, and there's currently no way to attach the
     varargs alias set to an INDIRECT_REF (FIXME!), so we can't
     varargs alias set to an INDIRECT_REF (FIXME!), so we can't
     consistently use the varargs alias set for loads from the varargs
     consistently use the varargs alias set for loads from the varargs
     area.  So don't use it anywhere.  */
     area.  So don't use it anywhere.  */
  return 0;
  return 0;
#else
#else
  if (varargs_set == -1)
  if (varargs_set == -1)
    varargs_set = new_alias_set ();
    varargs_set = new_alias_set ();
 
 
  return varargs_set;
  return varargs_set;
#endif
#endif
}
}
 
 
/* Likewise, but used for the fixed portions of the frame, e.g., register
/* Likewise, but used for the fixed portions of the frame, e.g., register
   save areas.  */
   save areas.  */
 
 
static GTY(()) alias_set_type frame_set = -1;
static GTY(()) alias_set_type frame_set = -1;
 
 
alias_set_type
alias_set_type
get_frame_alias_set (void)
get_frame_alias_set (void)
{
{
  if (frame_set == -1)
  if (frame_set == -1)
    frame_set = new_alias_set ();
    frame_set = new_alias_set ();
 
 
  return frame_set;
  return frame_set;
}
}
 
 
/* Inside SRC, the source of a SET, find a base address.  */
/* Inside SRC, the source of a SET, find a base address.  */
 
 
static rtx
static rtx
find_base_value (rtx src)
find_base_value (rtx src)
{
{
  unsigned int regno;
  unsigned int regno;
 
 
#if defined (FIND_BASE_TERM)
#if defined (FIND_BASE_TERM)
  /* Try machine-dependent ways to find the base term.  */
  /* Try machine-dependent ways to find the base term.  */
  src = FIND_BASE_TERM (src);
  src = FIND_BASE_TERM (src);
#endif
#endif
 
 
  switch (GET_CODE (src))
  switch (GET_CODE (src))
    {
    {
    case SYMBOL_REF:
    case SYMBOL_REF:
    case LABEL_REF:
    case LABEL_REF:
      return src;
      return src;
 
 
    case REG:
    case REG:
      regno = REGNO (src);
      regno = REGNO (src);
      /* At the start of a function, argument registers have known base
      /* At the start of a function, argument registers have known base
         values which may be lost later.  Returning an ADDRESS
         values which may be lost later.  Returning an ADDRESS
         expression here allows optimization based on argument values
         expression here allows optimization based on argument values
         even when the argument registers are used for other purposes.  */
         even when the argument registers are used for other purposes.  */
      if (regno < FIRST_PSEUDO_REGISTER && copying_arguments)
      if (regno < FIRST_PSEUDO_REGISTER && copying_arguments)
        return new_reg_base_value[regno];
        return new_reg_base_value[regno];
 
 
      /* If a pseudo has a known base value, return it.  Do not do this
      /* If a pseudo has a known base value, return it.  Do not do this
         for non-fixed hard regs since it can result in a circular
         for non-fixed hard regs since it can result in a circular
         dependency chain for registers which have values at function entry.
         dependency chain for registers which have values at function entry.
 
 
         The test above is not sufficient because the scheduler may move
         The test above is not sufficient because the scheduler may move
         a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN.  */
         a copy out of an arg reg past the NOTE_INSN_FUNCTION_BEGIN.  */
      if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno])
      if ((regno >= FIRST_PSEUDO_REGISTER || fixed_regs[regno])
          && regno < VEC_length (rtx, reg_base_value))
          && regno < VEC_length (rtx, reg_base_value))
        {
        {
          /* If we're inside init_alias_analysis, use new_reg_base_value
          /* If we're inside init_alias_analysis, use new_reg_base_value
             to reduce the number of relaxation iterations.  */
             to reduce the number of relaxation iterations.  */
          if (new_reg_base_value && new_reg_base_value[regno]
          if (new_reg_base_value && new_reg_base_value[regno]
              && DF_REG_DEF_COUNT (regno) == 1)
              && DF_REG_DEF_COUNT (regno) == 1)
            return new_reg_base_value[regno];
            return new_reg_base_value[regno];
 
 
          if (VEC_index (rtx, reg_base_value, regno))
          if (VEC_index (rtx, reg_base_value, regno))
            return VEC_index (rtx, reg_base_value, regno);
            return VEC_index (rtx, reg_base_value, regno);
        }
        }
 
 
      return 0;
      return 0;
 
 
    case MEM:
    case MEM:
      /* Check for an argument passed in memory.  Only record in the
      /* Check for an argument passed in memory.  Only record in the
         copying-arguments block; it is too hard to track changes
         copying-arguments block; it is too hard to track changes
         otherwise.  */
         otherwise.  */
      if (copying_arguments
      if (copying_arguments
          && (XEXP (src, 0) == arg_pointer_rtx
          && (XEXP (src, 0) == arg_pointer_rtx
              || (GET_CODE (XEXP (src, 0)) == PLUS
              || (GET_CODE (XEXP (src, 0)) == PLUS
                  && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx)))
                  && XEXP (XEXP (src, 0), 0) == arg_pointer_rtx)))
        return gen_rtx_ADDRESS (VOIDmode, src);
        return gen_rtx_ADDRESS (VOIDmode, src);
      return 0;
      return 0;
 
 
    case CONST:
    case CONST:
      src = XEXP (src, 0);
      src = XEXP (src, 0);
      if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
      if (GET_CODE (src) != PLUS && GET_CODE (src) != MINUS)
        break;
        break;
 
 
      /* ... fall through ...  */
      /* ... fall through ...  */
 
 
    case PLUS:
    case PLUS:
    case MINUS:
    case MINUS:
      {
      {
        rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1);
        rtx temp, src_0 = XEXP (src, 0), src_1 = XEXP (src, 1);
 
 
        /* If either operand is a REG that is a known pointer, then it
        /* If either operand is a REG that is a known pointer, then it
           is the base.  */
           is the base.  */
        if (REG_P (src_0) && REG_POINTER (src_0))
        if (REG_P (src_0) && REG_POINTER (src_0))
          return find_base_value (src_0);
          return find_base_value (src_0);
        if (REG_P (src_1) && REG_POINTER (src_1))
        if (REG_P (src_1) && REG_POINTER (src_1))
          return find_base_value (src_1);
          return find_base_value (src_1);
 
 
        /* If either operand is a REG, then see if we already have
        /* If either operand is a REG, then see if we already have
           a known value for it.  */
           a known value for it.  */
        if (REG_P (src_0))
        if (REG_P (src_0))
          {
          {
            temp = find_base_value (src_0);
            temp = find_base_value (src_0);
            if (temp != 0)
            if (temp != 0)
              src_0 = temp;
              src_0 = temp;
          }
          }
 
 
        if (REG_P (src_1))
        if (REG_P (src_1))
          {
          {
            temp = find_base_value (src_1);
            temp = find_base_value (src_1);
            if (temp!= 0)
            if (temp!= 0)
              src_1 = temp;
              src_1 = temp;
          }
          }
 
 
        /* If either base is named object or a special address
        /* If either base is named object or a special address
           (like an argument or stack reference), then use it for the
           (like an argument or stack reference), then use it for the
           base term.  */
           base term.  */
        if (src_0 != 0
        if (src_0 != 0
            && (GET_CODE (src_0) == SYMBOL_REF
            && (GET_CODE (src_0) == SYMBOL_REF
                || GET_CODE (src_0) == LABEL_REF
                || GET_CODE (src_0) == LABEL_REF
                || (GET_CODE (src_0) == ADDRESS
                || (GET_CODE (src_0) == ADDRESS
                    && GET_MODE (src_0) != VOIDmode)))
                    && GET_MODE (src_0) != VOIDmode)))
          return src_0;
          return src_0;
 
 
        if (src_1 != 0
        if (src_1 != 0
            && (GET_CODE (src_1) == SYMBOL_REF
            && (GET_CODE (src_1) == SYMBOL_REF
                || GET_CODE (src_1) == LABEL_REF
                || GET_CODE (src_1) == LABEL_REF
                || (GET_CODE (src_1) == ADDRESS
                || (GET_CODE (src_1) == ADDRESS
                    && GET_MODE (src_1) != VOIDmode)))
                    && GET_MODE (src_1) != VOIDmode)))
          return src_1;
          return src_1;
 
 
        /* Guess which operand is the base address:
        /* Guess which operand is the base address:
           If either operand is a symbol, then it is the base.  If
           If either operand is a symbol, then it is the base.  If
           either operand is a CONST_INT, then the other is the base.  */
           either operand is a CONST_INT, then the other is the base.  */
        if (CONST_INT_P (src_1) || CONSTANT_P (src_0))
        if (CONST_INT_P (src_1) || CONSTANT_P (src_0))
          return find_base_value (src_0);
          return find_base_value (src_0);
        else if (CONST_INT_P (src_0) || CONSTANT_P (src_1))
        else if (CONST_INT_P (src_0) || CONSTANT_P (src_1))
          return find_base_value (src_1);
          return find_base_value (src_1);
 
 
        return 0;
        return 0;
      }
      }
 
 
    case LO_SUM:
    case LO_SUM:
      /* The standard form is (lo_sum reg sym) so look only at the
      /* The standard form is (lo_sum reg sym) so look only at the
         second operand.  */
         second operand.  */
      return find_base_value (XEXP (src, 1));
      return find_base_value (XEXP (src, 1));
 
 
    case AND:
    case AND:
      /* If the second operand is constant set the base
      /* If the second operand is constant set the base
         address to the first operand.  */
         address to the first operand.  */
      if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0)
      if (CONST_INT_P (XEXP (src, 1)) && INTVAL (XEXP (src, 1)) != 0)
        return find_base_value (XEXP (src, 0));
        return find_base_value (XEXP (src, 0));
      return 0;
      return 0;
 
 
    case TRUNCATE:
    case TRUNCATE:
      /* As we do not know which address space the pointer is refering to, we can
      /* As we do not know which address space the pointer is refering to, we can
         handle this only if the target does not support different pointer or
         handle this only if the target does not support different pointer or
         address modes depending on the address space.  */
         address modes depending on the address space.  */
      if (!target_default_pointer_address_modes_p ())
      if (!target_default_pointer_address_modes_p ())
        break;
        break;
      if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode))
      if (GET_MODE_SIZE (GET_MODE (src)) < GET_MODE_SIZE (Pmode))
        break;
        break;
      /* Fall through.  */
      /* Fall through.  */
    case HIGH:
    case HIGH:
    case PRE_INC:
    case PRE_INC:
    case PRE_DEC:
    case PRE_DEC:
    case POST_INC:
    case POST_INC:
    case POST_DEC:
    case POST_DEC:
    case PRE_MODIFY:
    case PRE_MODIFY:
    case POST_MODIFY:
    case POST_MODIFY:
      return find_base_value (XEXP (src, 0));
      return find_base_value (XEXP (src, 0));
 
 
    case ZERO_EXTEND:
    case ZERO_EXTEND:
    case SIGN_EXTEND:   /* used for NT/Alpha pointers */
    case SIGN_EXTEND:   /* used for NT/Alpha pointers */
      /* As we do not know which address space the pointer is refering to, we can
      /* As we do not know which address space the pointer is refering to, we can
         handle this only if the target does not support different pointer or
         handle this only if the target does not support different pointer or
         address modes depending on the address space.  */
         address modes depending on the address space.  */
      if (!target_default_pointer_address_modes_p ())
      if (!target_default_pointer_address_modes_p ())
        break;
        break;
 
 
      {
      {
        rtx temp = find_base_value (XEXP (src, 0));
        rtx temp = find_base_value (XEXP (src, 0));
 
 
        if (temp != 0 && CONSTANT_P (temp))
        if (temp != 0 && CONSTANT_P (temp))
          temp = convert_memory_address (Pmode, temp);
          temp = convert_memory_address (Pmode, temp);
 
 
        return temp;
        return temp;
      }
      }
 
 
    default:
    default:
      break;
      break;
    }
    }
 
 
  return 0;
  return 0;
}
}
 
 
/* Called from init_alias_analysis indirectly through note_stores.  */
/* Called from init_alias_analysis indirectly through note_stores.  */
 
 
/* While scanning insns to find base values, reg_seen[N] is nonzero if
/* While scanning insns to find base values, reg_seen[N] is nonzero if
   register N has been set in this function.  */
   register N has been set in this function.  */
static char *reg_seen;
static char *reg_seen;
 
 
/* Addresses which are known not to alias anything else are identified
/* Addresses which are known not to alias anything else are identified
   by a unique integer.  */
   by a unique integer.  */
static int unique_id;
static int unique_id;
 
 
static void
static void
record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED)
record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED)
{
{
  unsigned regno;
  unsigned regno;
  rtx src;
  rtx src;
  int n;
  int n;
 
 
  if (!REG_P (dest))
  if (!REG_P (dest))
    return;
    return;
 
 
  regno = REGNO (dest);
  regno = REGNO (dest);
 
 
  gcc_assert (regno < VEC_length (rtx, reg_base_value));
  gcc_assert (regno < VEC_length (rtx, reg_base_value));
 
 
  /* If this spans multiple hard registers, then we must indicate that every
  /* If this spans multiple hard registers, then we must indicate that every
     register has an unusable value.  */
     register has an unusable value.  */
  if (regno < FIRST_PSEUDO_REGISTER)
  if (regno < FIRST_PSEUDO_REGISTER)
    n = hard_regno_nregs[regno][GET_MODE (dest)];
    n = hard_regno_nregs[regno][GET_MODE (dest)];
  else
  else
    n = 1;
    n = 1;
  if (n != 1)
  if (n != 1)
    {
    {
      while (--n >= 0)
      while (--n >= 0)
        {
        {
          reg_seen[regno + n] = 1;
          reg_seen[regno + n] = 1;
          new_reg_base_value[regno + n] = 0;
          new_reg_base_value[regno + n] = 0;
        }
        }
      return;
      return;
    }
    }
 
 
  if (set)
  if (set)
    {
    {
      /* A CLOBBER wipes out any old value but does not prevent a previously
      /* A CLOBBER wipes out any old value but does not prevent a previously
         unset register from acquiring a base address (i.e. reg_seen is not
         unset register from acquiring a base address (i.e. reg_seen is not
         set).  */
         set).  */
      if (GET_CODE (set) == CLOBBER)
      if (GET_CODE (set) == CLOBBER)
        {
        {
          new_reg_base_value[regno] = 0;
          new_reg_base_value[regno] = 0;
          return;
          return;
        }
        }
      src = SET_SRC (set);
      src = SET_SRC (set);
    }
    }
  else
  else
    {
    {
      if (reg_seen[regno])
      if (reg_seen[regno])
        {
        {
          new_reg_base_value[regno] = 0;
          new_reg_base_value[regno] = 0;
          return;
          return;
        }
        }
      reg_seen[regno] = 1;
      reg_seen[regno] = 1;
      new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode,
      new_reg_base_value[regno] = gen_rtx_ADDRESS (Pmode,
                                                   GEN_INT (unique_id++));
                                                   GEN_INT (unique_id++));
      return;
      return;
    }
    }
 
 
  /* If this is not the first set of REGNO, see whether the new value
  /* If this is not the first set of REGNO, see whether the new value
     is related to the old one.  There are two cases of interest:
     is related to the old one.  There are two cases of interest:
 
 
        (1) The register might be assigned an entirely new value
        (1) The register might be assigned an entirely new value
            that has the same base term as the original set.
            that has the same base term as the original set.
 
