C++ REG_P函数代码示例

static rtx
conforming_compare (rtx_insn *insn)
{
  rtx set, src, dest;

  set = single_set (insn);
  if (set == NULL)
    return NULL;

  src = SET_SRC (set);
  if (GET_CODE (src) != COMPARE)
    return NULL;

  dest = SET_DEST (set);
  if (!REG_P (dest) || REGNO (dest) != targetm.flags_regnum)
    return NULL;

  if (!REG_P (XEXP (src, 0)))
    return NULL;

  if (CONSTANT_P (XEXP (src, 1)) || REG_P (XEXP (src, 1)))
    return src;

  if (GET_CODE (XEXP (src, 1)) == UNSPEC)
    {
      for (int i = 0; i < XVECLEN (XEXP (src, 1), 0); i++)
	if (!REG_P (XVECEXP (XEXP (src, 1), 0, i)))
	  return NULL;
      return src;
    }

  return NULL;
}

static int crx_addr_reg_p (rtx addr_reg)
{
  rtx reg;

  if (REG_P (addr_reg))
    {
      reg = addr_reg;
    }
  else if ((GET_CODE (addr_reg) == SUBREG
	   && REG_P (SUBREG_REG (addr_reg))
	   && GET_MODE_SIZE (GET_MODE (SUBREG_REG (addr_reg)))
	   <= UNITS_PER_WORD))
    {
      reg = SUBREG_REG (addr_reg);
    }
  else
    return FALSE;

  if (GET_MODE (addr_reg) != Pmode)
    {
      return FALSE;
    }

  return TRUE;
}

static bool
should_replace_address (rtx old_rtx, rtx new_rtx, machine_mode mode,
			addr_space_t as, bool speed)
{
  int gain;

  if (rtx_equal_p (old_rtx, new_rtx)
      || !memory_address_addr_space_p (mode, new_rtx, as))
    return false;

  /* Copy propagation is always ok.  */
  if (REG_P (old_rtx) && REG_P (new_rtx))
    return true;

  /* Prefer the new address if it is less expensive.  */
  gain = (address_cost (old_rtx, mode, as, speed)
	  - address_cost (new_rtx, mode, as, speed));

  /* If the addresses have equivalent cost, prefer the new address
     if it has the highest `set_src_cost'.  That has the potential of
     eliminating the most insns without additional costs, and it
     is the same that cse.c used to do.  */
  if (gain == 0)
    gain = (set_src_cost (new_rtx, VOIDmode, speed)
	    - set_src_cost (old_rtx, VOIDmode, speed));

  return (gain > 0);
}

static bool
aarch_rev16_p_1 (rtx lhs, rtx rhs, enum machine_mode mode)
{
  if (GET_CODE (lhs) == AND
         && GET_CODE (XEXP (lhs, 0)) == ASHIFT
            && CONST_INT_P (XEXP (XEXP (lhs, 0), 1))
            && INTVAL (XEXP (XEXP (lhs, 0), 1)) == 8
            && REG_P (XEXP (XEXP (lhs, 0), 0))
         && CONST_INT_P (XEXP (lhs, 1))
      && GET_CODE (rhs) == AND
         && GET_CODE (XEXP (rhs, 0)) == LSHIFTRT
            && REG_P (XEXP (XEXP (rhs, 0), 0))
            && CONST_INT_P (XEXP (XEXP (rhs, 0), 1))
            && INTVAL (XEXP (XEXP (rhs, 0), 1)) == 8
         && CONST_INT_P (XEXP (rhs, 1))
      && REGNO (XEXP (XEXP (rhs, 0), 0)) == REGNO (XEXP (XEXP (lhs, 0), 0)))

