https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111115
Bug ID: 111115
Summary: Failure to vectorize conditional grouped store
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: rguenth at gcc dot gnu.org
Target Milestone: ---
void foo (float * __restrict x, int *flag)
{
for (int i = 0; i < 512; ++i)
{
if (flag[i])
{
float a = x[2*i+0] + 3.f;
float b = x[2*i+1] + 177.f;
x[2*i+0] = a;
x[2*i+1] = b;
}
}
}
fails to vectorize on x86_64 with -march=znver4 (it needs masked stores
enabled by tuning). This is because we do not support VMAT_CONTIGUOUS_PERMUTE
for either .MASK_LOAD nor .MASK_STORE. Simply enabling that shows we fail
to properly handle the mask part.
The proper solution is to handle them in SLP which they are not either.
