[Bug tree-optimization/69168] New: [6 Regression] ICE in vect_analyze_loop_2, at tree-vect-loop.c:2182

[doko at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69168

            Bug ID: 69168
           Summary: [6 Regression] ICE in vect_analyze_loop_2, at
                    tree-vect-loop.c:2182
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: doko at gcc dot gnu.org
  Target Milestone: ---

trunk r232077, powerpc64le-linux-gnu, works with -O2

reduced test case:

long a, b, e;
short *c;
int *d;
void fn1() {
  int i;
  for (; e; e--) {
    i = 2;
    for (; i; i--)
      a = b = *d++ / (1 << 9);
    b = b ? 8 : a;
    *c++ = *c++ = b;
  }
}

$ gcc -c -g -O3 virtch2.i
virtch2.i: In function 'fn1':
virtch2.i:4:6: internal compiler error: in vect_analyze_loop_2, at
tree-vect-loop.c:2182
 void fn1() {
      ^~~

0x108ea7fb vect_analyze_loop_2
        ../../src/gcc/tree-vect-loop.c:2182
0x108ea7fb vect_analyze_loop(loop*)
        ../../src/gcc/tree-vect-loop.c:2251
0x1090002f vectorize_loops()
        ../../src/gcc/tree-vectorizer.c:532
0x108167eb execute
        ../../src/gcc/tree-ssa-loop.c:420
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