gnu/dist/gcc4/gcc/testsuite/gcc.dg/tree-ssa/vrp14.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2" } */
   3
   4 struct tree_decl
   5 {
   6   union tree_decl_u1 {
   7     int f;
   8     long i;
   9     struct tree_decl_u1_a {
  10       unsigned int align : 24;
  11       unsigned int off_align : 8;
  12     } a;
  13   } u1;
  14 };
  15
  16 extern void abort (void);
  17
  18 unsigned int
  19 assemble_variable (struct tree_decl decl)
  20 {
  21   unsigned int align;
  22
  23   align = decl.u1.a.align;
  24
  25   if (align > (1 << ((8 * 4) < 64 ? (8 * 4) - 2 : 62)))
  26     align = (1 << ((8 * 4) < 64 ? (8 * 4) - 2 : 62));
  27
  28   /* VRP should not be propagating 0 to the RHS of this assignment.
  29      But it was erroneously applying a cast operation between types of
  30      different precision.  align is an unsigned int with range [0,
  31      0x4000000] but the .align field holds only 24 bits.  So the cast
  32      was returning a [0, 0] range.  */
  33   decl.u1.a.align = align;
  34
  35   return decl.u1.a.align;
  36 }
  37
  38 main ()
  39 {
  40   struct tree_decl decl;
  41   decl.u1.a.align = 13;
  42   unsigned int x = assemble_variable (decl);
  43   if (x == 0)
  44     abort ();
  45   return 0;
  46 }