gcc/testsuite/gcc.dg/tree-ssa/pr91680.c

   1 /* PR middle-end/91680 */
   2 /* { dg-do compile { target { ilp32 || lp64 } } } */
   3 /* { dg-options "-O2 -fdump-tree-forwprop1" } */
   4 /* { dg-final { scan-tree-dump-times " / " 1 "forwprop1" } } */
   5 /* { dg-final { scan-tree-dump-times " >> " 3 "forwprop1" } } */
   6
   7 __attribute__((noipa)) unsigned long long
   8 foo (unsigned char x)
   9 {
  10   unsigned long long q = 1 << x;
  11   return 256 / q;
  12 }
  13
  14 __attribute__((noipa)) unsigned long long
  15 bar (unsigned char x)
  16 {
  17   unsigned long long q = 1U << x;
  18   return 256 / q;
  19 }
  20
  21 __attribute__((noipa)) unsigned long long
  22 baz (unsigned char x, unsigned long long y)
  23 {
  24   /* This can't be optimized, at least not in C++ and maybe not
  25      in C89, because for x 31 q is -2147483648ULL, not
  26      2147483648ULL, and e.g. 2147483648ULL >> 31 is 1, while
  27      2147483648ULL / -2147483648ULL is 0.  */
  28   unsigned long long q = 1 << x;
  29   return y / q;
  30 }
  31
  32 __attribute__((noipa)) unsigned long long
  33 qux (unsigned char x, unsigned long long y)
  34 {
  35   unsigned long long q = 1U << x;
  36   return y / q;
  37 }