https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98212
Bug ID: 98212
Summary: X86 unoptimal code for float equallity comparison
followed by jump
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: denis.campredon at gmail dot com
Target Milestone: ---
For f1 code an unnecessary `comiss` instruction is used, the parity flag is
still set after the `jp` instruction.
For f2, I'm not sure if it's the optimal way to do that.
The same problems appear for `float`, `double` and `long double`
------
void f();
void f1(float a, float b) {
if (a != b)
f();
}
void f2(float a, float b) {
if (a == b)
f();
}
------
f1(float, float):
ucomiss xmm0, xmm1
jp .L4
comiss xmm0, xmm1
jne .L4
ret
.L4:
jmp f()
f2(float, float):
ucomiss xmm0, xmm1
jnp .L11
.L7:
ret
.L11:
jne .L7
jmp f()
------