 
        (2) The set might be a simple self-modification that
        (2) The set might be a simple self-modification that
            cannot change REGNO's base value.
            cannot change REGNO's base value.
 
 
     If neither case holds, reject the original base value as invalid.
     If neither case holds, reject the original base value as invalid.
     Note that the following situation is not detected:
     Note that the following situation is not detected:
 
 
         extern int x, y;  int *p = &x; p += (&y-&x);
         extern int x, y;  int *p = &x; p += (&y-&x);
 
 
     ANSI C does not allow computing the difference of addresses
     ANSI C does not allow computing the difference of addresses
     of distinct top level objects.  */
     of distinct top level objects.  */
  if (new_reg_base_value[regno] != 0
  if (new_reg_base_value[regno] != 0
      && find_base_value (src) != new_reg_base_value[regno])
      && find_base_value (src) != new_reg_base_value[regno])
    switch (GET_CODE (src))
    switch (GET_CODE (src))
      {
      {
      case LO_SUM:
      case LO_SUM:
      case MINUS:
      case MINUS:
        if (XEXP (src, 0) != dest && XEXP (src, 1) != dest)
        if (XEXP (src, 0) != dest && XEXP (src, 1) != dest)
          new_reg_base_value[regno] = 0;
          new_reg_base_value[regno] = 0;
        break;
        break;
      case PLUS:
      case PLUS:
        /* If the value we add in the PLUS is also a valid base value,
        /* If the value we add in the PLUS is also a valid base value,
           this might be the actual base value, and the original value
           this might be the actual base value, and the original value
           an index.  */
           an index.  */
        {
        {
          rtx other = NULL_RTX;
          rtx other = NULL_RTX;
 
 
          if (XEXP (src, 0) == dest)
          if (XEXP (src, 0) == dest)
            other = XEXP (src, 1);
            other = XEXP (src, 1);
          else if (XEXP (src, 1) == dest)
          else if (XEXP (src, 1) == dest)
            other = XEXP (src, 0);
            other = XEXP (src, 0);
 
 
          if (! other || find_base_value (other))
          if (! other || find_base_value (other))
            new_reg_base_value[regno] = 0;
            new_reg_base_value[regno] = 0;
          break;
          break;
        }
        }
      case AND:
      case AND:
        if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1)))
        if (XEXP (src, 0) != dest || !CONST_INT_P (XEXP (src, 1)))
          new_reg_base_value[regno] = 0;
          new_reg_base_value[regno] = 0;
        break;
        break;
      default:
      default:
        new_reg_base_value[regno] = 0;
        new_reg_base_value[regno] = 0;
        break;
        break;
      }
      }
  /* If this is the first set of a register, record the value.  */
  /* If this is the first set of a register, record the value.  */
  else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
  else if ((regno >= FIRST_PSEUDO_REGISTER || ! fixed_regs[regno])
           && ! reg_seen[regno] && new_reg_base_value[regno] == 0)
           && ! reg_seen[regno] && new_reg_base_value[regno] == 0)
    new_reg_base_value[regno] = find_base_value (src);
    new_reg_base_value[regno] = find_base_value (src);
 
 
  reg_seen[regno] = 1;
  reg_seen[regno] = 1;
}
}
 
 
/* If a value is known for REGNO, return it.  */
/* If a value is known for REGNO, return it.  */
 
 
rtx
rtx
get_reg_known_value (unsigned int regno)
get_reg_known_value (unsigned int regno)
{
{
  if (regno >= FIRST_PSEUDO_REGISTER)
  if (regno >= FIRST_PSEUDO_REGISTER)
    {
    {
      regno -= FIRST_PSEUDO_REGISTER;
      regno -= FIRST_PSEUDO_REGISTER;
      if (regno < reg_known_value_size)
      if (regno < reg_known_value_size)
        return reg_known_value[regno];
        return reg_known_value[regno];
    }
    }
  return NULL;
  return NULL;
}
}
 
 
/* Set it.  */
/* Set it.  */
 
 
static void
static void
set_reg_known_value (unsigned int regno, rtx val)
set_reg_known_value (unsigned int regno, rtx val)
{
{
  if (regno >= FIRST_PSEUDO_REGISTER)
  if (regno >= FIRST_PSEUDO_REGISTER)
    {
    {
      regno -= FIRST_PSEUDO_REGISTER;
      regno -= FIRST_PSEUDO_REGISTER;
      if (regno < reg_known_value_size)
      if (regno < reg_known_value_size)
        reg_known_value[regno] = val;
        reg_known_value[regno] = val;
    }
    }
}
}
 
 
/* Similarly for reg_known_equiv_p.  */
/* Similarly for reg_known_equiv_p.  */
 
 
bool
bool
get_reg_known_equiv_p (unsigned int regno)
get_reg_known_equiv_p (unsigned int regno)
{
{
  if (regno >= FIRST_PSEUDO_REGISTER)
  if (regno >= FIRST_PSEUDO_REGISTER)
    {
    {
      regno -= FIRST_PSEUDO_REGISTER;
      regno -= FIRST_PSEUDO_REGISTER;
      if (regno < reg_known_value_size)
      if (regno < reg_known_value_size)
        return reg_known_equiv_p[regno];
        return reg_known_equiv_p[regno];
    }
    }
  return false;
  return false;
}
}
 
 
static void
static void
set_reg_known_equiv_p (unsigned int regno, bool val)
set_reg_known_equiv_p (unsigned int regno, bool val)
{
{
  if (regno >= FIRST_PSEUDO_REGISTER)
  if (regno >= FIRST_PSEUDO_REGISTER)
    {
    {
      regno -= FIRST_PSEUDO_REGISTER;
      regno -= FIRST_PSEUDO_REGISTER;
      if (regno < reg_known_value_size)
      if (regno < reg_known_value_size)
        reg_known_equiv_p[regno] = val;
        reg_known_equiv_p[regno] = val;
    }
    }
}
}
 
 
 
 
/* Returns a canonical version of X, from the point of view alias
/* Returns a canonical version of X, from the point of view alias
   analysis.  (For example, if X is a MEM whose address is a register,
   analysis.  (For example, if X is a MEM whose address is a register,
   and the register has a known value (say a SYMBOL_REF), then a MEM
   and the register has a known value (say a SYMBOL_REF), then a MEM
   whose address is the SYMBOL_REF is returned.)  */
   whose address is the SYMBOL_REF is returned.)  */
 
 
rtx
rtx
canon_rtx (rtx x)
canon_rtx (rtx x)
{
{
  /* Recursively look for equivalences.  */
  /* Recursively look for equivalences.  */
  if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER)
  if (REG_P (x) && REGNO (x) >= FIRST_PSEUDO_REGISTER)
    {
    {
      rtx t = get_reg_known_value (REGNO (x));
      rtx t = get_reg_known_value (REGNO (x));
      if (t == x)
      if (t == x)
        return x;
        return x;
      if (t)
      if (t)
        return canon_rtx (t);
        return canon_rtx (t);
    }
    }
 
 
  if (GET_CODE (x) == PLUS)
  if (GET_CODE (x) == PLUS)
    {
    {
      rtx x0 = canon_rtx (XEXP (x, 0));
      rtx x0 = canon_rtx (XEXP (x, 0));
      rtx x1 = canon_rtx (XEXP (x, 1));
      rtx x1 = canon_rtx (XEXP (x, 1));
 
 
      if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1))
      if (x0 != XEXP (x, 0) || x1 != XEXP (x, 1))
        {
        {
          if (CONST_INT_P (x0))
          if (CONST_INT_P (x0))
            return plus_constant (x1, INTVAL (x0));
            return plus_constant (x1, INTVAL (x0));
          else if (CONST_INT_P (x1))
          else if (CONST_INT_P (x1))
            return plus_constant (x0, INTVAL (x1));
            return plus_constant (x0, INTVAL (x1));
          return gen_rtx_PLUS (GET_MODE (x), x0, x1);
          return gen_rtx_PLUS (GET_MODE (x), x0, x1);
        }
        }
    }
    }
 
 
  /* This gives us much better alias analysis when called from
  /* This gives us much better alias analysis when called from
     the loop optimizer.   Note we want to leave the original
     the loop optimizer.   Note we want to leave the original
     MEM alone, but need to return the canonicalized MEM with
     MEM alone, but need to return the canonicalized MEM with
     all the flags with their original values.  */
     all the flags with their original values.  */
  else if (MEM_P (x))
  else if (MEM_P (x))
    x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0)));
    x = replace_equiv_address_nv (x, canon_rtx (XEXP (x, 0)));
 
 
  return x;
  return x;
}
}
 
 
/* Return 1 if X and Y are identical-looking rtx's.
/* Return 1 if X and Y are identical-looking rtx's.
   Expect that X and Y has been already canonicalized.
   Expect that X and Y has been already canonicalized.
 
 
   We use the data in reg_known_value above to see if two registers with
   We use the data in reg_known_value above to see if two registers with
   different numbers are, in fact, equivalent.  */
   different numbers are, in fact, equivalent.  */
 
 
static int
static int
rtx_equal_for_memref_p (const_rtx x, const_rtx y)
rtx_equal_for_memref_p (const_rtx x, const_rtx y)
{
{
  int i;
  int i;
  int j;
  int j;
  enum rtx_code code;
  enum rtx_code code;
  const char *fmt;
  const char *fmt;
 
 
  if (x == 0 && y == 0)
  if (x == 0 && y == 0)
    return 1;
    return 1;
  if (x == 0 || y == 0)
  if (x == 0 || y == 0)
    return 0;
    return 0;
 
 
  if (x == y)
  if (x == y)
    return 1;
    return 1;
 
 
  code = GET_CODE (x);
  code = GET_CODE (x);
  /* Rtx's of different codes cannot be equal.  */
  /* Rtx's of different codes cannot be equal.  */
  if (code != GET_CODE (y))
  if (code != GET_CODE (y))
    return 0;
    return 0;
 
 
  /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
  /* (MULT:SI x y) and (MULT:HI x y) are NOT equivalent.
     (REG:SI x) and (REG:HI x) are NOT equivalent.  */
     (REG:SI x) and (REG:HI x) are NOT equivalent.  */
 
 
  if (GET_MODE (x) != GET_MODE (y))
  if (GET_MODE (x) != GET_MODE (y))
    return 0;
    return 0;
 
 
  /* Some RTL can be compared without a recursive examination.  */
  /* Some RTL can be compared without a recursive examination.  */
  switch (code)
  switch (code)
    {
    {
    case REG:
    case REG:
      return REGNO (x) == REGNO (y);
      return REGNO (x) == REGNO (y);
 
 
    case LABEL_REF:
    case LABEL_REF:
      return XEXP (x, 0) == XEXP (y, 0);
      return XEXP (x, 0) == XEXP (y, 0);
 
 
    case SYMBOL_REF:
    case SYMBOL_REF:
      return XSTR (x, 0) == XSTR (y, 0);
      return XSTR (x, 0) == XSTR (y, 0);
 
 
    case VALUE:
    case VALUE:
    case CONST_INT:
    case CONST_INT:
    case CONST_DOUBLE:
    case CONST_DOUBLE:
    case CONST_FIXED:
    case CONST_FIXED:
      /* There's no need to compare the contents of CONST_DOUBLEs or
      /* There's no need to compare the contents of CONST_DOUBLEs or
         CONST_INTs because pointer equality is a good enough
         CONST_INTs because pointer equality is a good enough
         comparison for these nodes.  */
         comparison for these nodes.  */
      return 0;
      return 0;
 
 
    default:
    default:
      break;
      break;
    }
    }
 
 
  /* canon_rtx knows how to handle plus.  No need to canonicalize.  */
  /* canon_rtx knows how to handle plus.  No need to canonicalize.  */
  if (code == PLUS)
  if (code == PLUS)
    return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
    return ((rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 0))
             && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)))
             && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 1)))
            || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1))
            || (rtx_equal_for_memref_p (XEXP (x, 0), XEXP (y, 1))
                && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0))));
                && rtx_equal_for_memref_p (XEXP (x, 1), XEXP (y, 0))));
  /* For commutative operations, the RTX match if the operand match in any
  /* For commutative operations, the RTX match if the operand match in any
     order.  Also handle the simple binary and unary cases without a loop.  */
     order.  Also handle the simple binary and unary cases without a loop.  */
  if (COMMUTATIVE_P (x))
  if (COMMUTATIVE_P (x))
    {
    {
      rtx xop0 = canon_rtx (XEXP (x, 0));
      rtx xop0 = canon_rtx (XEXP (x, 0));
      rtx yop0 = canon_rtx (XEXP (y, 0));
      rtx yop0 = canon_rtx (XEXP (y, 0));
      rtx yop1 = canon_rtx (XEXP (y, 1));
      rtx yop1 = canon_rtx (XEXP (y, 1));
 
 
      return ((rtx_equal_for_memref_p (xop0, yop0)
      return ((rtx_equal_for_memref_p (xop0, yop0)
               && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1))
               && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop1))
              || (rtx_equal_for_memref_p (xop0, yop1)
              || (rtx_equal_for_memref_p (xop0, yop1)
                  && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0)));
                  && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)), yop0)));
    }
    }
  else if (NON_COMMUTATIVE_P (x))
  else if (NON_COMMUTATIVE_P (x))
    {
    {
      return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
      return (rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
                                      canon_rtx (XEXP (y, 0)))
                                      canon_rtx (XEXP (y, 0)))
              && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)),
              && rtx_equal_for_memref_p (canon_rtx (XEXP (x, 1)),
                                         canon_rtx (XEXP (y, 1))));
                                         canon_rtx (XEXP (y, 1))));
    }
    }
  else if (UNARY_P (x))
  else if (UNARY_P (x))
    return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
    return rtx_equal_for_memref_p (canon_rtx (XEXP (x, 0)),
                                   canon_rtx (XEXP (y, 0)));
                                   canon_rtx (XEXP (y, 0)));
 
 
  /* Compare the elements.  If any pair of corresponding elements
  /* Compare the elements.  If any pair of corresponding elements
     fail to match, return 0 for the whole things.
     fail to match, return 0 for the whole things.
 
