예제 #1
0
/* Create candidate for INSN with rematerialization operand NOP and
   REGNO.  Insert the candidate into the table and set up the
   corresponding INSN_TO_CAND element.  */
static void
create_cand (rtx_insn *insn, int nop, int regno)
{
  lra_insn_recog_data_t id = lra_get_insn_recog_data (insn);
  rtx reg = *id->operand_loc[nop];
  gcc_assert (REG_P (reg));
  int op_regno = REGNO (reg);
  gcc_assert (op_regno >= FIRST_PSEUDO_REGISTER);
  cand_t cand = XNEW (struct cand);
  cand->insn = insn;
  cand->nop = nop;
  cand->regno = regno;
  cand->reload_regno = op_regno == regno ? -1 : op_regno;
  gcc_assert (cand->regno >= 0);
  cand_t cand_in_table = insert_cand (cand);
  insn_to_cand[INSN_UID (insn)] = cand_in_table;
  if (cand != cand_in_table)
    free (cand);
  else
    {
      /* A new cand.  */
      cand->index = all_cands.length ();
      all_cands.safe_push (cand);
      cand->next_regno_cand = regno_cands[cand->regno];
      regno_cands[cand->regno] = cand;
    }
}
예제 #2
0
/* Function for initialization of elimination once per function.  It
   sets up sp offset for each insn.  */
static void
init_elimination (void)
{
  bool stop_to_sp_elimination_p;
  basic_block bb;
  rtx_insn *insn;
  struct lra_elim_table *ep;

  init_elim_table ();
  FOR_EACH_BB_FN (bb, cfun)
    {
      curr_sp_change = 0;
      stop_to_sp_elimination_p = false;
      FOR_BB_INSNS (bb, insn)
	if (INSN_P (insn))
	  {
	    lra_get_insn_recog_data (insn)->sp_offset = curr_sp_change;
	    if (NONDEBUG_INSN_P (insn))
	      {
		mark_not_eliminable (PATTERN (insn), VOIDmode);
		if (curr_sp_change != 0
		    && find_reg_note (insn, REG_LABEL_OPERAND, NULL_RTX))
		  stop_to_sp_elimination_p = true;
	      }
	  }
      if (! frame_pointer_needed
	  && (curr_sp_change != 0 || stop_to_sp_elimination_p)
	  && bb->succs && bb->succs->length () != 0)
	for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS]; ep++)
	  if (ep->to == STACK_POINTER_REGNUM)
	    setup_can_eliminate (ep, false);
    }
예제 #3
0
/* If INSN can not be used for rematerialization, return negative
   value.  If INSN can be considered as a candidate for
   rematerialization, return value which is the operand number of the
   pseudo for which the insn can be used for rematerialization.  Here
   we consider the insns without any memory, spilled pseudo (except
   for the rematerialization pseudo), or dying or unused regs.  */
static int
operand_to_remat (rtx_insn *insn)
{
  lra_insn_recog_data_t id = lra_get_insn_recog_data (insn);
  struct lra_static_insn_data *static_id = id->insn_static_data;
  struct lra_insn_reg *reg, *found_reg = NULL;

