https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101044
Bug ID: 101044
Summary: -ABS(A) produces two neg instructions
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Target: x86_64-linux-gnu
Take:
int f4(int A)
{
return A <= 0? A : -A;
}
int f5(int A)
{
return A < 0? A : -A;
}
int f2(int A)
{
A = A < 0 ? -A : A;
return -A;
}
---- CUT ---
On x86_64 we get two neg for each of these functions now, we used to get none
sometime ago.
Right now we get for each of them:
movl %edi, %eax
negl %eax
cmovs %edi, %eax
negl %eax
----- CUT ---
Note aarch64 seems to be fine:
cmp w0, 0
csneg w0, w0, w0, lt