 
     Limit cases to types which actually appear in addresses.  */
     Limit cases to types which actually appear in addresses.  */
 
 
  fmt = GET_RTX_FORMAT (code);
  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
    {
      switch (fmt[i])
      switch (fmt[i])
        {
        {
        case 'i':
        case 'i':
          if (XINT (x, i) != XINT (y, i))
          if (XINT (x, i) != XINT (y, i))
            return 0;
            return 0;
          break;
          break;
 
 
        case 'E':
        case 'E':
          /* Two vectors must have the same length.  */
          /* Two vectors must have the same length.  */
          if (XVECLEN (x, i) != XVECLEN (y, i))
          if (XVECLEN (x, i) != XVECLEN (y, i))
            return 0;
            return 0;
 
 
          /* And the corresponding elements must match.  */
          /* And the corresponding elements must match.  */
          for (j = 0; j < XVECLEN (x, i); j++)
          for (j = 0; j < XVECLEN (x, i); j++)
            if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)),
            if (rtx_equal_for_memref_p (canon_rtx (XVECEXP (x, i, j)),
                                        canon_rtx (XVECEXP (y, i, j))) == 0)
                                        canon_rtx (XVECEXP (y, i, j))) == 0)
              return 0;
              return 0;
          break;
          break;
 
 
        case 'e':
        case 'e':
          if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)),
          if (rtx_equal_for_memref_p (canon_rtx (XEXP (x, i)),
                                      canon_rtx (XEXP (y, i))) == 0)
                                      canon_rtx (XEXP (y, i))) == 0)
            return 0;
            return 0;
          break;
          break;
 
 
          /* This can happen for asm operands.  */
          /* This can happen for asm operands.  */
        case 's':
        case 's':
          if (strcmp (XSTR (x, i), XSTR (y, i)))
          if (strcmp (XSTR (x, i), XSTR (y, i)))
            return 0;
            return 0;
          break;
          break;
 
 
        /* This can happen for an asm which clobbers memory.  */
        /* This can happen for an asm which clobbers memory.  */
        case '0':
        case '0':
          break;
          break;
 
 
          /* It is believed that rtx's at this level will never
          /* It is believed that rtx's at this level will never
             contain anything but integers and other rtx's,
             contain anything but integers and other rtx's,
             except for within LABEL_REFs and SYMBOL_REFs.  */
             except for within LABEL_REFs and SYMBOL_REFs.  */
        default:
        default:
          gcc_unreachable ();
          gcc_unreachable ();
        }
        }
    }
    }
  return 1;
  return 1;
}
}
 
 
rtx
rtx
find_base_term (rtx x)
find_base_term (rtx x)
{
{
  cselib_val *val;
  cselib_val *val;
  struct elt_loc_list *l;
  struct elt_loc_list *l;
 
 
#if defined (FIND_BASE_TERM)
#if defined (FIND_BASE_TERM)
  /* Try machine-dependent ways to find the base term.  */
  /* Try machine-dependent ways to find the base term.  */
  x = FIND_BASE_TERM (x);
  x = FIND_BASE_TERM (x);
#endif
#endif
 
 
  switch (GET_CODE (x))
  switch (GET_CODE (x))
    {
    {
    case REG:
    case REG:
      return REG_BASE_VALUE (x);
      return REG_BASE_VALUE (x);
 
 
    case TRUNCATE:
    case TRUNCATE:
      /* As we do not know which address space the pointer is refering to, we can
      /* As we do not know which address space the pointer is refering to, we can
         handle this only if the target does not support different pointer or
         handle this only if the target does not support different pointer or
         address modes depending on the address space.  */
         address modes depending on the address space.  */
      if (!target_default_pointer_address_modes_p ())
      if (!target_default_pointer_address_modes_p ())
        return 0;
        return 0;
      if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode))
      if (GET_MODE_SIZE (GET_MODE (x)) < GET_MODE_SIZE (Pmode))
        return 0;
        return 0;
      /* Fall through.  */
      /* Fall through.  */
    case HIGH:
    case HIGH:
    case PRE_INC:
    case PRE_INC:
    case PRE_DEC:
    case PRE_DEC:
    case POST_INC:
    case POST_INC:
    case POST_DEC:
    case POST_DEC:
    case PRE_MODIFY:
    case PRE_MODIFY:
    case POST_MODIFY:
    case POST_MODIFY:
      return find_base_term (XEXP (x, 0));
      return find_base_term (XEXP (x, 0));
 
 
    case ZERO_EXTEND:
    case ZERO_EXTEND:
    case SIGN_EXTEND:   /* Used for Alpha/NT pointers */
    case SIGN_EXTEND:   /* Used for Alpha/NT pointers */
      /* As we do not know which address space the pointer is refering to, we can
      /* As we do not know which address space the pointer is refering to, we can
         handle this only if the target does not support different pointer or
         handle this only if the target does not support different pointer or
         address modes depending on the address space.  */
         address modes depending on the address space.  */
      if (!target_default_pointer_address_modes_p ())
      if (!target_default_pointer_address_modes_p ())
        return 0;
        return 0;
 
 
      {
      {
        rtx temp = find_base_term (XEXP (x, 0));
        rtx temp = find_base_term (XEXP (x, 0));
 
 
        if (temp != 0 && CONSTANT_P (temp))
        if (temp != 0 && CONSTANT_P (temp))
          temp = convert_memory_address (Pmode, temp);
          temp = convert_memory_address (Pmode, temp);
 
 
        return temp;
        return temp;
      }
      }
 
 
    case VALUE:
    case VALUE:
      val = CSELIB_VAL_PTR (x);
      val = CSELIB_VAL_PTR (x);
      if (!val)
      if (!val)
        return 0;
        return 0;
      for (l = val->locs; l; l = l->next)
      for (l = val->locs; l; l = l->next)
        if ((x = find_base_term (l->loc)) != 0)
        if ((x = find_base_term (l->loc)) != 0)
          return x;
          return x;
      return 0;
      return 0;
 
 
    case LO_SUM:
    case LO_SUM:
      /* The standard form is (lo_sum reg sym) so look only at the
      /* The standard form is (lo_sum reg sym) so look only at the
         second operand.  */
         second operand.  */
      return find_base_term (XEXP (x, 1));
      return find_base_term (XEXP (x, 1));
 
 
    case CONST:
    case CONST:
      x = XEXP (x, 0);
      x = XEXP (x, 0);
      if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS)
      if (GET_CODE (x) != PLUS && GET_CODE (x) != MINUS)
        return 0;
        return 0;
      /* Fall through.  */
      /* Fall through.  */
    case PLUS:
    case PLUS:
    case MINUS:
    case MINUS:
      {
      {
        rtx tmp1 = XEXP (x, 0);
        rtx tmp1 = XEXP (x, 0);
        rtx tmp2 = XEXP (x, 1);
        rtx tmp2 = XEXP (x, 1);
 
 
        /* This is a little bit tricky since we have to determine which of
        /* This is a little bit tricky since we have to determine which of
           the two operands represents the real base address.  Otherwise this
           the two operands represents the real base address.  Otherwise this
           routine may return the index register instead of the base register.
           routine may return the index register instead of the base register.
 
 
           That may cause us to believe no aliasing was possible, when in
           That may cause us to believe no aliasing was possible, when in
           fact aliasing is possible.
           fact aliasing is possible.
 
 
           We use a few simple tests to guess the base register.  Additional
           We use a few simple tests to guess the base register.  Additional
           tests can certainly be added.  For example, if one of the operands
           tests can certainly be added.  For example, if one of the operands
           is a shift or multiply, then it must be the index register and the
           is a shift or multiply, then it must be the index register and the
           other operand is the base register.  */
           other operand is the base register.  */
 
 
        if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2))
        if (tmp1 == pic_offset_table_rtx && CONSTANT_P (tmp2))
          return find_base_term (tmp2);
          return find_base_term (tmp2);
 
 
        /* If either operand is known to be a pointer, then use it
        /* If either operand is known to be a pointer, then use it
           to determine the base term.  */
           to determine the base term.  */
        if (REG_P (tmp1) && REG_POINTER (tmp1))
        if (REG_P (tmp1) && REG_POINTER (tmp1))
          {
          {
            rtx base = find_base_term (tmp1);
            rtx base = find_base_term (tmp1);
            if (base)
            if (base)
              return base;
              return base;
          }
          }
 
 
        if (REG_P (tmp2) && REG_POINTER (tmp2))
        if (REG_P (tmp2) && REG_POINTER (tmp2))
          {
          {
            rtx base = find_base_term (tmp2);
            rtx base = find_base_term (tmp2);
            if (base)
            if (base)
              return base;
              return base;
          }
          }
 
 
        /* Neither operand was known to be a pointer.  Go ahead and find the
        /* Neither operand was known to be a pointer.  Go ahead and find the
           base term for both operands.  */
           base term for both operands.  */
        tmp1 = find_base_term (tmp1);
        tmp1 = find_base_term (tmp1);
        tmp2 = find_base_term (tmp2);
        tmp2 = find_base_term (tmp2);
 
 
        /* If either base term is named object or a special address
        /* If either base term is named object or a special address
           (like an argument or stack reference), then use it for the
           (like an argument or stack reference), then use it for the
           base term.  */
           base term.  */
        if (tmp1 != 0
        if (tmp1 != 0
            && (GET_CODE (tmp1) == SYMBOL_REF
            && (GET_CODE (tmp1) == SYMBOL_REF
                || GET_CODE (tmp1) == LABEL_REF
                || GET_CODE (tmp1) == LABEL_REF
                || (GET_CODE (tmp1) == ADDRESS
                || (GET_CODE (tmp1) == ADDRESS
                    && GET_MODE (tmp1) != VOIDmode)))
                    && GET_MODE (tmp1) != VOIDmode)))
          return tmp1;
          return tmp1;
 
 
        if (tmp2 != 0
        if (tmp2 != 0
            && (GET_CODE (tmp2) == SYMBOL_REF
            && (GET_CODE (tmp2) == SYMBOL_REF
                || GET_CODE (tmp2) == LABEL_REF
                || GET_CODE (tmp2) == LABEL_REF
                || (GET_CODE (tmp2) == ADDRESS
                || (GET_CODE (tmp2) == ADDRESS
                    && GET_MODE (tmp2) != VOIDmode)))
                    && GET_MODE (tmp2) != VOIDmode)))
          return tmp2;
          return tmp2;
 
 
        /* We could not determine which of the two operands was the
        /* We could not determine which of the two operands was the
           base register and which was the index.  So we can determine
           base register and which was the index.  So we can determine
           nothing from the base alias check.  */
           nothing from the base alias check.  */
        return 0;
        return 0;
      }
      }
 
 
    case AND:
    case AND:
      if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0)
      if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) != 0)
        return find_base_term (XEXP (x, 0));
        return find_base_term (XEXP (x, 0));
      return 0;
      return 0;
 
 
    case SYMBOL_REF:
    case SYMBOL_REF:
    case LABEL_REF:
    case LABEL_REF:
      return x;
      return x;
 
 
    default:
    default:
      return 0;
      return 0;
    }
    }
}
}
 
 
/* Return 0 if the addresses X and Y are known to point to different
/* Return 0 if the addresses X and Y are known to point to different
   objects, 1 if they might be pointers to the same object.  */
   objects, 1 if they might be pointers to the same object.  */
 
 
static int
static int
base_alias_check (rtx x, rtx y, enum machine_mode x_mode,
base_alias_check (rtx x, rtx y, enum machine_mode x_mode,
                  enum machine_mode y_mode)
                  enum machine_mode y_mode)
{
{
  rtx x_base = find_base_term (x);
  rtx x_base = find_base_term (x);
  rtx y_base = find_base_term (y);
  rtx y_base = find_base_term (y);
 
 
  /* If the address itself has no known base see if a known equivalent
  /* If the address itself has no known base see if a known equivalent
     value has one.  If either address still has no known base, nothing
     value has one.  If either address still has no known base, nothing
     is known about aliasing.  */
     is known about aliasing.  */
  if (x_base == 0)
  if (x_base == 0)
    {
    {
      rtx x_c;
      rtx x_c;
 
 
      if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x)
      if (! flag_expensive_optimizations || (x_c = canon_rtx (x)) == x)
        return 1;
        return 1;
 
 
      x_base = find_base_term (x_c);
      x_base = find_base_term (x_c);
      if (x_base == 0)
      if (x_base == 0)
        return 1;
        return 1;
    }
    }
 
 
  if (y_base == 0)
  if (y_base == 0)
    {
    {
      rtx y_c;
      rtx y_c;
      if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y)
      if (! flag_expensive_optimizations || (y_c = canon_rtx (y)) == y)
        return 1;
        return 1;
 
 
      y_base = find_base_term (y_c);
      y_base = find_base_term (y_c);
      if (y_base == 0)
      if (y_base == 0)
        return 1;
        return 1;
    }
    }
 
 
  /* If the base addresses are equal nothing is known about aliasing.  */
  /* If the base addresses are equal nothing is known about aliasing.  */
  if (rtx_equal_p (x_base, y_base))
  if (rtx_equal_p (x_base, y_base))
    return 1;
    return 1;
 
 
  /* The base addresses are different expressions.  If they are not accessed
  /* The base addresses are different expressions.  If they are not accessed
     via AND, there is no conflict.  We can bring knowledge of object
     via AND, there is no conflict.  We can bring knowledge of object
     alignment into play here.  For example, on alpha, "char a, b;" can
     alignment into play here.  For example, on alpha, "char a, b;" can
     alias one another, though "char a; long b;" cannot.  AND addesses may
     alias one another, though "char a; long b;" cannot.  AND addesses may
     implicitly alias surrounding objects; i.e. unaligned access in DImode
     implicitly alias surrounding objects; i.e. unaligned access in DImode
     via AND address can alias all surrounding object types except those
     via AND address can alias all surrounding object types except those
     with aligment 8 or higher.  */
     with aligment 8 or higher.  */
  if (GET_CODE (x) == AND && GET_CODE (y) == AND)
  if (GET_CODE (x) == AND && GET_CODE (y) == AND)
    return 1;
    return 1;
  if (GET_CODE (x) == AND
  if (GET_CODE (x) == AND
      && (!CONST_INT_P (XEXP (x, 1))
      && (!CONST_INT_P (XEXP (x, 1))
          || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
          || (int) GET_MODE_UNIT_SIZE (y_mode) < -INTVAL (XEXP (x, 1))))
    return 1;
    return 1;
  if (GET_CODE (y) == AND
  if (GET_CODE (y) == AND
      && (!CONST_INT_P (XEXP (y, 1))
      && (!CONST_INT_P (XEXP (y, 1))
          || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
          || (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
    return 1;
    return 1;
 
