[Bug target/78938] New: [7 Regression] ICE in expand_vec_cond_expr, at optabs.c:5636 w/ -mavx512bw -ftree-loop-vectorize -O1

[asolokha at gmx dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78938

            Bug ID: 78938
           Summary: [7 Regression] ICE in expand_vec_cond_expr, at
                    optabs.c:5636 w/ -mavx512bw -ftree-loop-vectorize -O1
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---
            Target: x86_64-pc-linux-gnu

gcc-7.0.0-alpha20161225 snapshot ICEs when compiling the following snippet w/
-mavx512bw -ftree-loop-vectorize -O1 (-O2, -O3, -Ofast):

short int y5;

void
ym (char c5)
{
  int sg = 1;

  for (;;)
    {
      int *ol = (int *)&y5;

      if (sg != 0)
        *ol = 0;
      while (c5 < 1)
        {
          int u9 = *ol != y5;
          int ie = c5 != 0;

          sg = (u9 == ie) ? 2 : 0;
          ++c5;
        }
    }
}

% x86_64-pc-linux-gnu-gcc-7.0.0-alpha20161225 -mavx512bw -O1
-ftree-loop-vectorize -c jmw6yft1.c
jmw6yft1.c: In function 'ym':
jmw6yft1.c:4:1: internal compiler error: in expand_vec_cond_expr, at
optabs.c:5636
 ym (char c5)
 ^~