gcc/testsuite/gcc.dg/torture/badshift.c

   1 /* PR rtl-optimization/20532 */
   2
   3 /* { dg-do run } */
   4 /* { dg-options "" } */
   5 /* { dg-options "-march=i386" { target { { i?86-*-* x86_64-*-* } && ia32 } } } */
   6
   7 /* We used to optimize the DImode shift-by-32 to zero because in combine
   8    we turned:
   9
  10      (v << 31) + (v << 31)
  11
  12    into:
  13
  14      (v * (((HOST_WIDE_INT)1 << 31) + ((HOST_WIDE_INT)1 << 31)))
  15
  16    With a 32-bit HOST_WIDE_INT, the coefficient overflowed to zero.  */
  17
  18 unsigned long long int badshift(unsigned long long int v)
  19 {
  20         return v << 31 << 1;
  21 }
  22
  23 extern void abort ();
  24
  25 int main() {
  26   if (badshift (1) == 0)
  27     abort ();
  28   return 0;
  29 }