[Bug c/81537] New: ice in vect_is_simple_reduction

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81537

            Bug ID: 81537
           Summary: ice in vect_is_simple_reduction
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

The following C code, when compiled by -O3 on recent revisions,
does this:

/home/dcb/gcc/results.250361/bin/gcc
/home/dcb/gcc/results.250426/bin/gcc
during GIMPLE pass: vect
bug372.c: In function ‘f’:
bug372.c:8:1: internal compiler error: Segmentation fault
 f(g) {
 ^
0xc6298f crash_signal
        ../../trunk/gcc/toplev.c:338
0xefca68 vect_is_simple_reduction
        ../../trunk/gcc/tree-vect-loop.c:3165
0xf00978 vect_force_simple_reduction(_loop_vec_info*, gimple*, bool*, bool)
        ../../trunk/gcc/tree-vect-loop.c:3298
0xf00978 vect_analyze_scalar_cycles_1
        ../../trunk/gcc/tree-vect-loop.c:857

The problem seems to exist between revision 250361 and 250426.

Code is

typedef h;
typedef k;
a;
b;
c;
d;
e;
f(g) {
  h *i = &e;
  k *j;
  if (d -= b)
    for (; *j; *j += 1) {
      g = g || (a = e ? c = j : 0) + *i;
      i = &d;
    }
}