https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94893
Bug ID: 94893
Summary: Sign function not getting optimized to simple compare
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
inline int sign(int x)
{
return (x >> 31) | ((unsigned)-x >> 31);
}
bool f(int x)
{
return sign(x) < 1;
}
With -O3, LLVM outputs :
f(int):
test edi, edi
setle al
ret
GCC outputs :
f(int):
mov eax, edi
sar edi, 31
neg eax
shr eax, 31
or eax, edi
setle al
ret
