[Bug tree-optimization/71752] New: [7 Regression] ICE in compute_live_loop_exits, at tree-ssa-loop-manip.c:229 w/ -O1 -ftree-vectorize

["asolokha at gmx dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71752

            Bug ID: 71752
           Summary: [7 Regression] ICE in compute_live_loop_exits, at
                    tree-ssa-loop-manip.c:229 w/ -O1 -ftree-vectorize
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-7.0.0-alpha20160703 ICEs when compiling the following reduced testcase w/
-O1 (-O2, -O3, -Ofast) -ftree-vectorize:

% x86_64-pc-linux-gnu-gcc-7.0.0-alpha20160703 -c -O1 -ftree-vectorize
foutgowu.c
foutgowu.c: In function 'w6':
foutgowu.c:4:1: internal compiler error: in compute_live_loop_exits, at
tree-ssa-loop-manip.c:229
 w6 (unsigned int z5, unsigned int jv)
 ^~

unsigned int q4, yg;

void
w6 (unsigned int z5, unsigned int jv)
{
  unsigned int *f2 = &jv;

  while (*f2 < 21)
    {
      q4 -= jv;
      z5 -= jv;
      f2 = &yg;
      ++(*f2);
    }
  if (z5 != 0)
    for (;;)
      {
      }
}