Example #1
0
File: ree.c Project: aixoss/gcc
static bool
combine_set_extension (ext_cand *cand, rtx curr_insn, rtx *orig_set)
{
  rtx orig_src = SET_SRC (*orig_set);
  enum machine_mode orig_mode = GET_MODE (SET_DEST (*orig_set));
  rtx new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (*orig_set)));
  rtx new_set;

  /* Merge constants by directly moving the constant into the register under
     some conditions.  Recall that RTL constants are sign-extended.  */
  if (GET_CODE (orig_src) == CONST_INT
      && HOST_BITS_PER_WIDE_INT >= GET_MODE_BITSIZE (cand->mode))
    {
      if (INTVAL (orig_src) >= 0 || cand->code == SIGN_EXTEND)
	new_set = gen_rtx_SET (VOIDmode, new_reg, orig_src);
      else
	{
	  /* Zero-extend the negative constant by masking out the bits outside
	     the source mode.  */
	  rtx new_const_int
	    = GEN_INT (INTVAL (orig_src) & GET_MODE_MASK (orig_mode));
	  new_set = gen_rtx_SET (VOIDmode, new_reg, new_const_int);
	}
    }
  else if (GET_MODE (orig_src) == VOIDmode)
    {
      /* This is mostly due to a call insn that should not be optimized.  */
      return false;
    }
  else if (GET_CODE (orig_src) == cand->code)
    {
      /* Here is a sequence of two extensions.  Try to merge them.  */
      rtx temp_extension
	= gen_rtx_fmt_e (cand->code, cand->mode, XEXP (orig_src, 0));
      rtx simplified_temp_extension = simplify_rtx (temp_extension);
      if (simplified_temp_extension)
        temp_extension = simplified_temp_extension;
      new_set = gen_rtx_SET (VOIDmode, new_reg, temp_extension);
    }
  else if (GET_CODE (orig_src) == IF_THEN_ELSE)
    {
      /* Only IF_THEN_ELSE of phi-type copies are combined.  Otherwise,
         in general, IF_THEN_ELSE should not be combined.  */
      return false;
    }
  else
    {
      /* This is the normal case.  */
      rtx temp_extension
	= gen_rtx_fmt_e (cand->code, cand->mode, orig_src);
      rtx simplified_temp_extension = simplify_rtx (temp_extension);
      if (simplified_temp_extension)
        temp_extension = simplified_temp_extension;
      new_set = gen_rtx_SET (VOIDmode, new_reg, temp_extension);
    }

  /* This change is a part of a group of changes.  Hence,
     validate_change will not try to commit the change.  */
  if (validate_change (curr_insn, orig_set, new_set, true)
      && update_reg_equal_equiv_notes (curr_insn, cand->mode, orig_mode,
				       cand->code))
    {
      if (dump_file)
        {
          fprintf (dump_file,
		   "Tentatively merged extension with definition:\n");
          print_rtl_single (dump_file, curr_insn);
        }
      return true;
    }

  return false;
}
Example #2
0
static bool
combine_set_extension (ext_cand *cand, rtx_insn *curr_insn, rtx *orig_set)
{
  rtx orig_src = SET_SRC (*orig_set);
  machine_mode orig_mode = GET_MODE (SET_DEST (*orig_set));
  rtx new_set;
  rtx cand_pat = PATTERN (cand->insn);

  /* If the extension's source/destination registers are not the same
     then we need to change the original load to reference the destination
     of the extension.  Then we need to emit a copy from that destination
     to the original destination of the load.  */
  rtx new_reg;
  bool copy_needed
    = (REGNO (SET_DEST (cand_pat)) != REGNO (XEXP (SET_SRC (cand_pat), 0)));
  if (copy_needed)
    new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (cand_pat)));
  else
    new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (*orig_set)));

#if 0
  /* Rethinking test.  Temporarily disabled.  */
  /* We're going to be widening the result of DEF_INSN, ensure that doing so
     doesn't change the number of hard registers needed for the result.  */
  if (HARD_REGNO_NREGS (REGNO (new_reg), cand->mode)
      != HARD_REGNO_NREGS (REGNO (SET_DEST (*orig_set)),
			   GET_MODE (SET_DEST (*orig_set))))
	return false;
#endif

