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-rw-r--r--llvm/lib/IR/ConstantFold.cpp149
1 files changed, 0 insertions, 149 deletions
diff --git a/llvm/lib/IR/ConstantFold.cpp b/llvm/lib/IR/ConstantFold.cpp
index 7b8b9a7b652d..693674ae0d06 100644
--- a/llvm/lib/IR/ConstantFold.cpp
+++ b/llvm/lib/IR/ConstantFold.cpp
@@ -120,66 +120,6 @@ static Constant *FoldBitCast(Constant *V, Type *DestTy) {
return nullptr;
}
-
-/// V is an integer constant which only has a subset of its bytes used.
-/// The bytes used are indicated by ByteStart (which is the first byte used,
-/// counting from the least significant byte) and ByteSize, which is the number
-/// of bytes used.
-///
-/// This function analyzes the specified constant to see if the specified byte
-/// range can be returned as a simplified constant. If so, the constant is
-/// returned, otherwise null is returned.
-static Constant *ExtractConstantBytes(Constant *C, unsigned ByteStart,
- unsigned ByteSize) {
- assert(C->getType()->isIntegerTy() &&
- (cast<IntegerType>(C->getType())->getBitWidth() & 7) == 0 &&
- "Non-byte sized integer input");
- [[maybe_unused]] unsigned CSize = cast<IntegerType>(C->getType())->getBitWidth()/8;
- assert(ByteSize && "Must be accessing some piece");
- assert(ByteStart+ByteSize <= CSize && "Extracting invalid piece from input");
- assert(ByteSize != CSize && "Should not extract everything");
-
- // Constant Integers are simple.
- if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
- APInt V = CI->getValue();
- if (ByteStart)
- V.lshrInPlace(ByteStart*8);
- V = V.trunc(ByteSize*8);
- return ConstantInt::get(CI->getContext(), V);
- }
-
- // In the input is a constant expr, we might be able to recursively simplify.
- // If not, we definitely can't do anything.
- ConstantExpr *CE = dyn_cast<ConstantExpr>(C);
- if (!CE) return nullptr;
-
- switch (CE->getOpcode()) {
- default: return nullptr;
- case Instruction::Shl: {
- ConstantInt *Amt = dyn_cast<ConstantInt>(CE->getOperand(1));
- if (!Amt)
- return nullptr;
- APInt ShAmt = Amt->getValue();
- // Cannot analyze non-byte shifts.
- if ((ShAmt & 7) != 0)
- return nullptr;
- ShAmt.lshrInPlace(3);
-
- // If the extract is known to be all zeros, return zero.
- if (ShAmt.uge(ByteStart + ByteSize))
- return Constant::getNullValue(
- IntegerType::get(CE->getContext(), ByteSize * 8));
- // If the extract is known to be fully in the input, extract it.
- if (ShAmt.ule(ByteStart))
- return ExtractConstantBytes(CE->getOperand(0),
- ByteStart - ShAmt.getZExtValue(), ByteSize);
-
- // TODO: Handle the 'partially zero' case.
- return nullptr;
- }
- }
-}
-
static Constant *foldMaybeUndesirableCast(unsigned opc, Constant *V,
Type *DestTy) {
return ConstantExpr::isDesirableCastOp(opc)
@@ -313,14 +253,6 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
CI->getValue().trunc(DestBitWidth));
}
- // The input must be a constantexpr. See if we can simplify this based on
- // the bytes we are demanding. Only do this if the source and dest are an
- // even multiple of a byte.
- if ((DestBitWidth & 7) == 0 &&
- (cast<IntegerType>(V->getType())->getBitWidth() & 7) == 0)
- if (Constant *Res = ExtractConstantBytes(V, 0, DestBitWidth / 8))
- return Res;
-
return nullptr;
}
case Instruction::BitCast:
@@ -1404,83 +1336,7 @@ Constant *llvm::ConstantFoldCompareInstruction(CmpInst::Predicate Predicate,
return nullptr;
}
-// Combine Indices - If the source pointer to this getelementptr instruction
-// is a getelementptr instruction, combine the indices of the two
-// getelementptr instructions into a single instruction.