  /* First find a pseudo which can be rematerialized.  */
  for (reg = id->regs; reg != NULL; reg = reg->next)
    /* True FRAME_POINTER_NEEDED might be because we can not follow
       changing sp offsets, e.g. alloca is used.  If the insn contains
       stack pointer in such case, we can not rematerialize it as we
       can not know sp offset at a rematerialization place.  */
    if (reg->regno == STACK_POINTER_REGNUM && frame_pointer_needed)
      return -1;
    else if (reg->type == OP_OUT && ! reg->subreg_p
	     && find_regno_note (insn, REG_UNUSED, reg->regno) == NULL)
      {
	/* We permits only one spilled reg.  */
	if (found_reg != NULL)
	  return -1;
	found_reg = reg;
      }
  if (found_reg == NULL)
    return -1;
  if (found_reg->regno < FIRST_PSEUDO_REGISTER)
    return -1;
  if (bad_for_rematerialization_p (PATTERN (insn)))
    return -1;
  /* Check the other regs are not spilled. */
  for (reg = id->regs; reg != NULL; reg = reg->next)
    if (found_reg == reg)
      continue;
    else if (reg->type == OP_INOUT)
      return -1;
    else if (reg->regno >= FIRST_PSEUDO_REGISTER
	     && reg_renumber[reg->regno] < 0)
      /* Another spilled reg.  */
      return -1;
    else if (reg->type == OP_IN)
      {
	if (find_regno_note (insn, REG_DEAD, reg->regno) != NULL)
	  /* We don't want to make live ranges longer.  */
	  return -1;
	/* Check that there is no output reg as the input one.  */
	for (struct lra_insn_reg *reg2 = id->regs;
	     reg2 != NULL;
	     reg2 = reg2->next)
	  if (reg2->type == OP_OUT && reg->regno == reg2->regno)
	    return -1;
      }
  /* Find the rematerialization operand.  */
  int nop = static_id->n_operands;
  for (int i = 0; i < nop; i++)
    if (REG_P (*id->operand_loc[i])
	&& (int) REGNO (*id->operand_loc[i]) == found_reg->regno)
      return i;
  return -1;
}
예제 #4
0
/* Equal function for candidates CAND1 and CAND2.  They are equal if
   the corresponding candidate insns have the same code, the same
   regno for rematerialization, the same input operands.  */
static int
cand_eq_p (const void *cand1, const void *cand2)
{
  const_cand_t c1 = (const_cand_t) cand1;
  const_cand_t c2 = (const_cand_t) cand2;
  lra_insn_recog_data_t id1 = lra_get_insn_recog_data (c1->insn);
  lra_insn_recog_data_t id2 = lra_get_insn_recog_data (c2->insn);
  struct lra_static_insn_data *static_id1 = id1->insn_static_data;
  int nops = static_id1->n_operands;

  if (c1->regno != c2->regno
      || INSN_CODE (c1->insn) < 0
      || INSN_CODE (c1->insn) != INSN_CODE (c2->insn))
    return false;
  gcc_assert (c1->nop == c2->nop);
  for (int i = 0; i < nops; i++)
    if (i != c1->nop && static_id1->operand[i].type == OP_IN
	&& *id1->operand_loc[i] != *id2->operand_loc[i])
      return false;
  return true;
}
예제 #5
0
/* Hash function for candidate CAND.  */
static hashval_t
cand_hash (const void *cand)
{
  const_cand_t c = (const_cand_t) cand;
  lra_insn_recog_data_t id = lra_get_insn_recog_data (c->insn);
  struct lra_static_insn_data *static_id = id->insn_static_data;
  int nops = static_id->n_operands;
  hashval_t hash = 0;

  for (int i = 0; i < nops; i++)
    if (i == c->nop)
      hash = iterative_hash_object (c->regno, hash);
    else if (static_id->operand[i].type == OP_IN)
      hash = iterative_hash_object (*id->operand_loc[i], hash);
  return hash;
}
예제 #6
0
파일: lra-remat.c 프로젝트: boomeer/gcc
/* If INSN can not be used for rematerialization, return negative
   value.  If INSN can be considered as a candidate for
   rematerialization, return value which is the operand number of the
   pseudo for which the insn can be used for rematerialization.  Here
   we consider the insns without any memory, spilled pseudo (except
   for the rematerialization pseudo), or dying or unused regs.  */
static int
operand_to_remat (rtx_insn *insn)
{
  lra_insn_recog_data_t id = lra_get_insn_recog_data (insn);
  struct lra_static_insn_data *static_id = id->insn_static_data;
  struct lra_insn_reg *reg, *found_reg = NULL;

