示例#1
0
static bool
copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd)
{
  bool anything_changed = false;
  rtx insn;

  for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
    {
      int n_ops, i, alt, predicated;
      bool is_asm, any_replacements;
      rtx set;
      bool replaced[MAX_RECOG_OPERANDS];
      bool changed = false;
      struct kill_set_value_data ksvd;

      if (!NONDEBUG_INSN_P (insn))
	{
	  if (DEBUG_INSN_P (insn))
	    {
	      rtx loc = INSN_VAR_LOCATION_LOC (insn);
	      if (!VAR_LOC_UNKNOWN_P (loc))
		replace_oldest_value_addr (&INSN_VAR_LOCATION_LOC (insn),
					   ALL_REGS, GET_MODE (loc),
					   ADDR_SPACE_GENERIC, insn, vd);
	    }

	  if (insn == BB_END (bb))
	    break;
	  else
	    continue;
	}

      set = single_set (insn);
      extract_insn (insn);
      if (! constrain_operands (1))
	fatal_insn_not_found (insn);
      preprocess_constraints ();
      alt = which_alternative;
      n_ops = recog_data.n_operands;
      is_asm = asm_noperands (PATTERN (insn)) >= 0;

      /* Simplify the code below by rewriting things to reflect
	 matching constraints.  Also promote OP_OUT to OP_INOUT
	 in predicated instructions.  */

      predicated = GET_CODE (PATTERN (insn)) == COND_EXEC;
      for (i = 0; i < n_ops; ++i)
	{
	  int matches = recog_op_alt[i][alt].matches;
	  if (matches >= 0)
	    recog_op_alt[i][alt].cl = recog_op_alt[matches][alt].cl;
	  if (matches >= 0 || recog_op_alt[i][alt].matched >= 0
	      || (predicated && recog_data.operand_type[i] == OP_OUT))
	    recog_data.operand_type[i] = OP_INOUT;
	}

      /* Apply changes to earlier DEBUG_INSNs if possible.  */
      if (vd->n_debug_insn_changes)
	note_uses (&PATTERN (insn), cprop_find_used_regs, vd);

      /* For each earlyclobber operand, zap the value data.  */
      for (i = 0; i < n_ops; i++)
	if (recog_op_alt[i][alt].earlyclobber)
	  kill_value (recog_data.operand[i], vd);

      /* Within asms, a clobber cannot overlap inputs or outputs.
	 I wouldn't think this were true for regular insns, but
	 scan_rtx treats them like that...  */
      note_stores (PATTERN (insn), kill_clobbered_value, vd);

      /* Kill all auto-incremented values.  */
      /* ??? REG_INC is useless, since stack pushes aren't done that way.  */
      for_each_rtx (&PATTERN (insn), kill_autoinc_value, vd);

      /* Kill all early-clobbered operands.  */
      for (i = 0; i < n_ops; i++)
	if (recog_op_alt[i][alt].earlyclobber)
	  kill_value (recog_data.operand[i], vd);

      /* Special-case plain move instructions, since we may well
	 be able to do the move from a different register class.  */
      if (set && REG_P (SET_SRC (set)))
	{
	  rtx src = SET_SRC (set);
	  unsigned int regno = REGNO (src);
	  enum machine_mode mode = GET_MODE (src);
	  unsigned int i;
	  rtx new_rtx;

	  /* If we are accessing SRC in some mode other that what we
	     set it in, make sure that the replacement is valid.  */
	  if (mode != vd->e[regno].mode)
	    {
	      if (hard_regno_nregs[regno][mode]
		  > hard_regno_nregs[regno][vd->e[regno].mode])
		goto no_move_special_case;

	      /* And likewise, if we are narrowing on big endian the transformation
		 is also invalid.  */
	      if (hard_regno_nregs[regno][mode]
		  < hard_regno_nregs[regno][vd->e[regno].mode]
		  && (GET_MODE_SIZE (vd->e[regno].mode) > UNITS_PER_WORD
		      ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN))
		goto no_move_special_case;
	    }

	  /* If the destination is also a register, try to find a source
	     register in the same class.  */
	  if (REG_P (SET_DEST (set)))
	    {
	      new_rtx = find_oldest_value_reg (REGNO_REG_CLASS (regno), src, vd);
	      if (new_rtx && validate_change (insn, &SET_SRC (set), new_rtx, 0))
		{
		  if (dump_file)
		    fprintf (dump_file,
			     "insn %u: replaced reg %u with %u\n",
			     INSN_UID (insn), regno, REGNO (new_rtx));
		  changed = true;
		  goto did_replacement;
		}
	      /* We need to re-extract as validate_change clobbers
		 recog_data.  */
	      extract_insn (insn);
	      if (! constrain_operands (1))
		fatal_insn_not_found (insn);
	      preprocess_constraints ();
	    }