    {
      rtx lhs_mask = XEXP (lhs, 1);
      rtx rhs_mask = XEXP (rhs, 1);

      return aarch_rev16_shright_mask_imm_p (rhs_mask, mode)
             && aarch_rev16_shleft_mask_imm_p (lhs_mask, mode);
    }

  return false;
}

static bool
arithmetic_flags_clobber_p (rtx_insn *insn)
{
  rtx pat, x;

  if (!NONJUMP_INSN_P (insn))
    return false;
  pat = PATTERN (insn);
  if (extract_asm_operands (pat))
    return false;

  if (GET_CODE (pat) == PARALLEL && XVECLEN (pat, 0) == 2)
    {
      x = XVECEXP (pat, 0, 0);
      if (GET_CODE (x) != SET)
	return false;
      x = SET_DEST (x);
      if (!REG_P (x))
	return false;

      x = XVECEXP (pat, 0, 1);
      if (GET_CODE (x) == CLOBBER)
	{
	  x = XEXP (x, 0);
	  if (REG_P (x) && REGNO (x) == targetm.flags_regnum)
	    return true;
	}
    }

  return false;
}

/* In case function does not return value,  we get clobber of pseudo followed
   by set to hard return value.  */
static rtx
skip_unreturned_value (rtx orig_insn)
{
  rtx insn = next_nonnote_insn (orig_insn);

  /* Skip possible clobber of pseudo return register.  */
  if (insn
      && GET_CODE (insn) == INSN
      && GET_CODE (PATTERN (insn)) == CLOBBER
      && REG_P (XEXP (PATTERN (insn), 0))
      && (REGNO (XEXP (PATTERN (insn), 0)) >= FIRST_PSEUDO_REGISTER))
    {
      rtx set_insn = next_nonnote_insn (insn);
      rtx set;
      if (!set_insn)
	return insn;
      set = single_set (set_insn);
      if (!set
	  || SET_SRC (set) != XEXP (PATTERN (insn), 0)
	  || SET_DEST (set) != current_function_return_rtx)
	return insn;
      return set_insn;
    }
  return orig_insn;
}

/* 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;
    }
}

/* Check if all uses in DEF_INSN can be used in TARGET_INSN.  This
   would require full computation of available expressions;
   we check only restricted conditions, see use_killed_between.  */
static bool
all_uses_available_at (rtx_insn *def_insn, rtx_insn *target_insn)
{
  df_ref use;
  struct df_insn_info *insn_info = DF_INSN_INFO_GET (def_insn);
  rtx def_set = single_set (def_insn);
  rtx_insn *next;

  gcc_assert (def_set);

  /* If target_insn comes right after def_insn, which is very common
     for addresses, we can use a quicker test.  Ignore debug insns
     other than target insns for this.  */
  next = NEXT_INSN (def_insn);
  while (next && next != target_insn && DEBUG_INSN_P (next))
    next = NEXT_INSN (next);
  if (next == target_insn && REG_P (SET_DEST (def_set)))
    {
      rtx def_reg = SET_DEST (def_set);

      /* If the insn uses the reg that it defines, the substitution is
         invalid.  */
      FOR_EACH_INSN_INFO_USE (use, insn_info)
	if (rtx_equal_p (DF_REF_REG (use), def_reg))
	  return false;
      FOR_EACH_INSN_INFO_EQ_USE (use, insn_info)
	if (rtx_equal_p (DF_REF_REG (use), def_reg))
	  return false;
    }

static inline int
ix86_carry_flag_operator_1 (rtx op, enum machine_mode mode ATTRIBUTE_UNUSED)
#line 1045 "../.././gcc/config/i386/predicates.md"
{
  enum machine_mode inmode = GET_MODE (XEXP (op, 0));
  enum rtx_code code = GET_CODE (op);

  if (!REG_P (XEXP (op, 0))
      || REGNO (XEXP (op, 0)) != FLAGS_REG
      || XEXP (op, 1) != const0_rtx)
    return 0;

  if (inmode == CCFPmode || inmode == CCFPUmode)
    {
      enum rtx_code second_code, bypass_code;
      ix86_fp_comparison_codes (code, &bypass_code, &code, &second_code);
      if (bypass_code != UNKNOWN || second_code != UNKNOWN)
	return 0;
      code = ix86_fp_compare_code_to_integer (code);
    }
  else if (inmode == CCCmode)
   return code == LTU || code == GTU;
  else if (inmode != CCmode)
    return 0;

  return code == LTU;
}

rtx
gen_lowpart_general (machine_mode mode, rtx x)
{
  rtx result = gen_lowpart_common (mode, x);

  if (result)
    return result;
  /* Handle SUBREGs and hard REGs that were rejected by
     simplify_gen_subreg.  */
  else if (REG_P (x) || GET_CODE (x) == SUBREG)
    {
      result = gen_lowpart_common (mode, copy_to_reg (x));
      gcc_assert (result != 0);
      return result;
    }
  else
    {
      /* The only additional case we can do is MEM.  */
      gcc_assert (MEM_P (x));