  /* Don't rematerialize insns which can change PC.  */
  if (JUMP_P (insn) || CALL_P (insn))
    return -1;
  /* First find a pseudo which can be rematerialized.  */
  for (reg = id->regs; reg != NULL; reg = reg->next)
    /* True FRAME_POINTER_NEEDED might be because we can not follow
       changing sp offsets, e.g. alloca is used.  If the insn contains
       stack pointer in such case, we can not rematerialize it as we
       can not know sp offset at a rematerialization place.  */
    if (reg->regno == STACK_POINTER_REGNUM && frame_pointer_needed)
      return -1;
    else if (reg->type == OP_OUT && ! reg->subreg_p
	     && find_regno_note (insn, REG_UNUSED, reg->regno) == NULL)
      {
	/* We permits only one spilled reg.  */
	if (found_reg != NULL)
	  return -1;
	found_reg = reg;
      }
    /* IRA calculates conflicts separately for subregs of two words
       pseudo.  Even if the pseudo lives, e.g. one its subreg can be
       used lately, another subreg hard register can be already used
       for something else.  In such case, it is not safe to
       rematerialize the insn.  */
    else if (reg->type == OP_IN && reg->subreg_p
	     && reg->regno >= FIRST_PSEUDO_REGISTER
	     && (GET_MODE_SIZE (PSEUDO_REGNO_MODE (reg->regno))
		 == 2 * UNITS_PER_WORD))
      return -1;
  if (found_reg == NULL)
    return -1;
  if (found_reg->regno < FIRST_PSEUDO_REGISTER)
    return -1;
  if (bad_for_rematerialization_p (PATTERN (insn)))
    return -1;
  /* Check the other regs are not spilled. */
  for (reg = id->regs; reg != NULL; reg = reg->next)
    if (found_reg == reg)
      continue;
    else if (reg->type == OP_INOUT)
      return -1;
    else if (reg->regno >= FIRST_PSEUDO_REGISTER
	     && reg_renumber[reg->regno] < 0)
      /* Another spilled reg.  */
      return -1;
    else if (reg->type == OP_IN)
      {
	if (find_regno_note (insn, REG_DEAD, reg->regno) != NULL)
	  /* We don't want to make live ranges longer.  */
	  return -1;
	/* Check that there is no output reg as the input one.  */
	for (struct lra_insn_reg *reg2 = id->regs;
	     reg2 != NULL;
	     reg2 = reg2->next)
	  if (reg2->type == OP_OUT && reg->regno == reg2->regno)
	    return -1;
	if (reg->regno < FIRST_PSEUDO_REGISTER)
	  for (struct lra_insn_reg *reg2 = static_id->hard_regs;
	       reg2 != NULL;
	       reg2 = reg2->next)
	    if (reg2->type == OP_OUT
		&& reg->regno <= reg2->regno
		&& (reg2->regno
		    < (reg->regno
		       + hard_regno_nregs[reg->regno][reg->biggest_mode])))
	      return -1;
      }
  /* Find the rematerialization operand.  */
  int nop = static_id->n_operands;
  for (int i = 0; i < nop; i++)
    if (REG_P (*id->operand_loc[i])
	&& (int) REGNO (*id->operand_loc[i]) == found_reg->regno)
      return i;
  return -1;
}
예제 #7
0
void
eliminate_regs_in_insn (rtx_insn *insn, bool replace_p, bool first_p,
			HOST_WIDE_INT update_sp_offset)
{
  int icode = recog_memoized (insn);
  rtx old_set = single_set (insn);
  bool validate_p;
  int i;
  rtx substed_operand[MAX_RECOG_OPERANDS];
  rtx orig_operand[MAX_RECOG_OPERANDS];
  struct lra_elim_table *ep;
  rtx plus_src, plus_cst_src;
  lra_insn_recog_data_t id;
  struct lra_static_insn_data *static_id;

  if (icode < 0 && asm_noperands (PATTERN (insn)) < 0 && ! DEBUG_INSN_P (insn))
    {
      lra_assert (GET_CODE (PATTERN (insn)) == USE
		  || GET_CODE (PATTERN (insn)) == CLOBBER
		  || GET_CODE (PATTERN (insn)) == ASM_INPUT);
      return;
    }

  /* Check for setting an eliminable register.	*/
  if (old_set != 0 && REG_P (SET_DEST (old_set))
      && (ep = get_elimination (SET_DEST (old_set))) != NULL)
    {
      for (ep = reg_eliminate; ep < &reg_eliminate[NUM_ELIMINABLE_REGS]; ep++)
	if (ep->from_rtx == SET_DEST (old_set) && ep->can_eliminate)
	  {
	    bool delete_p = replace_p;
	    
