OpenCores
URL https://opencores.org/ocsvn/openrisc/openrisc/trunk

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [gnu-old/] [gcc-4.2.2/] [gcc/] [tree-ssa-propagate.c] - Diff between revs 154 and 816

Go to most recent revision | Only display areas with differences | Details | Blame | View Log

Rev 154 Rev 816
/* Generic SSA value propagation engine.
/* Generic SSA value propagation engine.
   Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
   Contributed by Diego Novillo <dnovillo@redhat.com>
   Contributed by Diego Novillo <dnovillo@redhat.com>
 
 
   This file is part of GCC.
   This file is part of GCC.
 
 
   GCC is free software; you can redistribute it and/or modify it
   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
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 3, or (at your option) any
   Free Software Foundation; either version 3, or (at your option) any
   later version.
   later version.
 
 
   GCC is distributed in the hope that it will be useful, but WITHOUT
   GCC is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   ANY 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 "tree.h"
#include "tree.h"
#include "flags.h"
#include "flags.h"
#include "rtl.h"
#include "rtl.h"
#include "tm_p.h"
#include "tm_p.h"
#include "ggc.h"
#include "ggc.h"
#include "basic-block.h"
#include "basic-block.h"
#include "output.h"
#include "output.h"
#include "expr.h"
#include "expr.h"
#include "function.h"
#include "function.h"
#include "diagnostic.h"
#include "diagnostic.h"
#include "timevar.h"
#include "timevar.h"
#include "tree-dump.h"
#include "tree-dump.h"
#include "tree-flow.h"
#include "tree-flow.h"
#include "tree-pass.h"
#include "tree-pass.h"
#include "tree-ssa-propagate.h"
#include "tree-ssa-propagate.h"
#include "langhooks.h"
#include "langhooks.h"
#include "varray.h"
#include "varray.h"
#include "vec.h"
#include "vec.h"
 
 
/* This file implements a generic value propagation engine based on
/* This file implements a generic value propagation engine based on
   the same propagation used by the SSA-CCP algorithm [1].
   the same propagation used by the SSA-CCP algorithm [1].
 
 
   Propagation is performed by simulating the execution of every
   Propagation is performed by simulating the execution of every
   statement that produces the value being propagated.  Simulation
   statement that produces the value being propagated.  Simulation
   proceeds as follows:
   proceeds as follows:
 
 
   1- Initially, all edges of the CFG are marked not executable and
   1- Initially, all edges of the CFG are marked not executable and
      the CFG worklist is seeded with all the statements in the entry
      the CFG worklist is seeded with all the statements in the entry
      basic block (block 0).
      basic block (block 0).
 
 
   2- Every statement S is simulated with a call to the call-back
   2- Every statement S is simulated with a call to the call-back
      function SSA_PROP_VISIT_STMT.  This evaluation may produce 3
      function SSA_PROP_VISIT_STMT.  This evaluation may produce 3
      results:
      results:
 
 
        SSA_PROP_NOT_INTERESTING: Statement S produces nothing of
        SSA_PROP_NOT_INTERESTING: Statement S produces nothing of
            interest and does not affect any of the work lists.
            interest and does not affect any of the work lists.
 
 
        SSA_PROP_VARYING: The value produced by S cannot be determined
        SSA_PROP_VARYING: The value produced by S cannot be determined
            at compile time.  Further simulation of S is not required.
            at compile time.  Further simulation of S is not required.
            If S is a conditional jump, all the outgoing edges for the
            If S is a conditional jump, all the outgoing edges for the
            block are considered executable and added to the work
            block are considered executable and added to the work
            list.
            list.
 
 
        SSA_PROP_INTERESTING: S produces a value that can be computed
        SSA_PROP_INTERESTING: S produces a value that can be computed
            at compile time.  Its result can be propagated into the
            at compile time.  Its result can be propagated into the
            statements that feed from S.  Furthermore, if S is a
            statements that feed from S.  Furthermore, if S is a
            conditional jump, only the edge known to be taken is added
            conditional jump, only the edge known to be taken is added
            to the work list.  Edges that are known not to execute are
            to the work list.  Edges that are known not to execute are
            never simulated.
            never simulated.
 
 
   3- PHI nodes are simulated with a call to SSA_PROP_VISIT_PHI.  The
   3- PHI nodes are simulated with a call to SSA_PROP_VISIT_PHI.  The
      return value from SSA_PROP_VISIT_PHI has the same semantics as
      return value from SSA_PROP_VISIT_PHI has the same semantics as
      described in #2.
      described in #2.
 
 
   4- Three work lists are kept.  Statements are only added to these
   4- Three work lists are kept.  Statements are only added to these
      lists if they produce one of SSA_PROP_INTERESTING or
      lists if they produce one of SSA_PROP_INTERESTING or
      SSA_PROP_VARYING.
      SSA_PROP_VARYING.
 
 
        CFG_BLOCKS contains the list of blocks to be simulated.
        CFG_BLOCKS contains the list of blocks to be simulated.
            Blocks are added to this list if their incoming edges are
            Blocks are added to this list if their incoming edges are
            found executable.
            found executable.
 
 
        VARYING_SSA_EDGES contains the list of statements that feed
        VARYING_SSA_EDGES contains the list of statements that feed
            from statements that produce an SSA_PROP_VARYING result.
            from statements that produce an SSA_PROP_VARYING result.
            These are simulated first to speed up processing.
            These are simulated first to speed up processing.
 
 
        INTERESTING_SSA_EDGES contains the list of statements that
        INTERESTING_SSA_EDGES contains the list of statements that
            feed from statements that produce an SSA_PROP_INTERESTING
            feed from statements that produce an SSA_PROP_INTERESTING
            result.
            result.
 
 
   5- Simulation terminates when all three work lists are drained.
   5- Simulation terminates when all three work lists are drained.
 
 
   Before calling ssa_propagate, it is important to clear
   Before calling ssa_propagate, it is important to clear
   DONT_SIMULATE_AGAIN for all the statements in the program that
   DONT_SIMULATE_AGAIN for all the statements in the program that
   should be simulated.  This initialization allows an implementation
   should be simulated.  This initialization allows an implementation
   to specify which statements should never be simulated.
   to specify which statements should never be simulated.
 
 
   It is also important to compute def-use information before calling
   It is also important to compute def-use information before calling
   ssa_propagate.
   ssa_propagate.
 
 
   References:
   References:
 
 
     [1] Constant propagation with conditional branches,
     [1] Constant propagation with conditional branches,
         Wegman and Zadeck, ACM TOPLAS 13(2):181-210.
         Wegman and Zadeck, ACM TOPLAS 13(2):181-210.
 
 
     [2] Building an Optimizing Compiler,
     [2] Building an Optimizing Compiler,
         Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9.
         Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9.
 
 
     [3] Advanced Compiler Design and Implementation,
     [3] Advanced Compiler Design and Implementation,
         Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6  */
         Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6  */
 
 
/* Function pointers used to parameterize the propagation engine.  */
/* Function pointers used to parameterize the propagation engine.  */
static ssa_prop_visit_stmt_fn ssa_prop_visit_stmt;
static ssa_prop_visit_stmt_fn ssa_prop_visit_stmt;
static ssa_prop_visit_phi_fn ssa_prop_visit_phi;
static ssa_prop_visit_phi_fn ssa_prop_visit_phi;
 
 
/* Use the TREE_DEPRECATED bitflag to mark statements that have been
/* Use the TREE_DEPRECATED bitflag to mark statements that have been
   added to one of the SSA edges worklists.  This flag is used to
   added to one of the SSA edges worklists.  This flag is used to
   avoid visiting statements unnecessarily when draining an SSA edge
   avoid visiting statements unnecessarily when draining an SSA edge
   worklist.  If while simulating a basic block, we find a statement with
   worklist.  If while simulating a basic block, we find a statement with
   STMT_IN_SSA_EDGE_WORKLIST set, we clear it to prevent SSA edge
   STMT_IN_SSA_EDGE_WORKLIST set, we clear it to prevent SSA edge
   processing from visiting it again.  */
   processing from visiting it again.  */
#define STMT_IN_SSA_EDGE_WORKLIST(T)    TREE_DEPRECATED (T)
#define STMT_IN_SSA_EDGE_WORKLIST(T)    TREE_DEPRECATED (T)
 
 
/* A bitmap to keep track of executable blocks in the CFG.  */
/* A bitmap to keep track of executable blocks in the CFG.  */
static sbitmap executable_blocks;
static sbitmap executable_blocks;
 
 
/* Array of control flow edges on the worklist.  */
/* Array of control flow edges on the worklist.  */
static VEC(basic_block,heap) *cfg_blocks;
static VEC(basic_block,heap) *cfg_blocks;
 
 
static unsigned int cfg_blocks_num = 0;
static unsigned int cfg_blocks_num = 0;
static int cfg_blocks_tail;
static int cfg_blocks_tail;
static int cfg_blocks_head;
static int cfg_blocks_head;
 
 
static sbitmap bb_in_list;
static sbitmap bb_in_list;
 
 
/* Worklist of SSA edges which will need reexamination as their
/* Worklist of SSA edges which will need reexamination as their
   definition has changed.  SSA edges are def-use edges in the SSA
   definition has changed.  SSA edges are def-use edges in the SSA
   web.  For each D-U edge, we store the target statement or PHI node
   web.  For each D-U edge, we store the target statement or PHI node
   U.  */
   U.  */
static GTY(()) VEC(tree,gc) *interesting_ssa_edges;
static GTY(()) VEC(tree,gc) *interesting_ssa_edges;
 
 
/* Identical to INTERESTING_SSA_EDGES.  For performance reasons, the
/* Identical to INTERESTING_SSA_EDGES.  For performance reasons, the
   list of SSA edges is split into two.  One contains all SSA edges
   list of SSA edges is split into two.  One contains all SSA edges
   who need to be reexamined because their lattice value changed to
   who need to be reexamined because their lattice value changed to
   varying (this worklist), and the other contains all other SSA edges
   varying (this worklist), and the other contains all other SSA edges
   to be reexamined (INTERESTING_SSA_EDGES).
   to be reexamined (INTERESTING_SSA_EDGES).
 
