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[/] [openrisc/] [trunk/] [gnu-stable/] [gcc-4.5.1/] [gcc/] [dce.c] - Diff between revs 280 and 816

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/* RTL dead code elimination.
/* RTL dead code elimination.
   Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
   Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
 
 
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 "hashtab.h"
#include "hashtab.h"
#include "tm.h"
#include "tm.h"
#include "rtl.h"
#include "rtl.h"
#include "tree.h"
#include "tree.h"
#include "regs.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "hard-reg-set.h"
#include "flags.h"
#include "flags.h"
#include "except.h"
#include "except.h"
#include "df.h"
#include "df.h"
#include "cselib.h"
#include "cselib.h"
#include "dce.h"
#include "dce.h"
#include "timevar.h"
#include "timevar.h"
#include "tree-pass.h"
#include "tree-pass.h"
#include "dbgcnt.h"
#include "dbgcnt.h"
#include "tm_p.h"
#include "tm_p.h"
 
 
 
 
/* -------------------------------------------------------------------------
/* -------------------------------------------------------------------------
   Core mark/delete routines
   Core mark/delete routines
   ------------------------------------------------------------------------- */
   ------------------------------------------------------------------------- */
 
 
/* True if we are invoked while the df engine is running; in this case,
/* True if we are invoked while the df engine is running; in this case,
   we don't want to reenter it.  */
   we don't want to reenter it.  */
static bool df_in_progress = false;
static bool df_in_progress = false;
 
 
/* Instructions that have been marked but whose dependencies have not
/* Instructions that have been marked but whose dependencies have not
   yet been processed.  */
   yet been processed.  */
static VEC(rtx,heap) *worklist;
static VEC(rtx,heap) *worklist;
 
 
/* Bitmap of instructions marked as needed indexed by INSN_UID.  */
/* Bitmap of instructions marked as needed indexed by INSN_UID.  */
static sbitmap marked;
static sbitmap marked;
 
 
/* Bitmap obstacks used for block processing by the fast algorithm.  */
/* Bitmap obstacks used for block processing by the fast algorithm.  */
static bitmap_obstack dce_blocks_bitmap_obstack;
static bitmap_obstack dce_blocks_bitmap_obstack;
static bitmap_obstack dce_tmp_bitmap_obstack;
static bitmap_obstack dce_tmp_bitmap_obstack;
 
 
static bool find_call_stack_args (rtx, bool, bool, bitmap);
static bool find_call_stack_args (rtx, bool, bool, bitmap);
 
 
/* A subroutine for which BODY is part of the instruction being tested;
/* A subroutine for which BODY is part of the instruction being tested;
   either the top-level pattern, or an element of a PARALLEL.  The
   either the top-level pattern, or an element of a PARALLEL.  The
   instruction is known not to be a bare USE or CLOBBER.  */
   instruction is known not to be a bare USE or CLOBBER.  */
 
 
static bool
static bool
deletable_insn_p_1 (rtx body)
deletable_insn_p_1 (rtx body)
{
{
  switch (GET_CODE (body))
  switch (GET_CODE (body))
    {
    {
    case PREFETCH:
    case PREFETCH:
    case TRAP_IF:
    case TRAP_IF:
      /* The UNSPEC case was added here because the ia-64 claims that
      /* The UNSPEC case was added here because the ia-64 claims that
         USEs do not work after reload and generates UNSPECS rather
         USEs do not work after reload and generates UNSPECS rather
         than USEs.  Since dce is run after reload we need to avoid
         than USEs.  Since dce is run after reload we need to avoid
         deleting these even if they are dead.  If it turns out that
         deleting these even if they are dead.  If it turns out that
         USEs really do work after reload, the ia-64 should be
         USEs really do work after reload, the ia-64 should be
         changed, and the UNSPEC case can be removed.  */
         changed, and the UNSPEC case can be removed.  */
    case UNSPEC:
    case UNSPEC:
      return false;
      return false;
 
 
    default:
    default:
      return !volatile_refs_p (body);
      return !volatile_refs_p (body);
    }
    }
}
}
 
 
 
 
/* Return true if INSN is a normal instruction that can be deleted by
/* Return true if INSN is a normal instruction that can be deleted by
   the DCE pass.  */
   the DCE pass.  */
 
 
static bool
static bool
deletable_insn_p (rtx insn, bool fast, bitmap arg_stores)
deletable_insn_p (rtx insn, bool fast, bitmap arg_stores)
{
{
  rtx body, x;
  rtx body, x;
  int i;
  int i;
 
 
  if (CALL_P (insn)
  if (CALL_P (insn)
      /* We cannot delete calls inside of the recursive dce because
      /* We cannot delete calls inside of the recursive dce because
         this may cause basic blocks to be deleted and this messes up
         this may cause basic blocks to be deleted and this messes up
         the rest of the stack of optimization passes.  */
         the rest of the stack of optimization passes.  */
      && (!df_in_progress)
      && (!df_in_progress)
      /* We cannot delete pure or const sibling calls because it is
      /* We cannot delete pure or const sibling calls because it is
         hard to see the result.  */
         hard to see the result.  */
      && (!SIBLING_CALL_P (insn))
      && (!SIBLING_CALL_P (insn))
      /* We can delete dead const or pure calls as long as they do not
      /* We can delete dead const or pure calls as long as they do not
         infinite loop.  */
         infinite loop.  */
      && (RTL_CONST_OR_PURE_CALL_P (insn)
      && (RTL_CONST_OR_PURE_CALL_P (insn)
          && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
          && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
    return find_call_stack_args (insn, false, fast, arg_stores);
    return find_call_stack_args (insn, false, fast, arg_stores);
 
 
  /* Don't delete jumps, notes and the like.  */
  /* Don't delete jumps, notes and the like.  */
  if (!NONJUMP_INSN_P (insn))
  if (!NONJUMP_INSN_P (insn))
    return false;
    return false;
 
 
  /* Don't delete insns that can throw.  */
  /* Don't delete insns that can throw.  */
  if (!insn_nothrow_p (insn))
  if (!insn_nothrow_p (insn))
    return false;
    return false;
 
 
  body = PATTERN (insn);
  body = PATTERN (insn);
  switch (GET_CODE (body))
  switch (GET_CODE (body))
    {
    {
    case USE:
    case USE:
    case VAR_LOCATION:
    case VAR_LOCATION:
      return false;
      return false;
 
 
    case CLOBBER:
    case CLOBBER:
      if (fast)
      if (fast)
        {
        {
          /* A CLOBBER of a dead pseudo register serves no purpose.
          /* A CLOBBER of a dead pseudo register serves no purpose.
             That is not necessarily true for hard registers until
             That is not necessarily true for hard registers until
             after reload.  */
             after reload.  */
          x = XEXP (body, 0);
          x = XEXP (body, 0);
          return REG_P (x) && (!HARD_REGISTER_P (x) || reload_completed);
          return REG_P (x) && (!HARD_REGISTER_P (x) || reload_completed);
        }
        }
      else
      else
        /* Because of the way that use-def chains are built, it is not
        /* Because of the way that use-def chains are built, it is not
           possible to tell if the clobber is dead because it can
           possible to tell if the clobber is dead because it can
           never be the target of a use-def chain.  */
           never be the target of a use-def chain.  */
        return false;
        return false;
 
 
    case PARALLEL:
    case PARALLEL:
      for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
      for (i = XVECLEN (body, 0) - 1; i >= 0; i--)
        if (!deletable_insn_p_1 (XVECEXP (body, 0, i)))
        if (!deletable_insn_p_1 (XVECEXP (body, 0, i)))
          return false;
          return false;
      return true;
      return true;
 
 
    default:
    default:
      return deletable_insn_p_1 (body);
      return deletable_insn_p_1 (body);
    }
    }
}
}
 
 
 
 
/* Return true if INSN has been marked as needed.  */
/* Return true if INSN has been marked as needed.  */
 
 
static inline int
static inline int
marked_insn_p (rtx insn)
marked_insn_p (rtx insn)
{
{
  /* Artificial defs are always needed and they do not have an insn.
  /* Artificial defs are always needed and they do not have an insn.
     We should never see them here.  */
     We should never see them here.  */
  gcc_assert (insn);
  gcc_assert (insn);
  return TEST_BIT (marked, INSN_UID (insn));
  return TEST_BIT (marked, INSN_UID (insn));
}
}
 
