gcc/testsuite/gcc.dg/gnu23-tag-alias-3.c

   1 /* { dg-do run { target lto } }
   2  * { dg-options "-std=gnu23 -flto -O2" }
   3  */
   4
   5 /* These tests check that incompatible definitions of
   6    tagged types can be assumed not to alias and that
   7    this is exploited during optimization with LTO.  */
   8
   9 struct foo { int x; };
  10
  11 [[gnu::noinline,gnu::noipa]]
  12 int test_foo1(struct foo* a, void* b)
  13 {
  14         a->x = 1;
  15
  16         struct foo { int x; int y; }* p = b;
  17         p->x = 2;
  18
  19         return a->x;
  20 }
  21
  22 [[gnu::noinline,gnu::noipa]]
  23 int test_foo2(struct foo* a, void* b)
  24 {
  25         a->x = 1;
  26
  27         struct fox { int x; }* p = b;
  28         p->x = 2;
  29
  30         return a->x;
  31 }
  32
  33
  34 /* While these tests check that incompatible definitions
  35  * of enums can alias.  */
  36
  37 enum bar { A = 1, B = 3, C = 5, D = 9 };
  38
  39 [[gnu::noinline,gnu::noipa]]
  40 int test_bar1(enum bar* a, void* b)
  41 {
  42         *a = A;
  43
  44         enum bar { A = 1, B = 3, C = 6, D = 9 }* p = b;
  45         *p = B;
  46
  47         return *a;
  48 }
  49
  50 [[gnu::noinline,gnu::noipa]]
  51 int test_bar2(enum bar* a, void* b)
  52 {
  53         *a = A;
  54
  55         enum baX { A = 1, B = 3, C = 5, D = 9 }* p = b;
  56         *p = B;
  57
  58         return *a;
  59 }
  60
  61
  62 int main()
  63 {
  64         struct foo y;
  65
  66         if (1 != test_foo1(&y, &y))
  67                 __builtin_abort();
  68
  69         if (1 != test_foo2(&y, &y))
  70                 __builtin_abort();
  71
  72         enum bar z;
  73
  74         if (B != test_bar1(&z, &z))
  75                 __builtin_abort();
  76
  77         if (B != test_bar2(&z, &z))
  78                 __builtin_abort();
  79
  80         return 0;
  81 }
  82
  83