 
   Since most values in the program are VARYING, the ideal situation
   Since most values in the program are VARYING, the ideal situation
   is to move them to that lattice value as quickly as possible.
   is to move them to that lattice value as quickly as possible.
   Thus, it doesn't make sense to process any other type of lattice
   Thus, it doesn't make sense to process any other type of lattice
   value until all VARYING values are propagated fully, which is one
   value until all VARYING values are propagated fully, which is one
   thing using the VARYING worklist achieves.  In addition, if we
   thing using the VARYING worklist achieves.  In addition, if we
   don't use a separate worklist for VARYING edges, we end up with
   don't use a separate worklist for VARYING edges, we end up with
   situations where lattice values move from
   situations where lattice values move from
   UNDEFINED->INTERESTING->VARYING instead of UNDEFINED->VARYING.  */
   UNDEFINED->INTERESTING->VARYING instead of UNDEFINED->VARYING.  */
static GTY(()) VEC(tree,gc) *varying_ssa_edges;
static GTY(()) VEC(tree,gc) *varying_ssa_edges;
 
 
 
 
/* Return true if the block worklist empty.  */
/* Return true if the block worklist empty.  */
 
 
static inline bool
static inline bool
cfg_blocks_empty_p (void)
cfg_blocks_empty_p (void)
{
{
  return (cfg_blocks_num == 0);
  return (cfg_blocks_num == 0);
}
}
 
 
 
 
/* Add a basic block to the worklist.  The block must not be already
/* Add a basic block to the worklist.  The block must not be already
   in the worklist, and it must not be the ENTRY or EXIT block.  */
   in the worklist, and it must not be the ENTRY or EXIT block.  */
 
 
static void
static void
cfg_blocks_add (basic_block bb)
cfg_blocks_add (basic_block bb)
{
{
  gcc_assert (bb != ENTRY_BLOCK_PTR && bb != EXIT_BLOCK_PTR);
  gcc_assert (bb != ENTRY_BLOCK_PTR && bb != EXIT_BLOCK_PTR);
  gcc_assert (!TEST_BIT (bb_in_list, bb->index));
  gcc_assert (!TEST_BIT (bb_in_list, bb->index));
 
 
  if (cfg_blocks_empty_p ())
  if (cfg_blocks_empty_p ())
    {
    {
      cfg_blocks_tail = cfg_blocks_head = 0;
      cfg_blocks_tail = cfg_blocks_head = 0;
      cfg_blocks_num = 1;
      cfg_blocks_num = 1;
    }
    }
  else
  else
    {
    {
      cfg_blocks_num++;
      cfg_blocks_num++;
      if (cfg_blocks_num > VEC_length (basic_block, cfg_blocks))
      if (cfg_blocks_num > VEC_length (basic_block, cfg_blocks))
        {
        {
          /* We have to grow the array now.  Adjust to queue to occupy
          /* We have to grow the array now.  Adjust to queue to occupy
             the full space of the original array.  We do not need to
             the full space of the original array.  We do not need to
             initialize the newly allocated portion of the array
             initialize the newly allocated portion of the array
             because we keep track of CFG_BLOCKS_HEAD and
             because we keep track of CFG_BLOCKS_HEAD and
             CFG_BLOCKS_HEAD.  */
             CFG_BLOCKS_HEAD.  */
          cfg_blocks_tail = VEC_length (basic_block, cfg_blocks);
          cfg_blocks_tail = VEC_length (basic_block, cfg_blocks);
          cfg_blocks_head = 0;
          cfg_blocks_head = 0;
          VEC_safe_grow (basic_block, heap, cfg_blocks, 2 * cfg_blocks_tail);
          VEC_safe_grow (basic_block, heap, cfg_blocks, 2 * cfg_blocks_tail);
        }
        }
      else
      else
        cfg_blocks_tail = ((cfg_blocks_tail + 1)
        cfg_blocks_tail = ((cfg_blocks_tail + 1)
                           % VEC_length (basic_block, cfg_blocks));
                           % VEC_length (basic_block, cfg_blocks));
    }
    }
 
 
  VEC_replace (basic_block, cfg_blocks, cfg_blocks_tail, bb);
  VEC_replace (basic_block, cfg_blocks, cfg_blocks_tail, bb);
  SET_BIT (bb_in_list, bb->index);
  SET_BIT (bb_in_list, bb->index);
}
}
 
 
 
 
/* Remove a block from the worklist.  */
/* Remove a block from the worklist.  */
 
 
static basic_block
static basic_block
cfg_blocks_get (void)
cfg_blocks_get (void)
{
{
  basic_block bb;
  basic_block bb;
 
 
  bb = VEC_index (basic_block, cfg_blocks, cfg_blocks_head);
  bb = VEC_index (basic_block, cfg_blocks, cfg_blocks_head);
 
 
  gcc_assert (!cfg_blocks_empty_p ());
  gcc_assert (!cfg_blocks_empty_p ());
  gcc_assert (bb);
  gcc_assert (bb);
 
 
  cfg_blocks_head = ((cfg_blocks_head + 1)
  cfg_blocks_head = ((cfg_blocks_head + 1)
                     % VEC_length (basic_block, cfg_blocks));
                     % VEC_length (basic_block, cfg_blocks));
  --cfg_blocks_num;
  --cfg_blocks_num;
  RESET_BIT (bb_in_list, bb->index);
  RESET_BIT (bb_in_list, bb->index);
 
 
  return bb;
  return bb;
}
}
 
 
 
 
/* We have just defined a new value for VAR.  If IS_VARYING is true,
/* We have just defined a new value for VAR.  If IS_VARYING is true,
   add all immediate uses of VAR to VARYING_SSA_EDGES, otherwise add
   add all immediate uses of VAR to VARYING_SSA_EDGES, otherwise add
   them to INTERESTING_SSA_EDGES.  */
   them to INTERESTING_SSA_EDGES.  */
 
 
static void
static void
add_ssa_edge (tree var, bool is_varying)
add_ssa_edge (tree var, bool is_varying)
{
{
  imm_use_iterator iter;
  imm_use_iterator iter;
  use_operand_p use_p;
  use_operand_p use_p;
 
 
  FOR_EACH_IMM_USE_FAST (use_p, iter, var)
  FOR_EACH_IMM_USE_FAST (use_p, iter, var)
    {
    {
      tree use_stmt = USE_STMT (use_p);
      tree use_stmt = USE_STMT (use_p);
 
 
      if (!DONT_SIMULATE_AGAIN (use_stmt)
      if (!DONT_SIMULATE_AGAIN (use_stmt)
          && !STMT_IN_SSA_EDGE_WORKLIST (use_stmt))
          && !STMT_IN_SSA_EDGE_WORKLIST (use_stmt))
        {
        {
          STMT_IN_SSA_EDGE_WORKLIST (use_stmt) = 1;
          STMT_IN_SSA_EDGE_WORKLIST (use_stmt) = 1;
          if (is_varying)
          if (is_varying)
            VEC_safe_push (tree, gc, varying_ssa_edges, use_stmt);
            VEC_safe_push (tree, gc, varying_ssa_edges, use_stmt);
          else
          else
            VEC_safe_push (tree, gc, interesting_ssa_edges, use_stmt);
            VEC_safe_push (tree, gc, interesting_ssa_edges, use_stmt);
        }
        }
    }
    }
}
}
 
 
 
 
/* Add edge E to the control flow worklist.  */
/* Add edge E to the control flow worklist.  */
 
 
static void
static void
add_control_edge (edge e)
add_control_edge (edge e)
{
{
  basic_block bb = e->dest;
  basic_block bb = e->dest;
  if (bb == EXIT_BLOCK_PTR)
  if (bb == EXIT_BLOCK_PTR)
    return;
    return;
 
 
  /* If the edge had already been executed, skip it.  */
  /* If the edge had already been executed, skip it.  */
  if (e->flags & EDGE_EXECUTABLE)
  if (e->flags & EDGE_EXECUTABLE)
    return;
    return;
 
 
  e->flags |= EDGE_EXECUTABLE;
  e->flags |= EDGE_EXECUTABLE;
 
 
  /* If the block is already in the list, we're done.  */
  /* If the block is already in the list, we're done.  */
  if (TEST_BIT (bb_in_list, bb->index))
  if (TEST_BIT (bb_in_list, bb->index))
    return;
    return;
 
 
  cfg_blocks_add (bb);
  cfg_blocks_add (bb);
 
 
  if (dump_file && (dump_flags & TDF_DETAILS))
  if (dump_file && (dump_flags & TDF_DETAILS))
    fprintf (dump_file, "Adding Destination of edge (%d -> %d) to worklist\n\n",
    fprintf (dump_file, "Adding Destination of edge (%d -> %d) to worklist\n\n",
        e->src->index, e->dest->index);
        e->src->index, e->dest->index);
}
}
 
 
 
 
/* Simulate the execution of STMT and update the work lists accordingly.  */
/* Simulate the execution of STMT and update the work lists accordingly.  */
 
 
static void
static void
simulate_stmt (tree stmt)
simulate_stmt (tree stmt)
{
{
  enum ssa_prop_result val = SSA_PROP_NOT_INTERESTING;
  enum ssa_prop_result val = SSA_PROP_NOT_INTERESTING;
  edge taken_edge = NULL;
  edge taken_edge = NULL;
  tree output_name = NULL_TREE;
  tree output_name = NULL_TREE;
 