 
 
 
/* If INSN has not yet been marked as needed, mark it now, and add it to
/* If INSN has not yet been marked as needed, mark it now, and add it to
   the worklist.  */
   the worklist.  */
 
 
static void
static void
mark_insn (rtx insn, bool fast)
mark_insn (rtx insn, bool fast)
{
{
  if (!marked_insn_p (insn))
  if (!marked_insn_p (insn))
    {
    {
      if (!fast)
      if (!fast)
        VEC_safe_push (rtx, heap, worklist, insn);
        VEC_safe_push (rtx, heap, worklist, insn);
      SET_BIT (marked, INSN_UID (insn));
      SET_BIT (marked, INSN_UID (insn));
      if (dump_file)
      if (dump_file)
        fprintf (dump_file, "  Adding insn %d to worklist\n", INSN_UID (insn));
        fprintf (dump_file, "  Adding insn %d to worklist\n", INSN_UID (insn));
      if (CALL_P (insn)
      if (CALL_P (insn)
          && !df_in_progress
          && !df_in_progress
          && !SIBLING_CALL_P (insn)
          && !SIBLING_CALL_P (insn)
          && (RTL_CONST_OR_PURE_CALL_P (insn)
          && (RTL_CONST_OR_PURE_CALL_P (insn)
              && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
              && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)))
        find_call_stack_args (insn, true, fast, NULL);
        find_call_stack_args (insn, true, fast, NULL);
    }
    }
}
}
 
 
 
 
/* A note_stores callback used by mark_nonreg_stores.  DATA is the
/* A note_stores callback used by mark_nonreg_stores.  DATA is the
   instruction containing DEST.  */
   instruction containing DEST.  */
 
 
static void
static void
mark_nonreg_stores_1 (rtx dest, const_rtx pattern, void *data)
mark_nonreg_stores_1 (rtx dest, const_rtx pattern, void *data)
{
{
  if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
  if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
    mark_insn ((rtx) data, true);
    mark_insn ((rtx) data, true);
}
}
 
 
 
 
/* A note_stores callback used by mark_nonreg_stores.  DATA is the
/* A note_stores callback used by mark_nonreg_stores.  DATA is the
   instruction containing DEST.  */
   instruction containing DEST.  */
 
 
static void
static void
mark_nonreg_stores_2 (rtx dest, const_rtx pattern, void *data)
mark_nonreg_stores_2 (rtx dest, const_rtx pattern, void *data)
{
{
  if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
  if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
    mark_insn ((rtx) data, false);
    mark_insn ((rtx) data, false);
}
}
 
 
 
 
/* Mark INSN if BODY stores to a non-register destination.  */
/* Mark INSN if BODY stores to a non-register destination.  */
 
 
static void
static void
mark_nonreg_stores (rtx body, rtx insn, bool fast)
mark_nonreg_stores (rtx body, rtx insn, bool fast)
{
{
  if (fast)
  if (fast)
    note_stores (body, mark_nonreg_stores_1, insn);
    note_stores (body, mark_nonreg_stores_1, insn);
  else
  else
    note_stores (body, mark_nonreg_stores_2, insn);
    note_stores (body, mark_nonreg_stores_2, insn);
}
}
 
 
 
 
/* Try to find all stack stores of CALL_INSN arguments if
/* Try to find all stack stores of CALL_INSN arguments if
   ACCUMULATE_OUTGOING_ARGS.  If all stack stores have been found
   ACCUMULATE_OUTGOING_ARGS.  If all stack stores have been found
   and it is therefore safe to eliminate the call, return true,
   and it is therefore safe to eliminate the call, return true,
   otherwise return false.  This function should be first called
   otherwise return false.  This function should be first called
   with DO_MARK false, and only when the CALL_INSN is actually
   with DO_MARK false, and only when the CALL_INSN is actually
   going to be marked called again with DO_MARK true.  */
   going to be marked called again with DO_MARK true.  */
 
 
static bool
static bool
find_call_stack_args (rtx call_insn, bool do_mark, bool fast,
find_call_stack_args (rtx call_insn, bool do_mark, bool fast,
                      bitmap arg_stores)
                      bitmap arg_stores)
{
{
  rtx p, insn, prev_insn;
  rtx p, insn, prev_insn;
  bool ret;
  bool ret;
  HOST_WIDE_INT min_sp_off, max_sp_off;
  HOST_WIDE_INT min_sp_off, max_sp_off;
  bitmap sp_bytes;
  bitmap sp_bytes;
 
 
  gcc_assert (CALL_P (call_insn));
  gcc_assert (CALL_P (call_insn));
  if (!ACCUMULATE_OUTGOING_ARGS)
  if (!ACCUMULATE_OUTGOING_ARGS)
    return true;
    return true;
 
 
  if (!do_mark)
  if (!do_mark)
    {
    {
      gcc_assert (arg_stores);
      gcc_assert (arg_stores);
      bitmap_clear (arg_stores);
      bitmap_clear (arg_stores);
    }
    }
 
 
  min_sp_off = INTTYPE_MAXIMUM (HOST_WIDE_INT);
  min_sp_off = INTTYPE_MAXIMUM (HOST_WIDE_INT);
  max_sp_off = 0;
  max_sp_off = 0;
 
 
  /* First determine the minimum and maximum offset from sp for
  /* First determine the minimum and maximum offset from sp for
     stored arguments.  */
     stored arguments.  */
  for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
  for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
    if (GET_CODE (XEXP (p, 0)) == USE
    if (GET_CODE (XEXP (p, 0)) == USE
        && MEM_P (XEXP (XEXP (p, 0), 0)))
        && MEM_P (XEXP (XEXP (p, 0), 0)))
      {
      {
        rtx mem = XEXP (XEXP (p, 0), 0), addr, size;
        rtx mem = XEXP (XEXP (p, 0), 0), addr, size;
        HOST_WIDE_INT off = 0;
        HOST_WIDE_INT off = 0;
        size = MEM_SIZE (mem);
        size = MEM_SIZE (mem);
        if (size == NULL_RTX)
        if (size == NULL_RTX)
          return false;
          return false;
        addr = XEXP (mem, 0);
        addr = XEXP (mem, 0);
        if (GET_CODE (addr) == PLUS
        if (GET_CODE (addr) == PLUS
            && REG_P (XEXP (addr, 0))
            && REG_P (XEXP (addr, 0))
            && CONST_INT_P (XEXP (addr, 1)))
            && CONST_INT_P (XEXP (addr, 1)))
          {
          {
            off = INTVAL (XEXP (addr, 1));
            off = INTVAL (XEXP (addr, 1));
            addr = XEXP (addr, 0);
            addr = XEXP (addr, 0);
          }
          }
        if (addr != stack_pointer_rtx)
        if (addr != stack_pointer_rtx)
          {
          {
            if (!REG_P (addr))
            if (!REG_P (addr))
              return false;
              return false;
            /* If not fast, use chains to see if addr wasn't set to
            /* If not fast, use chains to see if addr wasn't set to
               sp + offset.  */
               sp + offset.  */
            if (!fast)
            if (!fast)
              {
              {
                df_ref *use_rec;
                df_ref *use_rec;
                struct df_link *defs;
                struct df_link *defs;
                rtx set;
                rtx set;
 
 
                for (use_rec = DF_INSN_USES (call_insn); *use_rec; use_rec++)
                for (use_rec = DF_INSN_USES (call_insn); *use_rec; use_rec++)
                  if (rtx_equal_p (addr, DF_REF_REG (*use_rec)))
                  if (rtx_equal_p (addr, DF_REF_REG (*use_rec)))
                    break;
                    break;
 
 
                if (*use_rec == NULL)
                if (*use_rec == NULL)
                  return false;
                  return false;
 
 
                for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
                for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
                  if (! DF_REF_IS_ARTIFICIAL (defs->ref))
                  if (! DF_REF_IS_ARTIFICIAL (defs->ref))
                    break;
                    break;
 
 
                if (defs == NULL)
                if (defs == NULL)
                  return false;
                  return false;
 
 
                set = single_set (DF_REF_INSN (defs->ref));
                set = single_set (DF_REF_INSN (defs->ref));
                if (!set)
                if (!set)
                  return false;
                  return false;
 
 
                if (GET_CODE (SET_SRC (set)) != PLUS
                if (GET_CODE (SET_SRC (set)) != PLUS
                    || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
                    || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
                    || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
                    || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
                  return false;
                  return false;
 
 
                off += INTVAL (XEXP (SET_SRC (set), 1));
                off += INTVAL (XEXP (SET_SRC (set), 1));
              }
              }
            else
            else
              return false;
              return false;
          }
          }
        min_sp_off = MIN (min_sp_off, off);
        min_sp_off = MIN (min_sp_off, off);
        max_sp_off = MAX (max_sp_off, off + INTVAL (size));
        max_sp_off = MAX (max_sp_off, off + INTVAL (size));
      }
      }
 
 
  if (min_sp_off >= max_sp_off)
  if (min_sp_off >= max_sp_off)
    return true;
    return true;
  sp_bytes = BITMAP_ALLOC (NULL);
  sp_bytes = BITMAP_ALLOC (NULL);
 
