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-rw-r--r--llvm/lib/Analysis/InstructionSimplify.cpp27
-rw-r--r--llvm/lib/Analysis/ValueTracking.cpp54
-rw-r--r--llvm/lib/IR/Value.cpp48
3 files changed, 32 insertions, 97 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index ce0b8a0fe64..0a2be059a9b 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -659,32 +659,7 @@ static Constant *stripAndComputeConstantOffsets(const DataLayout &DL, Value *&V,
Type *IntPtrTy = DL.getIntPtrType(V->getType())->getScalarType();
APInt Offset = APInt::getNullValue(IntPtrTy->getIntegerBitWidth());
- // Even though we don't look through PHI nodes, we could be called on an
- // instruction in an unreachable block, which may be on a cycle.
- SmallPtrSet<Value *, 4> Visited;
- Visited.insert(V);
- do {
- if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
- if ((!AllowNonInbounds && !GEP->isInBounds()) ||
- !GEP->accumulateConstantOffset(DL, Offset))
- break;
- V = GEP->getPointerOperand();
- } else if (Operator::getOpcode(V) == Instruction::BitCast) {
- V = cast<Operator>(V)->getOperand(0);
- } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
- if (GA->isInterposable())
- break;
- V = GA->getAliasee();
- } else {
- if (auto *Call = dyn_cast<CallBase>(V))
- if (Value *RV = Call->getReturnedArgOperand()) {
- V = RV;
- continue;
- }
- break;
- }
- assert(V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!");
- } while (Visited.insert(V).second);
+ V = V->stripAndAccumulateConstantOffsets(DL, Offset, AllowNonInbounds);
Constant *OffsetIntPtr = ConstantInt::get(IntPtrTy, Offset);
if (V->getType()->isVectorTy())
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 0b337ae50ef..27d8e324fad 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -38,7 +38,6 @@
#include "llvm/IR/Constant.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/Constants.h"
-#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Dominators.h"
@@ -3423,57 +3422,6 @@ Value *llvm::FindInsertedValue(Value *V, ArrayRef<unsigned> idx_range,
return nullptr;
}
-/// Analyze the specified pointer to see if it can be expressed as a base
-/// pointer plus a constant offset. Return the base and offset to the caller.
-Value *llvm::GetPointerBaseWithConstantOffset(Value *Ptr, int64_t &Offset,
- const DataLayout &DL) {
- unsigned BitWidth = DL.getIndexTypeSizeInBits(Ptr->getType());
- APInt ByteOffset(BitWidth, 0);
-
- // We walk up the defs but use a visited set to handle unreachable code. In
- // that case, we stop after accumulating the cycle once (not that it
- // matters).
- SmallPtrSet<Value *, 16> Visited;
- while (Visited.insert(Ptr).second) {
- if (Ptr->getType()->isVectorTy())
- break;
-
- if (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
- // If one of the values we have visited is an addrspacecast, then
- // the pointer type of this GEP may be different from the type
- // of the Ptr parameter which was passed to this function. This
- // means when we construct GEPOffset, we need to use the size
- // of GEP's pointer type rather than the size of the original
- // pointer type.
- APInt GEPOffset(DL.getIndexTypeSizeInBits(Ptr->getType()), 0);
- if (!GEP->accumulateConstantOffset(DL, GEPOffset))
- break;
-
- APInt OrigByteOffset(ByteOffset);
- ByteOffset += GEPOffset.sextOrTrunc(ByteOffset.getBitWidth());
- if (ByteOffset.getMinSignedBits() > 64) {
- // Stop traversal if the pointer offset wouldn't fit into int64_t
- // (this should be removed if Offset is updated to an APInt)
- ByteOffset = OrigByteOffset;
- break;
- }
-
- Ptr = GEP->getPointerOperand();
- } else if (Operator::getOpcode(Ptr) == Instruction::BitCast ||
- Operator::getOpcode(Ptr) == Instruction::AddrSpaceCast) {
- Ptr = cast<Operator>(Ptr)->getOperand(0);
- } else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(Ptr)) {
- if (GA->isInterposable())
- break;
- Ptr = GA->getAliasee();
- } else {
- break;
- }
- }
- Offset = ByteOffset.getSExtValue();
- return Ptr;
-}
-
bool llvm::isGEPBasedOnPointerToString(const GEPOperator *GEP,
unsigned CharSize) {
// Make sure the GEP has exactly three arguments.