 
  /* Don't bother visiting statements that are already
  /* Don't bother visiting statements that are already
     considered varying by the propagator.  */
     considered varying by the propagator.  */
  if (DONT_SIMULATE_AGAIN (stmt))
  if (DONT_SIMULATE_AGAIN (stmt))
    return;
    return;
 
 
  if (TREE_CODE (stmt) == PHI_NODE)
  if (TREE_CODE (stmt) == PHI_NODE)
    {
    {
      val = ssa_prop_visit_phi (stmt);
      val = ssa_prop_visit_phi (stmt);
      output_name = PHI_RESULT (stmt);
      output_name = PHI_RESULT (stmt);
    }
    }
  else
  else
    val = ssa_prop_visit_stmt (stmt, &taken_edge, &output_name);
    val = ssa_prop_visit_stmt (stmt, &taken_edge, &output_name);
 
 
  if (val == SSA_PROP_VARYING)
  if (val == SSA_PROP_VARYING)
    {
    {
      DONT_SIMULATE_AGAIN (stmt) = 1;
      DONT_SIMULATE_AGAIN (stmt) = 1;
 
 
      /* If the statement produced a new varying value, add the SSA
      /* If the statement produced a new varying value, add the SSA
         edges coming out of OUTPUT_NAME.  */
         edges coming out of OUTPUT_NAME.  */
      if (output_name)
      if (output_name)
        add_ssa_edge (output_name, true);
        add_ssa_edge (output_name, true);
 
 
      /* If STMT transfers control out of its basic block, add
      /* If STMT transfers control out of its basic block, add
         all outgoing edges to the work list.  */
         all outgoing edges to the work list.  */
      if (stmt_ends_bb_p (stmt))
      if (stmt_ends_bb_p (stmt))
        {
        {
          edge e;
          edge e;
          edge_iterator ei;
          edge_iterator ei;
          basic_block bb = bb_for_stmt (stmt);
          basic_block bb = bb_for_stmt (stmt);
          FOR_EACH_EDGE (e, ei, bb->succs)
          FOR_EACH_EDGE (e, ei, bb->succs)
            add_control_edge (e);
            add_control_edge (e);
        }
        }
    }
    }
  else if (val == SSA_PROP_INTERESTING)
  else if (val == SSA_PROP_INTERESTING)
    {
    {
      /* If the statement produced new value, add the SSA edges coming
      /* If the statement produced new value, add the SSA edges coming
         out of OUTPUT_NAME.  */
         out of OUTPUT_NAME.  */
      if (output_name)
      if (output_name)
        add_ssa_edge (output_name, false);
        add_ssa_edge (output_name, false);
 
 
      /* If we know which edge is going to be taken out of this block,
      /* If we know which edge is going to be taken out of this block,
         add it to the CFG work list.  */
         add it to the CFG work list.  */
      if (taken_edge)
      if (taken_edge)
        add_control_edge (taken_edge);
        add_control_edge (taken_edge);
    }
    }
}
}
 
 
/* Process an SSA edge worklist.  WORKLIST is the SSA edge worklist to
/* Process an SSA edge worklist.  WORKLIST is the SSA edge worklist to
   drain.  This pops statements off the given WORKLIST and processes
   drain.  This pops statements off the given WORKLIST and processes
   them until there are no more statements on WORKLIST.
   them until there are no more statements on WORKLIST.
   We take a pointer to WORKLIST because it may be reallocated when an
   We take a pointer to WORKLIST because it may be reallocated when an
   SSA edge is added to it in simulate_stmt.  */
   SSA edge is added to it in simulate_stmt.  */
 
 
static void
static void
process_ssa_edge_worklist (VEC(tree,gc) **worklist)
process_ssa_edge_worklist (VEC(tree,gc) **worklist)
{
{
  /* Drain the entire worklist.  */
  /* Drain the entire worklist.  */
  while (VEC_length (tree, *worklist) > 0)
  while (VEC_length (tree, *worklist) > 0)
    {
    {
      basic_block bb;
      basic_block bb;
 
 
      /* Pull the statement to simulate off the worklist.  */
      /* Pull the statement to simulate off the worklist.  */
      tree stmt = VEC_pop (tree, *worklist);
      tree stmt = VEC_pop (tree, *worklist);
 
 
      /* If this statement was already visited by simulate_block, then
      /* If this statement was already visited by simulate_block, then
         we don't need to visit it again here.  */
         we don't need to visit it again here.  */
      if (!STMT_IN_SSA_EDGE_WORKLIST (stmt))
      if (!STMT_IN_SSA_EDGE_WORKLIST (stmt))
        continue;
        continue;
 
 
      /* STMT is no longer in a worklist.  */
      /* STMT is no longer in a worklist.  */
      STMT_IN_SSA_EDGE_WORKLIST (stmt) = 0;
      STMT_IN_SSA_EDGE_WORKLIST (stmt) = 0;
 
 
      if (dump_file && (dump_flags & TDF_DETAILS))
      if (dump_file && (dump_flags & TDF_DETAILS))
        {
        {
          fprintf (dump_file, "\nSimulating statement (from ssa_edges): ");
          fprintf (dump_file, "\nSimulating statement (from ssa_edges): ");
          print_generic_stmt (dump_file, stmt, dump_flags);
          print_generic_stmt (dump_file, stmt, dump_flags);
        }
        }
 
 
      bb = bb_for_stmt (stmt);
      bb = bb_for_stmt (stmt);
 
 
      /* PHI nodes are always visited, regardless of whether or not
      /* PHI nodes are always visited, regardless of whether or not
         the destination block is executable.  Otherwise, visit the
         the destination block is executable.  Otherwise, visit the
         statement only if its block is marked executable.  */
         statement only if its block is marked executable.  */
      if (TREE_CODE (stmt) == PHI_NODE
      if (TREE_CODE (stmt) == PHI_NODE
          || TEST_BIT (executable_blocks, bb->index))
          || TEST_BIT (executable_blocks, bb->index))
        simulate_stmt (stmt);
        simulate_stmt (stmt);
    }
    }
}
}
 
 
 
 
/* Simulate the execution of BLOCK.  Evaluate the statement associated
/* Simulate the execution of BLOCK.  Evaluate the statement associated
   with each variable reference inside the block.  */
   with each variable reference inside the block.  */
 
 
static void
static void
simulate_block (basic_block block)
simulate_block (basic_block block)
{
{
  tree phi;
  tree phi;
 
 
  /* There is nothing to do for the exit block.  */
  /* There is nothing to do for the exit block.  */
  if (block == EXIT_BLOCK_PTR)
  if (block == EXIT_BLOCK_PTR)
    return;
    return;
 
 
  if (dump_file && (dump_flags & TDF_DETAILS))
  if (dump_file && (dump_flags & TDF_DETAILS))
    fprintf (dump_file, "\nSimulating block %d\n", block->index);
    fprintf (dump_file, "\nSimulating block %d\n", block->index);
 
 
  /* Always simulate PHI nodes, even if we have simulated this block
  /* Always simulate PHI nodes, even if we have simulated this block
     before.  */
     before.  */
  for (phi = phi_nodes (block); phi; phi = PHI_CHAIN (phi))
  for (phi = phi_nodes (block); phi; phi = PHI_CHAIN (phi))
    simulate_stmt (phi);
    simulate_stmt (phi);
 
 
  /* If this is the first time we've simulated this block, then we
  /* If this is the first time we've simulated this block, then we
     must simulate each of its statements.  */
     must simulate each of its statements.  */
  if (!TEST_BIT (executable_blocks, block->index))
  if (!TEST_BIT (executable_blocks, block->index))
    {
    {
      block_stmt_iterator j;
      block_stmt_iterator j;
      unsigned int normal_edge_count;
      unsigned int normal_edge_count;
      edge e, normal_edge;
      edge e, normal_edge;
      edge_iterator ei;
      edge_iterator ei;
 
 
      /* Note that we have simulated this block.  */
      /* Note that we have simulated this block.  */
      SET_BIT (executable_blocks, block->index);
      SET_BIT (executable_blocks, block->index);
 
 
      for (j = bsi_start (block); !bsi_end_p (j); bsi_next (&j))
      for (j = bsi_start (block); !bsi_end_p (j); bsi_next (&j))
        {
        {
          tree stmt = bsi_stmt (j);
          tree stmt = bsi_stmt (j);
 
 
          /* If this statement is already in the worklist then
          /* If this statement is already in the worklist then
             "cancel" it.  The reevaluation implied by the worklist
             "cancel" it.  The reevaluation implied by the worklist
             entry will produce the same value we generate here and
             entry will produce the same value we generate here and
             thus reevaluating it again from the worklist is
             thus reevaluating it again from the worklist is
             pointless.  */
             pointless.  */
          if (STMT_IN_SSA_EDGE_WORKLIST (stmt))
          if (STMT_IN_SSA_EDGE_WORKLIST (stmt))
            STMT_IN_SSA_EDGE_WORKLIST (stmt) = 0;
            STMT_IN_SSA_EDGE_WORKLIST (stmt) = 0;
 
 
          simulate_stmt (stmt);
          simulate_stmt (stmt);
        }
        }
 
 
      /* We can not predict when abnormal edges will be executed, so
      /* We can not predict when abnormal edges will be executed, so
         once a block is considered executable, we consider any
         once a block is considered executable, we consider any
         outgoing abnormal edges as executable.
         outgoing abnormal edges as executable.
 
