https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94308
Bug ID: 94308
Summary: [10 Regression] ICE in final_scan_insn_1 with
vzeroupper
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jakub at gcc dot gnu.org
Target Milestone: ---
/* { dg-do compile } */
/* { dg-options "-O2 -mfpmath=sse -mavx2 -mfma" } */
#include <x86intrin.h>
void
foo (float *x, const float *y, const float *z, unsigned int w)
{
unsigned int a;
const unsigned int b = w / 8;
const float *c = y;
const float *d = z;
__m256 e = _mm256_setzero_ps ();
__m256 f, g;
for (a = 0; a < b; a++)
{
f = _mm256_loadu_ps (c);
g = _mm256_loadu_ps (d);
c += 8;
d += 8;
e = _mm256_fmadd_ps (f, g, e);
}
__attribute__ ((aligned (32))) float h[8];
_mm256_storeu_ps (h, e);
_mm256_zeroupper ();
float i = h[0] + h[1] + h[2] + h[3] + h[4] + h[5] + h[6] + h[7];
for (a = b * 8; a < w; a++)
i += (*c++) * (*d++);
*x = i;
}
ICEs on i686-linux or x86_64-linux with -m32.
The problem is that the vzeroupper pass in this case fills in sets for all
xmm0..xmm7 regs, but doesn't force rerecognition of the insn, so it is still
considered avx_vzeroupper_1, but the splitter doesn't trigger for it.