#ifdef HARD_FRAME_POINTER_REGNUM
	    if (ep->from == FRAME_POINTER_REGNUM
		&& ep->to == HARD_FRAME_POINTER_REGNUM)
	      /* If this is setting the frame pointer register to the
		 hardware frame pointer register and this is an
		 elimination that will be done (tested above), this
		 insn is really adjusting the frame pointer downward
		 to compensate for the adjustment done before a
		 nonlocal goto.  */
	      {
		rtx src = SET_SRC (old_set);
		rtx off = remove_reg_equal_offset_note (insn, ep->to_rtx);
		
		/* We should never process such insn with non-zero
		   UPDATE_SP_OFFSET.  */
		lra_assert (update_sp_offset == 0);
		
		if (off != NULL_RTX
		    || src == ep->to_rtx
		    || (GET_CODE (src) == PLUS
			&& XEXP (src, 0) == ep->to_rtx
			&& CONST_INT_P (XEXP (src, 1))))
		  {
		    HOST_WIDE_INT offset;
		    
		    if (replace_p)
		      {
			SET_DEST (old_set) = ep->to_rtx;
			lra_update_insn_recog_data (insn);
			return;
		      }
		    offset = (off != NULL_RTX ? INTVAL (off)
			      : src == ep->to_rtx ? 0 : INTVAL (XEXP (src, 1)));
		    offset -= (ep->offset - ep->previous_offset);
		    src = plus_constant (Pmode, ep->to_rtx, offset);
		    
		    /* First see if this insn remains valid when we
		       make the change.  If not, keep the INSN_CODE
		       the same and let the constraint pass fit it
		       up.  */
		    validate_change (insn, &SET_SRC (old_set), src, 1);
		    validate_change (insn, &SET_DEST (old_set),
				     ep->from_rtx, 1);
		    if (! apply_change_group ())
		      {
			SET_SRC (old_set) = src;
			SET_DEST (old_set) = ep->from_rtx;
		      }
		    lra_update_insn_recog_data (insn);
		    /* Add offset note for future updates.  */
		    add_reg_note (insn, REG_EQUAL, src);
		    return;
		  }
	      }
#endif
	    
	    /* This insn isn't serving a useful purpose.  We delete it
	       when REPLACE is set.  */
	    if (delete_p)
	      lra_delete_dead_insn (insn);
	    return;
	  }
    }

  /* We allow one special case which happens to work on all machines we
     currently support: a single set with the source or a REG_EQUAL
     note being a PLUS of an eliminable register and a constant.  */
  plus_src = plus_cst_src = 0;
  if (old_set && REG_P (SET_DEST (old_set)))
    {
      if (GET_CODE (SET_SRC (old_set)) == PLUS)
	plus_src = SET_SRC (old_set);
      /* First see if the source is of the form (plus (...) CST).  */
      if (plus_src
	  && CONST_INT_P (XEXP (plus_src, 1)))
	plus_cst_src = plus_src;
      /* Check that the first operand of the PLUS is a hard reg or
	 the lowpart subreg of one.  */
      if (plus_cst_src)
	{
	  rtx reg = XEXP (plus_cst_src, 0);

	  if (GET_CODE (reg) == SUBREG && subreg_lowpart_p (reg))
	    reg = SUBREG_REG (reg);

	  if (!REG_P (reg) || REGNO (reg) >= FIRST_PSEUDO_REGISTER)
	    plus_cst_src = 0;
	}
    }
  if (plus_cst_src)
    {
      rtx reg = XEXP (plus_cst_src, 0);
      HOST_WIDE_INT offset = INTVAL (XEXP (plus_cst_src, 1));

      if (GET_CODE (reg) == SUBREG)
	reg = SUBREG_REG (reg);

      if (REG_P (reg) && (ep = get_elimination (reg)) != NULL)
	{
	  rtx to_rtx = replace_p ? ep->to_rtx : ep->from_rtx;