      /* The following exposes the use of "x" to CSE.  */
      scalar_int_mode xmode;
      if (is_a <scalar_int_mode> (GET_MODE (x), &xmode)
	  && GET_MODE_SIZE (xmode) <= UNITS_PER_WORD
	  && TRULY_NOOP_TRUNCATION_MODES_P (mode, xmode)
	  && !reload_completed)
	return gen_lowpart_general (mode, force_reg (xmode, x));

      poly_int64 offset = byte_lowpart_offset (mode, GET_MODE (x));
      return adjust_address (x, mode, offset);
    }
}

/* Return true if insn is an instruction that sets a target register.
   if CHECK_CONST is true, only return true if the source is constant.
   If such a set is found and REGNO is nonzero, assign the register number
   of the destination register to *REGNO.  */
static int
insn_sets_btr_p (const_rtx insn, int check_const, int *regno)
{
  rtx set;

  if (NONJUMP_INSN_P (insn)
      && (set = single_set (insn)))
    {
      rtx dest = SET_DEST (set);
      rtx src = SET_SRC (set);

      if (GET_CODE (dest) == SUBREG)
	dest = XEXP (dest, 0);

      if (REG_P (dest)
	  && TEST_HARD_REG_BIT (all_btrs, REGNO (dest)))
	{
	  gcc_assert (!btr_referenced_p (src, NULL));

	  if (!check_const || CONSTANT_P (src))
	    {
	      if (regno)
		*regno = REGNO (dest);
	      return 1;
	    }
	}
    }
  return 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;
}

bool
nds32_expand_strlen (rtx result, rtx str,
		     rtx target_char, rtx align ATTRIBUTE_UNUSED)
{
  rtx base_reg, backup_base_reg;
  rtx ffb_result;
  rtx target_char_ptr, length;
  rtx loop_label, tmp;

  if (optimize_size || optimize < 3)
    return false;

  gcc_assert (MEM_P (str));
  gcc_assert (CONST_INT_P (target_char) || REG_P (target_char));

  base_reg = copy_to_mode_reg (SImode, XEXP (str, 0));
  loop_label = gen_label_rtx ();

  ffb_result = gen_reg_rtx (Pmode);
  tmp = gen_reg_rtx (SImode);
  backup_base_reg = gen_reg_rtx (SImode);

  /* Emit loop version of strlen.
       move  $backup_base, $base
     .Lloop:
       lmw.bim $tmp, [$base], $tmp, 0
       ffb   $ffb_result, $tmp, $target_char   ! is there $target_char?
       beqz  $ffb_result, .Lloop
       add   $last_char_ptr, $base, $ffb_result
       sub   $length, $last_char_ptr, $backup_base  */

  /* move  $backup_base, $base  */
  emit_move_insn (backup_base_reg, base_reg);

  /* .Lloop:  */
  emit_label (loop_label);
  /* lmw.bim $tmp, [$base], $tmp, 0  */
  emit_insn (gen_unaligned_load_update_base_w (base_reg, tmp, base_reg));

  /*  ffb   $ffb_result, $tmp, $target_char   ! is there $target_char?  */
  emit_insn (gen_unspec_ffb (ffb_result, tmp, target_char));

  /* beqz  $ffb_result, .Lloop  */
  emit_cmp_and_jump_insns (ffb_result, const0_rtx, EQ, NULL,
			   SImode, 1, loop_label);

  /* add   $target_char_ptr, $base, $ffb_result   */
  target_char_ptr = expand_binop (Pmode, add_optab, base_reg,
				ffb_result, NULL_RTX, 0, OPTAB_WIDEN);

