gcc/testsuite/gcc.dg/pr19633-1.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2" } */
   3
   4 extern void abort (void);
   5 extern void link_error (void);
   6
   7 struct S
   8 {
   9   int w, x, y, z;
  10 };
  11
  12 struct T
  13 {
  14   int r;
  15   struct S s;
  16 };
  17
  18 struct S bar (struct S x, struct S *y)
  19 {
  20   y->w = 4;
  21   return *y;
  22 }
  23
  24 void
  25 foo (int a, struct T b)
  26 {
  27   struct S x;
  28   struct S *c = &x;
  29   if (a)
  30     c = &b.s;
  31   b.s.w = 3;
  32   /* This call should be marked as clobbering 'x' and 'b'.  */
  33   *c = bar (*c, c);
  34   if (b.s.w == 3)
  35     abort ();
  36 }
  37
  38 float Y;
  39
  40 struct S bar1 (struct S x, struct S y)
  41 {
  42   Y = 4;
  43   return x;
  44 }
  45
  46 void
  47 foo1 (int a, struct T b)
  48 {
  49   struct S x;
  50   struct S *c = &x;
  51   float z, *k = &z;
  52   if (a)
  53     c = &b.s;
  54   b.s.w = 3;
  55   /* This call should NOT be marked as clobbering 'x' and 'b'.  */
  56   x = bar1 (*c, *c);
  57   if (b.s.w != 3)
  58     link_error ();
  59 }
  60
  61 int main ()
  62 {
  63   struct T b;
  64   foo (3, b);
  65   foo1 (3, b);
  66   return 0;
  67 }