gcc/testsuite/gcc.c-torture/execute/pr15262-1.c

   1 /* PR 15262.
   2    The alias analyzer only considers relations between pointers and
   3    symbols.  If two pointers P and Q point to the same symbol S, then
   4    their respective memory tags will either be the same or they will
   5    have S in their alias set.
   6
   7    However, if there are no common symbols between P and Q, TBAA will
   8    currently miss their alias relationship altogether.  */
   9
  10 void abort (void);
  11
  12 struct A
  13 {
  14   int t;
  15   int i;
  16 };
  17
  18 int foo () { return 3; }
  19
  20 int
  21 main (void)
  22 {
  23   struct A loc, *locp;
  24   float f, g, *p;
  25   int T355, *T356;
  26
  27   /* Avoid the partial hack in TBAA that would consider memory tags if
  28      the program had no addressable symbols.  */
  29   f = 3;
  30   g = 2;
  31   p = foo () ? &g : &f;
  32   if (*p > 0.0)
  33     g = 1;
  34
  35   /* Store into *locp and cache its current value.  */
  36   locp = __builtin_malloc (sizeof (*locp));
  37   locp->i = 10;
  38   T355 = locp->i;
  39
  40   /* Take the address of one of locp's fields and write to it.  */
  41   T356 = &locp->i;
  42   *T356 = 1;
  43
  44   /* Read the recently stored value.  If TBAA fails, this will appear
  45      as a redundant load that will be replaced with '10'.  */
  46   T355 = locp->i;
  47   if (T355 != 1)
  48     abort ();
  49
  50   return 0;
  51 }