 
  /* Set bits in SP_BYTES bitmap for bytes relative to sp + min_sp_off
  /* Set bits in SP_BYTES bitmap for bytes relative to sp + min_sp_off
     which contain arguments.  Checking has been done in the previous
     which contain arguments.  Checking has been done in the previous
     loop.  */
     loop.  */
  for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
  for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
    if (GET_CODE (XEXP (p, 0)) == USE
    if (GET_CODE (XEXP (p, 0)) == USE
        && MEM_P (XEXP (XEXP (p, 0), 0)))
        && MEM_P (XEXP (XEXP (p, 0), 0)))
      {
      {
        rtx mem = XEXP (XEXP (p, 0), 0), addr;
        rtx mem = XEXP (XEXP (p, 0), 0), addr;
        HOST_WIDE_INT off = 0, byte;
        HOST_WIDE_INT off = 0, byte;
        addr = XEXP (mem, 0);
        addr = XEXP (mem, 0);
        if (GET_CODE (addr) == PLUS
        if (GET_CODE (addr) == PLUS
            && REG_P (XEXP (addr, 0))
            && REG_P (XEXP (addr, 0))
            && CONST_INT_P (XEXP (addr, 1)))
            && CONST_INT_P (XEXP (addr, 1)))
          {
          {
            off = INTVAL (XEXP (addr, 1));
            off = INTVAL (XEXP (addr, 1));
            addr = XEXP (addr, 0);
            addr = XEXP (addr, 0);
          }
          }
        if (addr != stack_pointer_rtx)
        if (addr != stack_pointer_rtx)
          {
          {
            df_ref *use_rec;
            df_ref *use_rec;
            struct df_link *defs;
            struct df_link *defs;
            rtx set;
            rtx set;
 
 
            for (use_rec = DF_INSN_USES (call_insn); *use_rec; use_rec++)
            for (use_rec = DF_INSN_USES (call_insn); *use_rec; use_rec++)
              if (rtx_equal_p (addr, DF_REF_REG (*use_rec)))
              if (rtx_equal_p (addr, DF_REF_REG (*use_rec)))
                break;
                break;
 
 
            for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
            for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
              if (! DF_REF_IS_ARTIFICIAL (defs->ref))
              if (! DF_REF_IS_ARTIFICIAL (defs->ref))
                break;
                break;
 
 
            set = single_set (DF_REF_INSN (defs->ref));
            set = single_set (DF_REF_INSN (defs->ref));
            off += INTVAL (XEXP (SET_SRC (set), 1));
            off += INTVAL (XEXP (SET_SRC (set), 1));
          }
          }
        for (byte = off; byte < off + INTVAL (MEM_SIZE (mem)); byte++)
        for (byte = off; byte < off + INTVAL (MEM_SIZE (mem)); byte++)
          {
          {
            if (!bitmap_set_bit (sp_bytes, byte - min_sp_off))
            if (!bitmap_set_bit (sp_bytes, byte - min_sp_off))
              gcc_unreachable ();
              gcc_unreachable ();
          }
          }
      }
      }
 
 
  /* Walk backwards, looking for argument stores.  The search stops
  /* Walk backwards, looking for argument stores.  The search stops
     when seeing another call, sp adjustment or memory store other than
     when seeing another call, sp adjustment or memory store other than
     argument store.  */
     argument store.  */
  ret = false;
  ret = false;
  for (insn = PREV_INSN (call_insn); insn; insn = prev_insn)
  for (insn = PREV_INSN (call_insn); insn; insn = prev_insn)
    {
    {
      rtx set, mem, addr;
      rtx set, mem, addr;
      HOST_WIDE_INT off, byte;
      HOST_WIDE_INT off, byte;
 
 
      if (insn == BB_HEAD (BLOCK_FOR_INSN (call_insn)))
      if (insn == BB_HEAD (BLOCK_FOR_INSN (call_insn)))
        prev_insn = NULL_RTX;
        prev_insn = NULL_RTX;
      else
      else
        prev_insn = PREV_INSN (insn);
        prev_insn = PREV_INSN (insn);
 
 
      if (CALL_P (insn))
      if (CALL_P (insn))
        break;
        break;
 
 
      if (!INSN_P (insn))
      if (!INSN_P (insn))
        continue;
        continue;
 
 
      set = single_set (insn);
      set = single_set (insn);
      if (!set || SET_DEST (set) == stack_pointer_rtx)
      if (!set || SET_DEST (set) == stack_pointer_rtx)
        break;
        break;
 
 
      if (!MEM_P (SET_DEST (set)))
      if (!MEM_P (SET_DEST (set)))
        continue;
        continue;
 
 
      mem = SET_DEST (set);
      mem = SET_DEST (set);
      addr = XEXP (mem, 0);
      addr = XEXP (mem, 0);
      off = 0;
      off = 0;
      if (GET_CODE (addr) == PLUS
      if (GET_CODE (addr) == PLUS
          && REG_P (XEXP (addr, 0))
          && REG_P (XEXP (addr, 0))
          && CONST_INT_P (XEXP (addr, 1)))
          && CONST_INT_P (XEXP (addr, 1)))
        {
        {
          off = INTVAL (XEXP (addr, 1));
          off = INTVAL (XEXP (addr, 1));
          addr = XEXP (addr, 0);
          addr = XEXP (addr, 0);
        }
        }
      if (addr != stack_pointer_rtx)
      if (addr != stack_pointer_rtx)
        {
        {
          if (!REG_P (addr))
          if (!REG_P (addr))
            break;
            break;
          if (!fast)
          if (!fast)
            {
            {
              df_ref *use_rec;
              df_ref *use_rec;
              struct df_link *defs;
              struct df_link *defs;
              rtx set;
              rtx set;
 
 
              for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
              for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
                if (rtx_equal_p (addr, DF_REF_REG (*use_rec)))
                if (rtx_equal_p (addr, DF_REF_REG (*use_rec)))
                  break;
                  break;
 
 
              if (*use_rec == NULL)
              if (*use_rec == NULL)
                break;
                break;
 
 
              for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
              for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
                if (! DF_REF_IS_ARTIFICIAL (defs->ref))
                if (! DF_REF_IS_ARTIFICIAL (defs->ref))
                  break;
                  break;
 
 
              if (defs == NULL)
              if (defs == NULL)
                break;
                break;
 
 
              set = single_set (DF_REF_INSN (defs->ref));
              set = single_set (DF_REF_INSN (defs->ref));
              if (!set)
              if (!set)
                break;
                break;
 
 
              if (GET_CODE (SET_SRC (set)) != PLUS
              if (GET_CODE (SET_SRC (set)) != PLUS
                  || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
                  || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
                  || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
                  || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
                break;
                break;
 
 
              off += INTVAL (XEXP (SET_SRC (set), 1));
              off += INTVAL (XEXP (SET_SRC (set), 1));
            }
            }
          else
          else
            break;
            break;
        }
        }
 
 
      if (GET_MODE_SIZE (GET_MODE (mem)) == 0)
      if (GET_MODE_SIZE (GET_MODE (mem)) == 0)
        break;
        break;
 
 
      for (byte = off; byte < off + GET_MODE_SIZE (GET_MODE (mem)); byte++)
      for (byte = off; byte < off + GET_MODE_SIZE (GET_MODE (mem)); byte++)
        {
        {
          if (byte < min_sp_off
          if (byte < min_sp_off
              || byte >= max_sp_off
              || byte >= max_sp_off
              || !bitmap_clear_bit (sp_bytes, byte - min_sp_off))
              || !bitmap_clear_bit (sp_bytes, byte - min_sp_off))
            break;
            break;
        }
        }
 
 
      if (!deletable_insn_p (insn, fast, NULL))
      if (!deletable_insn_p (insn, fast, NULL))
        break;
        break;
 
 
      if (do_mark)
      if (do_mark)
        mark_insn (insn, fast);
        mark_insn (insn, fast);
      else
      else
        bitmap_set_bit (arg_stores, INSN_UID (insn));
        bitmap_set_bit (arg_stores, INSN_UID (insn));
 
 
      if (bitmap_empty_p (sp_bytes))
      if (bitmap_empty_p (sp_bytes))
        {
        {
          ret = true;
          ret = true;
          break;
          break;
        }
        }
    }
    }
 
