[Bug c/71074] New: combine.c in simplify_comparison sanitizer detects left shift of negative value

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71074

            Bug ID: 71074
           Summary: combine.c in simplify_comparison sanitizer detects
                    left shift of negative value
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zeccav at gmail dot com
  Target Milestone: ---

/* gcc -O2 sanitizer undefined runtime error */
/* In gcc trunk 7.0 */
/* ../../gcc7/gcc/combine.c:12340:18: runtime error: left shift of negative
value -13 */
/* combine.c:12340 is "const_op <<= INTVAL (XEXP (op0, 1));" */
/* From PR target/49238 */
int bar (void);

void
foo (unsigned long long a, int b)
{
  int i;

    for (a = -12; a >= 10; a = bar ())
      break;

    if (i == bar () || bar () >= a)
      bar ();
}