  /* Merge constants by directly moving the constant into the register under
     some conditions.  Recall that RTL constants are sign-extended.  */
  if (GET_CODE (orig_src) == CONST_INT
      && HOST_BITS_PER_WIDE_INT >= GET_MODE_BITSIZE (cand->mode))
    {
      if (INTVAL (orig_src) >= 0 || cand->code == SIGN_EXTEND)
	new_set = gen_rtx_SET (new_reg, orig_src);
      else
	{
	  /* Zero-extend the negative constant by masking out the bits outside
	     the source mode.  */
	  rtx new_const_int
	    = gen_int_mode (INTVAL (orig_src) & GET_MODE_MASK (orig_mode),
			    GET_MODE (new_reg));
	  new_set = gen_rtx_SET (new_reg, new_const_int);
	}
    }
  else if (GET_MODE (orig_src) == VOIDmode)
    {
      /* This is mostly due to a call insn that should not be optimized.  */
      return false;
    }
  else if (GET_CODE (orig_src) == cand->code)
    {
      /* Here is a sequence of two extensions.  Try to merge them.  */
      rtx temp_extension
	= gen_rtx_fmt_e (cand->code, cand->mode, XEXP (orig_src, 0));
      rtx simplified_temp_extension = simplify_rtx (temp_extension);
      if (simplified_temp_extension)
        temp_extension = simplified_temp_extension;
      new_set = gen_rtx_SET (new_reg, temp_extension);
    }
  else if (GET_CODE (orig_src) == IF_THEN_ELSE)
    {
      /* Only IF_THEN_ELSE of phi-type copies are combined.  Otherwise,
         in general, IF_THEN_ELSE should not be combined.  */
      return false;
    }
  else
    {
      /* This is the normal case.  */
      rtx temp_extension
	= gen_rtx_fmt_e (cand->code, cand->mode, orig_src);
      rtx simplified_temp_extension = simplify_rtx (temp_extension);
      if (simplified_temp_extension)
        temp_extension = simplified_temp_extension;
      new_set = gen_rtx_SET (new_reg, temp_extension);
    }

  /* This change is a part of a group of changes.  Hence,
     validate_change will not try to commit the change.  */
  if (validate_change (curr_insn, orig_set, new_set, true)
      && update_reg_equal_equiv_notes (curr_insn, cand->mode, orig_mode,
				       cand->code))
    {
      if (dump_file)
        {
          fprintf (dump_file,
		   "Tentatively merged extension with definition %s:\n",
		   (copy_needed) ? "(copy needed)" : "");
          print_rtl_single (dump_file, curr_insn);
        }
      return true;
    }

  return false;
}
Example #3
0
static int
reload_cse_simplify_operands (rtx insn, rtx testreg)
{
  int i, j;

  /* For each operand, all registers that are equivalent to it.  */
  HARD_REG_SET equiv_regs[MAX_RECOG_OPERANDS];

  const char *constraints[MAX_RECOG_OPERANDS];

  /* Vector recording how bad an alternative is.  */
  int *alternative_reject;
  /* Vector recording how many registers can be introduced by choosing
     this alternative.  */
  int *alternative_nregs;
  /* Array of vectors recording, for each operand and each alternative,
     which hard register to substitute, or -1 if the operand should be
     left as it is.  */
  int *op_alt_regno[MAX_RECOG_OPERANDS];
  /* Array of alternatives, sorted in order of decreasing desirability.  */
  int *alternative_order;

  extract_insn (insn);

  if (recog_data.n_alternatives == 0 || recog_data.n_operands == 0)
    return 0;

  /* Figure out which alternative currently matches.  */
  if (! constrain_operands (1))
    fatal_insn_not_found (insn);

  alternative_reject = XALLOCAVEC (int, recog_data.n_alternatives);
  alternative_nregs = XALLOCAVEC (int, recog_data.n_alternatives);
  alternative_order = XALLOCAVEC (int, recog_data.n_alternatives);
  memset (alternative_reject, 0, recog_data.n_alternatives * sizeof (int));
  memset (alternative_nregs, 0, recog_data.n_alternatives * sizeof (int));

  /* For each operand, find out which regs are equivalent.  */
  for (i = 0; i < recog_data.n_operands; i++)
    {
      cselib_val *v;
      struct elt_loc_list *l;
      rtx op;
      enum machine_mode mode;

      CLEAR_HARD_REG_SET (equiv_regs[i]);

