gcc/testsuite/gcc.dg/pr93231.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -fdump-tree-forwprop2-details -Wno-shift-count-negative" } */
   3
   4 int ctz_ice1 (int x)
   5 {
   6   static const char table[32] =
   7     {
   8       0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
   9       31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
  10     };
  11
  12   return table[((int)((x & -x) * -0x077CB531)) >> 27];
  13 }
  14
  15 int ctz_ice2 (unsigned x)
  16 {
  17   static const char table[32] =
  18     {
  19       0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
  20       31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
  21     };
  22
  23   return table[((unsigned)((x & -x) * 0x077CB531U)) >> -27];
  24 }
  25
  26 // This should never match
  27 int ctz_fail (unsigned x)
  28 {
  29   static const unsigned short int table[32] =
  30     u"\x0100\x021c\x0e1d\x0318\x161e\x0f14\x1119\x0804\x1b1f\x170d\x1315\x0710\x0c1a\x0612\x050b\x090a";
  31
  32   return table[((x & -x) * 0x077CB531) >> 27];
  33 }
  34
  35 /* { dg-final { scan-tree-dump-not {= \.CTZ} "forwprop2" } } */