  /* sub   $length, $target_char_ptr, $backup_base  */
  length = expand_binop (Pmode, sub_optab, target_char_ptr,
			 backup_base_reg, NULL_RTX, 0, OPTAB_WIDEN);

  emit_move_insn (result, length);

  return true;
}

/* Generate code for transformations 3 and 4 (with MODE and OPERATION,
   operands OP1 and OP2, result TARGET, at most SUB subtractions, and
   probability of taking the optimal path(s) PROB1 and PROB2).  */
static rtx
gen_mod_subtract (enum machine_mode mode, enum rtx_code operation,
		  rtx target, rtx op1, rtx op2, int sub, int prob1, int prob2)
{
  rtx tmp, tmp1, jump;
  rtx end_label = gen_label_rtx ();
  rtx sequence;
  int i;

  start_sequence ();
  
  if (!REG_P (op2))
    {
      tmp = gen_reg_rtx (mode);
      emit_move_insn (tmp, copy_rtx (op2));
    }
  else
    tmp = op2;

  emit_move_insn (target, copy_rtx (op1));
  do_compare_rtx_and_jump (target, tmp, LTU, 0, mode, NULL_RTX,
			   NULL_RTX, end_label);

  /* Add branch probability to jump we just created.  */
  jump = get_last_insn ();
  REG_NOTES (jump) = gen_rtx_EXPR_LIST (REG_BR_PROB,
					GEN_INT (prob1), REG_NOTES (jump));

  for (i = 0; i < sub; i++)
    {
      tmp1 = expand_simple_binop (mode, MINUS, target, tmp, target,
	    			  0, OPTAB_WIDEN);
      if (tmp1 != target)
	emit_move_insn (target, tmp1);
      do_compare_rtx_and_jump (target, tmp, LTU, 0, mode, NULL_RTX,
    			       NULL_RTX, end_label);

      /* Add branch probability to jump we just created.  */
      jump = get_last_insn ();
      REG_NOTES (jump) = gen_rtx_EXPR_LIST (REG_BR_PROB,
					    GEN_INT (prob2), REG_NOTES (jump));
    }

  tmp1 = simplify_gen_binary (operation, mode, copy_rtx (target), copy_rtx (tmp));
  tmp1 = force_operand (tmp1, target);
  if (tmp1 != target)
    emit_move_insn (target, tmp1);
  
  emit_label (end_label);

  sequence = get_insns ();
  end_sequence ();
  rebuild_jump_labels (sequence);
  return sequence;
}

static rtx
propagate_rtx (rtx x, machine_mode mode, rtx old_rtx, rtx new_rtx,
	       bool speed)
{
  rtx tem;
  bool collapsed;
  int flags;

  if (REG_P (new_rtx) && REGNO (new_rtx) < FIRST_PSEUDO_REGISTER)
    return NULL_RTX;

  flags = 0;
  if (REG_P (new_rtx)
      || CONSTANT_P (new_rtx)
      || (GET_CODE (new_rtx) == SUBREG
	  && REG_P (SUBREG_REG (new_rtx))
	  && (GET_MODE_SIZE (mode)
	      <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (new_rtx))))))
    flags |= PR_CAN_APPEAR;
  if (!varying_mem_p (new_rtx))
    flags |= PR_HANDLE_MEM;

  if (speed)
    flags |= PR_OPTIMIZE_FOR_SPEED;

  tem = x;
  collapsed = propagate_rtx_1 (&tem, old_rtx, copy_rtx (new_rtx), flags);
  if (tem == x || !collapsed)
    return NULL_RTX;

  /* gen_lowpart_common will not be able to process VOIDmode entities other
     than CONST_INTs.  */
  if (GET_MODE (tem) == VOIDmode && !CONST_INT_P (tem))
    return NULL_RTX;

  if (GET_MODE (tem) == VOIDmode)
    tem = rtl_hooks.gen_lowpart_no_emit (mode, tem);
  else
    gcc_assert (GET_MODE (tem) == mode);

  return tem;
}