diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 5bbc90248b..1d172ced52 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -1243,22 +1243,8 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, APInt DemandedMask, // To compute this, we first compute the potential carry bits. These are // the bits which may be modified. I'm not aware of a better way to do // this scan. - APInt RHSVal(RHS->getValue()); - - bool CarryIn = false; - APInt CarryBits(BitWidth, 0); - const uint64_t *LHSKnownZeroRawVal = LHSKnownZero.getRawData(), - *RHSRawVal = RHSVal.getRawData(); - for (uint32_t i = 0; i != RHSVal.getNumWords(); ++i) { - uint64_t AddVal = ~LHSKnownZeroRawVal[i] + RHSRawVal[i], - XorVal = ~LHSKnownZeroRawVal[i] ^ RHSRawVal[i]; - uint64_t WordCarryBits = AddVal ^ XorVal + CarryIn; - if (AddVal < RHSRawVal[i]) - CarryIn = true; - else - CarryIn = false; - CarryBits.setWordToValue(i, WordCarryBits); - } + const APInt& RHSVal = RHS->getValue(); + APInt CarryBits((~LHSKnownZero + RHSVal) ^ (~LHSKnownZero ^ RHSVal)); // Now that we know which bits have carries, compute the known-1/0 sets. |