 
         At the same time, if this block has only one successor that is
         At the same time, if this block has only one successor that is
         reached by non-abnormal edges, then add that successor to the
         reached by non-abnormal edges, then add that successor to the
         worklist.  */
         worklist.  */
      normal_edge_count = 0;
      normal_edge_count = 0;
      normal_edge = NULL;
      normal_edge = NULL;
      FOR_EACH_EDGE (e, ei, block->succs)
      FOR_EACH_EDGE (e, ei, block->succs)
        {
        {
          if (e->flags & EDGE_ABNORMAL)
          if (e->flags & EDGE_ABNORMAL)
            add_control_edge (e);
            add_control_edge (e);
          else
          else
            {
            {
              normal_edge_count++;
              normal_edge_count++;
              normal_edge = e;
              normal_edge = e;
            }
            }
        }
        }
 
 
      if (normal_edge_count == 1)
      if (normal_edge_count == 1)
        add_control_edge (normal_edge);
        add_control_edge (normal_edge);
    }
    }
}
}
 
 
 
 
/* Initialize local data structures and work lists.  */
/* Initialize local data structures and work lists.  */
 
 
static void
static void
ssa_prop_init (void)
ssa_prop_init (void)
{
{
  edge e;
  edge e;
  edge_iterator ei;
  edge_iterator ei;
  basic_block bb;
  basic_block bb;
  size_t i;
  size_t i;
 
 
  /* Worklists of SSA edges.  */
  /* Worklists of SSA edges.  */
  interesting_ssa_edges = VEC_alloc (tree, gc, 20);
  interesting_ssa_edges = VEC_alloc (tree, gc, 20);
  varying_ssa_edges = VEC_alloc (tree, gc, 20);
  varying_ssa_edges = VEC_alloc (tree, gc, 20);
 
 
  executable_blocks = sbitmap_alloc (last_basic_block);
  executable_blocks = sbitmap_alloc (last_basic_block);
  sbitmap_zero (executable_blocks);
  sbitmap_zero (executable_blocks);
 
 
  bb_in_list = sbitmap_alloc (last_basic_block);
  bb_in_list = sbitmap_alloc (last_basic_block);
  sbitmap_zero (bb_in_list);
  sbitmap_zero (bb_in_list);
 
 
  if (dump_file && (dump_flags & TDF_DETAILS))
  if (dump_file && (dump_flags & TDF_DETAILS))
    dump_immediate_uses (dump_file);
    dump_immediate_uses (dump_file);
 
 
  cfg_blocks = VEC_alloc (basic_block, heap, 20);
  cfg_blocks = VEC_alloc (basic_block, heap, 20);
  VEC_safe_grow (basic_block, heap, cfg_blocks, 20);
  VEC_safe_grow (basic_block, heap, cfg_blocks, 20);
 
 
  /* Initialize the values for every SSA_NAME.  */
  /* Initialize the values for every SSA_NAME.  */
  for (i = 1; i < num_ssa_names; i++)
  for (i = 1; i < num_ssa_names; i++)
    if (ssa_name (i))
    if (ssa_name (i))
      SSA_NAME_VALUE (ssa_name (i)) = NULL_TREE;
      SSA_NAME_VALUE (ssa_name (i)) = NULL_TREE;
 
 
  /* Initially assume that every edge in the CFG is not executable.
  /* Initially assume that every edge in the CFG is not executable.
     (including the edges coming out of ENTRY_BLOCK_PTR).  */
     (including the edges coming out of ENTRY_BLOCK_PTR).  */
  FOR_ALL_BB (bb)
  FOR_ALL_BB (bb)
    {
    {
      block_stmt_iterator si;
      block_stmt_iterator si;
 
 
      for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
      for (si = bsi_start (bb); !bsi_end_p (si); bsi_next (&si))
        STMT_IN_SSA_EDGE_WORKLIST (bsi_stmt (si)) = 0;
        STMT_IN_SSA_EDGE_WORKLIST (bsi_stmt (si)) = 0;
 
 
      FOR_EACH_EDGE (e, ei, bb->succs)
      FOR_EACH_EDGE (e, ei, bb->succs)
        e->flags &= ~EDGE_EXECUTABLE;
        e->flags &= ~EDGE_EXECUTABLE;
    }
    }
 
 
  /* Seed the algorithm by adding the successors of the entry block to the
  /* Seed the algorithm by adding the successors of the entry block to the
     edge worklist.  */
     edge worklist.  */
  FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
  FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
    add_control_edge (e);
    add_control_edge (e);
}
}
 
 
 
 
/* Free allocated storage.  */
/* Free allocated storage.  */
 
 
static void
static void
ssa_prop_fini (void)
ssa_prop_fini (void)
{
{
  VEC_free (tree, gc, interesting_ssa_edges);
  VEC_free (tree, gc, interesting_ssa_edges);
  VEC_free (tree, gc, varying_ssa_edges);
  VEC_free (tree, gc, varying_ssa_edges);
  VEC_free (basic_block, heap, cfg_blocks);
  VEC_free (basic_block, heap, cfg_blocks);
  cfg_blocks = NULL;
  cfg_blocks = NULL;
  sbitmap_free (bb_in_list);
  sbitmap_free (bb_in_list);
  sbitmap_free (executable_blocks);
  sbitmap_free (executable_blocks);
}
}
 
 
 
 
/* Get the main expression from statement STMT.  */
/* Get the main expression from statement STMT.  */
 
 
tree
tree
get_rhs (tree stmt)
get_rhs (tree stmt)
{
{
  enum tree_code code = TREE_CODE (stmt);
  enum tree_code code = TREE_CODE (stmt);
 
 
  switch (code)
  switch (code)
    {
    {
    case RETURN_EXPR:
    case RETURN_EXPR:
      stmt = TREE_OPERAND (stmt, 0);
      stmt = TREE_OPERAND (stmt, 0);
      if (!stmt || TREE_CODE (stmt) != MODIFY_EXPR)
      if (!stmt || TREE_CODE (stmt) != MODIFY_EXPR)
        return stmt;
        return stmt;
      /* FALLTHRU */
      /* FALLTHRU */
 
 
    case MODIFY_EXPR:
    case MODIFY_EXPR:
      stmt = TREE_OPERAND (stmt, 1);
      stmt = TREE_OPERAND (stmt, 1);
      if (TREE_CODE (stmt) == WITH_SIZE_EXPR)
      if (TREE_CODE (stmt) == WITH_SIZE_EXPR)
        return TREE_OPERAND (stmt, 0);
        return TREE_OPERAND (stmt, 0);
      else
      else
        return stmt;
        return stmt;
 
 
    case COND_EXPR:
    case COND_EXPR:
      return COND_EXPR_COND (stmt);
      return COND_EXPR_COND (stmt);
    case SWITCH_EXPR:
    case SWITCH_EXPR:
      return SWITCH_COND (stmt);
      return SWITCH_COND (stmt);
    case GOTO_EXPR:
    case GOTO_EXPR:
      return GOTO_DESTINATION (stmt);
      return GOTO_DESTINATION (stmt);
    case LABEL_EXPR:
    case LABEL_EXPR:
      return LABEL_EXPR_LABEL (stmt);
      return LABEL_EXPR_LABEL (stmt);
 
 
    default:
    default:
      return stmt;
      return stmt;
    }
    }
}
}
 
 
 
 
/* Set the main expression of *STMT_P to EXPR.  If EXPR is not a valid
/* Set the main expression of *STMT_P to EXPR.  If EXPR is not a valid
   GIMPLE expression no changes are done and the function returns
   GIMPLE expression no changes are done and the function returns
   false.  */
   false.  */
 
 
bool
bool
set_rhs (tree *stmt_p, tree expr)
set_rhs (tree *stmt_p, tree expr)
{
{
  tree stmt = *stmt_p, op;
  tree stmt = *stmt_p, op;
  enum tree_code code = TREE_CODE (expr);
  enum tree_code code = TREE_CODE (expr);
  stmt_ann_t ann;
  stmt_ann_t ann;
  tree var;
  tree var;
  ssa_op_iter iter;
  ssa_op_iter iter;
 
 
  /* Verify the constant folded result is valid gimple.  */
  /* Verify the constant folded result is valid gimple.  */
  if (TREE_CODE_CLASS (code) == tcc_binary
  if (TREE_CODE_CLASS (code) == tcc_binary
      || TREE_CODE_CLASS (code) == tcc_comparison)
      || TREE_CODE_CLASS (code) == tcc_comparison)
    {
    {
      if (!is_gimple_val (TREE_OPERAND (expr, 0))
      if (!is_gimple_val (TREE_OPERAND (expr, 0))
          || !is_gimple_val (TREE_OPERAND (expr, 1)))
          || !is_gimple_val (TREE_OPERAND (expr, 1)))
        return false;
        return false;
    }
    }
  else if (TREE_CODE_CLASS (code) == tcc_unary)
  else if (TREE_CODE_CLASS (code) == tcc_unary)
    {
    {
      if (!is_gimple_val (TREE_OPERAND (expr, 0)))
      if (!is_gimple_val (TREE_OPERAND (expr, 0)))
        return false;
        return false;
    }
    }
  else if (code == ADDR_EXPR)
  else if (code == ADDR_EXPR)
    {
    {
      if (TREE_CODE (TREE_OPERAND (expr, 0)) == ARRAY_REF
      if (TREE_CODE (TREE_OPERAND (expr, 0)) == ARRAY_REF
          && !is_gimple_val (TREE_OPERAND (TREE_OPERAND (expr, 0), 1)))
          && !is_gimple_val (TREE_OPERAND (TREE_OPERAND (expr, 0), 1)))
        return false;
        return false;
    }
    }
  else if (code == COMPOUND_EXPR
  else if (code == COMPOUND_EXPR
           || code == MODIFY_EXPR)
           || code == MODIFY_EXPR)
    return false;
    return false;
 
