[Bug tree-optimization/66636] New: [6 Regression] ICE in vect_get_vec_def_for_stmt_copy, at tree-vect-stmts.c:1590

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66636

            Bug ID: 66636
           Summary: [6 Regression] ICE in vect_get_vec_def_for_stmt_copy,
                    at tree-vect-stmts.c:1590
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

struct X { double x; double y; };

struct X *x;
void foo (double px, int s)
{
  int i;
  for (i = 0; i < 256; ++i)
    {
      x[i*s].x = px;
      x[i*s].y = i + px;
    }
}

with -O3 -mavx2

This causes ammp in SPEC 2000 to ICE.