 
  /* Differing symbols not accessed via AND never alias.  */
  /* Differing symbols not accessed via AND never alias.  */
  if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS)
  if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS)
    return 0;
    return 0;
 
 
  /* If one address is a stack reference there can be no alias:
  /* If one address is a stack reference there can be no alias:
     stack references using different base registers do not alias,
     stack references using different base registers do not alias,
     a stack reference can not alias a parameter, and a stack reference
     a stack reference can not alias a parameter, and a stack reference
     can not alias a global.  */
     can not alias a global.  */
  if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode)
  if ((GET_CODE (x_base) == ADDRESS && GET_MODE (x_base) == Pmode)
      || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode))
      || (GET_CODE (y_base) == ADDRESS && GET_MODE (y_base) == Pmode))
    return 0;
    return 0;
 
 
  if (! flag_argument_noalias)
  if (! flag_argument_noalias)
    return 1;
    return 1;
 
 
  if (flag_argument_noalias > 1)
  if (flag_argument_noalias > 1)
    return 0;
    return 0;
 
 
  /* Weak noalias assertion (arguments are distinct, but may match globals).  */
  /* Weak noalias assertion (arguments are distinct, but may match globals).  */
  return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode);
  return ! (GET_MODE (x_base) == VOIDmode && GET_MODE (y_base) == VOIDmode);
}
}
 
 
/* Convert the address X into something we can use.  This is done by returning
/* Convert the address X into something we can use.  This is done by returning
   it unchanged unless it is a value; in the latter case we call cselib to get
   it unchanged unless it is a value; in the latter case we call cselib to get
   a more useful rtx.  */
   a more useful rtx.  */
 
 
rtx
rtx
get_addr (rtx x)
get_addr (rtx x)
{
{
  cselib_val *v;
  cselib_val *v;
  struct elt_loc_list *l;
  struct elt_loc_list *l;
 
 
  if (GET_CODE (x) != VALUE)
  if (GET_CODE (x) != VALUE)
    return x;
    return x;
  v = CSELIB_VAL_PTR (x);
  v = CSELIB_VAL_PTR (x);
  if (v)
  if (v)
    {
    {
      for (l = v->locs; l; l = l->next)
      for (l = v->locs; l; l = l->next)
        if (CONSTANT_P (l->loc))
        if (CONSTANT_P (l->loc))
          return l->loc;
          return l->loc;
      for (l = v->locs; l; l = l->next)
      for (l = v->locs; l; l = l->next)
        if (!REG_P (l->loc) && !MEM_P (l->loc))
        if (!REG_P (l->loc) && !MEM_P (l->loc))
          return l->loc;
          return l->loc;
      if (v->locs)
      if (v->locs)
        return v->locs->loc;
        return v->locs->loc;
    }
    }
  return x;
  return x;
}
}
 
 
/*  Return the address of the (N_REFS + 1)th memory reference to ADDR
/*  Return the address of the (N_REFS + 1)th memory reference to ADDR
    where SIZE is the size in bytes of the memory reference.  If ADDR
    where SIZE is the size in bytes of the memory reference.  If ADDR
    is not modified by the memory reference then ADDR is returned.  */
    is not modified by the memory reference then ADDR is returned.  */
 
 
static rtx
static rtx
addr_side_effect_eval (rtx addr, int size, int n_refs)
addr_side_effect_eval (rtx addr, int size, int n_refs)
{
{
  int offset = 0;
  int offset = 0;
 
 
  switch (GET_CODE (addr))
  switch (GET_CODE (addr))
    {
    {
    case PRE_INC:
    case PRE_INC:
      offset = (n_refs + 1) * size;
      offset = (n_refs + 1) * size;
      break;
      break;
    case PRE_DEC:
    case PRE_DEC:
      offset = -(n_refs + 1) * size;
      offset = -(n_refs + 1) * size;
      break;
      break;
    case POST_INC:
    case POST_INC:
      offset = n_refs * size;
      offset = n_refs * size;
      break;
      break;
    case POST_DEC:
    case POST_DEC:
      offset = -n_refs * size;
      offset = -n_refs * size;
      break;
      break;
 
 
    default:
    default:
      return addr;
      return addr;
    }
    }
 
 
  if (offset)
  if (offset)
    addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0),
    addr = gen_rtx_PLUS (GET_MODE (addr), XEXP (addr, 0),
                         GEN_INT (offset));
                         GEN_INT (offset));
  else
  else
    addr = XEXP (addr, 0);
    addr = XEXP (addr, 0);
  addr = canon_rtx (addr);
  addr = canon_rtx (addr);
 
 
  return addr;
  return addr;
}
}
 
 
/* Return one if X and Y (memory addresses) reference the
/* Return one if X and Y (memory addresses) reference the
   same location in memory or if the references overlap.
   same location in memory or if the references overlap.
   Return zero if they do not overlap, else return
   Return zero if they do not overlap, else return
   minus one in which case they still might reference the same location.
   minus one in which case they still might reference the same location.
 
 
   C is an offset accumulator.  When
   C is an offset accumulator.  When
   C is nonzero, we are testing aliases between X and Y + C.
   C is nonzero, we are testing aliases between X and Y + C.
   XSIZE is the size in bytes of the X reference,
   XSIZE is the size in bytes of the X reference,
   similarly YSIZE is the size in bytes for Y.
   similarly YSIZE is the size in bytes for Y.
   Expect that canon_rtx has been already called for X and Y.
   Expect that canon_rtx has been already called for X and Y.
 
 
   If XSIZE or YSIZE is zero, we do not know the amount of memory being
   If XSIZE or YSIZE is zero, we do not know the amount of memory being
   referenced (the reference was BLKmode), so make the most pessimistic
   referenced (the reference was BLKmode), so make the most pessimistic
   assumptions.
   assumptions.
 
 
   If XSIZE or YSIZE is negative, we may access memory outside the object
   If XSIZE or YSIZE is negative, we may access memory outside the object
   being referenced as a side effect.  This can happen when using AND to
   being referenced as a side effect.  This can happen when using AND to
   align memory references, as is done on the Alpha.
   align memory references, as is done on the Alpha.
 
 
   Nice to notice that varying addresses cannot conflict with fp if no
   Nice to notice that varying addresses cannot conflict with fp if no
   local variables had their addresses taken, but that's too hard now.
   local variables had their addresses taken, but that's too hard now.
 
 
   ???  Contrary to the tree alias oracle this does not return
   ???  Contrary to the tree alias oracle this does not return
   one for X + non-constant and Y + non-constant when X and Y are equal.
   one for X + non-constant and Y + non-constant when X and Y are equal.
   If that is fixed the TBAA hack for union type-punning can be removed.  */
   If that is fixed the TBAA hack for union type-punning can be removed.  */
 
 
static int
static int
memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
memrefs_conflict_p (int xsize, rtx x, int ysize, rtx y, HOST_WIDE_INT c)
{
{
  if (GET_CODE (x) == VALUE)
  if (GET_CODE (x) == VALUE)
    x = get_addr (x);
    x = get_addr (x);
  if (GET_CODE (y) == VALUE)
  if (GET_CODE (y) == VALUE)
    y = get_addr (y);
    y = get_addr (y);
  if (GET_CODE (x) == HIGH)
  if (GET_CODE (x) == HIGH)
    x = XEXP (x, 0);
    x = XEXP (x, 0);
  else if (GET_CODE (x) == LO_SUM)
  else if (GET_CODE (x) == LO_SUM)
    x = XEXP (x, 1);
    x = XEXP (x, 1);
  else
  else
    x = addr_side_effect_eval (x, xsize, 0);
    x = addr_side_effect_eval (x, xsize, 0);
  if (GET_CODE (y) == HIGH)
  if (GET_CODE (y) == HIGH)
    y = XEXP (y, 0);
    y = XEXP (y, 0);
  else if (GET_CODE (y) == LO_SUM)
  else if (GET_CODE (y) == LO_SUM)
    y = XEXP (y, 1);
    y = XEXP (y, 1);
  else
  else
    y = addr_side_effect_eval (y, ysize, 0);
    y = addr_side_effect_eval (y, ysize, 0);
 
 
  if (rtx_equal_for_memref_p (x, y))
  if (rtx_equal_for_memref_p (x, y))
    {
    {
      if (xsize <= 0 || ysize <= 0)
      if (xsize <= 0 || ysize <= 0)
        return 1;
        return 1;
      if (c >= 0 && xsize > c)
      if (c >= 0 && xsize > c)
        return 1;
        return 1;
      if (c < 0 && ysize+c > 0)
      if (c < 0 && ysize+c > 0)
        return 1;
        return 1;
      return 0;
      return 0;
    }
    }
 
 
  /* This code used to check for conflicts involving stack references and
  /* This code used to check for conflicts involving stack references and
     globals but the base address alias code now handles these cases.  */
     globals but the base address alias code now handles these cases.  */
 
 
  if (GET_CODE (x) == PLUS)
  if (GET_CODE (x) == PLUS)
    {
    {
      /* The fact that X is canonicalized means that this
      /* The fact that X is canonicalized means that this
         PLUS rtx is canonicalized.  */
         PLUS rtx is canonicalized.  */
      rtx x0 = XEXP (x, 0);
      rtx x0 = XEXP (x, 0);
      rtx x1 = XEXP (x, 1);
      rtx x1 = XEXP (x, 1);
 
 
      if (GET_CODE (y) == PLUS)
      if (GET_CODE (y) == PLUS)
        {
        {
          /* The fact that Y is canonicalized means that this
          /* The fact that Y is canonicalized means that this
             PLUS rtx is canonicalized.  */
             PLUS rtx is canonicalized.  */
          rtx y0 = XEXP (y, 0);
          rtx y0 = XEXP (y, 0);
          rtx y1 = XEXP (y, 1);
          rtx y1 = XEXP (y, 1);
 
 
          if (rtx_equal_for_memref_p (x1, y1))
          if (rtx_equal_for_memref_p (x1, y1))
            return memrefs_conflict_p (xsize, x0, ysize, y0, c);
            return memrefs_conflict_p (xsize, x0, ysize, y0, c);
          if (rtx_equal_for_memref_p (x0, y0))
          if (rtx_equal_for_memref_p (x0, y0))
            return memrefs_conflict_p (xsize, x1, ysize, y1, c);
            return memrefs_conflict_p (xsize, x1, ysize, y1, c);
          if (CONST_INT_P (x1))
          if (CONST_INT_P (x1))
            {
            {
              if (CONST_INT_P (y1))
              if (CONST_INT_P (y1))
                return memrefs_conflict_p (xsize, x0, ysize, y0,
                return memrefs_conflict_p (xsize, x0, ysize, y0,
                                           c - INTVAL (x1) + INTVAL (y1));
                                           c - INTVAL (x1) + INTVAL (y1));
              else
              else
                return memrefs_conflict_p (xsize, x0, ysize, y,
                return memrefs_conflict_p (xsize, x0, ysize, y,
                                           c - INTVAL (x1));
                                           c - INTVAL (x1));
            }
            }
          else if (CONST_INT_P (y1))
          else if (CONST_INT_P (y1))
            return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
            return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
 
 
          return -1;
          return -1;
        }
        }
      else if (CONST_INT_P (x1))
      else if (CONST_INT_P (x1))
        return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1));
        return memrefs_conflict_p (xsize, x0, ysize, y, c - INTVAL (x1));
    }
    }
  else if (GET_CODE (y) == PLUS)
  else if (GET_CODE (y) == PLUS)
    {
    {
      /* The fact that Y is canonicalized means that this
      /* The fact that Y is canonicalized means that this
         PLUS rtx is canonicalized.  */
         PLUS rtx is canonicalized.  */
      rtx y0 = XEXP (y, 0);
      rtx y0 = XEXP (y, 0);
      rtx y1 = XEXP (y, 1);
      rtx y1 = XEXP (y, 1);
 
 
      if (CONST_INT_P (y1))
      if (CONST_INT_P (y1))
        return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
        return memrefs_conflict_p (xsize, x, ysize, y0, c + INTVAL (y1));
      else
      else
        return -1;
        return -1;
    }
    }
 
 
  if (GET_CODE (x) == GET_CODE (y))
  if (GET_CODE (x) == GET_CODE (y))
    switch (GET_CODE (x))
    switch (GET_CODE (x))
      {
      {
      case MULT:
      case MULT:
        {
        {
          /* Handle cases where we expect the second operands to be the
          /* Handle cases where we expect the second operands to be the
             same, and check only whether the first operand would conflict
             same, and check only whether the first operand would conflict
             or not.  */
             or not.  */
          rtx x0, y0;
          rtx x0, y0;
          rtx x1 = canon_rtx (XEXP (x, 1));
          rtx x1 = canon_rtx (XEXP (x, 1));
          rtx y1 = canon_rtx (XEXP (y, 1));
          rtx y1 = canon_rtx (XEXP (y, 1));
          if (! rtx_equal_for_memref_p (x1, y1))
          if (! rtx_equal_for_memref_p (x1, y1))
            return -1;
            return -1;
          x0 = canon_rtx (XEXP (x, 0));
          x0 = canon_rtx (XEXP (x, 0));
          y0 = canon_rtx (XEXP (y, 0));
          y0 = canon_rtx (XEXP (y, 0));
          if (rtx_equal_for_memref_p (x0, y0))
          if (rtx_equal_for_memref_p (x0, y0))
            return (xsize == 0 || ysize == 0
            return (xsize == 0 || ysize == 0
                    || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
                    || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
 
