[Bug sanitizer/88109] New: UBSAN can't work with vector operations

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88109

            Bug ID: 88109
           Summary: UBSAN can't work with vector operations
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                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: ---

Following is not detected by UBSAN:

$ cat san.c
typedef int v2si __attribute__((__vector_size__(8)));

int main()
{
  v2si a = {0, 0};
  v2si b = {32, 32};

  /* Not detected.  */
  a >>= b;

  /* Detected.  */
  // a[0] >> 32;

  return 0;  
}

$ gcc san.c -fsanitize=undefined && ./a.out
[nothing]

Note that clang also can't catch that.