https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104704
Bug ID: 104704
Summary: [12 Regression] ix86_gen_scratch_sse_rtx doesn't work
explicit XMM7/XMM15/XMM31 usage
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: crazylht at gmail dot com, ubizjak at gmail dot com
Target Milestone: ---
ix86_gen_scratch_sse_rtx returns XMM7/XMM15/XMM31 as a scratch register to
prevent RTL optimizer from removing scratch vector register. But it introduces
a conflict with explicit XMM7/XMM15/XMM31 usage:
[hjl@gnu-tgl-2 scratch-2]$ cat x-2.c
/* { dg-do compile { target { ! ia32 } } } */
/* { dg-options "-O2 -march=x86-64 -mavx2" } */
#include <immintrin.h>
__m256d y, z;
int i;
__attribute__((noipa))
int
do_test (void)
{
register int xmm15 __asm ("xmm15") = i;
asm volatile ("" : "+v" (xmm15));
z = y;
register int xmm2 __asm ("xmm2") = xmm15;
asm volatile ("" : "+v" (xmm2));
return xmm2;
}
__attribute__((target("arch=x86-64")))
int
main (void)
{
if (__builtin_cpu_supports ("avx2"))
{
i = 4;
if (do_test () != 4)
__builtin_abort ();
}
return 0;
}
[hjl@gnu-tgl-2 scratch-2]$ make x-2
/export/build/gnu/tools-build/gcc-debug/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/tools-build/gcc-debug/build-x86_64-linux/gcc/ -O2
-march=x86-64 -mavx2 -S x-2.c
/export/build/gnu/tools-build/gcc-debug/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/tools-build/gcc-debug/build-x86_64-linux/gcc/ -O2
-march=x86-64 -o x-2 x-2.s
[hjl@gnu-tgl-2 scratch-2]$ ./x-2
Aborted (core dumped)
[hjl@gnu-tgl-2 scratch-2]$
