[Bug middle-end/61894] New: Fail to fold read from constant vector initializer

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61894

            Bug ID: 61894
           Summary: Fail to fold read from constant vector initializer
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org

The following is not handled by fold_const_aggregate_ref and siblings.


/* { dg-do run } */
/* { dg-options "-O" } */

extern void abort (void);

/* We should fold all reads from xconstant and eliminate it, removing
   the reference to blah which cannot be resolved at link time.  */
extern int blah;

typedef int v4si __attribute__((vector_size(16)));

static const struct {
    int *y;
    const v4si x[2] __attribute__((aligned(32)));
} xconstant = { &blah, { { 0, 1, 2, 3 }, { 2, 3, 4, 5 } } };

int main()
{
  if (sizeof (int) != 4)
    return 0;
  if (*(int *)&xconstant.x[0][0] != 0)
    abort ();
  if (*(int *)&xconstant.x[0][1] != 1)
  if (*(int *)&xconstant.x[0][2] != 2)
    abort ();
  if (*(int *)&xconstant.x[0][3] != 3)
    abort ();
  if (*(int *)&xconstant.x[1][0] != 2)
    abort ();
  if (*(int *)&xconstant.x[1][1] != 3)
    abort ();
  if (*(int *)&xconstant.x[1][2] != 4)
    abort ();
  if (*(int *)&xconstant.x[1][3] != 5)
    abort ();
  return 0;
}