 
  BITMAP_FREE (sp_bytes);
  BITMAP_FREE (sp_bytes);
  if (!ret && arg_stores)
  if (!ret && arg_stores)
    bitmap_clear (arg_stores);
    bitmap_clear (arg_stores);
 
 
  return ret;
  return ret;
}
}
 
 
 
 
/* Delete all REG_EQUAL notes of the registers INSN writes, to prevent
/* Delete all REG_EQUAL notes of the registers INSN writes, to prevent
   bad dangling REG_EQUAL notes. */
   bad dangling REG_EQUAL notes. */
 
 
static void
static void
delete_corresponding_reg_eq_notes (rtx insn)
delete_corresponding_reg_eq_notes (rtx insn)
{
{
  df_ref *def_rec;
  df_ref *def_rec;
  for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
  for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
    {
    {
      df_ref def = *def_rec;
      df_ref def = *def_rec;
      unsigned int regno = DF_REF_REGNO (def);
      unsigned int regno = DF_REF_REGNO (def);
      /* This loop is a little tricky.  We cannot just go down the
      /* This loop is a little tricky.  We cannot just go down the
         chain because it is being modified by the actions in the
         chain because it is being modified by the actions in the
         loop.  So we just get the head.  We plan to drain the list
         loop.  So we just get the head.  We plan to drain the list
         anyway.  */
         anyway.  */
      while (DF_REG_EQ_USE_CHAIN (regno))
      while (DF_REG_EQ_USE_CHAIN (regno))
        {
        {
          df_ref eq_use = DF_REG_EQ_USE_CHAIN (regno);
          df_ref eq_use = DF_REG_EQ_USE_CHAIN (regno);
          rtx noted_insn = DF_REF_INSN (eq_use);
          rtx noted_insn = DF_REF_INSN (eq_use);
          rtx note = find_reg_note (noted_insn, REG_EQUAL, NULL_RTX);
          rtx note = find_reg_note (noted_insn, REG_EQUAL, NULL_RTX);
          if (!note)
          if (!note)
            note = find_reg_note (noted_insn, REG_EQUIV, NULL_RTX);
            note = find_reg_note (noted_insn, REG_EQUIV, NULL_RTX);
 
 
          /* This assert is generally triggered when someone deletes a
          /* This assert is generally triggered when someone deletes a
             REG_EQUAL or REG_EQUIV note by hacking the list manually
             REG_EQUAL or REG_EQUIV note by hacking the list manually
             rather than calling remove_note.  */
             rather than calling remove_note.  */
          gcc_assert (note);
          gcc_assert (note);
          remove_note (noted_insn, note);
          remove_note (noted_insn, note);
        }
        }
    }
    }
}
}
 
 
 
 
/* Delete every instruction that hasn't been marked.  */
/* Delete every instruction that hasn't been marked.  */
 
 
static void
static void
delete_unmarked_insns (void)
delete_unmarked_insns (void)
{
{
  basic_block bb;
  basic_block bb;
  rtx insn, next;
  rtx insn, next;
  bool must_clean = false;
  bool must_clean = false;
 
 
  FOR_EACH_BB_REVERSE (bb)
  FOR_EACH_BB_REVERSE (bb)
    FOR_BB_INSNS_REVERSE_SAFE (bb, insn, next)
    FOR_BB_INSNS_REVERSE_SAFE (bb, insn, next)
      if (INSN_P (insn))
      if (INSN_P (insn))
        {
        {
          /* Always delete no-op moves.  */
          /* Always delete no-op moves.  */
          if (noop_move_p (insn))
          if (noop_move_p (insn))
            ;
            ;
 
 
          /* Otherwise rely only on the DCE algorithm.  */
          /* Otherwise rely only on the DCE algorithm.  */
          else if (marked_insn_p (insn))
          else if (marked_insn_p (insn))
            continue;
            continue;
 
 
          /* Beware that reaching a dbg counter limit here can result
          /* Beware that reaching a dbg counter limit here can result
             in miscompiled file.  This occurs when a group of insns
             in miscompiled file.  This occurs when a group of insns
             must be deleted together, typically because the kept insn
             must be deleted together, typically because the kept insn
             depends on the output from the deleted insn.  Deleting
             depends on the output from the deleted insn.  Deleting
             this insns in reverse order (both at the bb level and
             this insns in reverse order (both at the bb level and
             when looking at the blocks) minimizes this, but does not
             when looking at the blocks) minimizes this, but does not
             eliminate it, since it is possible for the using insn to
             eliminate it, since it is possible for the using insn to
             be top of a block and the producer to be at the bottom of
             be top of a block and the producer to be at the bottom of
             the block.  However, in most cases this will only result
             the block.  However, in most cases this will only result
             in an uninitialized use of an insn that is dead anyway.
             in an uninitialized use of an insn that is dead anyway.
 
 
             However, there is one rare case that will cause a
             However, there is one rare case that will cause a
             miscompile: deletion of non-looping pure and constant
             miscompile: deletion of non-looping pure and constant
             calls on a machine where ACCUMULATE_OUTGOING_ARGS is true.
             calls on a machine where ACCUMULATE_OUTGOING_ARGS is true.
             In this case it is possible to remove the call, but leave
             In this case it is possible to remove the call, but leave
             the argument pushes to the stack.  Because of the changes
             the argument pushes to the stack.  Because of the changes
             to the stack pointer, this will almost always lead to a
             to the stack pointer, this will almost always lead to a
             miscompile.  */
             miscompile.  */
          if (!dbg_cnt (dce))
          if (!dbg_cnt (dce))
            continue;
            continue;
 
 
          if (dump_file)
          if (dump_file)
            fprintf (dump_file, "DCE: Deleting insn %d\n", INSN_UID (insn));
            fprintf (dump_file, "DCE: Deleting insn %d\n", INSN_UID (insn));
 
 
          /* Before we delete the insn we have to delete REG_EQUAL notes
          /* Before we delete the insn we have to delete REG_EQUAL notes
             for the destination regs in order to avoid dangling notes.  */
             for the destination regs in order to avoid dangling notes.  */
          delete_corresponding_reg_eq_notes (insn);
          delete_corresponding_reg_eq_notes (insn);
 
 
          /* If a pure or const call is deleted, this may make the cfg
          /* If a pure or const call is deleted, this may make the cfg
             have unreachable blocks.  We rememeber this and call
             have unreachable blocks.  We rememeber this and call
             delete_unreachable_blocks at the end.  */
             delete_unreachable_blocks at the end.  */
          if (CALL_P (insn))
          if (CALL_P (insn))
            must_clean = true;
            must_clean = true;
 
 
          /* Now delete the insn.  */
          /* Now delete the insn.  */
          delete_insn_and_edges (insn);
          delete_insn_and_edges (insn);
        }
        }
 
 
  /* Deleted a pure or const call.  */
  /* Deleted a pure or const call.  */
  if (must_clean)
  if (must_clean)
    delete_unreachable_blocks ();
    delete_unreachable_blocks ();
}
}
 
 
 
 
/* Go through the instructions and mark those whose necessity is not
/* Go through the instructions and mark those whose necessity is not
   dependent on inter-instruction information.  Make sure all other
   dependent on inter-instruction information.  Make sure all other
   instructions are not marked.  */
   instructions are not marked.  */
 
 
static void
static void
prescan_insns_for_dce (bool fast)
prescan_insns_for_dce (bool fast)
{
{
  basic_block bb;
  basic_block bb;
  rtx insn, prev;
  rtx insn, prev;
  bitmap arg_stores = NULL;
  bitmap arg_stores = NULL;
 
 
  if (dump_file)
  if (dump_file)
    fprintf (dump_file, "Finding needed instructions:\n");
    fprintf (dump_file, "Finding needed instructions:\n");
 
 
  if (!df_in_progress && ACCUMULATE_OUTGOING_ARGS)
  if (!df_in_progress && ACCUMULATE_OUTGOING_ARGS)
    arg_stores = BITMAP_ALLOC (NULL);
    arg_stores = BITMAP_ALLOC (NULL);
 
