[Bug target/64252] New: [5 Regression] expand_vec_perm_pblendv caused miscompilation

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64252

            Bug ID: 64252
           Summary: [5 Regression] expand_vec_perm_pblendv caused
                    miscompilation
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jakub at gcc dot gnu.org

As Evgeny reported on gcc-patches, the following testcase is miscompiled on the
trunk with -O2 -mavx2:

typedef unsigned int V __attribute__((vector_size (32)));

__attribute__((noinline, noclone)) void
foo (V *a, V *b, V *c, V *d, V *e)
{
  V t = __builtin_shuffle (*a, *b, *c);
  V v = __builtin_shuffle (t, (V) { ~0U, ~0U, ~0U, ~0U, ~0U, ~0U, ~0U, ~0U },
(V) { 0, 1, 8, 3, 4, 5, 9, 7 });
  v = v + *d;
  *e = v;
}

int
main ()
{
  V a, b, c, d, e;
  int i;
  a = (V) { 1, 2, 3, 4, 5, 6, 7, 8 };
  b = (V) { 9, 10, 11, 12, 13, 14, 15, 16 };
  c = (V) { 1, 3, 5, 7, 9, 11, 13, 15 };
  d = (V) { 0, 0, 0, 0, 0, 0, 0, 0 };
  foo (&a, &b, &c, &d, &e);
  for (i = 0; i < 8; i++)
    if (e[i] != ((i == 2 || i == 6) ? ~0U : 2 + 2 * i))
      __builtin_abort ();
  return 0;
}