diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp index 249544a061f..ad6983abf83 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp @@ -264,6 +264,12 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); + // If the client is only demanding bits that we know, return the known + // constant. + if ((DemandedMask & ((RHSKnownZero | LHSKnownZero)| + (RHSKnownOne & LHSKnownOne))) == DemandedMask) + return Constant::getIntegerValue(VTy, RHSKnownOne & LHSKnownOne); + // If all of the demanded bits are known 1 on one side, return the other. // These bits cannot contribute to the result of the 'and'. if ((DemandedMask & ~LHSKnownZero & RHSKnownOne) == @@ -296,6 +302,12 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); + // If the client is only demanding bits that we know, return the known + // constant. + if ((DemandedMask & ((RHSKnownZero & LHSKnownZero)| + (RHSKnownOne | LHSKnownOne))) == DemandedMask) + return Constant::getIntegerValue(VTy, RHSKnownOne | LHSKnownOne); + // If all of the demanded bits are known zero on one side, return the other. // These bits cannot contribute to the result of the 'or'. if ((DemandedMask & ~LHSKnownOne & RHSKnownZero) == @@ -332,6 +344,18 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, assert(!(RHSKnownZero & RHSKnownOne) && "Bits known to be one AND zero?"); assert(!(LHSKnownZero & LHSKnownOne) && "Bits known to be one AND zero?"); + // Output known-0 bits are known if clear or set in both the LHS & RHS. + APInt IKnownZero = (RHSKnownZero & LHSKnownZero) | + (RHSKnownOne & LHSKnownOne); + // Output known-1 are known to be set if set in only one of the LHS, RHS. + APInt IKnownOne = (RHSKnownZero & LHSKnownOne) | + (RHSKnownOne & LHSKnownZero); + + // If the client is only demanding bits that we know, return the known + // constant. + if ((DemandedMask & (IKnownZero|IKnownOne)) == DemandedMask) + return Constant::getIntegerValue(VTy, IKnownOne); + // If all of the demanded bits are known zero on one side, return the other. // These bits cannot contribute to the result of the 'xor'. if ((DemandedMask & RHSKnownZero) == DemandedMask) |
