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1. Make more use of getLowBitsSet/getHighBitsSet.
2. Use APInt[] instead of "X & SignBit". 3. Clean up some codes. 4. Make the expression like "ShiftAmt = ShiftAmtC->getZExtValue()" safe. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35424 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -1313,7 +1313,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, APInt DemandedMask,
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RHSKnownOne <<= ShiftAmt;
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// low bits known zero.
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if (ShiftAmt)
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RHSKnownZero |= APInt::getAllOnesValue(ShiftAmt).zextOrCopy(BitWidth);
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RHSKnownZero |= APInt::getLowBitsSet(BitWidth, ShiftAmt);
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}
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break;
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case Instruction::LShr:
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@ -5608,7 +5608,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
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// shl uint X, 32 = 0 and shr ubyte Y, 9 = 0, ... just don't eliminate shr
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// of a signed value.
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//
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if (Op1->getZExtValue() >= TypeBits) { // shift amount always <= 32 bits
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if (Op1->getValue().getActiveBits() > 64 || Op1->getZExtValue() >= TypeBits) {
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if (I.getOpcode() != Instruction::AShr)
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return ReplaceInstUsesWith(I, Constant::getNullValue(Op0->getType()));
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else {
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@ -5751,8 +5751,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
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// operation.
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//
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if (isValid && !isLeftShift && I.getOpcode() == Instruction::AShr) {
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isValid = ((Op0C->getValue() & APInt::getSignBit(TypeBits)) != 0) ==
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highBitSet;
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isValid = Op0C->getValue()[TypeBits-1] == highBitSet;
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}
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if (isValid) {
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@ -5777,9 +5776,10 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
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if (ShiftOp && isa<ConstantInt>(ShiftOp->getOperand(1))) {
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ConstantInt *ShiftAmt1C = cast<ConstantInt>(ShiftOp->getOperand(1));
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// These shift amounts are always <= 32 bits.
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unsigned ShiftAmt1 = (unsigned)ShiftAmt1C->getZExtValue();
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unsigned ShiftAmt2 = (unsigned)Op1->getZExtValue();
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uint32_t ShiftAmt1 = ShiftAmt1C->getValue().getActiveBits() > 64 ?
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TypeBits : (uint32_t)ShiftAmt1C->getZExtValue();
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uint32_t ShiftAmt2 = Op1->getValue().getActiveBits() > 64 ?
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TypeBits : (uint32_t)Op1->getZExtValue();
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assert(ShiftAmt2 != 0 && "Should have been simplified earlier");
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if (ShiftAmt1 == 0) return 0; // Will be simplified in the future.
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Value *X = ShiftOp->getOperand(0);
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@ -5805,7 +5805,7 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
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BinaryOperator::createAShr(X, ConstantInt::get(Ty, AmtSum));
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InsertNewInstBefore(Shift, I);
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APInt Mask(Ty->getMask().lshr(ShiftAmt2));
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APInt Mask(APInt::getLowBitsSet(TypeBits, TypeBits - ShiftAmt2));
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return BinaryOperator::createAnd(Shift, ConstantInt::get(Mask));
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}
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@ -5828,11 +5828,14 @@ Instruction *InstCombiner::FoldShiftByConstant(Value *Op0, ConstantInt *Op1,
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// generators.
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const Type *SExtType = 0;
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switch (Ty->getBitWidth() - ShiftAmt1) {
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case 1 : SExtType = Type::Int1Ty; break;
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case 8 : SExtType = Type::Int8Ty; break;
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case 16 : SExtType = Type::Int16Ty; break;
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case 32 : SExtType = Type::Int32Ty; break;
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case 64 : SExtType = Type::Int64Ty; break;
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case 1 :
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case 8 :
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case 16 :
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case 32 :
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case 64 :
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case 128:
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SExtType = IntegerType::get(Ty->getBitWidth() - ShiftAmt1);
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break;
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default: break;
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}
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if (SExtType) {
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