validation/optim/shl-and1.c

   1 // If (t << S) is simplified into (x << S)
   2 // then the whole expression will be 0.
   3 // The test is only interesting if the sub-expression
   4 // (x & M) is referenced more than once
   5 // (because otherwise other simplifications apply).
   6 unsigned shl_and1(unsigned x)
   7 {
   8         unsigned t = (x & 0x000fffff);
   9         return ((t << 12) ^ (x << 12)) & t;
  10 }
  11
  12 /*
  13  * check-name: shl-and1
  14  * check-command: test-linearize -Wno-decl $file
  15  *
  16  * check-output-ignore
  17  * check-output-contains: ret\\..*\\$0$
  18  */