      /* cselib blows up on CODE_LABELs.  Trying to fix that doesn't seem
	 right, so avoid the problem here.  Likewise if we have a constant
         and the insn pattern doesn't tell us the mode we need.  */
      if (LABEL_P (recog_data.operand[i])
	  || (CONSTANT_P (recog_data.operand[i])
	      && recog_data.operand_mode[i] == VOIDmode))
	continue;

      op = recog_data.operand[i];
      mode = GET_MODE (op);
#ifdef LOAD_EXTEND_OP
      if (MEM_P (op)
	  && GET_MODE_BITSIZE (mode) < BITS_PER_WORD
	  && LOAD_EXTEND_OP (mode) != UNKNOWN)
	{
	  rtx set = single_set (insn);

	  /* We might have multiple sets, some of which do implicit
	     extension.  Punt on this for now.  */
	  if (! set)
	    continue;
	  /* If the destination is also a MEM or a STRICT_LOW_PART, no
	     extension applies.
	     Also, if there is an explicit extension, we don't have to
	     worry about an implicit one.  */
	  else if (MEM_P (SET_DEST (set))
		   || GET_CODE (SET_DEST (set)) == STRICT_LOW_PART
		   || GET_CODE (SET_SRC (set)) == ZERO_EXTEND
		   || GET_CODE (SET_SRC (set)) == SIGN_EXTEND)
	    ; /* Continue ordinary processing.  */
#ifdef CANNOT_CHANGE_MODE_CLASS
	  /* If the register cannot change mode to word_mode, it follows that
	     it cannot have been used in word_mode.  */
	  else if (REG_P (SET_DEST (set))
		   && CANNOT_CHANGE_MODE_CLASS (GET_MODE (SET_DEST (set)),
						word_mode,
						REGNO_REG_CLASS (REGNO (SET_DEST (set)))))
	    ; /* Continue ordinary processing.  */
#endif
	  /* If this is a straight load, make the extension explicit.  */
	  else if (REG_P (SET_DEST (set))
		   && recog_data.n_operands == 2
		   && SET_SRC (set) == op
		   && SET_DEST (set) == recog_data.operand[1-i])
	    {
	      validate_change (insn, recog_data.operand_loc[i],
			       gen_rtx_fmt_e (LOAD_EXTEND_OP (mode),
					      word_mode, op),
			       1);
	      validate_change (insn, recog_data.operand_loc[1-i],
			       gen_rtx_REG (word_mode, REGNO (SET_DEST (set))),
			       1);
	      if (! apply_change_group ())
		return 0;
	      return reload_cse_simplify_operands (insn, testreg);
	    }
	  else
	    /* ??? There might be arithmetic operations with memory that are
	       safe to optimize, but is it worth the trouble?  */
	    continue;
	}
#endif /* LOAD_EXTEND_OP */
      v = cselib_lookup (op, recog_data.operand_mode[i], 0);
      if (! v)
	continue;

      for (l = v->locs; l; l = l->next)
	if (REG_P (l->loc))
	  SET_HARD_REG_BIT (equiv_regs[i], REGNO (l->loc));
    }

  for (i = 0; i < recog_data.n_operands; i++)
    {
      enum machine_mode mode;
      int regno;
      const char *p;

      op_alt_regno[i] = XALLOCAVEC (int, recog_data.n_alternatives);
      for (j = 0; j < recog_data.n_alternatives; j++)
	op_alt_regno[i][j] = -1;

      p = constraints[i] = recog_data.constraints[i];
      mode = recog_data.operand_mode[i];

      /* Add the reject values for each alternative given by the constraints
	 for this operand.  */
      j = 0;
      while (*p != '\0')
	{
	  char c = *p++;
	  if (c == ',')
	    j++;
	  else if (c == '?')
	    alternative_reject[j] += 3;
	  else if (c == '!')
	    alternative_reject[j] += 300;
	}

      /* We won't change operands which are already registers.  We
	 also don't want to modify output operands.  */
      regno = true_regnum (recog_data.operand[i]);
      if (regno >= 0
	  || constraints[i][0] == '='
	  || constraints[i][0] == '+')
	continue;

      for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
	{
	  int rclass = (int) NO_REGS;

	  if (! TEST_HARD_REG_BIT (equiv_regs[i], regno))
	    continue;

	  SET_REGNO (testreg, regno);
	  PUT_MODE (testreg, mode);

