[Bug sanitizer/103519] New: Address sanitizer check missing for AVX512 masked load

["dlong at cadence dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103519

            Bug ID: 103519
           Summary: Address sanitizer check missing for AVX512 masked load
           Product: gcc
           Version: 11.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dlong at cadence dot com
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at gcc dot gnu.org
  Target Milestone: ---

Example with generated assembly available here: https://godbolt.org/z/WTo5sGThb

In this:

#include <x86intrin.h>

__m512d v;

void
access(float const *addr)
{
  __m512d val;
  __m256 val1;
  __mmask8 const k3 = 0x3f;
  val1=_mm256_maskz_loadu_ps(k3, addr);
  val=_mm512_cvtps_pd(val1);
  _mm512_storeu_pd((double *)&v, val);
}

when compiled with AVX512 instructions and -fsanitize=address, no address check
is generated for the maskz_load.

(FWIW, if the mask is folded into the conversion using maskz_cvtps_pd instead
then a check is generated.  However it's a check for a full 32-byte access even
though the CPU will only actually access 24-bytes due to the mask.)