 
  if (EXPR_HAS_LOCATION (stmt)
  if (EXPR_HAS_LOCATION (stmt)
      && EXPR_P (expr)
      && EXPR_P (expr)
      && ! EXPR_HAS_LOCATION (expr)
      && ! EXPR_HAS_LOCATION (expr)
      && TREE_SIDE_EFFECTS (expr)
      && TREE_SIDE_EFFECTS (expr)
      && TREE_CODE (expr) != LABEL_EXPR)
      && TREE_CODE (expr) != LABEL_EXPR)
    SET_EXPR_LOCATION (expr, EXPR_LOCATION (stmt));
    SET_EXPR_LOCATION (expr, EXPR_LOCATION (stmt));
 
 
  switch (TREE_CODE (stmt))
  switch (TREE_CODE (stmt))
    {
    {
    case RETURN_EXPR:
    case RETURN_EXPR:
      op = TREE_OPERAND (stmt, 0);
      op = TREE_OPERAND (stmt, 0);
      if (TREE_CODE (op) != MODIFY_EXPR)
      if (TREE_CODE (op) != MODIFY_EXPR)
        {
        {
          TREE_OPERAND (stmt, 0) = expr;
          TREE_OPERAND (stmt, 0) = expr;
          break;
          break;
        }
        }
      stmt = op;
      stmt = op;
      /* FALLTHRU */
      /* FALLTHRU */
 
 
    case MODIFY_EXPR:
    case MODIFY_EXPR:
      op = TREE_OPERAND (stmt, 1);
      op = TREE_OPERAND (stmt, 1);
      if (TREE_CODE (op) == WITH_SIZE_EXPR)
      if (TREE_CODE (op) == WITH_SIZE_EXPR)
        stmt = op;
        stmt = op;
      TREE_OPERAND (stmt, 1) = expr;
      TREE_OPERAND (stmt, 1) = expr;
      break;
      break;
 
 
    case COND_EXPR:
    case COND_EXPR:
      if (!is_gimple_condexpr (expr))
      if (!is_gimple_condexpr (expr))
        return false;
        return false;
      COND_EXPR_COND (stmt) = expr;
      COND_EXPR_COND (stmt) = expr;
      break;
      break;
    case SWITCH_EXPR:
    case SWITCH_EXPR:
      SWITCH_COND (stmt) = expr;
      SWITCH_COND (stmt) = expr;
      break;
      break;
    case GOTO_EXPR:
    case GOTO_EXPR:
      GOTO_DESTINATION (stmt) = expr;
      GOTO_DESTINATION (stmt) = expr;
      break;
      break;
    case LABEL_EXPR:
    case LABEL_EXPR:
      LABEL_EXPR_LABEL (stmt) = expr;
      LABEL_EXPR_LABEL (stmt) = expr;
      break;
      break;
 
 
    default:
    default:
      /* Replace the whole statement with EXPR.  If EXPR has no side
      /* Replace the whole statement with EXPR.  If EXPR has no side
         effects, then replace *STMT_P with an empty statement.  */
         effects, then replace *STMT_P with an empty statement.  */
      ann = stmt_ann (stmt);
      ann = stmt_ann (stmt);
      *stmt_p = TREE_SIDE_EFFECTS (expr) ? expr : build_empty_stmt ();
      *stmt_p = TREE_SIDE_EFFECTS (expr) ? expr : build_empty_stmt ();
      (*stmt_p)->common.ann = (tree_ann_t) ann;
      (*stmt_p)->common.ann = (tree_ann_t) ann;
 
 
      if (in_ssa_p
      if (in_ssa_p
          && TREE_SIDE_EFFECTS (expr))
          && TREE_SIDE_EFFECTS (expr))
        {
        {
          /* Fix all the SSA_NAMEs created by *STMT_P to point to its new
          /* Fix all the SSA_NAMEs created by *STMT_P to point to its new
             replacement.  */
             replacement.  */
          FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_DEFS)
          FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_DEFS)
            {
            {
              if (TREE_CODE (var) == SSA_NAME)
              if (TREE_CODE (var) == SSA_NAME)
                SSA_NAME_DEF_STMT (var) = *stmt_p;
                SSA_NAME_DEF_STMT (var) = *stmt_p;
            }
            }
        }
        }
      break;
      break;
    }
    }
 
 
  return true;
  return true;
}
}
 
 
 
 
/* Entry point to the propagation engine.
/* Entry point to the propagation engine.
 
 
   VISIT_STMT is called for every statement visited.
   VISIT_STMT is called for every statement visited.
   VISIT_PHI is called for every PHI node visited.  */
   VISIT_PHI is called for every PHI node visited.  */
 
 
void
void
ssa_propagate (ssa_prop_visit_stmt_fn visit_stmt,
ssa_propagate (ssa_prop_visit_stmt_fn visit_stmt,
               ssa_prop_visit_phi_fn visit_phi)
               ssa_prop_visit_phi_fn visit_phi)
{
{
  ssa_prop_visit_stmt = visit_stmt;
  ssa_prop_visit_stmt = visit_stmt;
  ssa_prop_visit_phi = visit_phi;
  ssa_prop_visit_phi = visit_phi;
 
 
  ssa_prop_init ();
  ssa_prop_init ();
 
 
  /* Iterate until the worklists are empty.  */
  /* Iterate until the worklists are empty.  */
  while (!cfg_blocks_empty_p ()
  while (!cfg_blocks_empty_p ()
         || VEC_length (tree, interesting_ssa_edges) > 0
         || VEC_length (tree, interesting_ssa_edges) > 0
         || VEC_length (tree, varying_ssa_edges) > 0)
         || VEC_length (tree, varying_ssa_edges) > 0)
    {
    {
      if (!cfg_blocks_empty_p ())
      if (!cfg_blocks_empty_p ())
        {
        {
          /* Pull the next block to simulate off the worklist.  */
          /* Pull the next block to simulate off the worklist.  */
          basic_block dest_block = cfg_blocks_get ();
          basic_block dest_block = cfg_blocks_get ();
          simulate_block (dest_block);
          simulate_block (dest_block);
        }
        }
 
 
      /* In order to move things to varying as quickly as
      /* In order to move things to varying as quickly as
         possible,process the VARYING_SSA_EDGES worklist first.  */
         possible,process the VARYING_SSA_EDGES worklist first.  */
      process_ssa_edge_worklist (&varying_ssa_edges);
      process_ssa_edge_worklist (&varying_ssa_edges);
 
 
      /* Now process the INTERESTING_SSA_EDGES worklist.  */
      /* Now process the INTERESTING_SSA_EDGES worklist.  */
      process_ssa_edge_worklist (&interesting_ssa_edges);
      process_ssa_edge_worklist (&interesting_ssa_edges);
    }
    }
 
 
  ssa_prop_fini ();
  ssa_prop_fini ();
}
}
 
 
 
 
/* Return the first V_MAY_DEF or V_MUST_DEF operand for STMT.  */
/* Return the first V_MAY_DEF or V_MUST_DEF operand for STMT.  */
 
 
tree
tree
first_vdef (tree stmt)
first_vdef (tree stmt)
{
{
  ssa_op_iter iter;
  ssa_op_iter iter;
  tree op;
  tree op;
 
 
  /* Simply return the first operand we arrive at.  */
  /* Simply return the first operand we arrive at.  */
  FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_DEFS)
  FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_VIRTUAL_DEFS)
    return (op);
    return (op);
 
 
  gcc_unreachable ();
  gcc_unreachable ();
}
}
 
 
 
 
/* Return true if STMT is of the form 'LHS = mem_ref', where 'mem_ref'
/* Return true if STMT is of the form 'LHS = mem_ref', where 'mem_ref'
   is a non-volatile pointer dereference, a structure reference or a
   is a non-volatile pointer dereference, a structure reference or a
   reference to a single _DECL.  Ignore volatile memory references
   reference to a single _DECL.  Ignore volatile memory references
   because they are not interesting for the optimizers.  */
   because they are not interesting for the optimizers.  */
 
 
bool
bool
stmt_makes_single_load (tree stmt)
stmt_makes_single_load (tree stmt)
{
{
  tree rhs;
  tree rhs;
 
 
  if (TREE_CODE (stmt) != MODIFY_EXPR)
  if (TREE_CODE (stmt) != MODIFY_EXPR)
    return false;
    return false;
 
 
  if (ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF|SSA_OP_VUSE))
  if (ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF|SSA_OP_VUSE))
    return false;
    return false;
 
 
  rhs = TREE_OPERAND (stmt, 1);
  rhs = TREE_OPERAND (stmt, 1);
  STRIP_NOPS (rhs);
  STRIP_NOPS (rhs);
 
 
  return (!TREE_THIS_VOLATILE (rhs)
  return (!TREE_THIS_VOLATILE (rhs)
          && (DECL_P (rhs)
          && (DECL_P (rhs)
              || REFERENCE_CLASS_P (rhs)));
              || REFERENCE_CLASS_P (rhs)));
}
}
 
 
 
