// icmp ne A, B is equal to xor A, B when A and B only really have one bit.
// It is also profitable to transform icmp eq into not(xor(A, B)) because that
// may lead to additional simplifications.
- if (Cmp->isEquality() && ZType == CmpOpType) {
- if (IntegerType *ITy = dyn_cast<IntegerType>(ZType)) {
- KnownBits KnownOp0 = computeKnownBits(Op0, 0, &Zext);
- KnownBits KnownOp1 = computeKnownBits(Op1, 0, &Zext);
-
- if (KnownOp0.Zero == KnownOp1.Zero && KnownOp0.One == KnownOp1.One) {
- APInt KnownBits = KnownOp0.Zero | KnownOp0.One;
- APInt UnknownBit = ~KnownBits;
- if (UnknownBit.countPopulation() == 1) {
- if (!DoTransform) return Cmp;
-
- Value *Result = Builder.CreateXor(Op0, Op1);
-
- // Mask off any bits that are set and won't be shifted away.
- if (KnownOp0.One.uge(UnknownBit))
- Result = Builder.CreateAnd(Result,
- ConstantInt::get(ITy, UnknownBit));
-
- // Shift the bit we're testing down to the lsb.
- Result = Builder.CreateLShr(
- Result, ConstantInt::get(ITy, UnknownBit.countTrailingZeros()));
-
- if (Pred == ICmpInst::ICMP_EQ)
- Result = Builder.CreateXor(Result, ConstantInt::get(ITy, 1));
- Result->takeName(Cmp);
- return replaceInstUsesWith(Zext, Result);
- }
- }
+ if (!isa<IntegerType>(ZType) || !Cmp->isEquality() || ZType != CmpOpType)
+ return nullptr;
+
+ KnownBits KnownOp0 = computeKnownBits(Op0, 0, &Zext);
+ KnownBits KnownOp1 = computeKnownBits(Op1, 0, &Zext);
+ if (KnownOp0.Zero == KnownOp1.Zero && KnownOp0.One == KnownOp1.One) {
+ APInt KnownBits = KnownOp0.Zero | KnownOp0.One;
+ APInt UnknownBit = ~KnownBits;
+ if (UnknownBit.countPopulation() == 1) {
+ if (!DoTransform) return Cmp;
+
+ Value *Result = Builder.CreateXor(Op0, Op1);
+
+ // Mask off any bits that are set and won't be shifted away.
+ if (KnownOp0.One.uge(UnknownBit))
+ Result = Builder.CreateAnd(Result, ConstantInt::get(ZType, UnknownBit));
+
+ // Shift the bit we're testing down to the lsb.
+ Result = Builder.CreateLShr(
+ Result, ConstantInt::get(ZType, UnknownBit.countTrailingZeros()));
+
+ if (Pred == ICmpInst::ICMP_EQ)
+ Result = Builder.CreateXor(Result, ConstantInt::get(ZType, 1));
+ Result->takeName(Cmp);
+ return replaceInstUsesWith(Zext, Result);
}
}