 
          /* Can't properly adjust our sizes.  */
          /* Can't properly adjust our sizes.  */
          if (!CONST_INT_P (x1))
          if (!CONST_INT_P (x1))
            return -1;
            return -1;
          xsize /= INTVAL (x1);
          xsize /= INTVAL (x1);
          ysize /= INTVAL (x1);
          ysize /= INTVAL (x1);
          c /= INTVAL (x1);
          c /= INTVAL (x1);
          return memrefs_conflict_p (xsize, x0, ysize, y0, c);
          return memrefs_conflict_p (xsize, x0, ysize, y0, c);
        }
        }
 
 
      default:
      default:
        break;
        break;
      }
      }
 
 
  /* Treat an access through an AND (e.g. a subword access on an Alpha)
  /* Treat an access through an AND (e.g. a subword access on an Alpha)
     as an access with indeterminate size.  Assume that references
     as an access with indeterminate size.  Assume that references
     besides AND are aligned, so if the size of the other reference is
     besides AND are aligned, so if the size of the other reference is
     at least as large as the alignment, assume no other overlap.  */
     at least as large as the alignment, assume no other overlap.  */
  if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1)))
  if (GET_CODE (x) == AND && CONST_INT_P (XEXP (x, 1)))
    {
    {
      if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
      if (GET_CODE (y) == AND || ysize < -INTVAL (XEXP (x, 1)))
        xsize = -1;
        xsize = -1;
      return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c);
      return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)), ysize, y, c);
    }
    }
  if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1)))
  if (GET_CODE (y) == AND && CONST_INT_P (XEXP (y, 1)))
    {
    {
      /* ??? If we are indexing far enough into the array/structure, we
      /* ??? If we are indexing far enough into the array/structure, we
         may yet be able to determine that we can not overlap.  But we
         may yet be able to determine that we can not overlap.  But we
         also need to that we are far enough from the end not to overlap
         also need to that we are far enough from the end not to overlap
         a following reference, so we do nothing with that for now.  */
         a following reference, so we do nothing with that for now.  */
      if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1)))
      if (GET_CODE (x) == AND || xsize < -INTVAL (XEXP (y, 1)))
        ysize = -1;
        ysize = -1;
      return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c);
      return memrefs_conflict_p (xsize, x, ysize, canon_rtx (XEXP (y, 0)), c);
    }
    }
 
 
  if (CONSTANT_P (x))
  if (CONSTANT_P (x))
    {
    {
      if (CONST_INT_P (x) && CONST_INT_P (y))
      if (CONST_INT_P (x) && CONST_INT_P (y))
        {
        {
          c += (INTVAL (y) - INTVAL (x));
          c += (INTVAL (y) - INTVAL (x));
          return (xsize <= 0 || ysize <= 0
          return (xsize <= 0 || ysize <= 0
                  || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
                  || (c >= 0 && xsize > c) || (c < 0 && ysize+c > 0));
        }
        }
 
 
      if (GET_CODE (x) == CONST)
      if (GET_CODE (x) == CONST)
        {
        {
          if (GET_CODE (y) == CONST)
          if (GET_CODE (y) == CONST)
            return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
            return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
                                       ysize, canon_rtx (XEXP (y, 0)), c);
                                       ysize, canon_rtx (XEXP (y, 0)), c);
          else
          else
            return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
            return memrefs_conflict_p (xsize, canon_rtx (XEXP (x, 0)),
                                       ysize, y, c);
                                       ysize, y, c);
        }
        }
      if (GET_CODE (y) == CONST)
      if (GET_CODE (y) == CONST)
        return memrefs_conflict_p (xsize, x, ysize,
        return memrefs_conflict_p (xsize, x, ysize,
                                   canon_rtx (XEXP (y, 0)), c);
                                   canon_rtx (XEXP (y, 0)), c);
 
 
      if (CONSTANT_P (y))
      if (CONSTANT_P (y))
        return (xsize <= 0 || ysize <= 0
        return (xsize <= 0 || ysize <= 0
                || (rtx_equal_for_memref_p (x, y)
                || (rtx_equal_for_memref_p (x, y)
                    && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0))));
                    && ((c >= 0 && xsize > c) || (c < 0 && ysize+c > 0))));
 
 
      return -1;
      return -1;
    }
    }
 
 
  return -1;
  return -1;
}
}
 
 
/* Functions to compute memory dependencies.
/* Functions to compute memory dependencies.
 
 
   Since we process the insns in execution order, we can build tables
   Since we process the insns in execution order, we can build tables
   to keep track of what registers are fixed (and not aliased), what registers
   to keep track of what registers are fixed (and not aliased), what registers
   are varying in known ways, and what registers are varying in unknown
   are varying in known ways, and what registers are varying in unknown
   ways.
   ways.
 
 
   If both memory references are volatile, then there must always be a
   If both memory references are volatile, then there must always be a
   dependence between the two references, since their order can not be
   dependence between the two references, since their order can not be
   changed.  A volatile and non-volatile reference can be interchanged
   changed.  A volatile and non-volatile reference can be interchanged
   though.
   though.
 
 
   A MEM_IN_STRUCT reference at a non-AND varying address can never
   A MEM_IN_STRUCT reference at a non-AND varying address can never
   conflict with a non-MEM_IN_STRUCT reference at a fixed address.  We
   conflict with a non-MEM_IN_STRUCT reference at a fixed address.  We
   also must allow AND addresses, because they may generate accesses
   also must allow AND addresses, because they may generate accesses
   outside the object being referenced.  This is used to generate
   outside the object being referenced.  This is used to generate
   aligned addresses from unaligned addresses, for instance, the alpha
   aligned addresses from unaligned addresses, for instance, the alpha
   storeqi_unaligned pattern.  */
   storeqi_unaligned pattern.  */
 
 
/* Read dependence: X is read after read in MEM takes place.  There can
/* Read dependence: X is read after read in MEM takes place.  There can
   only be a dependence here if both reads are volatile.  */
   only be a dependence here if both reads are volatile.  */
 
 
int
int
read_dependence (const_rtx mem, const_rtx x)
read_dependence (const_rtx mem, const_rtx x)
{
{
  return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem);
  return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem);
}
}
 
 
/* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and
/* Returns MEM1 if and only if MEM1 is a scalar at a fixed address and
   MEM2 is a reference to a structure at a varying address, or returns
   MEM2 is a reference to a structure at a varying address, or returns
   MEM2 if vice versa.  Otherwise, returns NULL_RTX.  If a non-NULL
   MEM2 if vice versa.  Otherwise, returns NULL_RTX.  If a non-NULL
   value is returned MEM1 and MEM2 can never alias.  VARIES_P is used
   value is returned MEM1 and MEM2 can never alias.  VARIES_P is used
   to decide whether or not an address may vary; it should return
   to decide whether or not an address may vary; it should return
   nonzero whenever variation is possible.
   nonzero whenever variation is possible.
   MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2.  */
   MEM1_ADDR and MEM2_ADDR are the addresses of MEM1 and MEM2.  */
 
 
static const_rtx
static const_rtx
fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr,
fixed_scalar_and_varying_struct_p (const_rtx mem1, const_rtx mem2, rtx mem1_addr,
                                   rtx mem2_addr,
                                   rtx mem2_addr,
                                   bool (*varies_p) (const_rtx, bool))
                                   bool (*varies_p) (const_rtx, bool))
{
{
  if (! flag_strict_aliasing)
  if (! flag_strict_aliasing)
    return NULL_RTX;
    return NULL_RTX;
 
 
  if (MEM_ALIAS_SET (mem2)
  if (MEM_ALIAS_SET (mem2)
      && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2)
      && MEM_SCALAR_P (mem1) && MEM_IN_STRUCT_P (mem2)
      && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1))
      && !varies_p (mem1_addr, 1) && varies_p (mem2_addr, 1))
    /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a
    /* MEM1 is a scalar at a fixed address; MEM2 is a struct at a
       varying address.  */
       varying address.  */
    return mem1;
    return mem1;
 
 
  if (MEM_ALIAS_SET (mem1)
  if (MEM_ALIAS_SET (mem1)
      && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2)
      && MEM_IN_STRUCT_P (mem1) && MEM_SCALAR_P (mem2)
      && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1))
      && varies_p (mem1_addr, 1) && !varies_p (mem2_addr, 1))
    /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a
    /* MEM2 is a scalar at a fixed address; MEM1 is a struct at a
       varying address.  */
       varying address.  */
    return mem2;
    return mem2;
 
 
  return NULL_RTX;
  return NULL_RTX;
}
}
 
 
/* Returns nonzero if something about the mode or address format MEM1
/* Returns nonzero if something about the mode or address format MEM1
   indicates that it might well alias *anything*.  */
   indicates that it might well alias *anything*.  */
 
 
static int
static int
aliases_everything_p (const_rtx mem)
aliases_everything_p (const_rtx mem)
{
{
  if (GET_CODE (XEXP (mem, 0)) == AND)
  if (GET_CODE (XEXP (mem, 0)) == AND)
    /* If the address is an AND, it's very hard to know at what it is
    /* If the address is an AND, it's very hard to know at what it is
       actually pointing.  */
       actually pointing.  */
    return 1;
    return 1;
 
 
  return 0;
  return 0;
}
}
 
 
/* Return true if we can determine that the fields referenced cannot
/* Return true if we can determine that the fields referenced cannot
   overlap for any pair of objects.  */
   overlap for any pair of objects.  */
 
 
static bool
static bool
nonoverlapping_component_refs_p (const_tree x, const_tree y)
nonoverlapping_component_refs_p (const_tree x, const_tree y)
{
{
  const_tree fieldx, fieldy, typex, typey, orig_y;
  const_tree fieldx, fieldy, typex, typey, orig_y;
 
 
  if (!flag_strict_aliasing)
  if (!flag_strict_aliasing)
    return false;
    return false;
 
 
  do
  do
    {
    {
      /* The comparison has to be done at a common type, since we don't
      /* The comparison has to be done at a common type, since we don't
         know how the inheritance hierarchy works.  */
         know how the inheritance hierarchy works.  */
      orig_y = y;
      orig_y = y;
      do
      do
        {
        {
          fieldx = TREE_OPERAND (x, 1);
          fieldx = TREE_OPERAND (x, 1);
          typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx));
          typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx));
 
 
          y = orig_y;
          y = orig_y;
          do
          do
            {
            {
              fieldy = TREE_OPERAND (y, 1);
              fieldy = TREE_OPERAND (y, 1);
              typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy));
              typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy));
 
 
              if (typex == typey)
              if (typex == typey)
                goto found;
                goto found;
 
 
              y = TREE_OPERAND (y, 0);
              y = TREE_OPERAND (y, 0);
            }
            }
          while (y && TREE_CODE (y) == COMPONENT_REF);
          while (y && TREE_CODE (y) == COMPONENT_REF);
 
 
          x = TREE_OPERAND (x, 0);
          x = TREE_OPERAND (x, 0);
        }
        }
      while (x && TREE_CODE (x) == COMPONENT_REF);
      while (x && TREE_CODE (x) == COMPONENT_REF);
      /* Never found a common type.  */
      /* Never found a common type.  */
      return false;
      return false;
 
 
    found:
    found:
      /* If we're left with accessing different fields of a structure,
      /* If we're left with accessing different fields of a structure,
         then no overlap.  */
         then no overlap.  */
      if (TREE_CODE (typex) == RECORD_TYPE
      if (TREE_CODE (typex) == RECORD_TYPE
          && fieldx != fieldy)
          && fieldx != fieldy)
        return true;
        return true;
 
 
      /* The comparison on the current field failed.  If we're accessing
      /* The comparison on the current field failed.  If we're accessing
         a very nested structure, look at the next outer level.  */
         a very nested structure, look at the next outer level.  */
      x = TREE_OPERAND (x, 0);
      x = TREE_OPERAND (x, 0);
      y = TREE_OPERAND (y, 0);
      y = TREE_OPERAND (y, 0);
    }
    }
  while (x && y
  while (x && y
         && TREE_CODE (x) == COMPONENT_REF
         && TREE_CODE (x) == COMPONENT_REF
         && TREE_CODE (y) == COMPONENT_REF);
         && TREE_CODE (y) == COMPONENT_REF);
 
 
  return false;
  return false;
}
}
 
 
/* Look at the bottom of the COMPONENT_REF list for a DECL, and return it.  */
/* Look at the bottom of the COMPONENT_REF list for a DECL, and return it.  */
 
 
static tree
static tree
decl_for_component_ref (tree x)
decl_for_component_ref (tree x)
{
{
  do
  do
    {
    {
      x = TREE_OPERAND (x, 0);
      x = TREE_OPERAND (x, 0);
    }
    }
  while (x && TREE_CODE (x) == COMPONENT_REF);
  while (x && TREE_CODE (x) == COMPONENT_REF);
 
 
  return x && DECL_P (x) ? x : NULL_TREE;
  return x && DECL_P (x) ? x : NULL_TREE;
}
}
 
 
/* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the
/* Walk up the COMPONENT_REF list and adjust OFFSET to compensate for the
   offset of the field reference.  */
   offset of the field reference.  */
 
 
static rtx
static rtx
adjust_offset_for_component_ref (tree x, rtx offset)
adjust_offset_for_component_ref (tree x, rtx offset)
{
{
  HOST_WIDE_INT ioffset;
  HOST_WIDE_INT ioffset;
 
 
  if (! offset)
  if (! offset)
    return NULL_RTX;
    return NULL_RTX;
 
 
  ioffset = INTVAL (offset);
  ioffset = INTVAL (offset);
  do
  do
    {
    {
      tree offset = component_ref_field_offset (x);
      tree offset = component_ref_field_offset (x);
      tree field = TREE_OPERAND (x, 1);
      tree field = TREE_OPERAND (x, 1);
 
 
      if (! host_integerp (offset, 1))
      if (! host_integerp (offset, 1))
        return NULL_RTX;
        return NULL_RTX;
      ioffset += (tree_low_cst (offset, 1)
      ioffset += (tree_low_cst (offset, 1)
                  + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
                  + (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
                     / BITS_PER_UNIT));
                     / BITS_PER_UNIT));
 
 
      x = TREE_OPERAND (x, 0);
      x = TREE_OPERAND (x, 0);
    }
    }
  while (x && TREE_CODE (x) == COMPONENT_REF);
  while (x && TREE_CODE (x) == COMPONENT_REF);
 
 
  return GEN_INT (ioffset);
  return GEN_INT (ioffset);
}
}
 
 
/* Return nonzero if we can determine the exprs corresponding to memrefs
/* Return nonzero if we can determine the exprs corresponding to memrefs
   X and Y and they do not overlap.  */
   X and Y and they do not overlap.  */
 
 
int
int
nonoverlapping_memrefs_p (const_rtx x, const_rtx y)
nonoverlapping_memrefs_p (const_rtx x, const_rtx y)
{
{
  tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
  tree exprx = MEM_EXPR (x), expry = MEM_EXPR (y);
  rtx rtlx, rtly;
  rtx rtlx, rtly;
  rtx basex, basey;
  rtx basex, basey;
  rtx moffsetx, moffsety;
  rtx moffsetx, moffsety;
  HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem;
  HOST_WIDE_INT offsetx = 0, offsety = 0, sizex, sizey, tem;
 
 
  /* Unless both have exprs, we can't tell anything.  */
  /* Unless both have exprs, we can't tell anything.  */
  if (exprx == 0 || expry == 0)
  if (exprx == 0 || expry == 0)
    return 0;
    return 0;
 
