gcc/testsuite/gcc.dg/alias-14.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2" } */
   3 #include <stddef.h>
   4 void *a;
   5 int *b;
   6 struct c {void * a;} c;
   7 struct d {short * a;} d;
   8
   9 int *ip= (int *)(size_t)2;
  10 int **ipp = &ip;
  11
  12 int
  13 main()
  14 {
  15   float **ptr;
  16   void **uptr;
  17   int* const* cipp = (int* const*)ipp;
  18   /* as an extension we consider void * universal. Writes to it should alias.  */
  19   asm ("":"=r"(ptr):"0"(&a));
  20   a=NULL;
  21   *ptr=(float*)(size_t)1;
  22   if (!a)
  23     __builtin_abort ();
  24   a=NULL;
  25   if (*ptr)
  26     __builtin_abort ();
  27
  28   asm ("":"=r"(uptr):"0"(&b));
  29   b=NULL;
  30   *uptr=(void*)(size_t)1;
  31   if (!b)
  32     __builtin_abort ();
  33   b=NULL;
  34   if (*uptr)
  35     __builtin_abort ();
  36
  37   /* Check that we disambiguate int * and char *.  */
  38   asm ("":"=r"(ptr):"0"(&b));
  39   b=NULL;
  40   *ptr=(float*)(size_t)1;
  41   if (b)
  42     __builtin_abort ();
  43
  44   /* Again we should make void * in the structure conflict with any pointer.  */
  45   asm ("":"=r"(ptr):"0"(&c));
  46   c.a=NULL;
  47   *ptr=(float*)(size_t)1;
  48   if (!c.a)
  49     __builtin_abort ();
  50   c.a=NULL;
  51   if (*ptr)
  52     __builtin_abort ();
  53
  54   asm ("":"=r"(uptr):"0"(&d));
  55   d.a=NULL;
  56   *uptr=(void*)(size_t)1;
  57   if (!d.a)
  58     __builtin_abort ();
  59   d.a=NULL;
  60   if (*uptr)
  61     __builtin_abort ();
  62
  63   if ((void *)*cipp != (void*)(size_t)2)
  64     __builtin_abort ();
  65   *ipp = NULL;
  66   if (*cipp)
  67     __builtin_abort ();
  68
  69   return 0;
  70 }