-static Constant *foldGEPOfGEP(GEPOperator *GEP, Type *PointeeTy, bool InBounds,
- ArrayRef<Value *> Idxs) {
- if (PointeeTy != GEP->getResultElementType())
- return nullptr;
-
- // Leave inrange handling to DL-aware constant folding.
- if (GEP->getInRange())
- return nullptr;
-
- Constant *Idx0 = cast<Constant>(Idxs[0]);
- if (Idx0->isNullValue()) {
- // Handle the simple case of a zero index.
- SmallVector<Value*, 16> NewIndices;
- NewIndices.reserve(Idxs.size() + GEP->getNumIndices());
- NewIndices.append(GEP->idx_begin(), GEP->idx_end());
- NewIndices.append(Idxs.begin() + 1, Idxs.end());
- return ConstantExpr::getGetElementPtr(
- GEP->getSourceElementType(), cast<Constant>(GEP->getPointerOperand()),
- NewIndices, InBounds && GEP->isInBounds());
- }
-
- gep_type_iterator LastI = gep_type_end(GEP);
- for (gep_type_iterator I = gep_type_begin(GEP), E = gep_type_end(GEP);
- I != E; ++I)
- LastI = I;
-
- // We can't combine GEPs if the last index is a struct type.
- if (!LastI.isSequential())
- return nullptr;
- // We could perform the transform with non-constant index, but prefer leaving
- // it as GEP of GEP rather than GEP of add for now.
- ConstantInt *CI = dyn_cast<ConstantInt>(Idx0);
- if (!CI)
- return nullptr;
-
- // TODO: This code may be extended to handle vectors as well.
- auto *LastIdx = cast<Constant>(GEP->getOperand(GEP->getNumOperands()-1));
- Type *LastIdxTy = LastIdx->getType();
- if (LastIdxTy->isVectorTy())
- return nullptr;
-
- SmallVector<Value*, 16> NewIndices;
- NewIndices.reserve(Idxs.size() + GEP->getNumIndices());
- NewIndices.append(GEP->idx_begin(), GEP->idx_end() - 1);
-
- // Add the last index of the source with the first index of the new GEP.
- // Make sure to handle the case when they are actually different types.
- if (LastIdxTy != Idx0->getType()) {
- unsigned CommonExtendedWidth =
- std::max(LastIdxTy->getIntegerBitWidth(),
- Idx0->getType()->getIntegerBitWidth());
- CommonExtendedWidth = std::max(CommonExtendedWidth, 64U);
-
- Type *CommonTy =
- Type::getIntNTy(LastIdxTy->getContext(), CommonExtendedWidth);
- if (Idx0->getType() != CommonTy)
- Idx0 = ConstantFoldCastInstruction(Instruction::SExt, Idx0, CommonTy);
- if (LastIdx->getType() != CommonTy)
- LastIdx =
- ConstantFoldCastInstruction(Instruction::SExt, LastIdx, CommonTy);
- if (!Idx0 || !LastIdx)
- return nullptr;
- }
-
- NewIndices.push_back(ConstantExpr::get(Instruction::Add, Idx0, LastIdx));
- NewIndices.append(Idxs.begin() + 1, Idxs.end());
-
- return ConstantExpr::getGetElementPtr(
- GEP->getSourceElementType(), cast<Constant>(GEP->getPointerOperand()),
- NewIndices, InBounds && GEP->isInBounds());
-}
-
Constant *llvm::ConstantFoldGetElementPtr(Type *PointeeTy, Constant *C,
- bool InBounds,
std::optional<ConstantRange> InRange,
ArrayRef<Value *> Idxs) {
if (Idxs.empty()) return C;
@@ -1510,10 +1366,5 @@ Constant *llvm::ConstantFoldGetElementPtr(Type *PointeeTy, Constant *C,
cast<VectorType>(GEPTy)->getElementCount(), C)
: C;
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
- if (auto *GEP = dyn_cast<GEPOperator>(CE))
- if (Constant *C = foldGEPOfGEP(GEP, PointeeTy, InBounds, Idxs))
- return C;
-
return nullptr;
}
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-31 12:39:01 +0000