	  /* We found a register equal to this operand.  Now look for all
	     alternatives that can accept this register and have not been
	     assigned a register they can use yet.  */
	  j = 0;
	  p = constraints[i];
	  for (;;)
	    {
	      char c = *p;

	      switch (c)
		{
		case '=':  case '+':  case '?':
		case '#':  case '&':  case '!':
		case '*':  case '%':
		case '0':  case '1':  case '2':  case '3':  case '4':
		case '5':  case '6':  case '7':  case '8':  case '9':
		case '<':  case '>':  case 'V':  case 'o':
		case 'E':  case 'F':  case 'G':  case 'H':
		case 's':  case 'i':  case 'n':
		case 'I':  case 'J':  case 'K':  case 'L':
		case 'M':  case 'N':  case 'O':  case 'P':
		case 'p':  case 'X':  case TARGET_MEM_CONSTRAINT:
		  /* These don't say anything we care about.  */
		  break;

		case 'g': case 'r':
		  rclass = reg_class_subunion[(int) rclass][(int) GENERAL_REGS];
		  break;

		default:
		  rclass
		    = (reg_class_subunion
		       [(int) rclass]
		       [(int) REG_CLASS_FROM_CONSTRAINT ((unsigned char) c, p)]);
		  break;

		case ',': case '\0':
		  /* See if REGNO fits this alternative, and set it up as the
		     replacement register if we don't have one for this
		     alternative yet and the operand being replaced is not
		     a cheap CONST_INT.  */
		  if (op_alt_regno[i][j] == -1
		      && reg_fits_class_p (testreg, rclass, 0, mode)
		      && (GET_CODE (recog_data.operand[i]) != CONST_INT
			  || (rtx_cost (recog_data.operand[i], SET,
			  		optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)))
			      > rtx_cost (testreg, SET,
			  		optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn))))))
		    {
		      alternative_nregs[j]++;
		      op_alt_regno[i][j] = regno;
		    }
		  j++;
		  rclass = (int) NO_REGS;
		  break;
		}
	      p += CONSTRAINT_LEN (c, p);

	      if (c == '\0')
		break;
	    }
	}
    }

  /* Record all alternatives which are better or equal to the currently
     matching one in the alternative_order array.  */
  for (i = j = 0; i < recog_data.n_alternatives; i++)
    if (alternative_reject[i] <= alternative_reject[which_alternative])
      alternative_order[j++] = i;
  recog_data.n_alternatives = j;

  /* Sort it.  Given a small number of alternatives, a dumb algorithm
     won't hurt too much.  */
  for (i = 0; i < recog_data.n_alternatives - 1; i++)
    {
      int best = i;
      int best_reject = alternative_reject[alternative_order[i]];
      int best_nregs = alternative_nregs[alternative_order[i]];
      int tmp;

      for (j = i + 1; j < recog_data.n_alternatives; j++)
	{
	  int this_reject = alternative_reject[alternative_order[j]];
	  int this_nregs = alternative_nregs[alternative_order[j]];

	  if (this_reject < best_reject
	      || (this_reject == best_reject && this_nregs > best_nregs))
	    {
	      best = j;
	      best_reject = this_reject;
	      best_nregs = this_nregs;
	    }
	}

      tmp = alternative_order[best];
      alternative_order[best] = alternative_order[i];
      alternative_order[i] = tmp;
    }

  /* Substitute the operands as determined by op_alt_regno for the best
     alternative.  */
  j = alternative_order[0];

  for (i = 0; i < recog_data.n_operands; i++)
    {
      enum machine_mode mode = recog_data.operand_mode[i];
      if (op_alt_regno[i][j] == -1)
	continue;

      validate_change (insn, recog_data.operand_loc[i],
		       gen_rtx_REG (mode, op_alt_regno[i][j]), 1);
    }

  for (i = recog_data.n_dups - 1; i >= 0; i--)
    {
      int op = recog_data.dup_num[i];
      enum machine_mode mode = recog_data.operand_mode[op];

      if (op_alt_regno[op][j] == -1)
	continue;

      validate_change (insn, recog_data.dup_loc[i],
		       gen_rtx_REG (mode, op_alt_regno[op][j]), 1);
    }

  return apply_change_group ();
}
Example #4
0
/* Scan X and replace any eliminable registers (such as fp) with a
   replacement (such as sp) if SUBST_P, plus an offset.  The offset is
   a change in the offset between the eliminable register and its
   substitution if UPDATE_P, or the full offset if FULL_P, or
   otherwise zero.  If FULL_P, we also use the SP offsets for
   elimination to SP.  If UPDATE_P, use UPDATE_SP_OFFSET for updating
   offsets of register elimnable to SP.  If UPDATE_SP_OFFSET is
   non-zero, don't use difference of the offset and the previous
   offset.