	  /* Otherwise, try all valid registers and see if its valid.  */
	  for (i = vd->e[regno].oldest_regno; i != regno;
	       i = vd->e[i].next_regno)
	    {
	      new_rtx = maybe_mode_change (vd->e[i].mode, vd->e[regno].mode,
				       mode, i, regno);
	      if (new_rtx != NULL_RTX)
		{
		  if (validate_change (insn, &SET_SRC (set), new_rtx, 0))
		    {
		      ORIGINAL_REGNO (new_rtx) = ORIGINAL_REGNO (src);
		      REG_ATTRS (new_rtx) = REG_ATTRS (src);
		      REG_POINTER (new_rtx) = REG_POINTER (src);
		      if (dump_file)
			fprintf (dump_file,
				 "insn %u: replaced reg %u with %u\n",
				 INSN_UID (insn), regno, REGNO (new_rtx));
		      changed = true;
		      goto did_replacement;
		    }
		  /* We need to re-extract as validate_change clobbers
		     recog_data.  */
		  extract_insn (insn);
		  if (! constrain_operands (1))
		    fatal_insn_not_found (insn);
		  preprocess_constraints ();
		}
	    }
	}
      no_move_special_case:

      any_replacements = false;

      /* For each input operand, replace a hard register with the
	 eldest live copy that's in an appropriate register class.  */
      for (i = 0; i < n_ops; i++)
	{
	  replaced[i] = false;

	  /* Don't scan match_operand here, since we've no reg class
	     information to pass down.  Any operands that we could
	     substitute in will be represented elsewhere.  */
	  if (recog_data.constraints[i][0] == '\0')
	    continue;

	  /* Don't replace in asms intentionally referencing hard regs.  */
	  if (is_asm && REG_P (recog_data.operand[i])
	      && (REGNO (recog_data.operand[i])
		  == ORIGINAL_REGNO (recog_data.operand[i])))
	    continue;

	  if (recog_data.operand_type[i] == OP_IN)
	    {
	      if (recog_op_alt[i][alt].is_address)
		replaced[i]
		  = replace_oldest_value_addr (recog_data.operand_loc[i],
					       recog_op_alt[i][alt].cl,
					       VOIDmode, ADDR_SPACE_GENERIC,
					       insn, vd);
	      else if (REG_P (recog_data.operand[i]))
		replaced[i]
		  = replace_oldest_value_reg (recog_data.operand_loc[i],
					      recog_op_alt[i][alt].cl,
					      insn, vd);
	      else if (MEM_P (recog_data.operand[i]))
		replaced[i] = replace_oldest_value_mem (recog_data.operand[i],
							insn, vd);
	    }
	  else if (MEM_P (recog_data.operand[i]))
	    replaced[i] = replace_oldest_value_mem (recog_data.operand[i],
						    insn, vd);

	  /* If we performed any replacement, update match_dups.  */
	  if (replaced[i])
	    {
	      int j;
	      rtx new_rtx;

	      new_rtx = *recog_data.operand_loc[i];
	      recog_data.operand[i] = new_rtx;
	      for (j = 0; j < recog_data.n_dups; j++)
		if (recog_data.dup_num[j] == i)
		  validate_unshare_change (insn, recog_data.dup_loc[j], new_rtx, 1);

	      any_replacements = true;
	    }
	}

      if (any_replacements)
	{
	  if (! apply_change_group ())
	    {
	      for (i = 0; i < n_ops; i++)
		if (replaced[i])
		  {
		    rtx old = *recog_data.operand_loc[i];
		    recog_data.operand[i] = old;
		  }

	      if (dump_file)
		fprintf (dump_file,
			 "insn %u: reg replacements not verified\n",
			 INSN_UID (insn));
	    }
	  else
	    changed = true;
	}

    did_replacement:
      if (changed)
	{
	  anything_changed = true;

	  /* If something changed, perhaps further changes to earlier
	     DEBUG_INSNs can be applied.  */
	  if (vd->n_debug_insn_changes)
	    note_uses (&PATTERN (insn), cprop_find_used_regs, vd);
	}

      ksvd.vd = vd;
      ksvd.ignore_set_reg = NULL_RTX;