 
  /* For spill-slot accesses make sure we have valid offsets.  */
  /* For spill-slot accesses make sure we have valid offsets.  */
  if ((exprx == get_spill_slot_decl (false)
  if ((exprx == get_spill_slot_decl (false)
       && ! MEM_OFFSET (x))
       && ! MEM_OFFSET (x))
      || (expry == get_spill_slot_decl (false)
      || (expry == get_spill_slot_decl (false)
          && ! MEM_OFFSET (y)))
          && ! MEM_OFFSET (y)))
    return 0;
    return 0;
 
 
  /* If both are field references, we may be able to determine something.  */
  /* If both are field references, we may be able to determine something.  */
  if (TREE_CODE (exprx) == COMPONENT_REF
  if (TREE_CODE (exprx) == COMPONENT_REF
      && TREE_CODE (expry) == COMPONENT_REF
      && TREE_CODE (expry) == COMPONENT_REF
      && nonoverlapping_component_refs_p (exprx, expry))
      && nonoverlapping_component_refs_p (exprx, expry))
    return 1;
    return 1;
 
 
 
 
  /* If the field reference test failed, look at the DECLs involved.  */
  /* If the field reference test failed, look at the DECLs involved.  */
  moffsetx = MEM_OFFSET (x);
  moffsetx = MEM_OFFSET (x);
  if (TREE_CODE (exprx) == COMPONENT_REF)
  if (TREE_CODE (exprx) == COMPONENT_REF)
    {
    {
      if (TREE_CODE (expry) == VAR_DECL
      if (TREE_CODE (expry) == VAR_DECL
          && POINTER_TYPE_P (TREE_TYPE (expry)))
          && POINTER_TYPE_P (TREE_TYPE (expry)))
        {
        {
         tree field = TREE_OPERAND (exprx, 1);
         tree field = TREE_OPERAND (exprx, 1);
         tree fieldcontext = DECL_FIELD_CONTEXT (field);
         tree fieldcontext = DECL_FIELD_CONTEXT (field);
         if (ipa_type_escape_field_does_not_clobber_p (fieldcontext,
         if (ipa_type_escape_field_does_not_clobber_p (fieldcontext,
                                                       TREE_TYPE (field)))
                                                       TREE_TYPE (field)))
           return 1;
           return 1;
        }
        }
      {
      {
        tree t = decl_for_component_ref (exprx);
        tree t = decl_for_component_ref (exprx);
        if (! t)
        if (! t)
          return 0;
          return 0;
        moffsetx = adjust_offset_for_component_ref (exprx, moffsetx);
        moffsetx = adjust_offset_for_component_ref (exprx, moffsetx);
        exprx = t;
        exprx = t;
      }
      }
    }
    }
  else if (INDIRECT_REF_P (exprx))
  else if (INDIRECT_REF_P (exprx))
    {
    {
      exprx = TREE_OPERAND (exprx, 0);
      exprx = TREE_OPERAND (exprx, 0);
      if (flag_argument_noalias < 2
      if (flag_argument_noalias < 2
          || TREE_CODE (exprx) != PARM_DECL)
          || TREE_CODE (exprx) != PARM_DECL)
        return 0;
        return 0;
    }
    }
 
 
  moffsety = MEM_OFFSET (y);
  moffsety = MEM_OFFSET (y);
  if (TREE_CODE (expry) == COMPONENT_REF)
  if (TREE_CODE (expry) == COMPONENT_REF)
    {
    {
      if (TREE_CODE (exprx) == VAR_DECL
      if (TREE_CODE (exprx) == VAR_DECL
          && POINTER_TYPE_P (TREE_TYPE (exprx)))
          && POINTER_TYPE_P (TREE_TYPE (exprx)))
        {
        {
         tree field = TREE_OPERAND (expry, 1);
         tree field = TREE_OPERAND (expry, 1);
         tree fieldcontext = DECL_FIELD_CONTEXT (field);
         tree fieldcontext = DECL_FIELD_CONTEXT (field);
         if (ipa_type_escape_field_does_not_clobber_p (fieldcontext,
         if (ipa_type_escape_field_does_not_clobber_p (fieldcontext,
                                                       TREE_TYPE (field)))
                                                       TREE_TYPE (field)))
           return 1;
           return 1;
        }
        }
      {
      {
        tree t = decl_for_component_ref (expry);
        tree t = decl_for_component_ref (expry);
        if (! t)
        if (! t)
          return 0;
          return 0;
        moffsety = adjust_offset_for_component_ref (expry, moffsety);
        moffsety = adjust_offset_for_component_ref (expry, moffsety);
        expry = t;
        expry = t;
      }
      }
    }
    }
  else if (INDIRECT_REF_P (expry))
  else if (INDIRECT_REF_P (expry))
    {
    {
      expry = TREE_OPERAND (expry, 0);
      expry = TREE_OPERAND (expry, 0);
      if (flag_argument_noalias < 2
      if (flag_argument_noalias < 2
          || TREE_CODE (expry) != PARM_DECL)
          || TREE_CODE (expry) != PARM_DECL)
        return 0;
        return 0;
    }
    }
 
 
  if (! DECL_P (exprx) || ! DECL_P (expry))
  if (! DECL_P (exprx) || ! DECL_P (expry))
    return 0;
    return 0;
 
 
  /* With invalid code we can end up storing into the constant pool.
  /* With invalid code we can end up storing into the constant pool.
     Bail out to avoid ICEing when creating RTL for this.
     Bail out to avoid ICEing when creating RTL for this.
     See gfortran.dg/lto/20091028-2_0.f90.  */
     See gfortran.dg/lto/20091028-2_0.f90.  */
  if (TREE_CODE (exprx) == CONST_DECL
  if (TREE_CODE (exprx) == CONST_DECL
      || TREE_CODE (expry) == CONST_DECL)
      || TREE_CODE (expry) == CONST_DECL)
    return 1;
    return 1;
 
 
  rtlx = DECL_RTL (exprx);
  rtlx = DECL_RTL (exprx);
  rtly = DECL_RTL (expry);
  rtly = DECL_RTL (expry);
 
 
  /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they
  /* If either RTL is not a MEM, it must be a REG or CONCAT, meaning they
     can't overlap unless they are the same because we never reuse that part
     can't overlap unless they are the same because we never reuse that part
     of the stack frame used for locals for spilled pseudos.  */
     of the stack frame used for locals for spilled pseudos.  */
  if ((!MEM_P (rtlx) || !MEM_P (rtly))
  if ((!MEM_P (rtlx) || !MEM_P (rtly))
      && ! rtx_equal_p (rtlx, rtly))
      && ! rtx_equal_p (rtlx, rtly))
    return 1;
    return 1;
 
 
  /* If we have MEMs refering to different address spaces (which can
  /* If we have MEMs refering to different address spaces (which can
     potentially overlap), we cannot easily tell from the addresses
     potentially overlap), we cannot easily tell from the addresses
     whether the references overlap.  */
     whether the references overlap.  */
  if (MEM_P (rtlx) && MEM_P (rtly)
  if (MEM_P (rtlx) && MEM_P (rtly)
      && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly))
      && MEM_ADDR_SPACE (rtlx) != MEM_ADDR_SPACE (rtly))
    return 0;
    return 0;
 
 
  /* Get the base and offsets of both decls.  If either is a register, we
  /* Get the base and offsets of both decls.  If either is a register, we
     know both are and are the same, so use that as the base.  The only
     know both are and are the same, so use that as the base.  The only
     we can avoid overlap is if we can deduce that they are nonoverlapping
     we can avoid overlap is if we can deduce that they are nonoverlapping
     pieces of that decl, which is very rare.  */
     pieces of that decl, which is very rare.  */
  basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx;
  basex = MEM_P (rtlx) ? XEXP (rtlx, 0) : rtlx;
  if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1)))
  if (GET_CODE (basex) == PLUS && CONST_INT_P (XEXP (basex, 1)))
    offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0);
    offsetx = INTVAL (XEXP (basex, 1)), basex = XEXP (basex, 0);
 
 
  basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly;
  basey = MEM_P (rtly) ? XEXP (rtly, 0) : rtly;
  if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1)))
  if (GET_CODE (basey) == PLUS && CONST_INT_P (XEXP (basey, 1)))
    offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0);
    offsety = INTVAL (XEXP (basey, 1)), basey = XEXP (basey, 0);
 
 
  /* If the bases are different, we know they do not overlap if both
  /* If the bases are different, we know they do not overlap if both
     are constants or if one is a constant and the other a pointer into the
     are constants or if one is a constant and the other a pointer into the
     stack frame.  Otherwise a different base means we can't tell if they
     stack frame.  Otherwise a different base means we can't tell if they
     overlap or not.  */
     overlap or not.  */
  if (! rtx_equal_p (basex, basey))
  if (! rtx_equal_p (basex, basey))
    return ((CONSTANT_P (basex) && CONSTANT_P (basey))
    return ((CONSTANT_P (basex) && CONSTANT_P (basey))
            || (CONSTANT_P (basex) && REG_P (basey)
            || (CONSTANT_P (basex) && REG_P (basey)
                && REGNO_PTR_FRAME_P (REGNO (basey)))
                && REGNO_PTR_FRAME_P (REGNO (basey)))
            || (CONSTANT_P (basey) && REG_P (basex)
            || (CONSTANT_P (basey) && REG_P (basex)
                && REGNO_PTR_FRAME_P (REGNO (basex))));
                && REGNO_PTR_FRAME_P (REGNO (basex))));
 
 
  sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx))
  sizex = (!MEM_P (rtlx) ? (int) GET_MODE_SIZE (GET_MODE (rtlx))
           : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx))
           : MEM_SIZE (rtlx) ? INTVAL (MEM_SIZE (rtlx))
           : -1);
           : -1);
  sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly))
  sizey = (!MEM_P (rtly) ? (int) GET_MODE_SIZE (GET_MODE (rtly))
           : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) :
           : MEM_SIZE (rtly) ? INTVAL (MEM_SIZE (rtly)) :
           -1);
           -1);
 
 
  /* If we have an offset for either memref, it can update the values computed
  /* If we have an offset for either memref, it can update the values computed
     above.  */
     above.  */
  if (moffsetx)
  if (moffsetx)
    offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx);
    offsetx += INTVAL (moffsetx), sizex -= INTVAL (moffsetx);
  if (moffsety)
  if (moffsety)
    offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety);
    offsety += INTVAL (moffsety), sizey -= INTVAL (moffsety);
 
 
  /* If a memref has both a size and an offset, we can use the smaller size.
  /* If a memref has both a size and an offset, we can use the smaller size.
     We can't do this if the offset isn't known because we must view this
     We can't do this if the offset isn't known because we must view this
     memref as being anywhere inside the DECL's MEM.  */
     memref as being anywhere inside the DECL's MEM.  */
  if (MEM_SIZE (x) && moffsetx)
  if (MEM_SIZE (x) && moffsetx)
    sizex = INTVAL (MEM_SIZE (x));
    sizex = INTVAL (MEM_SIZE (x));
  if (MEM_SIZE (y) && moffsety)
  if (MEM_SIZE (y) && moffsety)
    sizey = INTVAL (MEM_SIZE (y));
    sizey = INTVAL (MEM_SIZE (y));
 
 
  /* Put the values of the memref with the lower offset in X's values.  */
  /* Put the values of the memref with the lower offset in X's values.  */
  if (offsetx > offsety)
  if (offsetx > offsety)
    {
    {
      tem = offsetx, offsetx = offsety, offsety = tem;
      tem = offsetx, offsetx = offsety, offsety = tem;
      tem = sizex, sizex = sizey, sizey = tem;
      tem = sizex, sizex = sizey, sizey = tem;
    }
    }
 
 
  /* If we don't know the size of the lower-offset value, we can't tell
  /* If we don't know the size of the lower-offset value, we can't tell
     if they conflict.  Otherwise, we do the test.  */
     if they conflict.  Otherwise, we do the test.  */
  return sizex >= 0 && offsety >= offsetx + sizex;
  return sizex >= 0 && offsety >= offsetx + sizex;
}
}
 
 
/* True dependence: X is read after store in MEM takes place.  */
/* True dependence: X is read after store in MEM takes place.  */
 
 
int
int
true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x,
true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x,
                 bool (*varies) (const_rtx, bool))
                 bool (*varies) (const_rtx, bool))
{
{
  rtx x_addr, mem_addr;
  rtx x_addr, mem_addr;
  rtx base;
  rtx base;
  int ret;
  int ret;
 
 
  if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
  if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
    return 1;
    return 1;
 
 
  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
     This is used in epilogue deallocation functions, and in cselib.  */
     This is used in epilogue deallocation functions, and in cselib.  */
  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
    return 1;
    return 1;
  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
    return 1;
    return 1;
  if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
  if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
      || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
      || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
    return 1;
    return 1;
 
 
  /* Read-only memory is by definition never modified, and therefore can't
  /* Read-only memory is by definition never modified, and therefore can't
     conflict with anything.  We don't expect to find read-only set on MEM,
     conflict with anything.  We don't expect to find read-only set on MEM,
     but stupid user tricks can produce them, so don't die.  */
     but stupid user tricks can produce them, so don't die.  */
  if (MEM_READONLY_P (x))
  if (MEM_READONLY_P (x))
    return 0;
    return 0;
 