 
  FOR_EACH_BB (bb)
  FOR_EACH_BB (bb)
    {
    {
      FOR_BB_INSNS_REVERSE_SAFE (bb, insn, prev)
      FOR_BB_INSNS_REVERSE_SAFE (bb, insn, prev)
        if (INSN_P (insn))
        if (INSN_P (insn))
          {
          {
            /* Don't mark argument stores now.  They will be marked
            /* Don't mark argument stores now.  They will be marked
               if needed when the associated CALL is marked.  */
               if needed when the associated CALL is marked.  */
            if (arg_stores && bitmap_bit_p (arg_stores, INSN_UID (insn)))
            if (arg_stores && bitmap_bit_p (arg_stores, INSN_UID (insn)))
              continue;
              continue;
            if (deletable_insn_p (insn, fast, arg_stores))
            if (deletable_insn_p (insn, fast, arg_stores))
              mark_nonreg_stores (PATTERN (insn), insn, fast);
              mark_nonreg_stores (PATTERN (insn), insn, fast);
            else
            else
              mark_insn (insn, fast);
              mark_insn (insn, fast);
          }
          }
      /* find_call_stack_args only looks at argument stores in the
      /* find_call_stack_args only looks at argument stores in the
         same bb.  */
         same bb.  */
      if (arg_stores)
      if (arg_stores)
        bitmap_clear (arg_stores);
        bitmap_clear (arg_stores);
    }
    }
 
 
  if (arg_stores)
  if (arg_stores)
    BITMAP_FREE (arg_stores);
    BITMAP_FREE (arg_stores);
 
 
  if (dump_file)
  if (dump_file)
    fprintf (dump_file, "Finished finding needed instructions:\n");
    fprintf (dump_file, "Finished finding needed instructions:\n");
}
}
 
 
 
 
/* UD-based DSE routines. */
/* UD-based DSE routines. */
 
 
/* Mark instructions that define artificially-used registers, such as
/* Mark instructions that define artificially-used registers, such as
   the frame pointer and the stack pointer.  */
   the frame pointer and the stack pointer.  */
 
 
static void
static void
mark_artificial_uses (void)
mark_artificial_uses (void)
{
{
  basic_block bb;
  basic_block bb;
  struct df_link *defs;
  struct df_link *defs;
  df_ref *use_rec;
  df_ref *use_rec;
 
 
  FOR_ALL_BB (bb)
  FOR_ALL_BB (bb)
    {
    {
      for (use_rec = df_get_artificial_uses (bb->index);
      for (use_rec = df_get_artificial_uses (bb->index);
           *use_rec; use_rec++)
           *use_rec; use_rec++)
        for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
        for (defs = DF_REF_CHAIN (*use_rec); defs; defs = defs->next)
          if (! DF_REF_IS_ARTIFICIAL (defs->ref))
          if (! DF_REF_IS_ARTIFICIAL (defs->ref))
            mark_insn (DF_REF_INSN (defs->ref), false);
            mark_insn (DF_REF_INSN (defs->ref), false);
    }
    }
}
}
 
 
 
 
/* Mark every instruction that defines a register value that INSN uses.  */
/* Mark every instruction that defines a register value that INSN uses.  */
 
 
static void
static void
mark_reg_dependencies (rtx insn)
mark_reg_dependencies (rtx insn)
{
{
  struct df_link *defs;
  struct df_link *defs;
  df_ref *use_rec;
  df_ref *use_rec;
 
 
  if (DEBUG_INSN_P (insn))
  if (DEBUG_INSN_P (insn))
    return;
    return;
 
 
  for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
  for (use_rec = DF_INSN_USES (insn); *use_rec; use_rec++)
    {
    {
      df_ref use = *use_rec;
      df_ref use = *use_rec;
      if (dump_file)
      if (dump_file)
        {
        {
          fprintf (dump_file, "Processing use of ");
          fprintf (dump_file, "Processing use of ");
          print_simple_rtl (dump_file, DF_REF_REG (use));
          print_simple_rtl (dump_file, DF_REF_REG (use));
          fprintf (dump_file, " in insn %d:\n", INSN_UID (insn));
          fprintf (dump_file, " in insn %d:\n", INSN_UID (insn));
        }
        }
      for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
      for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
        if (! DF_REF_IS_ARTIFICIAL (defs->ref))
        if (! DF_REF_IS_ARTIFICIAL (defs->ref))
          mark_insn (DF_REF_INSN (defs->ref), false);
          mark_insn (DF_REF_INSN (defs->ref), false);
    }
    }
}
}
 
 
 
 
/* Initialize global variables for a new DCE pass.  */
/* Initialize global variables for a new DCE pass.  */
 
 
static void
static void
init_dce (bool fast)
init_dce (bool fast)
{
{
  if (!df_in_progress)
  if (!df_in_progress)
    {
    {
      if (!fast)
      if (!fast)
        df_chain_add_problem (DF_UD_CHAIN);
        df_chain_add_problem (DF_UD_CHAIN);
      df_analyze ();
      df_analyze ();
    }
    }
 
 
  if (dump_file)
  if (dump_file)
    df_dump (dump_file);
    df_dump (dump_file);
 
 
  if (fast)
  if (fast)
    {
    {
      bitmap_obstack_initialize (&dce_blocks_bitmap_obstack);
      bitmap_obstack_initialize (&dce_blocks_bitmap_obstack);
      bitmap_obstack_initialize (&dce_tmp_bitmap_obstack);
      bitmap_obstack_initialize (&dce_tmp_bitmap_obstack);
    }
    }
 
 
  marked = sbitmap_alloc (get_max_uid () + 1);
  marked = sbitmap_alloc (get_max_uid () + 1);
  sbitmap_zero (marked);
  sbitmap_zero (marked);
}
}
 
 
 
 
/* Free the data allocated by init_dce.  */
/* Free the data allocated by init_dce.  */
 
 
static void
static void
fini_dce (bool fast)
fini_dce (bool fast)
{
{
  sbitmap_free (marked);
  sbitmap_free (marked);
 
 
  if (fast)
  if (fast)
    {
    {
      bitmap_obstack_release (&dce_blocks_bitmap_obstack);
      bitmap_obstack_release (&dce_blocks_bitmap_obstack);
      bitmap_obstack_release (&dce_tmp_bitmap_obstack);
      bitmap_obstack_release (&dce_tmp_bitmap_obstack);
    }
    }
}
}
 
 
 
 
/* UD-chain based DCE.  */
/* UD-chain based DCE.  */
 
 
static unsigned int
static unsigned int
rest_of_handle_ud_dce (void)
rest_of_handle_ud_dce (void)
{
{
  rtx insn;
  rtx insn;
 
 
  init_dce (false);
  init_dce (false);
 
 
  prescan_insns_for_dce (false);
  prescan_insns_for_dce (false);
  mark_artificial_uses ();
  mark_artificial_uses ();
  while (VEC_length (rtx, worklist) > 0)
  while (VEC_length (rtx, worklist) > 0)
    {
    {
      insn = VEC_pop (rtx, worklist);
      insn = VEC_pop (rtx, worklist);
      mark_reg_dependencies (insn);
      mark_reg_dependencies (insn);
    }
    }
  VEC_free (rtx, heap, worklist);
  VEC_free (rtx, heap, worklist);
 