   MEM_MODE is the mode of an enclosing MEM.  We need this to know how
   much to adjust a register for, e.g., PRE_DEC.  Also, if we are
   inside a MEM, we are allowed to replace a sum of a hard register
   and the constant zero with the hard register, which we cannot do
   outside a MEM.  In addition, we need to record the fact that a
   hard register is referenced outside a MEM.

   If we make full substitution to SP for non-null INSN, add the insn
   sp offset.  */
rtx
lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode,
		      bool subst_p, bool update_p,
		      HOST_WIDE_INT update_sp_offset, bool full_p)
{
  enum rtx_code code = GET_CODE (x);
  struct lra_elim_table *ep;
  rtx new_rtx;
  int i, j;
  const char *fmt;
  int copied = 0;

  lra_assert (!update_p || !full_p);
  lra_assert (update_sp_offset == 0 || (!subst_p && update_p && !full_p));
  if (! current_function_decl)
    return x;

  switch (code)
    {
    CASE_CONST_ANY:
    case CONST:
    case SYMBOL_REF:
    case CODE_LABEL:
    case PC:
    case CC0:
    case ASM_INPUT:
    case ADDR_VEC:
    case ADDR_DIFF_VEC:
    case RETURN:
      return x;

    case REG:
      /* First handle the case where we encounter a bare hard register
	 that is eliminable.  Replace it with a PLUS.  */
      if ((ep = get_elimination (x)) != NULL)
	{
	  rtx to = subst_p ? ep->to_rtx : ep->from_rtx;

	  if (update_sp_offset != 0)
	    {
	      if (ep->to_rtx == stack_pointer_rtx)
		return plus_constant (Pmode, to, update_sp_offset);
	      return to;
	    }
	  else if (update_p)
	    return plus_constant (Pmode, to, ep->offset - ep->previous_offset);
	  else if (full_p)
	    return plus_constant (Pmode, to,
				  ep->offset
				  - (insn != NULL_RTX
				     && ep->to_rtx == stack_pointer_rtx
				     ? lra_get_insn_recog_data (insn)->sp_offset
				     : 0));
	  else
	    return to;
	}
      return x;

    case PLUS:
      /* If this is the sum of an eliminable register and a constant, rework
	 the sum.  */
      if (REG_P (XEXP (x, 0)) && CONSTANT_P (XEXP (x, 1)))
	{
	  if ((ep = get_elimination (XEXP (x, 0))) != NULL)
	    {
	      HOST_WIDE_INT offset;
	      rtx to = subst_p ? ep->to_rtx : ep->from_rtx;

	      if (! update_p && ! full_p)
		return gen_rtx_PLUS (Pmode, to, XEXP (x, 1));
	      
	      if (update_sp_offset != 0)
		offset = ep->to_rtx == stack_pointer_rtx ? update_sp_offset : 0;
	      else
		offset = (update_p
			  ? ep->offset - ep->previous_offset : ep->offset);
	      if (full_p && insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx)
		offset -= lra_get_insn_recog_data (insn)->sp_offset;
	      if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) == -offset)
		return to;
	      else
		return gen_rtx_PLUS (Pmode, to,
				     plus_constant (Pmode,
						    XEXP (x, 1), offset));
	    }

	  /* If the hard register is not eliminable, we are done since
	     the other operand is a constant.  */
	  return x;
	}

      /* If this is part of an address, we want to bring any constant
	 to the outermost PLUS.  We will do this by doing hard
	 register replacement in our operands and seeing if a constant
	 shows up in one of them.

	 Note that there is no risk of modifying the structure of the
	 insn, since we only get called for its operands, thus we are
	 either modifying the address inside a MEM, or something like
	 an address operand of a load-address insn.  */

      {
	rtx new0 = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode,
					 subst_p, update_p,
					 update_sp_offset, full_p);
	rtx new1 = lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode,
					 subst_p, update_p,
					 update_sp_offset, full_p);

	new0 = move_plus_up (new0);
	new1 = move_plus_up (new1);
	if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1))
	  return form_sum (new0, new1);
      }
      return x;

    case MULT:
      /* If this is the product of an eliminable hard register and a
	 constant, apply the distribute law and move the constant out
	 so that we have (plus (mult ..) ..).  This is needed in order
	 to keep load-address insns valid.  This case is pathological.
	 We ignore the possibility of overflow here.  */
      if (REG_P (XEXP (x, 0)) && CONST_INT_P (XEXP (x, 1))
	  && (ep = get_elimination (XEXP (x, 0))) != NULL)
	{
	  rtx to = subst_p ? ep->to_rtx : ep->from_rtx;

