[Bug target/98522] New: _mm_cvttps_pi32 and _mm_cvtps_pi32 raise spurious FP exceptions

[foom at fuhm dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98522

            Bug ID: 98522
           Summary: _mm_cvttps_pi32 and _mm_cvtps_pi32 raise spurious FP
                    exceptions
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: foom at fuhm dot net
  Target Milestone: ---

This is a regression due to the MMX in SSE work in GCC10. As far as I can tell,
it affects only these two functions.

Example test, which should return 0, but instead throws SIGFPE:

#pragma stdc fenv_access

#define _GNU_SOURCE
#include <emmintrin.h>
#include <fenv.h>

__attribute__((noinline)) __m64 test(__m128 a) {
  return _mm_cvtt_ps2pi(a);
}

int main() {
  feenableexcept(FE_INVALID);
  __m128 x = (__m128)(__m128i){0x0000000000000000LL, 0x7fffffffffffffffLL};
  volatile __m64 y = test(x);
}


In GCC 10 and trunk, the function test is compiled to:
        cvttps2dq       xmm0, xmm0
        ret
which will convert the upper 64 bits as well as the lower 64 bits -- and
therefore raises FP exceptions accordingly. But, it ought to be ignoring the
upper 64bits.