gcc/common.md

;; Common GCC machine description file, shared by all targets.
;; Copyright (C) 2014-2026 Free Software Foundation, Inc.
;;
;; This file is part of GCC.
;;
;; 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 Software Foundation; either version 3, or (at your option)
;; any later version.
;;
;; GCC is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with GCC; see the file COPYING3.  If not see
;; <http://www.gnu.org/licenses/>.  */

;; This predicate is intended to be paired with register constraints that use
;; register filters to impose an alignment.  Operands that are aligned via
;; TARGET_HARD_REGNO_MODE_OK should use normal register_operands instead.
(define_predicate "aligned_register_operand"
  (match_code "reg,subreg")
{
  /* Require the offset in a non-paradoxical subreg to be naturally aligned.
     For example, if we have a subreg of something that is double the size of
     this operand, the offset must select the first or second half of it.  */
  if (SUBREG_P (op)
      && multiple_p (SUBREG_BYTE (op), GET_MODE_SIZE (GET_MODE (op))))
    op = SUBREG_REG (op);
  if (!REG_P (op))
    return false;

  if (HARD_REGISTER_P (op))
    {
      if (!in_hard_reg_set_p (operand_reg_set, GET_MODE (op), REGNO (op)))
	return false;

      /* Reject hard registers that would need reloading, so that the reload
	 is visible to IRA and to pre-RA optimizers.  */
      if (REGNO (op) % REG_NREGS (op) != 0)
	return false;
    }
  return true;
})

(define_register_constraint "r" "GENERAL_REGS"
  "Matches any general register.")

(define_memory_constraint "TARGET_MEM_CONSTRAINT"
  "Matches any valid memory."
  (and (match_code "mem")
       (match_test "memory_address_addr_space_p (GET_MODE (op), XEXP (op, 0),
						 MEM_ADDR_SPACE (op))")))

(define_memory_constraint "o"
  "Matches an offsettable memory reference."
  (and (match_code "mem")
       (match_test "offsettable_nonstrict_memref_p (op)")))

;; "V" matches TARGET_MEM_CONSTRAINTs that are rejected by "o".
;; This means that it is not a memory constraint in the usual sense,
;; since reloading the address into a base register would make the
;; address offsettable.
(define_constraint "V"
  "Matches a non-offsettable memory reference."
  (and (match_code "mem")
       (match_test "memory_address_addr_space_p (GET_MODE (op), XEXP (op, 0),
						 MEM_ADDR_SPACE (op))")
       (not (match_test "offsettable_nonstrict_memref_p (op)"))))

;; Like "V", this is not a memory constraint, since reloading the address
;; into a base register would cause it not to match.
(define_constraint "<"
  "Matches a pre-dec or post-dec operand."
  (and (match_code "mem")
       (ior (match_test "GET_CODE (XEXP (op, 0)) == PRE_DEC")
       	    (match_test "GET_CODE (XEXP (op, 0)) == POST_DEC"))))

;; See the comment for "<".
(define_constraint ">"
  "Matches a pre-inc or post-inc operand."
  (and (match_code "mem")
       (ior (match_test "GET_CODE (XEXP (op, 0)) == PRE_INC")
       	    (match_test "GET_CODE (XEXP (op, 0)) == POST_INC"))))

(define_address_constraint "p"
  "Matches a general address."
  (match_test "address_operand (op, VOIDmode)"))

(define_constraint "i"
  "Matches a general integer constant."
  (and (match_test "CONSTANT_P (op)")
       (match_test "!flag_pic || raw_constraint_p || LEGITIMATE_PIC_OPERAND_P (op)")))

(define_constraint "s"
  "Matches a symbolic integer constant."
  (and (match_test "CONSTANT_P (op)")
       (match_test "!CONST_SCALAR_INT_P (op)")
       (match_test "!flag_pic || raw_constraint_p || LEGITIMATE_PIC_OPERAND_P (op)")))

(define_constraint ":"
  "Defines a symbol."
  (and (match_test "CONSTANT_P (op)")
       (match_test "!CONST_SCALAR_INT_P (op)")))

(define_constraint "n"
  "Matches a non-symbolic integer constant."
  (and (match_test "CONST_SCALAR_INT_P (op)")
       (match_test "!flag_pic || raw_constraint_p || LEGITIMATE_PIC_OPERAND_P (op)")))

(define_constraint "E"
  "Matches a floating-point constant."
  (ior (match_test "CONST_DOUBLE_AS_FLOAT_P (op)")
       (match_test "GET_CODE (op) == CONST_VECTOR
		    && GET_MODE_CLASS (GET_MODE (op)) == MODE_VECTOR_FLOAT")))

;; There is no longer a distinction between "E" and "F".
(define_constraint "F"
  "Matches a floating-point constant."
  (ior (match_test "CONST_DOUBLE_AS_FLOAT_P (op)")
       (match_test "GET_CODE (op) == CONST_VECTOR
		    && GET_MODE_CLASS (GET_MODE (op)) == MODE_VECTOR_FLOAT")))

(define_constraint "X"
  "Matches anything."
  (match_test "true"))