	  if (update_sp_offset != 0)
	    {
	      if (ep->to_rtx == stack_pointer_rtx)
		return plus_constant (Pmode,
				      gen_rtx_MULT (Pmode, to, XEXP (x, 1)),
				      update_sp_offset * INTVAL (XEXP (x, 1)));
	      return gen_rtx_MULT (Pmode, to, XEXP (x, 1));
	    }
	  else if (update_p)
	    return plus_constant (Pmode,
				  gen_rtx_MULT (Pmode, to, XEXP (x, 1)),
				  (ep->offset - ep->previous_offset)
				  * INTVAL (XEXP (x, 1)));
	  else if (full_p)
	    {
	      HOST_WIDE_INT offset = ep->offset;

	      if (insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx)
		offset -= lra_get_insn_recog_data (insn)->sp_offset;
	      return
		plus_constant (Pmode,
			       gen_rtx_MULT (Pmode, to, XEXP (x, 1)),
			       offset * INTVAL (XEXP (x, 1)));
	    }
	  else
	    return gen_rtx_MULT (Pmode, to, XEXP (x, 1));
	}

      /* fall through */

    case CALL:
    case COMPARE:
    /* See comments before PLUS about handling MINUS.  */
    case MINUS:
    case DIV:	   case UDIV:
    case MOD:	   case UMOD:
    case AND:	   case IOR:	  case XOR:
    case ROTATERT: case ROTATE:
    case ASHIFTRT: case LSHIFTRT: case ASHIFT:
    case NE:	   case EQ:
    case GE:	   case GT:	  case GEU:    case GTU:
    case LE:	   case LT:	  case LEU:    case LTU:
      {
	rtx new0 = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode,
					 subst_p, update_p, 
					 update_sp_offset, full_p);
	rtx new1 = XEXP (x, 1)
		   ? lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode,
					   subst_p, update_p,
					   update_sp_offset, full_p) : 0;

	if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1))
	  return gen_rtx_fmt_ee (code, GET_MODE (x), new0, new1);
      }
      return x;

    case EXPR_LIST:
      /* If we have something in XEXP (x, 0), the usual case,
	 eliminate it.	*/
      if (XEXP (x, 0))
	{
	  new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode,
					  subst_p, update_p,
					  update_sp_offset, full_p);
	  if (new_rtx != XEXP (x, 0))
	    {
	      /* If this is a REG_DEAD note, it is not valid anymore.
		 Using the eliminated version could result in creating a
		 REG_DEAD note for the stack or frame pointer.	*/
	      if (REG_NOTE_KIND (x) == REG_DEAD)
		return (XEXP (x, 1)
			? lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode,
						subst_p, update_p,
						update_sp_offset, full_p)
			: NULL_RTX);

	      x = alloc_reg_note (REG_NOTE_KIND (x), new_rtx, XEXP (x, 1));
	    }
	}

      /* fall through */

    case INSN_LIST:
    case INT_LIST:
      /* Now do eliminations in the rest of the chain.	If this was
	 an EXPR_LIST, this might result in allocating more memory than is
	 strictly needed, but it simplifies the code.  */
      if (XEXP (x, 1))
	{
	  new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode,
					  subst_p, update_p,
					  update_sp_offset, full_p);
	  if (new_rtx != XEXP (x, 1))
	    return
	      gen_rtx_fmt_ee (GET_CODE (x), GET_MODE (x),
			      XEXP (x, 0), new_rtx);
	}
      return x;

    case PRE_INC:
    case POST_INC:
    case PRE_DEC:
    case POST_DEC:
      /* We do not support elimination of a register that is modified.
	 elimination_effects has already make sure that this does not
	 happen.  */
      return x;

    case PRE_MODIFY:
    case POST_MODIFY:
      /* We do not support elimination of a hard register that is
	 modified.  LRA has already make sure that this does not
	 happen. The only remaining case we need to consider here is
	 that the increment value may be an eliminable register.  */
      if (GET_CODE (XEXP (x, 1)) == PLUS
	  && XEXP (XEXP (x, 1), 0) == XEXP (x, 0))
	{
	  rtx new_rtx = lra_eliminate_regs_1 (insn, XEXP (XEXP (x, 1), 1),
					      mem_mode, subst_p, update_p,
					      update_sp_offset, full_p);

