gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-99.c

   1 /* { dg-do compile } */
   2 /* Disable FRE1 because that for the sake of __builtin_object_size
   3    will not consider the equality but still valueize 'i', defeating
   4    the purpose of the check.  */
   5 /* { dg-options "-O -fdump-tree-fre3 -fdisable-tree-fre1" } */
   6
   7 struct S { int a[4]; };
   8
   9 int i;
  10 int bar (struct S *p)
  11 {
  12   char *q = (char *)p + 4;
  13   i = 1;
  14   int *r = &((struct S *)p)->a[i];
  15   return q == (char *)r;
  16 }
  17 int baz (struct S *p)
  18 {
  19   i = 1;
  20   int *r = &((struct S *)p)->a[i];
  21   char *q = (char *)p + 4;
  22   return q == (char *)r;
  23 }
  24
  25 /* Verify FRE can handle valueizing &p->a[i] and value-numbering it
  26    equal to a POINTER_PLUS_EXPR.  */
  27 /* { dg-final { scan-tree-dump-times "return 1;" 2 "fre3" } } */