[1/2,v2] xtensa: Recover constant synthesis for HImode after LRA transition
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Commit Message
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.
---
gcc/config/xtensa/xtensa.md | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
Comments
On Sun, Feb 4, 2024 at 2:20 AM Takayuki 'January June' Suwa
<jjsuwa_sys3175@yahoo.co.jp> wrote:
>
> 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.
> ---
> gcc/config/xtensa/xtensa.md | 22 ++++++++++++++--------
> 1 file changed, 14 insertions(+), 8 deletions(-)
Regtested for target=xtensa-linux-uclibc, no new regressions.
Committed to master.
@@ -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;
})