	  if (new_rtx != XEXP (XEXP (x, 1), 1))
	    return gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (x, 0),
				   gen_rtx_PLUS (GET_MODE (x),
						 XEXP (x, 0), new_rtx));
	}
      return x;

    case STRICT_LOW_PART:
    case NEG:	       case NOT:
    case SIGN_EXTEND:  case ZERO_EXTEND:
    case TRUNCATE:     case FLOAT_EXTEND: case FLOAT_TRUNCATE:
    case FLOAT:	       case FIX:
    case UNSIGNED_FIX: case UNSIGNED_FLOAT:
    case ABS:
    case SQRT:
    case FFS:
    case CLZ:
    case CTZ:
    case POPCOUNT:
    case PARITY:
    case BSWAP:
      new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode,
				      subst_p, update_p,
				      update_sp_offset, full_p);
      if (new_rtx != XEXP (x, 0))
	return gen_rtx_fmt_e (code, GET_MODE (x), new_rtx);
      return x;

    case SUBREG:
      new_rtx = lra_eliminate_regs_1 (insn, SUBREG_REG (x), mem_mode,
				      subst_p, update_p,
				      update_sp_offset, full_p);

      if (new_rtx != SUBREG_REG (x))
	{
	  int x_size = GET_MODE_SIZE (GET_MODE (x));
	  int new_size = GET_MODE_SIZE (GET_MODE (new_rtx));

	  if (MEM_P (new_rtx) && x_size <= new_size)
	    {
	      SUBREG_REG (x) = new_rtx;
	      alter_subreg (&x, false);
	      return x;
	    }
	  else if (! subst_p)
	    {
	      /* LRA can transform subregs itself.  So don't call
		 simplify_gen_subreg until LRA transformations are
		 finished.  Function simplify_gen_subreg can do
		 non-trivial transformations (like truncation) which
		 might make LRA work to fail.  */
	      SUBREG_REG (x) = new_rtx;
	      return x;
	    }
	  else
	    return simplify_gen_subreg (GET_MODE (x), new_rtx,
					GET_MODE (new_rtx), SUBREG_BYTE (x));
	}

      return x;

    case MEM:
      /* Our only special processing is to pass the mode of the MEM to our
	 recursive call and copy the flags.  While we are here, handle this
	 case more efficiently.	 */
      return
	replace_equiv_address_nv
	(x,
	 lra_eliminate_regs_1 (insn, XEXP (x, 0), GET_MODE (x),
			       subst_p, update_p, update_sp_offset, full_p));

    case USE:
      /* Handle insn_list USE that a call to a pure function may generate.  */
      new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), VOIDmode,
				      subst_p, update_p, update_sp_offset, full_p);
      if (new_rtx != XEXP (x, 0))
	return gen_rtx_USE (GET_MODE (x), new_rtx);
      return x;

    case CLOBBER:
    case SET:
      gcc_unreachable ();

    default:
      break;
    }

  /* Process each of our operands recursively.	If any have changed, make a
     copy of the rtx.  */
  fmt = GET_RTX_FORMAT (code);
  for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
    {
      if (*fmt == 'e')
	{
	  new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, i), mem_mode,
					  subst_p, update_p,
					  update_sp_offset, full_p);
	  if (new_rtx != XEXP (x, i) && ! copied)
	    {
	      x = shallow_copy_rtx (x);
	      copied = 1;
	    }
	  XEXP (x, i) = new_rtx;
	}
      else if (*fmt == 'E')
	{
	  int copied_vec = 0;
	  for (j = 0; j < XVECLEN (x, i); j++)
	    {
	      new_rtx = lra_eliminate_regs_1 (insn, XVECEXP (x, i, j), mem_mode,
					      subst_p, update_p,
					      update_sp_offset, full_p);
	      if (new_rtx != XVECEXP (x, i, j) && ! copied_vec)
		{
		  rtvec new_v = gen_rtvec_v (XVECLEN (x, i),
					     XVEC (x, i)->elem);
		  if (! copied)
		    {
		      x = shallow_copy_rtx (x);
		      copied = 1;
		    }
		  XVEC (x, i) = new_v;
		  copied_vec = 1;
		}
	      XVECEXP (x, i, j) = new_rtx;
	    }
	}
    }

  return x;
}
Example #5
0
static int
reload_cse_simplify_set (rtx set, rtx insn)
{
  int did_change = 0;
  int dreg;
  rtx src;
  enum reg_class dclass;
  int old_cost;
  cselib_val *val;
  struct elt_loc_list *l;
#ifdef LOAD_EXTEND_OP
  enum rtx_code extend_op = UNKNOWN;
#endif
  bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn));

  dreg = true_regnum (SET_DEST (set));
  if (dreg < 0)
    return 0;

  src = SET_SRC (set);
  if (side_effects_p (src) || true_regnum (src) >= 0)
    return 0;

  dclass = REGNO_REG_CLASS (dreg);

