https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127847
Bug ID: 127847
Summary: Hoist can move expr reading asm goto outputs before
asm goto
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: vineetg at gcc dot gnu.org
Target Milestone: ---
Hoist can move an expression which depends on output of asm goto to before the
asm.
__attribute__((noipa, cold)) int
f1 (int a)
{
int x;
asm goto ("" : "=r" (x) : "0" (a) : : lab);
return (x + 100) ^ 1;
lab:
return (x + 100) ^ 2;
}
// triggers at -Os; cold causes it to happen at -O2 and -O3 too.
// f1 (5) must be 104, but generates 101
f1:
movl $101, %eax
ret
.L4:
movl $102, %eax
ret
Verified the problem exists on both x86 and aarch64.
