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Insert boolean not on equal to zero comparisons

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Implements the transformation (x == 0) -> (!x) via the boolean not
opcode, inside the two's complement arithmetic normalization pass.
This commit is contained in:
Valentina Sona
2023-04-19 22:27:30 +02:00
committed by Pietro Fezzardi
parent 8dfd7c2d96
commit 8429c35f2e
1 changed files with 28 additions and 3 deletions
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lib/IRCanonicalization/TwosComplementArithmeticNormalizationPass.cpp
+28 -3
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@@ -74,6 +74,29 @@ public:
}
};
class BooleanNotBuilder {
OpaqueFunctionsPool<llvm::Type *> Pool;
llvm::IRBuilder<> Builder;
public:
BooleanNotBuilder(llvm::Function &F) :
Pool(F.getParent(), false), Builder(F.getContext()) {
initBooleanNotPool(Pool);
}
void SetInsertPoint(llvm::Instruction *I) { Builder.SetInsertPoint(I); }
llvm::CallInst *operator()(llvm::Type *IntType, llvm::Value *Val) {
revng_assert(isa<llvm::IntegerType>(IntType));
llvm::Function *Func = Pool.get(IntType,
Builder.getIntNTy(1),
IntType,
"boolean_not");
return Builder.CreateCall(Func, { Val });
}
};
using Predicate = llvm::ICmpInst::Predicate;
static bool isGreater(Predicate P) {
@@ -86,6 +109,7 @@ bool TANP::runOnFunction(llvm::Function &F) {
UnaryMinusBuilder BuildUnaryMinus{ F };
BinaryNotBuilder BuildBinaryNot{ F };
BooleanNotBuilder BuildBooleanNot{ F };
llvm::IRBuilder<> Builder{ F.getContext() };
bool Changed = false;
@@ -179,7 +203,6 @@ bool TANP::runOnFunction(llvm::Function &F) {
} else if (Predicate Pred;
match(&I, m_ICmp(Pred, m_Value(Val), m_APInt(Int)))) {
const auto IntType = Val->getType();
llvm::Value *Unknown = nullptr;
@@ -243,12 +266,14 @@ bool TANP::runOnFunction(llvm::Function &F) {
else
NewV = Builder.CreateAnd(NewV, WrappingComparison);
}
} else if (Int->isSignBitSet()
and Int->isSignedIntN(IntType->getIntegerBitWidth())) {
} else if (Int->isNegative()) {
BuildUnaryMinus.SetInsertPoint(&I);
auto UnaryMinus = BuildUnaryMinus(IntType, *Int);
Builder.SetInsertPoint(UnaryMinus->getNextNonDebugInstruction());
NewV = Builder.CreateICmp(Pred, Val, UnaryMinus);
} else if (Pred == Predicate::ICMP_EQ and Int->isNullValue()) {
BuildBooleanNot.SetInsertPoint(&I);
NewV = BuildBooleanNot(Val->getType(), Val);
}
}