 
  /* Before any insns are deleted, we must remove the chains since
  /* Before any insns are deleted, we must remove the chains since
     they are not bidirectional.  */
     they are not bidirectional.  */
  df_remove_problem (df_chain);
  df_remove_problem (df_chain);
  delete_unmarked_insns ();
  delete_unmarked_insns ();
 
 
  fini_dce (false);
  fini_dce (false);
  return 0;
  return 0;
}
}
 
 
 
 
static bool
static bool
gate_ud_dce (void)
gate_ud_dce (void)
{
{
  return optimize > 1 && flag_dce
  return optimize > 1 && flag_dce
    && dbg_cnt (dce_ud);
    && dbg_cnt (dce_ud);
}
}
 
 
struct rtl_opt_pass pass_ud_rtl_dce =
struct rtl_opt_pass pass_ud_rtl_dce =
{
{
 {
 {
  RTL_PASS,
  RTL_PASS,
  "ud dce",                             /* name */
  "ud dce",                             /* name */
  gate_ud_dce,                          /* gate */
  gate_ud_dce,                          /* gate */
  rest_of_handle_ud_dce,                /* execute */
  rest_of_handle_ud_dce,                /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  0,                                    /* static_pass_number */
  TV_DCE,                               /* tv_id */
  TV_DCE,                               /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0,                                    /* todo_flags_start */
  TODO_dump_func |
  TODO_dump_func |
  TODO_df_finish | TODO_verify_rtl_sharing |
  TODO_df_finish | TODO_verify_rtl_sharing |
  TODO_ggc_collect                     /* todo_flags_finish */
  TODO_ggc_collect                     /* todo_flags_finish */
 }
 }
};
};
 
 
 
 
/* -------------------------------------------------------------------------
/* -------------------------------------------------------------------------
   Fast DCE functions
   Fast DCE functions
   ------------------------------------------------------------------------- */
   ------------------------------------------------------------------------- */
 
 
/* Process basic block BB.  Return true if the live_in set has
/* Process basic block BB.  Return true if the live_in set has
   changed. REDO_OUT is true if the info at the bottom of the block
   changed. REDO_OUT is true if the info at the bottom of the block
   needs to be recalculated before starting.  AU is the proper set of
   needs to be recalculated before starting.  AU is the proper set of
   artificial uses. */
   artificial uses. */
 
 
static bool
static bool
byte_dce_process_block (basic_block bb, bool redo_out, bitmap au)
byte_dce_process_block (basic_block bb, bool redo_out, bitmap au)
{
{
  bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
  bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
  rtx insn;
  rtx insn;
  bool block_changed;
  bool block_changed;
  df_ref *def_rec;
  df_ref *def_rec;
 
 
  if (redo_out)
  if (redo_out)
    {
    {
      /* Need to redo the live_out set of this block if when one of
      /* Need to redo the live_out set of this block if when one of
         the succs of this block has had a change in it live in
         the succs of this block has had a change in it live in
         set.  */
         set.  */
      edge e;
      edge e;
      edge_iterator ei;
      edge_iterator ei;
      df_confluence_function_n con_fun_n = df_byte_lr->problem->con_fun_n;
      df_confluence_function_n con_fun_n = df_byte_lr->problem->con_fun_n;
      bitmap_clear (DF_BYTE_LR_OUT (bb));
      bitmap_clear (DF_BYTE_LR_OUT (bb));
      FOR_EACH_EDGE (e, ei, bb->succs)
      FOR_EACH_EDGE (e, ei, bb->succs)
        (*con_fun_n) (e);
        (*con_fun_n) (e);
    }
    }
 
 
  if (dump_file)
  if (dump_file)
    {
    {
      fprintf (dump_file, "processing block %d live out = ", bb->index);
      fprintf (dump_file, "processing block %d live out = ", bb->index);
      df_print_byte_regset (dump_file, DF_BYTE_LR_OUT (bb));
      df_print_byte_regset (dump_file, DF_BYTE_LR_OUT (bb));
    }
    }
 
 
  bitmap_copy (local_live, DF_BYTE_LR_OUT (bb));
  bitmap_copy (local_live, DF_BYTE_LR_OUT (bb));
 
 
  df_byte_lr_simulate_artificial_refs_at_end (bb, local_live);
  df_byte_lr_simulate_artificial_refs_at_end (bb, local_live);
 
 
  FOR_BB_INSNS_REVERSE (bb, insn)
  FOR_BB_INSNS_REVERSE (bb, insn)
    if (INSN_P (insn))
    if (INSN_P (insn))
      {
      {
        /* The insn is needed if there is someone who uses the output.  */
        /* The insn is needed if there is someone who uses the output.  */
        for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
        for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
          {
          {
            df_ref def = *def_rec;
            df_ref def = *def_rec;
            unsigned int last;
            unsigned int last;
            unsigned int dregno = DF_REF_REGNO (def);
            unsigned int dregno = DF_REF_REGNO (def);
            unsigned int start = df_byte_lr_get_regno_start (dregno);
            unsigned int start = df_byte_lr_get_regno_start (dregno);
            unsigned int len = df_byte_lr_get_regno_len (dregno);
            unsigned int len = df_byte_lr_get_regno_len (dregno);
 
 
            unsigned int sb;
            unsigned int sb;
            unsigned int lb;
            unsigned int lb;
            /* This is one of the only places where DF_MM_MAY should
            /* This is one of the only places where DF_MM_MAY should
               be used for defs.  Need to make sure that we are
               be used for defs.  Need to make sure that we are
               checking for all of the bits that may be used.  */
               checking for all of the bits that may be used.  */
 
 
            if (!df_compute_accessed_bytes (def, DF_MM_MAY, &sb, &lb))
            if (!df_compute_accessed_bytes (def, DF_MM_MAY, &sb, &lb))
              {
              {
                start += sb;
                start += sb;
                len = lb - sb;
                len = lb - sb;
              }
              }
 
 
            if (bitmap_bit_p (au, dregno))
            if (bitmap_bit_p (au, dregno))
              {
              {
                mark_insn (insn, true);
                mark_insn (insn, true);
                goto quickexit;
                goto quickexit;
              }
              }
 
 
            last = start + len;
            last = start + len;
            while (start < last)
            while (start < last)
              if (bitmap_bit_p (local_live, start++))
              if (bitmap_bit_p (local_live, start++))
                {
                {
                  mark_insn (insn, true);
                  mark_insn (insn, true);
                  goto quickexit;
                  goto quickexit;
                }
                }
          }
          }
 
 
      quickexit:
      quickexit:
 
 
        /* No matter if the instruction is needed or not, we remove
        /* No matter if the instruction is needed or not, we remove
           any regno in the defs from the live set.  */
           any regno in the defs from the live set.  */
        df_byte_lr_simulate_defs (insn, local_live);
        df_byte_lr_simulate_defs (insn, local_live);
 
 
        /* On the other hand, we do not allow the dead uses to set
        /* On the other hand, we do not allow the dead uses to set
           anything in local_live.  */
           anything in local_live.  */
        if (marked_insn_p (insn))
        if (marked_insn_p (insn))
          df_byte_lr_simulate_uses (insn, local_live);
          df_byte_lr_simulate_uses (insn, local_live);
 
 
        if (dump_file)
        if (dump_file)
          {
          {
            fprintf (dump_file, "finished processing insn %d live out = ",
            fprintf (dump_file, "finished processing insn %d live out = ",
                     INSN_UID (insn));
                     INSN_UID (insn));
            df_print_byte_regset (dump_file, local_live);
            df_print_byte_regset (dump_file, local_live);
          }
          }
      }
      }
 
 
  df_byte_lr_simulate_artificial_refs_at_top (bb, local_live);
  df_byte_lr_simulate_artificial_refs_at_top (bb, local_live);
 
 
  block_changed = !bitmap_equal_p (local_live, DF_BYTE_LR_IN (bb));
  block_changed = !bitmap_equal_p (local_live, DF_BYTE_LR_IN (bb));
  if (block_changed)
  if (block_changed)
    bitmap_copy (DF_BYTE_LR_IN (bb), local_live);
    bitmap_copy (DF_BYTE_LR_IN (bb), local_live);
  BITMAP_FREE (local_live);
  BITMAP_FREE (local_live);
  return block_changed;
  return block_changed;
}
}
 
 
 
