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xtensa: Recover constant synthesis for HImode after LRA transition

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After LRA transition, HImode constants that don't fit into signed 12 bits
are no longer subject to constant synthesis:

    /* example */
    void test(void) {
      short foo = 32767;
      __asm__ ("" :: "r"(foo));
    }

    ;; before
    	.literal_position
    	.literal .LC0, 32767
    test:
    	l32r	a9, .LC0
    	ret.n

This patch fixes that:

    ;; after
    test:
    	movi.n	a9, -1
    	extui	a9, a9, 17, 15
    	ret.n

gcc/ChangeLog:

	* config/xtensa/xtensa.md (SHI): New mode iterator.
	(2 split patterns related to constsynth):
	Change to also accept HImode operands.
This commit is contained in:
Takayuki 'January June' Suwa 2024-02-04 19:20:16 +09:00 • committed by Max Filippov
parent 777df37a12
commit 7c2c7dd24b
1 changed files with 14 additions and 8 deletions
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22
gcc/config/xtensa/xtensa.md
View file

@ -87,6 +87,10 @@
;; the same template.
(define_mode_iterator HQI [HI QI])
;; This mode iterator allows the SI and HI patterns to be defined from
;; the same template.
(define_mode_iterator SHI [SI HI])
;; Attributes.
@ -1291,28 +1295,30 @@
(set_attr "length" "2,2,2,2,2,2,3,3,3,3,6,3,3,3,3,3")])
(define_split
[(set (match_operand:SI 0 "register_operand")
(match_operand:SI 1 "const_int_operand"))]
[(set (match_operand:SHI 0 "register_operand")
(match_operand:SHI 1 "const_int_operand"))]
"!TARGET_CONST16 && !TARGET_AUTO_LITPOOLS
&& ! xtensa_split1_finished_p ()
&& ! xtensa_simm12b (INTVAL (operands[1]))"
[(set (match_dup 0)
(match_dup 1))]
{
operands[1] = force_const_mem (SImode, operands[1]);
operands[1] = force_const_mem (<MODE>mode, operands[1]);
})
(define_split
[(set (match_operand:SI 0 "register_operand")
(match_operand:SI 1 "constantpool_operand"))]
[(set (match_operand:SHI 0 "register_operand")
(match_operand:SHI 1 "constantpool_operand"))]
"! optimize_debug && reload_completed"
[(const_int 0)]
{
rtx x = avoid_constant_pool_reference (operands[1]);
rtx x = avoid_constant_pool_reference (operands[1]), dst = operands[0];
if (! CONST_INT_P (x))
FAIL;
if (! xtensa_constantsynth (operands[0], INTVAL (x)))
emit_move_insn (operands[0], x);
if (<MODE>mode == HImode)
dst = gen_rtx_REG (SImode, REGNO (dst));
if (! xtensa_constantsynth (dst, INTVAL (x)))
emit_move_insn (dst, x);
DONE;
})