#ifdef LOAD_EXTEND_OP
  /* When replacing a memory with a register, we need to honor assumptions
     that combine made wrt the contents of sign bits.  We'll do this by
     generating an extend instruction instead of a reg->reg copy.  Thus
     the destination must be a register that we can widen.  */
  if (MEM_P (src)
      && GET_MODE_BITSIZE (GET_MODE (src)) < BITS_PER_WORD
      && (extend_op = LOAD_EXTEND_OP (GET_MODE (src))) != UNKNOWN
      && !REG_P (SET_DEST (set)))
    return 0;
#endif

  val = cselib_lookup (src, GET_MODE (SET_DEST (set)), 0);
  if (! val)
    return 0;

  /* If memory loads are cheaper than register copies, don't change them.  */
  if (MEM_P (src))
    old_cost = MEMORY_MOVE_COST (GET_MODE (src), dclass, 1);
  else if (REG_P (src))
    old_cost = REGISTER_MOVE_COST (GET_MODE (src),
				   REGNO_REG_CLASS (REGNO (src)), dclass);
  else
    old_cost = rtx_cost (src, SET, speed);

  for (l = val->locs; l; l = l->next)
    {
      rtx this_rtx = l->loc;
      int this_cost;

      if (CONSTANT_P (this_rtx) && ! references_value_p (this_rtx, 0))
	{
#ifdef LOAD_EXTEND_OP
	  if (extend_op != UNKNOWN)
	    {
	      HOST_WIDE_INT this_val;

	      /* ??? I'm lazy and don't wish to handle CONST_DOUBLE.  Other
		 constants, such as SYMBOL_REF, cannot be extended.  */
	      if (GET_CODE (this_rtx) != CONST_INT)
		continue;

	      this_val = INTVAL (this_rtx);
	      switch (extend_op)
		{
		case ZERO_EXTEND:
		  this_val &= GET_MODE_MASK (GET_MODE (src));
		  break;
		case SIGN_EXTEND:
		  /* ??? In theory we're already extended.  */
		  if (this_val == trunc_int_for_mode (this_val, GET_MODE (src)))
		    break;
		default:
		  gcc_unreachable ();
		}
	      this_rtx = GEN_INT (this_val);
	    }
#endif
	  this_cost = rtx_cost (this_rtx, SET, speed);
	}
      else if (REG_P (this_rtx))
	{
#ifdef LOAD_EXTEND_OP
	  if (extend_op != UNKNOWN)
	    {
	      this_rtx = gen_rtx_fmt_e (extend_op, word_mode, this_rtx);
	      this_cost = rtx_cost (this_rtx, SET, speed);
	    }
	  else
#endif
	    this_cost = REGISTER_MOVE_COST (GET_MODE (this_rtx),
					    REGNO_REG_CLASS (REGNO (this_rtx)),
					    dclass);
	}
      else
	continue;

      /* If equal costs, prefer registers over anything else.  That
	 tends to lead to smaller instructions on some machines.  */
      if (this_cost < old_cost
	  || (this_cost == old_cost
	      && REG_P (this_rtx)
	      && !REG_P (SET_SRC (set))))
	{
#ifdef LOAD_EXTEND_OP
	  if (GET_MODE_BITSIZE (GET_MODE (SET_DEST (set))) < BITS_PER_WORD
	      && extend_op != UNKNOWN
#ifdef CANNOT_CHANGE_MODE_CLASS
	      && !CANNOT_CHANGE_MODE_CLASS (GET_MODE (SET_DEST (set)),
					    word_mode,
					    REGNO_REG_CLASS (REGNO (SET_DEST (set))))
#endif
	      )
	    {
	      rtx wide_dest = gen_rtx_REG (word_mode, REGNO (SET_DEST (set)));
	      ORIGINAL_REGNO (wide_dest) = ORIGINAL_REGNO (SET_DEST (set));
	      validate_change (insn, &SET_DEST (set), wide_dest, 1);
	    }
#endif

	  validate_unshare_change (insn, &SET_SRC (set), this_rtx, 1);
	  old_cost = this_cost, did_change = 1;
	}
    }

  return did_change;
}