https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112533
Bug ID: 112533
Summary: missed optimization (~A & C) == (~B & C) => (A & C) ==
(B & C)
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: vanyacpp at gmail dot com
Target Milestone: ---
On this code
static bool is_even(unsigned a)
{
return a % 2 == 0;
}
bool same_evenness(unsigned a, unsigned b)
{
return is_even(a) == is_even(b);
}
GCC -02 currently produces
same_evenness:
notl %esi // (1)
notl %edi // (2)
andl $1, %esi
andl $1, %edi
cmpb %dil, %sil
sete %al
ret
The NOTs (1) and (2) are redundant. It would be great if GCC could optimize
them out.