      /* Clobber call-clobbered registers.  */
      if (CALL_P (insn))
	{
	  unsigned int set_regno = INVALID_REGNUM;
	  unsigned int set_nregs = 0;
	  unsigned int regno;
	  rtx exp;
	  hard_reg_set_iterator hrsi;

	  for (exp = CALL_INSN_FUNCTION_USAGE (insn); exp; exp = XEXP (exp, 1))
	    {
	      rtx x = XEXP (exp, 0);
	      if (GET_CODE (x) == SET)
		{
		  rtx dest = SET_DEST (x);
		  kill_value (dest, vd);
		  set_value_regno (REGNO (dest), GET_MODE (dest), vd);
		  copy_value (dest, SET_SRC (x), vd);
		  ksvd.ignore_set_reg = dest;
		  set_regno = REGNO (dest);
		  set_nregs
		    = hard_regno_nregs[set_regno][GET_MODE (dest)];
		  break;
		}
	    }

	  EXECUTE_IF_SET_IN_HARD_REG_SET (regs_invalidated_by_call, 0, regno, hrsi)
	    if (regno < set_regno || regno >= set_regno + set_nregs)
	      kill_value_regno (regno, 1, vd);

	  /* If SET was seen in CALL_INSN_FUNCTION_USAGE, and SET_SRC
	     of the SET isn't in regs_invalidated_by_call hard reg set,
	     but instead among CLOBBERs on the CALL_INSN, we could wrongly
	     assume the value in it is still live.  */
	  if (ksvd.ignore_set_reg)
	    note_stores (PATTERN (insn), kill_clobbered_value, vd);
	}

      /* Notice stores.  */
      note_stores (PATTERN (insn), kill_set_value, &ksvd);

      /* Notice copies.  */
      if (set && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set)))
	copy_value (SET_DEST (set), SET_SRC (set), vd);

      if (insn == BB_END (bb))
	break;
    }

  return anything_changed;
}
示例#2
0
文件: dce.c 项目: AHelper/gcc
static bool
find_call_stack_args (rtx_call_insn *call_insn, bool do_mark, bool fast,
		      bitmap arg_stores)
{
  rtx p;
  rtx_insn *insn, *prev_insn;
  bool ret;
  HOST_WIDE_INT min_sp_off, max_sp_off;
  bitmap sp_bytes;

  gcc_assert (CALL_P (call_insn));
  if (!ACCUMULATE_OUTGOING_ARGS)
    return true;

  if (!do_mark)
    {
      gcc_assert (arg_stores);
      bitmap_clear (arg_stores);
    }

  min_sp_off = INTTYPE_MAXIMUM (HOST_WIDE_INT);
  max_sp_off = 0;

  /* First determine the minimum and maximum offset from sp for
     stored arguments.  */
  for (p = CALL_INSN_FUNCTION_USAGE (call_insn); p; p = XEXP (p, 1))
    if (GET_CODE (XEXP (p, 0)) == USE
	&& MEM_P (XEXP (XEXP (p, 0), 0)))
      {
	rtx mem = XEXP (XEXP (p, 0), 0), addr;
	HOST_WIDE_INT off = 0, size;
	if (!MEM_SIZE_KNOWN_P (mem))
	  return false;
	size = MEM_SIZE (mem);
	addr = XEXP (mem, 0);
	if (GET_CODE (addr) == PLUS
	    && REG_P (XEXP (addr, 0))
	    && CONST_INT_P (XEXP (addr, 1)))
	  {
	    off = INTVAL (XEXP (addr, 1));
	    addr = XEXP (addr, 0);
	  }
	if (addr != stack_pointer_rtx)
	  {
	    if (!REG_P (addr))
	      return false;
	    /* If not fast, use chains to see if addr wasn't set to
	       sp + offset.  */
	    if (!fast)
	      {
		df_ref use;
		struct df_link *defs;
		rtx set;

		FOR_EACH_INSN_USE (use, call_insn)
		  if (rtx_equal_p (addr, DF_REF_REG (use)))
		    break;

		if (use == NULL)
		  return false;

		for (defs = DF_REF_CHAIN (use); defs; defs = defs->next)
		  if (! DF_REF_IS_ARTIFICIAL (defs->ref))
		    break;

		if (defs == NULL)
		  return false;

		set = single_set (DF_REF_INSN (defs->ref));
		if (!set)
		  return false;

		if (GET_CODE (SET_SRC (set)) != PLUS
		    || XEXP (SET_SRC (set), 0) != stack_pointer_rtx
		    || !CONST_INT_P (XEXP (SET_SRC (set), 1)))
		  return false;

		off += INTVAL (XEXP (SET_SRC (set), 1));
	      }
	    else
	      return false;