 
  /* If we have MEMs refering to different address spaces (which can
  /* If we have MEMs refering to different address spaces (which can
     potentially overlap), we cannot easily tell from the addresses
     potentially overlap), we cannot easily tell from the addresses
     whether the references overlap.  */
     whether the references overlap.  */
  if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
  if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
    return 1;
    return 1;
 
 
  if (mem_mode == VOIDmode)
  if (mem_mode == VOIDmode)
    mem_mode = GET_MODE (mem);
    mem_mode = GET_MODE (mem);
 
 
  x_addr = XEXP (x, 0);
  x_addr = XEXP (x, 0);
  mem_addr = XEXP (mem, 0);
  mem_addr = XEXP (mem, 0);
  if (!((GET_CODE (x_addr) == VALUE
  if (!((GET_CODE (x_addr) == VALUE
         && GET_CODE (mem_addr) != VALUE
         && GET_CODE (mem_addr) != VALUE
         && reg_mentioned_p (x_addr, mem_addr))
         && reg_mentioned_p (x_addr, mem_addr))
        || (GET_CODE (x_addr) != VALUE
        || (GET_CODE (x_addr) != VALUE
            && GET_CODE (mem_addr) == VALUE
            && GET_CODE (mem_addr) == VALUE
            && reg_mentioned_p (mem_addr, x_addr))))
            && reg_mentioned_p (mem_addr, x_addr))))
    {
    {
      x_addr = get_addr (x_addr);
      x_addr = get_addr (x_addr);
      mem_addr = get_addr (mem_addr);
      mem_addr = get_addr (mem_addr);
    }
    }
 
 
  base = find_base_term (x_addr);
  base = find_base_term (x_addr);
  if (base && (GET_CODE (base) == LABEL_REF
  if (base && (GET_CODE (base) == LABEL_REF
               || (GET_CODE (base) == SYMBOL_REF
               || (GET_CODE (base) == SYMBOL_REF
                   && CONSTANT_POOL_ADDRESS_P (base))))
                   && CONSTANT_POOL_ADDRESS_P (base))))
    return 0;
    return 0;
 
 
  if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
  if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
    return 0;
    return 0;
 
 
  x_addr = canon_rtx (x_addr);
  x_addr = canon_rtx (x_addr);
  mem_addr = canon_rtx (mem_addr);
  mem_addr = canon_rtx (mem_addr);
 
 
  if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
  if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
                                 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
                                 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
    return ret;
    return ret;
 
 
  if (DIFFERENT_ALIAS_SETS_P (x, mem))
  if (DIFFERENT_ALIAS_SETS_P (x, mem))
    return 0;
    return 0;
 
 
  if (nonoverlapping_memrefs_p (mem, x))
  if (nonoverlapping_memrefs_p (mem, x))
    return 0;
    return 0;
 
 
  if (aliases_everything_p (x))
  if (aliases_everything_p (x))
    return 1;
    return 1;
 
 
  /* We cannot use aliases_everything_p to test MEM, since we must look
  /* We cannot use aliases_everything_p to test MEM, since we must look
     at MEM_MODE, rather than GET_MODE (MEM).  */
     at MEM_MODE, rather than GET_MODE (MEM).  */
  if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
  if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
    return 1;
    return 1;
 
 
  /* In true_dependence we also allow BLKmode to alias anything.  Why
  /* In true_dependence we also allow BLKmode to alias anything.  Why
     don't we do this in anti_dependence and output_dependence?  */
     don't we do this in anti_dependence and output_dependence?  */
  if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
  if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
    return 1;
    return 1;
 
 
  if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
  if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
    return 0;
    return 0;
 
 
  return rtx_refs_may_alias_p (x, mem, true);
  return rtx_refs_may_alias_p (x, mem, true);
}
}
 
 
/* Canonical true dependence: X is read after store in MEM takes place.
/* Canonical true dependence: X is read after store in MEM takes place.
   Variant of true_dependence which assumes MEM has already been
   Variant of true_dependence which assumes MEM has already been
   canonicalized (hence we no longer do that here).
   canonicalized (hence we no longer do that here).
   The mem_addr argument has been added, since true_dependence computed
   The mem_addr argument has been added, since true_dependence computed
   this value prior to canonicalizing.
   this value prior to canonicalizing.
   If x_addr is non-NULL, it is used in preference of XEXP (x, 0).  */
   If x_addr is non-NULL, it is used in preference of XEXP (x, 0).  */
 
 
int
int
canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
                       const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool))
                       const_rtx x, rtx x_addr, bool (*varies) (const_rtx, bool))
{
{
  int ret;
  int ret;
 
 
  if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
  if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
    return 1;
    return 1;
 
 
  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
     This is used in epilogue deallocation functions.  */
     This is used in epilogue deallocation functions.  */
  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
    return 1;
    return 1;
  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
    return 1;
    return 1;
  if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
  if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
      || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
      || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
    return 1;
    return 1;
 
 
  /* Read-only memory is by definition never modified, and therefore can't
  /* Read-only memory is by definition never modified, and therefore can't
     conflict with anything.  We don't expect to find read-only set on MEM,
     conflict with anything.  We don't expect to find read-only set on MEM,
     but stupid user tricks can produce them, so don't die.  */
     but stupid user tricks can produce them, so don't die.  */
  if (MEM_READONLY_P (x))
  if (MEM_READONLY_P (x))
    return 0;
    return 0;
 
 
  /* If we have MEMs refering to different address spaces (which can
  /* If we have MEMs refering to different address spaces (which can
     potentially overlap), we cannot easily tell from the addresses
     potentially overlap), we cannot easily tell from the addresses
     whether the references overlap.  */
     whether the references overlap.  */
  if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
  if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
    return 1;
    return 1;
 
 
  if (! x_addr)
  if (! x_addr)
    {
    {
      x_addr = XEXP (x, 0);
      x_addr = XEXP (x, 0);
      if (!((GET_CODE (x_addr) == VALUE
      if (!((GET_CODE (x_addr) == VALUE
             && GET_CODE (mem_addr) != VALUE
             && GET_CODE (mem_addr) != VALUE
             && reg_mentioned_p (x_addr, mem_addr))
             && reg_mentioned_p (x_addr, mem_addr))
            || (GET_CODE (x_addr) != VALUE
            || (GET_CODE (x_addr) != VALUE
                && GET_CODE (mem_addr) == VALUE
                && GET_CODE (mem_addr) == VALUE
                && reg_mentioned_p (mem_addr, x_addr))))
                && reg_mentioned_p (mem_addr, x_addr))))
        x_addr = get_addr (x_addr);
        x_addr = get_addr (x_addr);
    }
    }
 
 
  if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
  if (! base_alias_check (x_addr, mem_addr, GET_MODE (x), mem_mode))
    return 0;
    return 0;
 
 
  x_addr = canon_rtx (x_addr);
  x_addr = canon_rtx (x_addr);
  if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
  if ((ret = memrefs_conflict_p (GET_MODE_SIZE (mem_mode), mem_addr,
                                 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
                                 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
    return ret;
    return ret;
 
 
  if (DIFFERENT_ALIAS_SETS_P (x, mem))
  if (DIFFERENT_ALIAS_SETS_P (x, mem))
    return 0;
    return 0;
 
 
  if (nonoverlapping_memrefs_p (x, mem))
  if (nonoverlapping_memrefs_p (x, mem))
    return 0;
    return 0;
 
 
  if (aliases_everything_p (x))
  if (aliases_everything_p (x))
    return 1;
    return 1;
 
 
  /* We cannot use aliases_everything_p to test MEM, since we must look
  /* We cannot use aliases_everything_p to test MEM, since we must look
     at MEM_MODE, rather than GET_MODE (MEM).  */
     at MEM_MODE, rather than GET_MODE (MEM).  */
  if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
  if (mem_mode == QImode || GET_CODE (mem_addr) == AND)
    return 1;
    return 1;
 
 
  /* In true_dependence we also allow BLKmode to alias anything.  Why
  /* In true_dependence we also allow BLKmode to alias anything.  Why
     don't we do this in anti_dependence and output_dependence?  */
     don't we do this in anti_dependence and output_dependence?  */
  if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
  if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
    return 1;
    return 1;
 
 
  if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
  if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies))
    return 0;
    return 0;
 
 
  return rtx_refs_may_alias_p (x, mem, true);
  return rtx_refs_may_alias_p (x, mem, true);
}
}
 
 
/* Returns nonzero if a write to X might alias a previous read from
/* Returns nonzero if a write to X might alias a previous read from
   (or, if WRITEP is nonzero, a write to) MEM.  */
   (or, if WRITEP is nonzero, a write to) MEM.  */
 
 
static int
static int
write_dependence_p (const_rtx mem, const_rtx x, int writep)
write_dependence_p (const_rtx mem, const_rtx x, int writep)
{
{
  rtx x_addr, mem_addr;
  rtx x_addr, mem_addr;
  const_rtx fixed_scalar;
  const_rtx fixed_scalar;
  rtx base;
  rtx base;
  int ret;
  int ret;
 
 
  if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
  if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
    return 1;
    return 1;
 
 
  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
     This is used in epilogue deallocation functions.  */
     This is used in epilogue deallocation functions.  */
  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
    return 1;
    return 1;
  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
    return 1;
    return 1;
  if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
  if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
      || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
      || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
    return 1;
    return 1;
 
 
  /* A read from read-only memory can't conflict with read-write memory.  */
  /* A read from read-only memory can't conflict with read-write memory.  */
  if (!writep && MEM_READONLY_P (mem))
  if (!writep && MEM_READONLY_P (mem))
    return 0;
    return 0;
 
 
  /* If we have MEMs refering to different address spaces (which can
  /* If we have MEMs refering to different address spaces (which can
     potentially overlap), we cannot easily tell from the addresses
     potentially overlap), we cannot easily tell from the addresses
     whether the references overlap.  */
     whether the references overlap.  */
  if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
  if (MEM_ADDR_SPACE (mem) != MEM_ADDR_SPACE (x))
    return 1;
    return 1;
 
 
  x_addr = XEXP (x, 0);
  x_addr = XEXP (x, 0);
  mem_addr = XEXP (mem, 0);
  mem_addr = XEXP (mem, 0);
  if (!((GET_CODE (x_addr) == VALUE
  if (!((GET_CODE (x_addr) == VALUE
         && GET_CODE (mem_addr) != VALUE
         && GET_CODE (mem_addr) != VALUE
         && reg_mentioned_p (x_addr, mem_addr))
         && reg_mentioned_p (x_addr, mem_addr))
        || (GET_CODE (x_addr) != VALUE
        || (GET_CODE (x_addr) != VALUE
            && GET_CODE (mem_addr) == VALUE
            && GET_CODE (mem_addr) == VALUE
            && reg_mentioned_p (mem_addr, x_addr))))
            && reg_mentioned_p (mem_addr, x_addr))))
    {
    {
      x_addr = get_addr (x_addr);
      x_addr = get_addr (x_addr);
      mem_addr = get_addr (mem_addr);
      mem_addr = get_addr (mem_addr);
    }
    }
 
 
  if (! writep)
  if (! writep)
    {
    {
      base = find_base_term (mem_addr);
      base = find_base_term (mem_addr);
      if (base && (GET_CODE (base) == LABEL_REF
      if (base && (GET_CODE (base) == LABEL_REF
                   || (GET_CODE (base) == SYMBOL_REF
                   || (GET_CODE (base) == SYMBOL_REF
                       && CONSTANT_POOL_ADDRESS_P (base))))
                       && CONSTANT_POOL_ADDRESS_P (base))))
        return 0;
        return 0;
    }
    }
 
 
  if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
  if (! base_alias_check (x_addr, mem_addr, GET_MODE (x),
                          GET_MODE (mem)))
                          GET_MODE (mem)))
    return 0;
    return 0;
 
 
  x_addr = canon_rtx (x_addr);
  x_addr = canon_rtx (x_addr);
  mem_addr = canon_rtx (mem_addr);
  mem_addr = canon_rtx (mem_addr);
 
 
  if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
  if ((ret = memrefs_conflict_p (SIZE_FOR_MODE (mem), mem_addr,
                                 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
                                 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
    return ret;
    return ret;
 
 
  if (nonoverlapping_memrefs_p (x, mem))
  if (nonoverlapping_memrefs_p (x, mem))
    return 0;
    return 0;
 
 
  fixed_scalar
  fixed_scalar
    = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
    = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr,
                                         rtx_addr_varies_p);
                                         rtx_addr_varies_p);
 
 
  if ((fixed_scalar == mem && !aliases_everything_p (x))
  if ((fixed_scalar == mem && !aliases_everything_p (x))
      || (fixed_scalar == x && !aliases_everything_p (mem)))
      || (fixed_scalar == x && !aliases_everything_p (mem)))
    return 0;
    return 0;
 
 
  return rtx_refs_may_alias_p (x, mem, false);
  return rtx_refs_may_alias_p (x, mem, false);
}
}
 
 
/* Anti dependence: X is written after read in MEM takes place.  */
/* Anti dependence: X is written after read in MEM takes place.  */
 
 
int
int
anti_dependence (const_rtx mem, const_rtx x)
anti_dependence (const_rtx mem, const_rtx x)
{
{
  return write_dependence_p (mem, x, /*writep=*/0);
  return write_dependence_p (mem, x, /*writep=*/0);
}
}
 
 
/* Output dependence: X is written after store in MEM takes place.  */
/* Output dependence: X is written after store in MEM takes place.  */
 
 
int
int
output_dependence (const_rtx mem, const_rtx x)
output_dependence (const_rtx mem, const_rtx x)
{
{
  return write_dependence_p (mem, x, /*writep=*/1);
  return write_dependence_p (mem, x, /*writep=*/1);
}
}


 
 
void
void
init_alias_target (void)
init_alias_target (void)
{
{
  int i;
  int i;
 
 
  memset (static_reg_base_value, 0, sizeof static_reg_base_value);
  memset (static_reg_base_value, 0, sizeof static_reg_base_value);
 
 
  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    /* Check whether this register can hold an incoming pointer
    /* Check whether this register can hold an incoming pointer
       argument.  FUNCTION_ARG_REGNO_P tests outgoing register
       argument.  FUNCTION_ARG_REGNO_P tests outgoing register
       numbers, so translate if necessary due to register windows.  */
       numbers, so translate if necessary due to register windows.  */
    if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i))
    if (FUNCTION_ARG_REGNO_P (OUTGOING_REGNO (i))
        && HARD_REGNO_MODE_OK (i, Pmode))
        && HARD_REGNO_MODE_OK (i, Pmode))
      static_reg_base_value[i]
      static_reg_base_value[i]
        = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i));
        = gen_rtx_ADDRESS (VOIDmode, gen_rtx_REG (Pmode, i));
 
 
  static_reg_base_value[STACK_POINTER_REGNUM]
  static_reg_base_value[STACK_POINTER_REGNUM]
    = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx);
    = gen_rtx_ADDRESS (Pmode, stack_pointer_rtx);
  static_reg_base_value[ARG_POINTER_REGNUM]
  static_reg_base_value[ARG_POINTER_REGNUM]
    = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx);
    = gen_rtx_ADDRESS (Pmode, arg_pointer_rtx);
  static_reg_base_value[FRAME_POINTER_REGNUM]
  static_reg_base_value[FRAME_POINTER_REGNUM]
    = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx);
    = gen_rtx_ADDRESS (Pmode, frame_pointer_rtx);
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
  static_reg_base_value[HARD_FRAME_POINTER_REGNUM]
  static_reg_base_value[HARD_FRAME_POINTER_REGNUM]
    = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx);
    = gen_rtx_ADDRESS (Pmode, hard_frame_pointer_rtx);
#endif
#endif
}
}
 
