diff options
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp index f0c96bdf768..249544a061f 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp @@ -71,7 +71,7 @@ bool InstCombiner::SimplifyDemandedInstructionBits(Instruction &Inst) { APInt DemandedMask(APInt::getAllOnesValue(BitWidth)); Value *V = SimplifyDemandedUseBits(&Inst, DemandedMask, - KnownZero, KnownOne, 0); + KnownZero, KnownOne, 0, &Inst); if (!V) return false; if (V == &Inst) return true; ReplaceInstUsesWith(Inst, V); @@ -85,7 +85,8 @@ bool InstCombiner::SimplifyDemandedBits(Use &U, APInt DemandedMask, APInt &KnownZero, APInt &KnownOne, unsigned Depth) { Value *NewVal = SimplifyDemandedUseBits(U.get(), DemandedMask, - KnownZero, KnownOne, Depth); + KnownZero, KnownOne, Depth, + dyn_cast<Instruction>(U.getUser())); if (!NewVal) return false; U = NewVal; return true; @@ -115,7 +116,8 @@ bool InstCombiner::SimplifyDemandedBits(Use &U, APInt DemandedMask, /// in the context where the specified bits are demanded, but not for all users. Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, APInt &KnownZero, APInt &KnownOne, - unsigned Depth) { + unsigned Depth, + Instruction *CxtI) { assert(V != nullptr && "Null pointer of Value???"); assert(Depth <= 6 && "Limit Search Depth"); uint32_t BitWidth = DemandedMask.getBitWidth(); @@ -158,7 +160,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, Instruction *I = dyn_cast<Instruction>(V); if (!I) { - computeKnownBits(V, KnownZero, KnownOne, Depth); + computeKnownBits(V, KnownZero, KnownOne, Depth, CxtI); return nullptr; // Only analyze instructions. } @@ -172,8 +174,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, // this instruction has a simpler value in that context. if (I->getOpcode() == Instruction::And) { // If either the LHS or the RHS are Zero, the result is zero. - computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1); - computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1); + computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1, + CxtI); + computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, + CxtI); // 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' in this @@ -194,8 +198,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, // only bits from X or Y are demanded. // If either the LHS or the RHS are One, the result is One. - computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1); - computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1); + computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1, + CxtI); + computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, + CxtI); // 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' in this @@ -219,8 +225,10 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, // We can simplify (X^Y) -> X or Y in the user's context if we know that // only bits from X or Y are demanded. - computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1); - computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1); + computeKnownBits(I->getOperand(1), RHSKnownZero, RHSKnownOne, Depth+1, + CxtI); + computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, + CxtI); // If all of the demanded bits are known zero on one side, return the // other. @@ -231,7 +239,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, } // Compute the KnownZero/KnownOne bits to simplify things downstream. - computeKnownBits(I, KnownZero, KnownOne, Depth); + computeKnownBits(I, KnownZero, KnownOne, Depth, CxtI); return nullptr; } @@ -244,7 +252,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, switch (I->getOpcode()) { default: - computeKnownBits(I, KnownZero, KnownOne, Depth); + computeKnownBits(I, KnownZero, KnownOne, Depth, CxtI); break; case Instruction::And: // If either the LHS or the RHS are Zero, the result is zero. @@ -595,7 +603,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, // Otherwise just hand the sub off to computeKnownBits to fill in // the known zeros and ones. - computeKnownBits(V, KnownZero, KnownOne, Depth); + computeKnownBits(V, KnownZero, KnownOne, Depth, CxtI); // Turn this into a xor if LHS is 2^n-1 and the remaining bits are known // zero. @@ -766,7 +774,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, // remainder is zero. if (DemandedMask.isNegative() && KnownZero.isNonNegative()) { APInt LHSKnownZero(BitWidth, 0), LHSKnownOne(BitWidth, 0); - computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1); + computeKnownBits(I->getOperand(0), LHSKnownZero, LHSKnownOne, Depth+1, + CxtI); // If it's known zero, our sign bit is also zero. if (LHSKnownZero.isNegative()) KnownZero.setBit(KnownZero.getBitWidth() - 1); @@ -828,7 +837,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask, return nullptr; } } - computeKnownBits(V, KnownZero, KnownOne, Depth); + computeKnownBits(V, KnownZero, KnownOne, Depth, CxtI); break; } |
