gcc/testsuite/gcc.dg/tree-ssa/vrp14.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2" } */
   3 /* { dg-require-effective-target int32plus } */
   4
   5 struct tree_decl
   6 {
   7   union tree_decl_u1 {
   8     int f;
   9     long i;
  10     struct tree_decl_u1_a {
  11       unsigned int align : 24;
  12       unsigned int off_align : 8;
  13     } a;
  14   } u1;
  15 };
  16
  17 extern void abort (void);
  18
  19 unsigned int
  20 assemble_variable (struct tree_decl decl)
  21 {
  22   unsigned int align;
  23
  24   align = decl.u1.a.align;
  25
  26   if (align > (1 << ((8 * 4) < 64 ? (8 * 4) - 2 : 62)))
  27     align = (1 << ((8 * 4) < 64 ? (8 * 4) - 2 : 62));
  28
  29   /* VRP should not be propagating 0 to the RHS of this assignment.
  30      But it was erroneously applying a cast operation between types of
  31      different precision.  align is an unsigned int with range [0,
  32      0x4000000] but the .align field holds only 24 bits.  So the cast
  33      was returning a [0, 0] range.  */
  34   decl.u1.a.align = align;
  35
  36   return decl.u1.a.align;
  37 }
  38
  39 main ()
  40 {
  41   struct tree_decl decl;
  42   decl.u1.a.align = 13;
  43   unsigned int x = assemble_variable (decl);
  44   if (x == 0)
  45     abort ();
  46   return 0;
  47 }