 
/* Process basic block BB.  Return true if the live_in set has
/* Process basic block BB.  Return true if the live_in set has
   changed. REDO_OUT is true if the info at the bottom of the block
   changed. REDO_OUT is true if the info at the bottom of the block
   needs to be recalculated before starting.  AU is the proper set of
   needs to be recalculated before starting.  AU is the proper set of
   artificial uses. */
   artificial uses. */
 
 
static bool
static bool
dce_process_block (basic_block bb, bool redo_out, bitmap au)
dce_process_block (basic_block bb, bool redo_out, bitmap au)
{
{
  bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
  bitmap local_live = BITMAP_ALLOC (&dce_tmp_bitmap_obstack);
  rtx insn;
  rtx insn;
  bool block_changed;
  bool block_changed;
  df_ref *def_rec;
  df_ref *def_rec;
 
 
  if (redo_out)
  if (redo_out)
    {
    {
      /* Need to redo the live_out set of this block if when one of
      /* Need to redo the live_out set of this block if when one of
         the succs of this block has had a change in it live in
         the succs of this block has had a change in it live in
         set.  */
         set.  */
      edge e;
      edge e;
      edge_iterator ei;
      edge_iterator ei;
      df_confluence_function_n con_fun_n = df_lr->problem->con_fun_n;
      df_confluence_function_n con_fun_n = df_lr->problem->con_fun_n;
      bitmap_clear (DF_LR_OUT (bb));
      bitmap_clear (DF_LR_OUT (bb));
      FOR_EACH_EDGE (e, ei, bb->succs)
      FOR_EACH_EDGE (e, ei, bb->succs)
        (*con_fun_n) (e);
        (*con_fun_n) (e);
    }
    }
 
 
  if (dump_file)
  if (dump_file)
    {
    {
      fprintf (dump_file, "processing block %d lr out = ", bb->index);
      fprintf (dump_file, "processing block %d lr out = ", bb->index);
      df_print_regset (dump_file, DF_LR_OUT (bb));
      df_print_regset (dump_file, DF_LR_OUT (bb));
    }
    }
 
 
  bitmap_copy (local_live, DF_LR_OUT (bb));
  bitmap_copy (local_live, DF_LR_OUT (bb));
 
 
  df_simulate_initialize_backwards (bb, local_live);
  df_simulate_initialize_backwards (bb, local_live);
 
 
  FOR_BB_INSNS_REVERSE (bb, insn)
  FOR_BB_INSNS_REVERSE (bb, insn)
    if (INSN_P (insn))
    if (INSN_P (insn))
      {
      {
        bool needed = false;
        bool needed = false;
 
 
        /* The insn is needed if there is someone who uses the output.  */
        /* The insn is needed if there is someone who uses the output.  */
        for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
        for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
          if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
          if (bitmap_bit_p (local_live, DF_REF_REGNO (*def_rec))
              || bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
              || bitmap_bit_p (au, DF_REF_REGNO (*def_rec)))
            {
            {
              needed = true;
              needed = true;
              break;
              break;
            }
            }
 
 
        if (needed)
        if (needed)
          mark_insn (insn, true);
          mark_insn (insn, true);
 
 
        /* No matter if the instruction is needed or not, we remove
        /* No matter if the instruction is needed or not, we remove
           any regno in the defs from the live set.  */
           any regno in the defs from the live set.  */
        df_simulate_defs (insn, local_live);
        df_simulate_defs (insn, local_live);
 
 
        /* On the other hand, we do not allow the dead uses to set
        /* On the other hand, we do not allow the dead uses to set
           anything in local_live.  */
           anything in local_live.  */
        if (marked_insn_p (insn))
        if (marked_insn_p (insn))
          df_simulate_uses (insn, local_live);
          df_simulate_uses (insn, local_live);
      }
      }
 
 
  df_simulate_finalize_backwards (bb, local_live);
  df_simulate_finalize_backwards (bb, local_live);
 
 
  block_changed = !bitmap_equal_p (local_live, DF_LR_IN (bb));
  block_changed = !bitmap_equal_p (local_live, DF_LR_IN (bb));
  if (block_changed)
  if (block_changed)
    bitmap_copy (DF_LR_IN (bb), local_live);
    bitmap_copy (DF_LR_IN (bb), local_live);
 
 
  BITMAP_FREE (local_live);
  BITMAP_FREE (local_live);
  return block_changed;
  return block_changed;
}
}
 
 
 
 
/* Perform fast DCE once initialization is done.  If BYTE_LEVEL is
/* Perform fast DCE once initialization is done.  If BYTE_LEVEL is
   true, use the byte level dce, otherwise do it at the pseudo
   true, use the byte level dce, otherwise do it at the pseudo
   level.  */
   level.  */
 
 
static void
static void
fast_dce (bool byte_level)
fast_dce (bool byte_level)
{
{
  int *postorder = df_get_postorder (DF_BACKWARD);
  int *postorder = df_get_postorder (DF_BACKWARD);
  int n_blocks = df_get_n_blocks (DF_BACKWARD);
  int n_blocks = df_get_n_blocks (DF_BACKWARD);
  /* The set of blocks that have been seen on this iteration.  */
  /* The set of blocks that have been seen on this iteration.  */
  bitmap processed = BITMAP_ALLOC (&dce_blocks_bitmap_obstack);
  bitmap processed = BITMAP_ALLOC (&dce_blocks_bitmap_obstack);
  /* The set of blocks that need to have the out vectors reset because
  /* The set of blocks that need to have the out vectors reset because
     the in of one of their successors has changed.  */
     the in of one of their successors has changed.  */
  bitmap redo_out = BITMAP_ALLOC (&dce_blocks_bitmap_obstack);
  bitmap redo_out = BITMAP_ALLOC (&dce_blocks_bitmap_obstack);
  bitmap all_blocks = BITMAP_ALLOC (&dce_blocks_bitmap_obstack);
  bitmap all_blocks = BITMAP_ALLOC (&dce_blocks_bitmap_obstack);
  bool global_changed = true;
  bool global_changed = true;
 
 
  /* These regs are considered always live so if they end up dying
  /* These regs are considered always live so if they end up dying
     because of some def, we need to bring the back again.  Calling
     because of some def, we need to bring the back again.  Calling
     df_simulate_fixup_sets has the disadvantage of calling
     df_simulate_fixup_sets has the disadvantage of calling
     bb_has_eh_pred once per insn, so we cache the information
     bb_has_eh_pred once per insn, so we cache the information
     here.  */
     here.  */
  bitmap au = df->regular_block_artificial_uses;
  bitmap au = df->regular_block_artificial_uses;
  bitmap au_eh = df->eh_block_artificial_uses;
  bitmap au_eh = df->eh_block_artificial_uses;
  int i;
  int i;
 
 
  prescan_insns_for_dce (true);
  prescan_insns_for_dce (true);
 
 
  for (i = 0; i < n_blocks; i++)
  for (i = 0; i < n_blocks; i++)
    bitmap_set_bit (all_blocks, postorder[i]);
    bitmap_set_bit (all_blocks, postorder[i]);
 
 
  while (global_changed)
  while (global_changed)
    {
    {
      global_changed = false;
      global_changed = false;
 
 
      for (i = 0; i < n_blocks; i++)
      for (i = 0; i < n_blocks; i++)
        {
        {
          int index = postorder[i];
          int index = postorder[i];
          basic_block bb = BASIC_BLOCK (index);
          basic_block bb = BASIC_BLOCK (index);
          bool local_changed;
          bool local_changed;
 
 
          if (index < NUM_FIXED_BLOCKS)
          if (index < NUM_FIXED_BLOCKS)
            {
            {
              bitmap_set_bit (processed, index);
              bitmap_set_bit (processed, index);
              continue;
              continue;
            }
            }
 
 
          if (byte_level)
          if (byte_level)
            local_changed
            local_changed
              = byte_dce_process_block (bb, bitmap_bit_p (redo_out, index),
              = byte_dce_process_block (bb, bitmap_bit_p (redo_out, index),
                                          bb_has_eh_pred (bb) ? au_eh : au);
                                          bb_has_eh_pred (bb) ? au_eh : au);
          else
          else
            local_changed
            local_changed
              = dce_process_block (bb, bitmap_bit_p (redo_out, index),
              = dce_process_block (bb, bitmap_bit_p (redo_out, index),
                                   bb_has_eh_pred (bb) ? au_eh : au);
                                   bb_has_eh_pred (bb) ? au_eh : au);
          bitmap_set_bit (processed, index);
          bitmap_set_bit (processed, index);
 
 
          if (local_changed)
          if (local_changed)
            {
            {
              edge e;
              edge e;
              edge_iterator ei;
              edge_iterator ei;
              FOR_EACH_EDGE (e, ei, bb->preds)
              FOR_EACH_EDGE (e, ei, bb->preds)
                if (bitmap_bit_p (processed, e->src->index))
                if (bitmap_bit_p (processed, e->src->index))
                  /* Be tricky about when we need to iterate the
                  /* Be tricky about when we need to iterate the
                     analysis.  We only have redo the analysis if the
                     analysis.  We only have redo the analysis if the
                     bitmaps change at the top of a block that is the
                     bitmaps change at the top of a block that is the
                     entry to a loop.  */
                     entry to a loop.  */
                  global_changed = true;
                  global_changed = true;
                else
                else
                  bitmap_set_bit (redo_out, e->src->index);
                  bitmap_set_bit (redo_out, e->src->index);
            }
            }
        }
        }
 
 
      if (global_changed)
      if (global_changed)
        {
        {
          /* Turn off the RUN_DCE flag to prevent recursive calls to
          /* Turn off the RUN_DCE flag to prevent recursive calls to
             dce.  */
             dce.  */
          int old_flag = df_clear_flags (DF_LR_RUN_DCE);
          int old_flag = df_clear_flags (DF_LR_RUN_DCE);
 
