Fix Transforms/InstCombine/2006-09-15-CastToBool.ll and PR913

llvm-svn: 30405
2006-09-16 03:14:10 +00:00 · 2006-09-16 03:14:10 +00:00 · 850465d53f
parent 5772ba4f50
commit 850465d53f
1 changed files with 5 additions and 0 deletions
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@ -1011,6 +1011,11 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
    // If this is an integer truncate or noop, just look in the input.
    if (SrcTy->getPrimitiveSizeInBits() >= 
        I->getType()->getPrimitiveSizeInBits()) {
+      // Cast to bool is a comparison against 0, which demands all bits.  We
+      // can't propagate anything useful up.
+      if (I->getType() == Type::BoolTy)
+        break;
+      
      if (SimplifyDemandedBits(I->getOperand(0), DemandedMask,
                               KnownZero, KnownOne, Depth+1))
        return true;