[Bug target/71554] New: Miscompilation of __builtin_mul_overflow on i686

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71554

            Bug ID: 71554
           Summary: Miscompilation of __builtin_mul_overflow on i686
           Product: gcc
           Version: 5.4.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org
  Target Milestone: ---

Following testcase is miscompiled with -O2 -m32 on 5.x:

int v;

__attribute__ ((noinline, noclone)) void
bar (void)
{
  v++;
}

__attribute__ ((noinline, noclone))
void
foo (unsigned int x)
{
  signed int y = ((-__INT_MAX__ - 1) / 2);
  signed int r;
  if (__builtin_mul_overflow (x, y, &r))
    bar ();
}

int
main ()
{
  foo (2);
  if (v)
    __builtin_abort ();
  return 0;
}