	  if (! replace_p)
	    {
	      if (update_sp_offset == 0)
		offset += (ep->offset - ep->previous_offset);
	      if (ep->to_rtx == stack_pointer_rtx)
		{
		  if (first_p)
		    offset -= lra_get_insn_recog_data (insn)->sp_offset;
		  else
		    offset += update_sp_offset;
		}
	      offset = trunc_int_for_mode (offset, GET_MODE (plus_cst_src));
	    }

	  if (GET_CODE (XEXP (plus_cst_src, 0)) == SUBREG)
	    to_rtx = gen_lowpart (GET_MODE (XEXP (plus_cst_src, 0)), to_rtx);
	  /* If we have a nonzero offset, and the source is already a
	     simple REG, the following transformation would increase
	     the cost of the insn by replacing a simple REG with (plus
	     (reg sp) CST).  So try only when we already had a PLUS
	     before.  */
	  if (offset == 0 || plus_src)
	    {
	      rtx new_src = plus_constant (GET_MODE (to_rtx), to_rtx, offset);

	      old_set = single_set (insn);

	      /* First see if this insn remains valid when we make the
		 change.  If not, try to replace the whole pattern
		 with a simple set (this may help if the original insn
		 was a PARALLEL that was only recognized as single_set
		 due to REG_UNUSED notes).  If this isn't valid
		 either, keep the INSN_CODE the same and let the
		 constraint pass fix it up.  */
	      if (! validate_change (insn, &SET_SRC (old_set), new_src, 0))
		{
		  rtx new_pat = gen_rtx_SET (SET_DEST (old_set), new_src);

		  if (! validate_change (insn, &PATTERN (insn), new_pat, 0))
		    SET_SRC (old_set) = new_src;
		}
	      lra_update_insn_recog_data (insn);
	      /* This can't have an effect on elimination offsets, so skip
		 right to the end.  */
	      return;
	    }
	}
    }

  /* Eliminate all eliminable registers occurring in operands that
     can be handled by the constraint pass.  */
  id = lra_get_insn_recog_data (insn);
  static_id = id->insn_static_data;
  validate_p = false;
  for (i = 0; i < static_id->n_operands; i++)
    {
      orig_operand[i] = *id->operand_loc[i];
      substed_operand[i] = *id->operand_loc[i];

      /* For an asm statement, every operand is eliminable.  */
      if (icode < 0 || insn_data[icode].operand[i].eliminable)
	{
	  /* Check for setting a hard register that we know about.  */
	  if (static_id->operand[i].type != OP_IN
	      && REG_P (orig_operand[i]))
	    {
	      /* If we are assigning to a hard register that can be
		 eliminated, it must be as part of a PARALLEL, since
		 the code above handles single SETs.  This reg can not
		 be longer eliminated -- it is forced by
		 mark_not_eliminable.  */
	      for (ep = reg_eliminate;
		   ep < &reg_eliminate[NUM_ELIMINABLE_REGS];
		   ep++)
		lra_assert (ep->from_rtx != orig_operand[i]
			    || ! ep->can_eliminate);
	    }

	  /* Companion to the above plus substitution, we can allow
	     invariants as the source of a plain move.	*/
	  substed_operand[i]
	    = lra_eliminate_regs_1 (insn, *id->operand_loc[i], VOIDmode,
				    replace_p, ! replace_p && ! first_p,
				    update_sp_offset, first_p);
	  if (substed_operand[i] != orig_operand[i])
	    validate_p = true;
	}
    }

  if (! validate_p)
    return;

  /* Substitute the operands; the new values are in the substed_operand
     array.  */
  for (i = 0; i < static_id->n_operands; i++)
    *id->operand_loc[i] = substed_operand[i];
  for (i = 0; i < static_id->n_dups; i++)
    *id->dup_loc[i] = substed_operand[(int) static_id->dup_num[i]];

  /* If we had a move insn but now we don't, re-recognize it.
     This will cause spurious re-recognition if the old move had a
     PARALLEL since the new one still will, but we can't call
     single_set without having put new body into the insn and the
     re-recognition won't hurt in this rare case.  */
  id = lra_update_insn_recog_data (insn);
  static_id = id->insn_static_data;
}
예제 #8
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;
}