 
/* Return true if STMT is of the form 'mem_ref = RHS', where 'mem_ref'
/* Return true if STMT is of the form 'mem_ref = RHS', where 'mem_ref'
   is a non-volatile pointer dereference, a structure reference or a
   is a non-volatile pointer dereference, a structure reference or a
   reference to a single _DECL.  Ignore volatile memory references
   reference to a single _DECL.  Ignore volatile memory references
   because they are not interesting for the optimizers.  */
   because they are not interesting for the optimizers.  */
 
 
bool
bool
stmt_makes_single_store (tree stmt)
stmt_makes_single_store (tree stmt)
{
{
  tree lhs;
  tree lhs;
 
 
  if (TREE_CODE (stmt) != MODIFY_EXPR)
  if (TREE_CODE (stmt) != MODIFY_EXPR)
    return false;
    return false;
 
 
  if (ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF|SSA_OP_VMUSTDEF))
  if (ZERO_SSA_OPERANDS (stmt, SSA_OP_VMAYDEF|SSA_OP_VMUSTDEF))
    return false;
    return false;
 
 
  lhs = TREE_OPERAND (stmt, 0);
  lhs = TREE_OPERAND (stmt, 0);
  STRIP_NOPS (lhs);
  STRIP_NOPS (lhs);
 
 
  return (!TREE_THIS_VOLATILE (lhs)
  return (!TREE_THIS_VOLATILE (lhs)
          && (DECL_P (lhs)
          && (DECL_P (lhs)
              || REFERENCE_CLASS_P (lhs)));
              || REFERENCE_CLASS_P (lhs)));
}
}
 
 
 
 
/* If STMT makes a single memory load and all the virtual use operands
/* If STMT makes a single memory load and all the virtual use operands
   have the same value in array VALUES, return it.  Otherwise, return
   have the same value in array VALUES, return it.  Otherwise, return
   NULL.  */
   NULL.  */
 
 
prop_value_t *
prop_value_t *
get_value_loaded_by (tree stmt, prop_value_t *values)
get_value_loaded_by (tree stmt, prop_value_t *values)
{
{
  ssa_op_iter i;
  ssa_op_iter i;
  tree vuse;
  tree vuse;
  prop_value_t *prev_val = NULL;
  prop_value_t *prev_val = NULL;
  prop_value_t *val = NULL;
  prop_value_t *val = NULL;
 
 
  FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, i, SSA_OP_VIRTUAL_USES)
  FOR_EACH_SSA_TREE_OPERAND (vuse, stmt, i, SSA_OP_VIRTUAL_USES)
    {
    {
      val = &values[SSA_NAME_VERSION (vuse)];
      val = &values[SSA_NAME_VERSION (vuse)];
      if (prev_val && prev_val->value != val->value)
      if (prev_val && prev_val->value != val->value)
        return NULL;
        return NULL;
      prev_val = val;
      prev_val = val;
    }
    }
 
 
  return val;
  return val;
}
}
 
 
 
 
/* Propagation statistics.  */
/* Propagation statistics.  */
struct prop_stats_d
struct prop_stats_d
{
{
  long num_const_prop;
  long num_const_prop;
  long num_copy_prop;
  long num_copy_prop;
  long num_pred_folded;
  long num_pred_folded;
};
};
 
 
static struct prop_stats_d prop_stats;
static struct prop_stats_d prop_stats;
 
 
/* Replace USE references in statement STMT with the values stored in
/* Replace USE references in statement STMT with the values stored in
   PROP_VALUE. Return true if at least one reference was replaced.  If
   PROP_VALUE. Return true if at least one reference was replaced.  If
   REPLACED_ADDRESSES_P is given, it will be set to true if an address
   REPLACED_ADDRESSES_P is given, it will be set to true if an address
   constant was replaced.  */
   constant was replaced.  */
 
 
bool
bool
replace_uses_in (tree stmt, bool *replaced_addresses_p,
replace_uses_in (tree stmt, bool *replaced_addresses_p,
                 prop_value_t *prop_value)
                 prop_value_t *prop_value)
{
{
  bool replaced = false;
  bool replaced = false;
  use_operand_p use;
  use_operand_p use;
  ssa_op_iter iter;
  ssa_op_iter iter;
 
 
  FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE)
  FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE)
    {
    {
      tree tuse = USE_FROM_PTR (use);
      tree tuse = USE_FROM_PTR (use);
      tree val = prop_value[SSA_NAME_VERSION (tuse)].value;
      tree val = prop_value[SSA_NAME_VERSION (tuse)].value;
 
 
      if (val == tuse || val == NULL_TREE)
      if (val == tuse || val == NULL_TREE)
        continue;
        continue;
 
 
      if (TREE_CODE (stmt) == ASM_EXPR
      if (TREE_CODE (stmt) == ASM_EXPR
          && !may_propagate_copy_into_asm (tuse))
          && !may_propagate_copy_into_asm (tuse))
        continue;
        continue;
 
 
      if (!may_propagate_copy (tuse, val))
      if (!may_propagate_copy (tuse, val))
        continue;
        continue;
 
 
      if (TREE_CODE (val) != SSA_NAME)
      if (TREE_CODE (val) != SSA_NAME)
        prop_stats.num_const_prop++;
        prop_stats.num_const_prop++;
      else
      else
        prop_stats.num_copy_prop++;
        prop_stats.num_copy_prop++;
 
 
      propagate_value (use, val);
      propagate_value (use, val);
 
 
      replaced = true;
      replaced = true;
      if (POINTER_TYPE_P (TREE_TYPE (tuse)) && replaced_addresses_p)
      if (POINTER_TYPE_P (TREE_TYPE (tuse)) && replaced_addresses_p)
        *replaced_addresses_p = true;
        *replaced_addresses_p = true;
    }
    }
 
 
  return replaced;
  return replaced;
}
}
 
 
 
 
/* Replace the VUSE references in statement STMT with the values
/* Replace the VUSE references in statement STMT with the values
   stored in PROP_VALUE.  Return true if a reference was replaced.  If
   stored in PROP_VALUE.  Return true if a reference was replaced.  If
   REPLACED_ADDRESSES_P is given, it will be set to true if an address
   REPLACED_ADDRESSES_P is given, it will be set to true if an address
   constant was replaced.
   constant was replaced.
 
 
   Replacing VUSE operands is slightly more complex than replacing
   Replacing VUSE operands is slightly more complex than replacing
   regular USEs.  We are only interested in two types of replacements
   regular USEs.  We are only interested in two types of replacements
   here:
   here:
 
 
   1- If the value to be replaced is a constant or an SSA name for a
   1- If the value to be replaced is a constant or an SSA name for a
      GIMPLE register, then we are making a copy/constant propagation
      GIMPLE register, then we are making a copy/constant propagation
      from a memory store.  For instance,
      from a memory store.  For instance,
 
 
        # a_3 = V_MAY_DEF <a_2>
        # a_3 = V_MAY_DEF <a_2>
        a.b = x_1;
        a.b = x_1;
        ...
        ...
        # VUSE <a_3>
        # VUSE <a_3>
        y_4 = a.b;
        y_4 = a.b;
 
 
      This replacement is only possible iff STMT is an assignment
      This replacement is only possible iff STMT is an assignment
      whose RHS is identical to the LHS of the statement that created
      whose RHS is identical to the LHS of the statement that created
      the VUSE(s) that we are replacing.  Otherwise, we may do the
      the VUSE(s) that we are replacing.  Otherwise, we may do the
      wrong replacement:
      wrong replacement:
 
 
        # a_3 = V_MAY_DEF <a_2>
        # a_3 = V_MAY_DEF <a_2>
        # b_5 = V_MAY_DEF <b_4>
        # b_5 = V_MAY_DEF <b_4>
        *p = 10;
        *p = 10;
        ...
        ...
        # VUSE <b_5>
        # VUSE <b_5>
        x_8 = b;
        x_8 = b;
 
 
      Even though 'b_5' acquires the value '10' during propagation,
      Even though 'b_5' acquires the value '10' during propagation,
      there is no way for the propagator to tell whether the
      there is no way for the propagator to tell whether the
      replacement is correct in every reached use, because values are
      replacement is correct in every reached use, because values are
      computed at definition sites.  Therefore, when doing final
      computed at definition sites.  Therefore, when doing final
      substitution of propagated values, we have to check each use
      substitution of propagated values, we have to check each use
      site.  Since the RHS of STMT ('b') is different from the LHS of
      site.  Since the RHS of STMT ('b') is different from the LHS of
      the originating statement ('*p'), we cannot replace 'b' with
      the originating statement ('*p'), we cannot replace 'b' with
      '10'.
      '10'.
 
 
      Similarly, when merging values from PHI node arguments,
      Similarly, when merging values from PHI node arguments,
      propagators need to take care not to merge the same values
      propagators need to take care not to merge the same values
      stored in different locations:
      stored in different locations:
 
 
                if (...)
                if (...)
                  # a_3 = V_MAY_DEF <a_2>
                  # a_3 = V_MAY_DEF <a_2>
                  a.b = 3;
                  a.b = 3;
                else
                else
                  # a_4 = V_MAY_DEF <a_2>
                  # a_4 = V_MAY_DEF <a_2>
                  a.c = 3;
                  a.c = 3;
                # a_5 = PHI <a_3, a_4>
                # a_5 = PHI <a_3, a_4>
 
 
      It would be wrong to propagate '3' into 'a_5' because that
      It would be wrong to propagate '3' into 'a_5' because that
      operation merges two stores to different memory locations.
      operation merges two stores to different memory locations.
 
