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i386: Check AX input in any_mul_highpart peepholes

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When applying peephole optimization to transform

	mov imm, %reg0
	mov %reg1, %AX_REG
	imul %reg0

to

	mov imm, %AX_REG
	imul %reg1

disable peephole optimization if reg1 == AX_REG.

gcc/

	PR target/103785
	* config/i386/i386.md: Swap operand order in comments and check
	AX input in any_mul_highpart peepholes.

gcc/testsuite/

	PR target/103785
	* gcc.target/i386/pr103785.c: New test.
This commit is contained in:
H.J. Lu 2021-12-24 12:50:21 -08:00
parent 9525c26bf1
commit d87483015d
2 changed files with 45 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

10
gcc/config/i386/i386.md
View file

@ -8578,7 +8578,7 @@
(set_attr "mode" "SI")])
;; Highpart multiplication peephole2s to tweak register allocation.
;; mov %rdx,imm; mov %rax,%rdi; imulq %rdx -> mov %rax,imm; imulq %rdi
;; mov imm,%rdx; mov %rdi,%rax; imulq %rdx -> mov imm,%rax; imulq %rdi
(define_peephole2
[(set (match_operand:SWI48 0 "general_reg_operand")
(match_operand:SWI48 1 "immediate_operand"))
@ -8588,7 +8588,8 @@
(any_mul_highpart:SWI48 (match_dup 2) (match_dup 0)))
(clobber (match_dup 2))
(clobber (reg:CC FLAGS_REG))])]
"REGNO (operands[0]) != REGNO (operands[2])
"REGNO (operands[3]) != AX_REG
&& REGNO (operands[0]) != REGNO (operands[2])
&& REGNO (operands[0]) != REGNO (operands[3])
&& (REGNO (operands[0]) == REGNO (operands[4])
|| peep2_reg_dead_p (3, operands[0]))"
@ -8608,7 +8609,10 @@
(any_mul_highpart:SI (match_dup 2) (match_dup 0))))
(clobber (match_dup 2))
(clobber (reg:CC FLAGS_REG))])]
"REGNO (operands[0]) != REGNO (operands[2])
"TARGET_64BIT
&& REGNO (operands[3]) != AX_REG
&& REGNO (operands[0]) != REGNO (operands[2])
&& REGNO (operands[2]) != REGNO (operands[3])
&& REGNO (operands[0]) != REGNO (operands[3])
&& (REGNO (operands[0]) == REGNO (operands[4])
|| peep2_reg_dead_p (3, operands[0]))"

38
gcc/testsuite/gcc.target/i386/pr103785.c Normal file
View file

@ -0,0 +1,38 @@
/* { dg-do run } */
/* { dg-options "-O2" } */
#include <stdlib.h>
struct wrapper_t
{
long k;
long e;
};
struct wrapper_t **table;
__attribute__ ((weak, regparm (2)))
void
update (long k, long e)
{
struct wrapper_t *elmt;
elmt = table[k % 3079];
if (elmt == 0)
return;
elmt->e = e;
}
int
main ()
{
table = (struct wrapper_t **) malloc (20 * sizeof (struct wrapper_t *));
for (int i = 0; i < 20; i++)
table[i] = (struct wrapper_t *) calloc (sizeof (struct wrapper_t), 1);
if (table[10]->e != 0)
abort ();
update (10, 20);
if (table[10]->e != 20)
abort ();
return 0;
}