https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91250
Bug ID: 91250
Summary: Missed optimization: is not used vfnmsub213ss
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: zamazan4ik at tut dot by
Target Milestone: ---
For this code:
float foo(float a, float b, float c)
{
return a * -b - c;
}
gcc(trunk) with '-O3 -ffast-math -march=haswell' produces this:
foo(float, float, float):
vfmadd132ss xmm0, xmm2, xmm1
vxorps xmm0, xmm0, XMMWORD PTR .LC0[rip]
ret
clang (trunk) with '-O3 -ffast-math -march=haswell' produces this:
foo(float, float, float):
vfnmsub213ss xmm0, xmm1, xmm2 # xmm0 = -(xmm1 * xmm0) - xmm2
ret
Note: playground on godbolt - https://godbolt.org/z/NTMVdg