 
 
 
   2- If the value to be replaced is an SSA name for a virtual
   2- If the value to be replaced is an SSA name for a virtual
      register, then we simply replace each VUSE operand with its
      register, then we simply replace each VUSE operand with its
      value from PROP_VALUE.  This is the same replacement done by
      value from PROP_VALUE.  This is the same replacement done by
      replace_uses_in.  */
      replace_uses_in.  */
 
 
static bool
static bool
replace_vuses_in (tree stmt, bool *replaced_addresses_p,
replace_vuses_in (tree stmt, bool *replaced_addresses_p,
                  prop_value_t *prop_value)
                  prop_value_t *prop_value)
{
{
  bool replaced = false;
  bool replaced = false;
  ssa_op_iter iter;
  ssa_op_iter iter;
  use_operand_p vuse;
  use_operand_p vuse;
 
 
  if (stmt_makes_single_load (stmt))
  if (stmt_makes_single_load (stmt))
    {
    {
      /* If STMT is an assignment whose RHS is a single memory load,
      /* If STMT is an assignment whose RHS is a single memory load,
         see if we are trying to propagate a constant or a GIMPLE
         see if we are trying to propagate a constant or a GIMPLE
         register (case #1 above).  */
         register (case #1 above).  */
      prop_value_t *val = get_value_loaded_by (stmt, prop_value);
      prop_value_t *val = get_value_loaded_by (stmt, prop_value);
      tree rhs = TREE_OPERAND (stmt, 1);
      tree rhs = TREE_OPERAND (stmt, 1);
 
 
      if (val
      if (val
          && val->value
          && val->value
          && (is_gimple_reg (val->value)
          && (is_gimple_reg (val->value)
              || is_gimple_min_invariant (val->value))
              || is_gimple_min_invariant (val->value))
          && simple_cst_equal (rhs, val->mem_ref) == 1)
          && simple_cst_equal (rhs, val->mem_ref) == 1)
 
 
        {
        {
          /* If we are replacing a constant address, inform our
          /* If we are replacing a constant address, inform our
             caller.  */
             caller.  */
          if (TREE_CODE (val->value) != SSA_NAME
          if (TREE_CODE (val->value) != SSA_NAME
              && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1)))
              && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (stmt, 1)))
              && replaced_addresses_p)
              && replaced_addresses_p)
            *replaced_addresses_p = true;
            *replaced_addresses_p = true;
 
 
          /* We can only perform the substitution if the load is done
          /* We can only perform the substitution if the load is done
             from the same memory location as the original store.
             from the same memory location as the original store.
             Since we already know that there are no intervening
             Since we already know that there are no intervening
             stores between DEF_STMT and STMT, we only need to check
             stores between DEF_STMT and STMT, we only need to check
             that the RHS of STMT is the same as the memory reference
             that the RHS of STMT is the same as the memory reference
             propagated together with the value.  */
             propagated together with the value.  */
          TREE_OPERAND (stmt, 1) = val->value;
          TREE_OPERAND (stmt, 1) = val->value;
 
 
          if (TREE_CODE (val->value) != SSA_NAME)
          if (TREE_CODE (val->value) != SSA_NAME)
            prop_stats.num_const_prop++;
            prop_stats.num_const_prop++;
          else
          else
            prop_stats.num_copy_prop++;
            prop_stats.num_copy_prop++;
 
 
          /* Since we have replaced the whole RHS of STMT, there
          /* Since we have replaced the whole RHS of STMT, there
             is no point in checking the other VUSEs, as they will
             is no point in checking the other VUSEs, as they will
             all have the same value.  */
             all have the same value.  */
          return true;
          return true;
        }
        }
    }
    }
 
 
  /* Otherwise, the values for every VUSE operand must be other
  /* Otherwise, the values for every VUSE operand must be other
     SSA_NAMEs that can be propagated into STMT.  */
     SSA_NAMEs that can be propagated into STMT.  */
  FOR_EACH_SSA_USE_OPERAND (vuse, stmt, iter, SSA_OP_VIRTUAL_USES)
  FOR_EACH_SSA_USE_OPERAND (vuse, stmt, iter, SSA_OP_VIRTUAL_USES)
    {
    {
      tree var = USE_FROM_PTR (vuse);
      tree var = USE_FROM_PTR (vuse);
      tree val = prop_value[SSA_NAME_VERSION (var)].value;
      tree val = prop_value[SSA_NAME_VERSION (var)].value;
 
 
      if (val == NULL_TREE || var == val)
      if (val == NULL_TREE || var == val)
        continue;
        continue;
 
 
      /* Constants and copies propagated between real and virtual
      /* Constants and copies propagated between real and virtual
         operands are only possible in the cases handled above.  They
         operands are only possible in the cases handled above.  They
         should be ignored in any other context.  */
         should be ignored in any other context.  */
      if (is_gimple_min_invariant (val) || is_gimple_reg (val))
      if (is_gimple_min_invariant (val) || is_gimple_reg (val))
        continue;
        continue;
 
 
      propagate_value (vuse, val);
      propagate_value (vuse, val);
      prop_stats.num_copy_prop++;
      prop_stats.num_copy_prop++;
      replaced = true;
      replaced = true;
    }
    }
 
 
  return replaced;
  return replaced;
}
}
 
 
 
 
/* Replace propagated values into all the arguments for PHI using the
/* Replace propagated values into all the arguments for PHI using the
   values from PROP_VALUE.  */
   values from PROP_VALUE.  */
 
 
static void
static void
replace_phi_args_in (tree phi, prop_value_t *prop_value)
replace_phi_args_in (tree phi, prop_value_t *prop_value)
{
{
  int i;
  int i;
  bool replaced = false;
  bool replaced = false;
  tree prev_phi = NULL;
  tree prev_phi = NULL;
 
 
  if (dump_file && (dump_flags & TDF_DETAILS))
  if (dump_file && (dump_flags & TDF_DETAILS))
    prev_phi = unshare_expr (phi);
    prev_phi = unshare_expr (phi);
 
 
  for (i = 0; i < PHI_NUM_ARGS (phi); i++)
  for (i = 0; i < PHI_NUM_ARGS (phi); i++)
    {
    {
      tree arg = PHI_ARG_DEF (phi, i);
      tree arg = PHI_ARG_DEF (phi, i);
 
 
      if (TREE_CODE (arg) == SSA_NAME)
      if (TREE_CODE (arg) == SSA_NAME)
        {
        {
          tree val = prop_value[SSA_NAME_VERSION (arg)].value;
          tree val = prop_value[SSA_NAME_VERSION (arg)].value;
 
 
          if (val && val != arg && may_propagate_copy (arg, val))
          if (val && val != arg && may_propagate_copy (arg, val))
            {
            {
              if (TREE_CODE (val) != SSA_NAME)
              if (TREE_CODE (val) != SSA_NAME)
                prop_stats.num_const_prop++;
                prop_stats.num_const_prop++;
              else
              else
                prop_stats.num_copy_prop++;
                prop_stats.num_copy_prop++;
 
 
              propagate_value (PHI_ARG_DEF_PTR (phi, i), val);
              propagate_value (PHI_ARG_DEF_PTR (phi, i), val);
              replaced = true;
              replaced = true;
 
 
              /* If we propagated a copy and this argument flows
              /* If we propagated a copy and this argument flows
                 through an abnormal edge, update the replacement
                 through an abnormal edge, update the replacement
                 accordingly.  */
                 accordingly.  */
              if (TREE_CODE (val) == SSA_NAME
              if (TREE_CODE (val) == SSA_NAME
                  && PHI_ARG_EDGE (phi, i)->flags & EDGE_ABNORMAL)
                  && PHI_ARG_EDGE (phi, i)->flags & EDGE_ABNORMAL)
                SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
                SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1;
            }
            }
        }
        }
    }
    }
 
 
  if (replaced && dump_file && (dump_flags & TDF_DETAILS))
  if (replaced && dump_file && (dump_flags & TDF_DETAILS))
    {
    {
      fprintf (dump_file, "Folded PHI node: ");
      fprintf (dump_file, "Folded PHI node: ");
      print_generic_stmt (dump_file, prev_phi, TDF_SLIM);
      print_generic_stmt (dump_file, prev_phi, TDF_SLIM);
      fprintf (dump_file, "           into: ");
      fprintf (dump_file, "           into: ");
      print_generic_stmt (dump_file, phi, TDF_SLIM);
      print_generic_stmt (dump_file, phi, TDF_SLIM);
      fprintf (dump_file, "\n");
      fprintf (dump_file, "\n");
    }
    }
}
}
 
 
 
 
/* If STMT has a predicate whose value can be computed using the value
/* If STMT has a predicate whose value can be computed using the value
   range information computed by VRP, compute its value and return true.
   range information computed by VRP, compute its value and return true.
   Otherwise, return false.  */
   Otherwise, return false.  */
 
 
static bool
static bool
fold_predicate_in (tree stmt)
fold_predicate_in (tree stmt)
{
{
  tree *pred_p = NULL;
  tree *pred_p = NULL;
  bool modify_expr_p = false;
  bool modify_expr_p = false;
  tree val;
  tree val;
 
 
  if (TREE_CODE (stmt) == MODIFY_EXPR
  if (TREE_CODE (stmt) == MODIFY_EXPR
      && COMPARISON_CLASS_P (TREE_OPERAND (stmt, 1)))
      && COMPARISON_CLASS_P (TREE_OPERAND (stmt, 1)))
    {
    {
      modify_expr_p = true;
      modify_expr_p = true;
      pred_p = &TREE_OPERAND (stmt, 1);
      pred_p = &TREE_OPERAND (stmt, 1);
    }
    }
  else if (TREE_CODE (stmt) == COND_EXPR)
  else if (TREE_CODE (stmt) == COND_EXPR)
    pred_p = &COND_EXPR_COND (stmt);
    pred_p = &COND_EXPR_COND (stmt);
  else
  else
    return false;
    return false;
 
 
  val = vrp_evaluate_conditional (*pred_p, stmt);
  val = vrp_evaluate_conditional (*pred_p, stmt);
  if (val)
  if (val)
    {
    {
      if (modify_expr_p)
      if (modify_expr_p)
        val = fold_convert (TREE_TYPE (*pred_p), val);
        val = fold_convert (TREE_TYPE (*pred_p), val);
 
 
      if (dump_file)
      if (dump_file)
        {
        {
          fprintf (dump_file, "Folding predicate ");
          fprintf (dump_file, "Folding predicate ");
          print_generic_expr (dump_file, *pred_p, 0);
          print_generic_expr (dump_file, *pred_p, 0);
          fprintf (dump_file, " to ");
          fprintf (dump_file, " to ");
          print_generic_expr (dump_file, val, 0);
          print_generic_expr (dump_file, val, 0);
          fprintf (dump_file, "\n");
          fprintf (dump_file, "\n");
        }
        }
 
 
      prop_stats.num_pred_folded++;
      prop_stats.num_pred_folded++;
      *pred_p = val;
      *pred_p = val;
      return true;
      return true;
    }
    }
 
 
  return false;
  return false;
}
}
 
 
 
 
/* Perform final substitution and folding of propagated values.
/* Perform final substitution and folding of propagated values.
 