 
/* Set MEMORY_MODIFIED when X modifies DATA (that is assumed
/* Set MEMORY_MODIFIED when X modifies DATA (that is assumed
   to be memory reference.  */
   to be memory reference.  */
static bool memory_modified;
static bool memory_modified;
static void
static void
memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data)
memory_modified_1 (rtx x, const_rtx pat ATTRIBUTE_UNUSED, void *data)
{
{
  if (MEM_P (x))
  if (MEM_P (x))
    {
    {
      if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data))
      if (anti_dependence (x, (const_rtx)data) || output_dependence (x, (const_rtx)data))
        memory_modified = true;
        memory_modified = true;
    }
    }
}
}
 
 
 
 
/* Return true when INSN possibly modify memory contents of MEM
/* Return true when INSN possibly modify memory contents of MEM
   (i.e. address can be modified).  */
   (i.e. address can be modified).  */
bool
bool
memory_modified_in_insn_p (const_rtx mem, const_rtx insn)
memory_modified_in_insn_p (const_rtx mem, const_rtx insn)
{
{
  if (!INSN_P (insn))
  if (!INSN_P (insn))
    return false;
    return false;
  memory_modified = false;
  memory_modified = false;
  note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem));
  note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem));
  return memory_modified;
  return memory_modified;
}
}
 
 
/* Initialize the aliasing machinery.  Initialize the REG_KNOWN_VALUE
/* Initialize the aliasing machinery.  Initialize the REG_KNOWN_VALUE
   array.  */
   array.  */
 
 
void
void
init_alias_analysis (void)
init_alias_analysis (void)
{
{
  unsigned int maxreg = max_reg_num ();
  unsigned int maxreg = max_reg_num ();
  int changed, pass;
  int changed, pass;
  int i;
  int i;
  unsigned int ui;
  unsigned int ui;
  rtx insn;
  rtx insn;
 
 
  timevar_push (TV_ALIAS_ANALYSIS);
  timevar_push (TV_ALIAS_ANALYSIS);
 
 
  reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER;
  reg_known_value_size = maxreg - FIRST_PSEUDO_REGISTER;
  reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size);
  reg_known_value = GGC_CNEWVEC (rtx, reg_known_value_size);
  reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size);
  reg_known_equiv_p = XCNEWVEC (bool, reg_known_value_size);
 
 
  /* If we have memory allocated from the previous run, use it.  */
  /* If we have memory allocated from the previous run, use it.  */
  if (old_reg_base_value)
  if (old_reg_base_value)
    reg_base_value = old_reg_base_value;
    reg_base_value = old_reg_base_value;
 
 
  if (reg_base_value)
  if (reg_base_value)
    VEC_truncate (rtx, reg_base_value, 0);
    VEC_truncate (rtx, reg_base_value, 0);
 
 
  VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg);
  VEC_safe_grow_cleared (rtx, gc, reg_base_value, maxreg);
 
 
  new_reg_base_value = XNEWVEC (rtx, maxreg);
  new_reg_base_value = XNEWVEC (rtx, maxreg);
  reg_seen = XNEWVEC (char, maxreg);
  reg_seen = XNEWVEC (char, maxreg);
 
 
  /* The basic idea is that each pass through this loop will use the
  /* The basic idea is that each pass through this loop will use the
     "constant" information from the previous pass to propagate alias
     "constant" information from the previous pass to propagate alias
     information through another level of assignments.
     information through another level of assignments.
 
 
     This could get expensive if the assignment chains are long.  Maybe
     This could get expensive if the assignment chains are long.  Maybe
     we should throttle the number of iterations, possibly based on
     we should throttle the number of iterations, possibly based on
     the optimization level or flag_expensive_optimizations.
     the optimization level or flag_expensive_optimizations.
 
 
     We could propagate more information in the first pass by making use
     We could propagate more information in the first pass by making use
     of DF_REG_DEF_COUNT to determine immediately that the alias information
     of DF_REG_DEF_COUNT to determine immediately that the alias information
     for a pseudo is "constant".
     for a pseudo is "constant".
 
 
     A program with an uninitialized variable can cause an infinite loop
     A program with an uninitialized variable can cause an infinite loop
     here.  Instead of doing a full dataflow analysis to detect such problems
     here.  Instead of doing a full dataflow analysis to detect such problems
     we just cap the number of iterations for the loop.
     we just cap the number of iterations for the loop.
 
 
     The state of the arrays for the set chain in question does not matter
     The state of the arrays for the set chain in question does not matter
     since the program has undefined behavior.  */
     since the program has undefined behavior.  */
 
 
  pass = 0;
  pass = 0;
  do
  do
    {
    {
      /* Assume nothing will change this iteration of the loop.  */
      /* Assume nothing will change this iteration of the loop.  */
      changed = 0;
      changed = 0;
 
 
      /* We want to assign the same IDs each iteration of this loop, so
      /* We want to assign the same IDs each iteration of this loop, so
         start counting from zero each iteration of the loop.  */
         start counting from zero each iteration of the loop.  */
      unique_id = 0;
      unique_id = 0;
 
 
      /* We're at the start of the function each iteration through the
      /* We're at the start of the function each iteration through the
         loop, so we're copying arguments.  */
         loop, so we're copying arguments.  */
      copying_arguments = true;
      copying_arguments = true;
 
 
      /* Wipe the potential alias information clean for this pass.  */
      /* Wipe the potential alias information clean for this pass.  */
      memset (new_reg_base_value, 0, maxreg * sizeof (rtx));
      memset (new_reg_base_value, 0, maxreg * sizeof (rtx));
 
 
      /* Wipe the reg_seen array clean.  */
      /* Wipe the reg_seen array clean.  */
      memset (reg_seen, 0, maxreg);
      memset (reg_seen, 0, maxreg);
 
 
      /* Mark all hard registers which may contain an address.
      /* Mark all hard registers which may contain an address.
         The stack, frame and argument pointers may contain an address.
         The stack, frame and argument pointers may contain an address.
         An argument register which can hold a Pmode value may contain
         An argument register which can hold a Pmode value may contain
         an address even if it is not in BASE_REGS.
         an address even if it is not in BASE_REGS.
 
 
         The address expression is VOIDmode for an argument and
         The address expression is VOIDmode for an argument and
         Pmode for other registers.  */
         Pmode for other registers.  */
 
 
      memcpy (new_reg_base_value, static_reg_base_value,
      memcpy (new_reg_base_value, static_reg_base_value,
              FIRST_PSEUDO_REGISTER * sizeof (rtx));
              FIRST_PSEUDO_REGISTER * sizeof (rtx));
 
 
      /* Walk the insns adding values to the new_reg_base_value array.  */
      /* Walk the insns adding values to the new_reg_base_value array.  */
      for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
      for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
        {
        {
          if (INSN_P (insn))
          if (INSN_P (insn))
            {
            {
              rtx note, set;
              rtx note, set;
 
 
#if defined (HAVE_prologue) || defined (HAVE_epilogue)
#if defined (HAVE_prologue) || defined (HAVE_epilogue)
              /* The prologue/epilogue insns are not threaded onto the
              /* The prologue/epilogue insns are not threaded onto the
                 insn chain until after reload has completed.  Thus,
                 insn chain until after reload has completed.  Thus,
                 there is no sense wasting time checking if INSN is in
                 there is no sense wasting time checking if INSN is in
                 the prologue/epilogue until after reload has completed.  */
                 the prologue/epilogue until after reload has completed.  */
              if (reload_completed
              if (reload_completed
                  && prologue_epilogue_contains (insn))
                  && prologue_epilogue_contains (insn))
                continue;
                continue;
#endif
#endif
 
 
              /* If this insn has a noalias note, process it,  Otherwise,
              /* If this insn has a noalias note, process it,  Otherwise,
                 scan for sets.  A simple set will have no side effects
                 scan for sets.  A simple set will have no side effects
                 which could change the base value of any other register.  */
                 which could change the base value of any other register.  */
 
 
              if (GET_CODE (PATTERN (insn)) == SET
              if (GET_CODE (PATTERN (insn)) == SET
                  && REG_NOTES (insn) != 0
                  && REG_NOTES (insn) != 0
                  && find_reg_note (insn, REG_NOALIAS, NULL_RTX))
                  && find_reg_note (insn, REG_NOALIAS, NULL_RTX))
                record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL);
                record_set (SET_DEST (PATTERN (insn)), NULL_RTX, NULL);
              else
              else
                note_stores (PATTERN (insn), record_set, NULL);
                note_stores (PATTERN (insn), record_set, NULL);
 
 
              set = single_set (insn);
              set = single_set (insn);
 
 
              if (set != 0
              if (set != 0
                  && REG_P (SET_DEST (set))
                  && REG_P (SET_DEST (set))
                  && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
                  && REGNO (SET_DEST (set)) >= FIRST_PSEUDO_REGISTER)
                {
                {
                  unsigned int regno = REGNO (SET_DEST (set));
                  unsigned int regno = REGNO (SET_DEST (set));
                  rtx src = SET_SRC (set);
                  rtx src = SET_SRC (set);
                  rtx t;
                  rtx t;
 
 
                  note = find_reg_equal_equiv_note (insn);
                  note = find_reg_equal_equiv_note (insn);
                  if (note && REG_NOTE_KIND (note) == REG_EQUAL
                  if (note && REG_NOTE_KIND (note) == REG_EQUAL
                      && DF_REG_DEF_COUNT (regno) != 1)
                      && DF_REG_DEF_COUNT (regno) != 1)
                    note = NULL_RTX;
                    note = NULL_RTX;
 
 
                  if (note != NULL_RTX
                  if (note != NULL_RTX
                      && GET_CODE (XEXP (note, 0)) != EXPR_LIST
                      && GET_CODE (XEXP (note, 0)) != EXPR_LIST
                      && ! rtx_varies_p (XEXP (note, 0), 1)
                      && ! rtx_varies_p (XEXP (note, 0), 1)
                      && ! reg_overlap_mentioned_p (SET_DEST (set),
                      && ! reg_overlap_mentioned_p (SET_DEST (set),
                                                    XEXP (note, 0)))
                                                    XEXP (note, 0)))
                    {
                    {
                      set_reg_known_value (regno, XEXP (note, 0));
                      set_reg_known_value (regno, XEXP (note, 0));
                      set_reg_known_equiv_p (regno,
                      set_reg_known_equiv_p (regno,
                        REG_NOTE_KIND (note) == REG_EQUIV);
                        REG_NOTE_KIND (note) == REG_EQUIV);
                    }
                    }
                  else if (DF_REG_DEF_COUNT (regno) == 1
                  else if (DF_REG_DEF_COUNT (regno) == 1
                           && GET_CODE (src) == PLUS
                           && GET_CODE (src) == PLUS
                           && REG_P (XEXP (src, 0))
                           && REG_P (XEXP (src, 0))
                           && (t = get_reg_known_value (REGNO (XEXP (src, 0))))
                           && (t = get_reg_known_value (REGNO (XEXP (src, 0))))
                           && CONST_INT_P (XEXP (src, 1)))
                           && CONST_INT_P (XEXP (src, 1)))
                    {
                    {
                      t = plus_constant (t, INTVAL (XEXP (src, 1)));
                      t = plus_constant (t, INTVAL (XEXP (src, 1)));
                      set_reg_known_value (regno, t);
                      set_reg_known_value (regno, t);
                      set_reg_known_equiv_p (regno, 0);
                      set_reg_known_equiv_p (regno, 0);
                    }
                    }
                  else if (DF_REG_DEF_COUNT (regno) == 1
                  else if (DF_REG_DEF_COUNT (regno) == 1
                           && ! rtx_varies_p (src, 1))
                           && ! rtx_varies_p (src, 1))
                    {
                    {
                      set_reg_known_value (regno, src);
                      set_reg_known_value (regno, src);
                      set_reg_known_equiv_p (regno, 0);
                      set_reg_known_equiv_p (regno, 0);
                    }
                    }
                }
                }
            }
            }
          else if (NOTE_P (insn)
          else if (NOTE_P (insn)
                   && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG)
                   && NOTE_KIND (insn) == NOTE_INSN_FUNCTION_BEG)
            copying_arguments = false;
            copying_arguments = false;
        }
        }
 
 
      /* Now propagate values from new_reg_base_value to reg_base_value.  */
      /* Now propagate values from new_reg_base_value to reg_base_value.  */
      gcc_assert (maxreg == (unsigned int) max_reg_num ());
      gcc_assert (maxreg == (unsigned int) max_reg_num ());
 
 
      for (ui = 0; ui < maxreg; ui++)
      for (ui = 0; ui < maxreg; ui++)
        {
        {
          if (new_reg_base_value[ui]
          if (new_reg_base_value[ui]
              && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui)
              && new_reg_base_value[ui] != VEC_index (rtx, reg_base_value, ui)
              && ! rtx_equal_p (new_reg_base_value[ui],
              && ! rtx_equal_p (new_reg_base_value[ui],
                                VEC_index (rtx, reg_base_value, ui)))
                                VEC_index (rtx, reg_base_value, ui)))
            {
            {
              VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]);
              VEC_replace (rtx, reg_base_value, ui, new_reg_base_value[ui]);
              changed = 1;
              changed = 1;
            }
            }
        }
        }
    }
    }
  while (changed && ++pass < MAX_ALIAS_LOOP_PASSES);
  while (changed && ++pass < MAX_ALIAS_LOOP_PASSES);
 
 
  /* Fill in the remaining entries.  */
  /* Fill in the remaining entries.  */
  for (i = 0; i < (int)reg_known_value_size; i++)
  for (i = 0; i < (int)reg_known_value_size; i++)
    if (reg_known_value[i] == 0)
    if (reg_known_value[i] == 0)
      reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER];
      reg_known_value[i] = regno_reg_rtx[i + FIRST_PSEUDO_REGISTER];
 
 
  /* Clean up.  */
  /* Clean up.  */
  free (new_reg_base_value);
  free (new_reg_base_value);
  new_reg_base_value = 0;
  new_reg_base_value = 0;
  free (reg_seen);
  free (reg_seen);
  reg_seen = 0;
  reg_seen = 0;
  timevar_pop (TV_ALIAS_ANALYSIS);
  timevar_pop (TV_ALIAS_ANALYSIS);
}
}
 
 
void
void
end_alias_analysis (void)
end_alias_analysis (void)
{
{
  old_reg_base_value = reg_base_value;
  old_reg_base_value = reg_base_value;
  ggc_free (reg_known_value);
  ggc_free (reg_known_value);
  reg_known_value = 0;
  reg_known_value = 0;
  reg_known_value_size = 0;
  reg_known_value_size = 0;
  free (reg_known_equiv_p);
  free (reg_known_equiv_p);
  reg_known_equiv_p = 0;
  reg_known_equiv_p = 0;
}
}
 
 
#include "gt-alias.h"
#include "gt-alias.h"
 
 

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