 
          /* So something was deleted that requires a redo.  Do it on
          /* So something was deleted that requires a redo.  Do it on
             the cheap.  */
             the cheap.  */
          delete_unmarked_insns ();
          delete_unmarked_insns ();
          sbitmap_zero (marked);
          sbitmap_zero (marked);
          bitmap_clear (processed);
          bitmap_clear (processed);
          bitmap_clear (redo_out);
          bitmap_clear (redo_out);
 
 
          /* We do not need to rescan any instructions.  We only need
          /* We do not need to rescan any instructions.  We only need
             to redo the dataflow equations for the blocks that had a
             to redo the dataflow equations for the blocks that had a
             change at the top of the block.  Then we need to redo the
             change at the top of the block.  Then we need to redo the
             iteration.  */
             iteration.  */
          if (byte_level)
          if (byte_level)
            df_analyze_problem (df_byte_lr, all_blocks, postorder, n_blocks);
            df_analyze_problem (df_byte_lr, all_blocks, postorder, n_blocks);
          else
          else
            df_analyze_problem (df_lr, all_blocks, postorder, n_blocks);
            df_analyze_problem (df_lr, all_blocks, postorder, n_blocks);
 
 
          if (old_flag & DF_LR_RUN_DCE)
          if (old_flag & DF_LR_RUN_DCE)
            df_set_flags (DF_LR_RUN_DCE);
            df_set_flags (DF_LR_RUN_DCE);
 
 
          prescan_insns_for_dce (true);
          prescan_insns_for_dce (true);
        }
        }
    }
    }
 
 
  delete_unmarked_insns ();
  delete_unmarked_insns ();
 
 
  BITMAP_FREE (processed);
  BITMAP_FREE (processed);
  BITMAP_FREE (redo_out);
  BITMAP_FREE (redo_out);
  BITMAP_FREE (all_blocks);
  BITMAP_FREE (all_blocks);
}
}
 
 
 
 
/* Fast register level DCE.  */
/* Fast register level DCE.  */
 
 
static unsigned int
static unsigned int
rest_of_handle_fast_dce (void)
rest_of_handle_fast_dce (void)
{
{
  init_dce (true);
  init_dce (true);
  fast_dce (false);
  fast_dce (false);
  fini_dce (true);
  fini_dce (true);
  return 0;
  return 0;
}
}
 
 
 
 
/* Fast byte level DCE.  */
/* Fast byte level DCE.  */
 
 
static unsigned int
static unsigned int
rest_of_handle_fast_byte_dce (void)
rest_of_handle_fast_byte_dce (void)
{
{
  df_byte_lr_add_problem ();
  df_byte_lr_add_problem ();
  init_dce (true);
  init_dce (true);
  fast_dce (true);
  fast_dce (true);
  fini_dce (true);
  fini_dce (true);
  return 0;
  return 0;
}
}
 
 
 
 
/* This is an internal call that is used by the df live register
/* This is an internal call that is used by the df live register
   problem to run fast dce as a side effect of creating the live
   problem to run fast dce as a side effect of creating the live
   information.  The stack is organized so that the lr problem is run,
   information.  The stack is organized so that the lr problem is run,
   this pass is run, which updates the live info and the df scanning
   this pass is run, which updates the live info and the df scanning
   info, and then returns to allow the rest of the problems to be run.
   info, and then returns to allow the rest of the problems to be run.
 
 
   This can be called by elsewhere but it will not update the bit
   This can be called by elsewhere but it will not update the bit
   vectors for any other problems than LR.  */
   vectors for any other problems than LR.  */
 
 
void
void
run_fast_df_dce (void)
run_fast_df_dce (void)
{
{
  if (flag_dce)
  if (flag_dce)
    {
    {
      /* If dce is able to delete something, it has to happen
      /* If dce is able to delete something, it has to happen
         immediately.  Otherwise there will be problems handling the
         immediately.  Otherwise there will be problems handling the
         eq_notes.  */
         eq_notes.  */
      int old_flags =
      int old_flags =
        df_clear_flags (DF_DEFER_INSN_RESCAN + DF_NO_INSN_RESCAN);
        df_clear_flags (DF_DEFER_INSN_RESCAN + DF_NO_INSN_RESCAN);
 
 
      df_in_progress = true;
      df_in_progress = true;
      rest_of_handle_fast_dce ();
      rest_of_handle_fast_dce ();
      df_in_progress = false;
      df_in_progress = false;
 
 
      df_set_flags (old_flags);
      df_set_flags (old_flags);
    }
    }
}
}
 
 
 
 
/* Run a fast DCE pass.  */
/* Run a fast DCE pass.  */
 
 
void
void
run_fast_dce (void)
run_fast_dce (void)
{
{
  if (flag_dce)
  if (flag_dce)
    rest_of_handle_fast_dce ();
    rest_of_handle_fast_dce ();
}
}
 
 
 
 
static bool
static bool
gate_fast_dce (void)
gate_fast_dce (void)
{
{
  return optimize > 0 && flag_dce
  return optimize > 0 && flag_dce
    && dbg_cnt (dce_fast);
    && dbg_cnt (dce_fast);
}
}
 
 
struct rtl_opt_pass pass_fast_rtl_dce =
struct rtl_opt_pass pass_fast_rtl_dce =
{
{
 {
 {
  RTL_PASS,
  RTL_PASS,
  "rtl dce",                            /* name */
  "rtl dce",                            /* name */
  gate_fast_dce,                        /* gate */
  gate_fast_dce,                        /* gate */
  rest_of_handle_fast_dce,              /* execute */
  rest_of_handle_fast_dce,              /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  0,                                    /* static_pass_number */
  TV_DCE,                               /* tv_id */
  TV_DCE,                               /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0,                                    /* todo_flags_start */
  TODO_dump_func |
  TODO_dump_func |
  TODO_df_finish | TODO_verify_rtl_sharing |
  TODO_df_finish | TODO_verify_rtl_sharing |
  TODO_ggc_collect                      /* todo_flags_finish */
  TODO_ggc_collect                      /* todo_flags_finish */
 }
 }
};
};
 
 
struct rtl_opt_pass pass_fast_rtl_byte_dce =
struct rtl_opt_pass pass_fast_rtl_byte_dce =
{
{
 {
 {
  RTL_PASS,
  RTL_PASS,
  "byte-dce",                           /* name */
  "byte-dce",                           /* name */
  gate_fast_dce,                        /* gate */
  gate_fast_dce,                        /* gate */
  rest_of_handle_fast_byte_dce,         /* execute */
  rest_of_handle_fast_byte_dce,         /* execute */
  NULL,                                 /* sub */
  NULL,                                 /* sub */
  NULL,                                 /* next */
  NULL,                                 /* next */
  0,                                    /* static_pass_number */
  0,                                    /* static_pass_number */
  TV_DCE,                               /* tv_id */
  TV_DCE,                               /* tv_id */
  0,                                    /* properties_required */
  0,                                    /* properties_required */
  0,                                    /* properties_provided */
  0,                                    /* properties_provided */
  0,                                    /* properties_destroyed */
  0,                                    /* properties_destroyed */
  0,                                    /* todo_flags_start */
  0,                                    /* todo_flags_start */
  TODO_dump_func |
  TODO_dump_func |
  TODO_df_finish | TODO_verify_rtl_sharing |
  TODO_df_finish | TODO_verify_rtl_sharing |
  TODO_ggc_collect                      /* todo_flags_finish */
  TODO_ggc_collect                      /* todo_flags_finish */
 }
 }
};
};
 
 

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