 
   PROP_VALUE[I] contains the single value that should be substituted
   PROP_VALUE[I] contains the single value that should be substituted
   at every use of SSA name N_I.  If PROP_VALUE is NULL, no values are
   at every use of SSA name N_I.  If PROP_VALUE is NULL, no values are
   substituted.
   substituted.
 
 
   If USE_RANGES_P is true, statements that contain predicate
   If USE_RANGES_P is true, statements that contain predicate
   expressions are evaluated with a call to vrp_evaluate_conditional.
   expressions are evaluated with a call to vrp_evaluate_conditional.
   This will only give meaningful results when called from tree-vrp.c
   This will only give meaningful results when called from tree-vrp.c
   (the information used by vrp_evaluate_conditional is built by the
   (the information used by vrp_evaluate_conditional is built by the
   VRP pass).  */
   VRP pass).  */
 
 
void
void
substitute_and_fold (prop_value_t *prop_value, bool use_ranges_p)
substitute_and_fold (prop_value_t *prop_value, bool use_ranges_p)
{
{
  basic_block bb;
  basic_block bb;
 
 
  if (prop_value == NULL && !use_ranges_p)
  if (prop_value == NULL && !use_ranges_p)
    return;
    return;
 
 
  if (dump_file && (dump_flags & TDF_DETAILS))
  if (dump_file && (dump_flags & TDF_DETAILS))
    fprintf (dump_file, "\nSubstituing values and folding statements\n\n");
    fprintf (dump_file, "\nSubstituing values and folding statements\n\n");
 
 
  memset (&prop_stats, 0, sizeof (prop_stats));
  memset (&prop_stats, 0, sizeof (prop_stats));
 
 
  /* Substitute values in every statement of every basic block.  */
  /* Substitute values in every statement of every basic block.  */
  FOR_EACH_BB (bb)
  FOR_EACH_BB (bb)
    {
    {
      block_stmt_iterator i;
      block_stmt_iterator i;
      tree phi;
      tree phi;
 
 
      /* Propagate known values into PHI nodes.  */
      /* Propagate known values into PHI nodes.  */
      if (prop_value)
      if (prop_value)
        for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
        for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
          replace_phi_args_in (phi, prop_value);
          replace_phi_args_in (phi, prop_value);
 
 
      for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
      for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
        {
        {
          bool replaced_address, did_replace;
          bool replaced_address, did_replace;
          tree prev_stmt = NULL;
          tree prev_stmt = NULL;
          tree stmt = bsi_stmt (i);
          tree stmt = bsi_stmt (i);
 
 
          /* Ignore ASSERT_EXPRs.  They are used by VRP to generate
          /* Ignore ASSERT_EXPRs.  They are used by VRP to generate
             range information for names and they are discarded
             range information for names and they are discarded
             afterwards.  */
             afterwards.  */
          if (TREE_CODE (stmt) == MODIFY_EXPR
          if (TREE_CODE (stmt) == MODIFY_EXPR
              && TREE_CODE (TREE_OPERAND (stmt, 1)) == ASSERT_EXPR)
              && TREE_CODE (TREE_OPERAND (stmt, 1)) == ASSERT_EXPR)
            continue;
            continue;
 
 
          /* Replace the statement with its folded version and mark it
          /* Replace the statement with its folded version and mark it
             folded.  */
             folded.  */
          did_replace = false;
          did_replace = false;
          replaced_address = false;
          replaced_address = false;
          if (dump_file && (dump_flags & TDF_DETAILS))
          if (dump_file && (dump_flags & TDF_DETAILS))
            prev_stmt = unshare_expr (stmt);
            prev_stmt = unshare_expr (stmt);
 
 
          /* If we have range information, see if we can fold
          /* If we have range information, see if we can fold
             predicate expressions.  */
             predicate expressions.  */
          if (use_ranges_p)
          if (use_ranges_p)
            did_replace = fold_predicate_in (stmt);
            did_replace = fold_predicate_in (stmt);
 
 
          if (prop_value)
          if (prop_value)
            {
            {
              /* Only replace real uses if we couldn't fold the
              /* Only replace real uses if we couldn't fold the
                 statement using value range information (value range
                 statement using value range information (value range
                 information is not collected on virtuals, so we only
                 information is not collected on virtuals, so we only
                 need to check this for real uses).  */
                 need to check this for real uses).  */
              if (!did_replace)
              if (!did_replace)
                did_replace |= replace_uses_in (stmt, &replaced_address,
                did_replace |= replace_uses_in (stmt, &replaced_address,
                                                prop_value);
                                                prop_value);
 
 
              did_replace |= replace_vuses_in (stmt, &replaced_address,
              did_replace |= replace_vuses_in (stmt, &replaced_address,
                                               prop_value);
                                               prop_value);
            }
            }
 
 
          /* If we made a replacement, fold and cleanup the statement.  */
          /* If we made a replacement, fold and cleanup the statement.  */
          if (did_replace)
          if (did_replace)
            {
            {
              tree old_stmt = stmt;
              tree old_stmt = stmt;
              tree rhs;
              tree rhs;
 
 
              fold_stmt (bsi_stmt_ptr (i));
              fold_stmt (bsi_stmt_ptr (i));
              stmt = bsi_stmt (i);
              stmt = bsi_stmt (i);
 
 
              /* If we folded a builtin function, we'll likely
              /* If we folded a builtin function, we'll likely
                 need to rename VDEFs.  */
                 need to rename VDEFs.  */
              mark_new_vars_to_rename (stmt);
              mark_new_vars_to_rename (stmt);
 
 
              /* If we cleaned up EH information from the statement,
              /* If we cleaned up EH information from the statement,
                 remove EH edges.  */
                 remove EH edges.  */
              if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
              if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt))
                tree_purge_dead_eh_edges (bb);
                tree_purge_dead_eh_edges (bb);
 
 
              rhs = get_rhs (stmt);
              rhs = get_rhs (stmt);
              if (TREE_CODE (rhs) == ADDR_EXPR)
              if (TREE_CODE (rhs) == ADDR_EXPR)
                recompute_tree_invariant_for_addr_expr (rhs);
                recompute_tree_invariant_for_addr_expr (rhs);
 
 
              if (dump_file && (dump_flags & TDF_DETAILS))
              if (dump_file && (dump_flags & TDF_DETAILS))
                {
                {
                  fprintf (dump_file, "Folded statement: ");
                  fprintf (dump_file, "Folded statement: ");
                  print_generic_stmt (dump_file, prev_stmt, TDF_SLIM);
                  print_generic_stmt (dump_file, prev_stmt, TDF_SLIM);
                  fprintf (dump_file, "            into: ");
                  fprintf (dump_file, "            into: ");
                  print_generic_stmt (dump_file, stmt, TDF_SLIM);
                  print_generic_stmt (dump_file, stmt, TDF_SLIM);
                  fprintf (dump_file, "\n");
                  fprintf (dump_file, "\n");
                }
                }
            }
            }
 
 
          /* Some statements may be simplified using ranges.  For
          /* Some statements may be simplified using ranges.  For
             example, division may be replaced by shifts, modulo
             example, division may be replaced by shifts, modulo
             replaced with bitwise and, etc.   Do this after
             replaced with bitwise and, etc.   Do this after
             substituting constants, folding, etc so that we're
             substituting constants, folding, etc so that we're
             presented with a fully propagated, canonicalized
             presented with a fully propagated, canonicalized
             statement.  */
             statement.  */
          if (use_ranges_p)
          if (use_ranges_p)
            simplify_stmt_using_ranges (stmt);
            simplify_stmt_using_ranges (stmt);
 
 
        }
        }
    }
    }
 
 
  if (dump_file && (dump_flags & TDF_STATS))
  if (dump_file && (dump_flags & TDF_STATS))
    {
    {
      fprintf (dump_file, "Constants propagated: %6ld\n",
      fprintf (dump_file, "Constants propagated: %6ld\n",
               prop_stats.num_const_prop);
               prop_stats.num_const_prop);
      fprintf (dump_file, "Copies propagated:    %6ld\n",
      fprintf (dump_file, "Copies propagated:    %6ld\n",
               prop_stats.num_copy_prop);
               prop_stats.num_copy_prop);
      fprintf (dump_file, "Predicates folded:    %6ld\n",
      fprintf (dump_file, "Predicates folded:    %6ld\n",
               prop_stats.num_pred_folded);
               prop_stats.num_pred_folded);
    }
    }
}
}
 
 
#include "gt-tree-ssa-propagate.h"
#include "gt-tree-ssa-propagate.h"
 
 

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.