@@ -4401,7 +4349,7 @@ const Value *llvm::getGuaranteedNonFullPoisonOp(const Instruction *I) {
// Note: It's really tempting to think that a conditional branch or
// switch should be listed here, but that's incorrect. It's not
// branching off of poison which is UB, it is executing a side effecting
- // instruction which follows the branch.
+ // instruction which follows the branch.
return nullptr;
}
}
diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index 9e0a43ce1e3..b7f77dc3043 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -555,13 +555,13 @@ const Value *Value::stripPointerCastsAndInvariantGroups() const {
}
const Value *
-Value::stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
- APInt &Offset) const {
- if (!getType()->isPointerTy())
+Value::stripAndAccumulateConstantOffsets(const DataLayout &DL, APInt &Offset,
+ bool AllowNonInbounds) const {
+ if (!getType()->isPtrOrPtrVectorTy())
return this;
- assert(Offset.getBitWidth() == DL.getIndexSizeInBits(cast<PointerType>(
- getType())->getAddressSpace()) &&
+ unsigned BitWidth = Offset.getBitWidth();
+ assert(BitWidth == DL.getIndexTypeSizeInBits(getType()) &&
"The offset bit width does not match the DL specification.");
// Even though we don't look through PHI nodes, we could be called on an
@@ -571,27 +571,39 @@ Value::stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
const Value *V = this;
do {
if (auto *GEP = dyn_cast<GEPOperator>(V)) {
- if (!GEP->isInBounds())
+ // If in-bounds was requested, we do not strip non-in-bounds GEPs.
+ if (!AllowNonInbounds && !GEP->isInBounds())
return V;
- APInt GEPOffset(Offset);
+
+ // If one of the values we have visited is an addrspacecast, then
+ // the pointer type of this GEP may be different from the type
+ // of the Ptr parameter which was passed to this function. This
+ // means when we construct GEPOffset, we need to use the size
+ // of GEP's pointer type rather than the size of the original
+ // pointer type.
+ APInt GEPOffset(DL.getIndexTypeSizeInBits(V->getType()), 0);
if (!GEP->accumulateConstantOffset(DL, GEPOffset))
return V;
- Offset = GEPOffset;
+
+ // Stop traversal if the pointer offset wouldn't fit in the bit-width
+ // provided by the Offset argument. This can happen due to AddrSpaceCast
+ // stripping.
+ if (GEPOffset.getMinSignedBits() > BitWidth)
+ return V;
+
+ Offset += GEPOffset.sextOrTrunc(BitWidth);
V = GEP->getPointerOperand();
- } else if (Operator::getOpcode(V) == Instruction::BitCast) {
+ } else if (Operator::getOpcode(V) == Instruction::BitCast ||
+ Operator::getOpcode(V) == Instruction::AddrSpaceCast) {
V = cast<Operator>(V)->getOperand(0);
} else if (auto *GA = dyn_cast<GlobalAlias>(V)) {
- V = GA->getAliasee();
- } else {
- if (const auto *Call = dyn_cast<CallBase>(V))
- if (const Value *RV = Call->getReturnedArgOperand()) {
+ if (!GA->isInterposable())
+ V = GA->getAliasee();
+ } else if (const auto *Call = dyn_cast<CallBase>(V)) {
+ if (const Value *RV = Call->getReturnedArgOperand())
V = RV;
- continue;
- }
-
- return V;
}
- assert(V->getType()->isPointerTy() && "Unexpected operand type!");
+ assert(V->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!");
} while (Visited.insert(V).second);
return V;
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