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-rw-r--r--llvm/lib/IR/ConstantFold.cpp59
1 files changed, 29 insertions, 30 deletions
diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp
index a52cd72..3243ddd 100644
--- a/llvm/lib/IR/ConstantFold.cpp
+++ b/llvm/lib/IR/ConstantFold.cpp
@@ -630,7 +630,7 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
V.convertToInteger(IntVal, APFloat::rmTowardZero, &ignored)) {
// Undefined behavior invoked - the destination type can't represent
// the input constant.
- return UndefValue::get(DestTy);
+ return PoisonValue::get(DestTy);
}
return ConstantInt::get(FPC->getContext(), IntVal);
}
@@ -916,7 +916,7 @@ Constant *llvm::ConstantFoldInsertElementInstruction(Constant *Val,
unsigned NumElts = ValTy->getNumElements();
if (CIdx->uge(NumElts))
- return UndefValue::get(Val->getType());
+ return PoisonValue::get(Val->getType());
SmallVector<Constant*, 16> Result;
Result.reserve(NumElts);
@@ -1144,23 +1144,21 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
}
case Instruction::SDiv:
case Instruction::UDiv:
- // X / undef -> undef
- if (isa<UndefValue>(C2))
- return C2;
- // undef / 0 -> undef
+ // X / undef -> poison
+ // X / 0 -> poison
+ if (match(C2, m_CombineOr(m_Undef(), m_Zero())))
+ return PoisonValue::get(C2->getType());
// undef / 1 -> undef
- if (match(C2, m_Zero()) || match(C2, m_One()))
+ if (match(C2, m_One()))
return C1;
// undef / X -> 0 otherwise
return Constant::getNullValue(C1->getType());
case Instruction::URem:
case Instruction::SRem:
- // X % undef -> undef
- if (match(C2, m_Undef()))
- return C2;
- // undef % 0 -> undef
- if (match(C2, m_Zero()))
- return C1;
+ // X % undef -> poison
+ // X % 0 -> poison
+ if (match(C2, m_CombineOr(m_Undef(), m_Zero())))
+ return PoisonValue::get(C2->getType());
// undef % X -> 0 otherwise
return Constant::getNullValue(C1->getType());
case Instruction::Or: // X | undef -> -1
@@ -1168,28 +1166,28 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
return C1;
return Constant::getAllOnesValue(C1->getType()); // undef | X -> ~0
case Instruction::LShr:
- // X >>l undef -> undef
+ // X >>l undef -> poison
if (isa<UndefValue>(C2))
- return C2;
+ return PoisonValue::get(C2->getType());
// undef >>l 0 -> undef
if (match(C2, m_Zero()))
return C1;
// undef >>l X -> 0
return Constant::getNullValue(C1->getType());
case Instruction::AShr:
- // X >>a undef -> undef
+ // X >>a undef -> poison
if (isa<UndefValue>(C2))
- return C2;
+ return PoisonValue::get(C2->getType());
// undef >>a 0 -> undef
if (match(C2, m_Zero()))
return C1;
- // TODO: undef >>a X -> undef if the shift is exact
+ // TODO: undef >>a X -> poison if the shift is exact
// undef >>a X -> 0
return Constant::getNullValue(C1->getType());
case Instruction::Shl:
// X << undef -> undef
if (isa<UndefValue>(C2))
- return C2;
+ return PoisonValue::get(C2->getType());
// undef << 0 -> undef
if (match(C2, m_Zero()))
return C1;
@@ -1242,14 +1240,14 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
if (CI2->isOne())
return C1; // X / 1 == X
if (CI2->isZero())
- return UndefValue::get(CI2->getType()); // X / 0 == undef
+ return PoisonValue::get(CI2->getType()); // X / 0 == poison
break;
case Instruction::URem:
case Instruction::SRem:
if (CI2->isOne())
return Constant::getNullValue(CI2->getType()); // X % 1 == 0
if (CI2->isZero())
- return UndefValue::get(CI2->getType()); // X % 0 == undef
+ return PoisonValue::get(CI2->getType()); // X % 0 == poison
break;
case Instruction::And:
if (CI2->isZero()) return C2; // X & 0 == 0
@@ -1363,7 +1361,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
case Instruction::SDiv:
assert(!CI2->isZero() && "Div by zero handled above");
if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
- return UndefValue::get(CI1->getType()); // MIN_INT / -1 -> undef
+ return PoisonValue::get(CI1->getType()); // MIN_INT / -1 -> poison
return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
case Instruction::URem:
assert(!CI2->isZero() && "Div by zero handled above");
@@ -1371,7 +1369,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
case Instruction::SRem:
assert(!CI2->isZero() && "Div by zero handled above");
if (C2V.isAllOnesValue() && C1V.isMinSignedValue())
- return UndefValue::get(CI1->getType()); // MIN_INT % -1 -> undef
+ return PoisonValue::get(CI1->getType()); // MIN_INT % -1 -> poison
return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
case Instruction::And:
return ConstantInt::get(CI1->getContext(), C1V & C2V);
@@ -1382,15 +1380,15 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
case Instruction::Shl:
if (C2V.ult(C1V.getBitWidth()))
return ConstantInt::get(CI1->getContext(), C1V.shl(C2V));
- return UndefValue::get(C1->getType()); // too big shift is undef
+ return PoisonValue::get(C1->getType()); // too big shift is poison
case Instruction::LShr:
if (C2V.ult(C1V.getBitWidth()))
return ConstantInt::get(CI1->getContext(), C1V.lshr(C2V));
- return UndefValue::get(C1->getType()); // too big shift is undef
+ return PoisonValue::get(C1->getType()); // too big shift is poison
case Instruction::AShr:
if (C2V.ult(C1V.getBitWidth()))
return ConstantInt::get(CI1->getContext(), C1V.ashr(C2V));
- return UndefValue::get(C1->getType()); // too big shift is undef
+ return PoisonValue::get(C1->getType()); // too big shift is poison
}
}
@@ -1436,7 +1434,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
// Fast path for splatted constants.
if (Constant *C2Splat = C2->getSplatValue()) {
if (Instruction::isIntDivRem(Opcode) && C2Splat->isNullValue())
- return UndefValue::get(VTy);
+ return PoisonValue::get(VTy);
if (Constant *C1Splat = C1->getSplatValue()) {
return ConstantVector::getSplat(
VTy->getElementCount(),
@@ -1453,9 +1451,9 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
Constant *LHS = ConstantExpr::getExtractElement(C1, ExtractIdx);
Constant *RHS = ConstantExpr::getExtractElement(C2, ExtractIdx);
- // If any element of a divisor vector is zero, the whole op is undef.
+ // If any element of a divisor vector is zero, the whole op is poison.
if (Instruction::isIntDivRem(Opcode) && RHS->isNullValue())
- return UndefValue::get(VTy);
+ return PoisonValue::get(VTy);
Result.push_back(ConstantExpr::get(Opcode, LHS, RHS));
}
@@ -2338,7 +2336,8 @@ Constant *llvm::ConstantFoldGetElementPtr(Type *PointeeTy, Constant *C,
return PoisonValue::get(GEPTy);
if (isa<UndefValue>(C))
- return UndefValue::get(GEPTy);
+ // If inbounds, we can choose an out-of-bounds pointer as a base pointer.
+ return InBounds ? PoisonValue::get(GEPTy) : UndefValue::get(GEPTy);
Constant *Idx0 = cast<Constant>(Idxs[0]);
if (Idxs.size() == 1 && (Idx0->isNullValue() || isa<UndefValue>(Idx0)))
generated by cgit v1.1 at 2025-10-15 21:05:15 +0000