[Bug tree-optimization/53693] [4.7/4.8 regression] ICE in vect_get_vec_def_for_stmt_copy, at tree-vect-stmts.c:1438

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53693

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-06-18 
10:22:24 UTC ---
Reduced testcase, it seems we are getting conflicts between two patterns.

void
filter_scanlines (void *src_buffer, void *dst_buffer, int dst_pitch, int width)
{
  int x;
  unsigned short *src, *dst_a, *dst_b;

  src = (unsigned short *) src_buffer;
  dst_a = (unsigned short *) dst_buffer;
  dst_b = ((unsigned short *) dst_buffer) + (dst_pitch >> 1);

  for (x = 0; x < width; x++)
    {
      unsigned char gs, gh;
      gs = src[x];
      gh = gs + (gs >> 1);
      dst_a[x] = (gh << 5) | (gh);
      dst_b[x] = ((gs  - gh) << 5)  | (gs  - gh);
    }
}