[llvm] r273126 - Address Eli's post-commit comments
David Majnemer via llvm-commits
llvm-commits at lists.llvm.org
Sun Jun 19 14:36:36 PDT 2016
Author: majnemer
Date: Sun Jun 19 16:36:35 2016
New Revision: 273126
URL: http://llvm.org/viewvc/llvm-project?rev=273126&view=rev
Log:
Address Eli's post-commit comments
Use an APInt to handle pointers of arbitrary width, let
accumulateConstantOffset handle overflow issues.
Modified:
llvm/trunk/lib/Transforms/Scalar/LoadCombine.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LoadCombine.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoadCombine.cpp?rev=273126&r1=273125&r2=273126&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoadCombine.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoadCombine.cpp Sun Jun 19 16:36:35 2016
@@ -40,7 +40,7 @@ STATISTIC(NumLoadsCombined, "Number of l
namespace {
struct PointerOffsetPair {
Value *Pointer;
- int64_t Offset;
+ APInt Offset;
};
struct LoadPOPPair {
@@ -93,22 +93,25 @@ bool LoadCombine::doInitialization(Funct
}
PointerOffsetPair LoadCombine::getPointerOffsetPair(LoadInst &LI) {
+ auto &DL = LI.getModule()->getDataLayout();
+
PointerOffsetPair POP;
POP.Pointer = LI.getPointerOperand();
- POP.Offset = 0;
+ unsigned BitWidth = DL.getPointerSizeInBits(LI.getPointerAddressSpace());
+ POP.Offset = APInt(BitWidth, 0);
+
while (isa<BitCastInst>(POP.Pointer) || isa<GetElementPtrInst>(POP.Pointer)) {
if (auto *GEP = dyn_cast<GetElementPtrInst>(POP.Pointer)) {
- auto &DL = LI.getModule()->getDataLayout();
- unsigned BitWidth = DL.getPointerTypeSizeInBits(GEP->getType());
- APInt Offset(BitWidth, 0);
- if (GEP->accumulateConstantOffset(DL, Offset))
- POP.Offset += Offset.getSExtValue();
- else
+ APInt LastOffset = POP.Offset;
+ if (!GEP->accumulateConstantOffset(DL, POP.Offset)) {
// Can't handle GEPs with variable indices.
+ POP.Offset = LastOffset;
return POP;
+ }
POP.Pointer = GEP->getPointerOperand();
- } else if (auto *BC = dyn_cast<BitCastInst>(POP.Pointer))
+ } else if (auto *BC = dyn_cast<BitCastInst>(POP.Pointer)) {
POP.Pointer = BC->getOperand(0);
+ }
}
return POP;
}
@@ -121,8 +124,8 @@ bool LoadCombine::combineLoads(
continue;
std::sort(Loads.second.begin(), Loads.second.end(),
[](const LoadPOPPair &A, const LoadPOPPair &B) {
- return A.POP.Offset < B.POP.Offset;
- });
+ return A.POP.Offset.slt(B.POP.Offset);
+ });
if (aggregateLoads(Loads.second))
Combined = true;
}
@@ -139,7 +142,7 @@ bool LoadCombine::aggregateLoads(SmallVe
SmallVector<LoadPOPPair, 8> AggregateLoads;
bool Combined = false;
bool ValidPrevOffset = false;
- int64_t PrevOffset = 0;
+ APInt PrevOffset;
uint64_t PrevSize = 0;
for (auto &L : Loads) {
if (ValidPrevOffset == false) {
@@ -153,8 +156,8 @@ bool LoadCombine::aggregateLoads(SmallVe
}
if (L.Load->getAlignment() > BaseLoad->getAlignment())
continue;
- int64_t PrevEnd = PrevOffset + PrevSize;
- if (L.POP.Offset > PrevEnd) {
+ APInt PrevEnd = PrevOffset + PrevSize;
+ if (L.POP.Offset.sgt(PrevEnd)) {
// No other load will be combinable
if (combineLoads(AggregateLoads))
Combined = true;
@@ -208,7 +211,7 @@ bool LoadCombine::combineLoads(SmallVect
Value *Ptr = Builder->CreateConstGEP1_64(
Builder->CreatePointerCast(Loads[0].POP.Pointer,
Builder->getInt8PtrTy(AddressSpace)),
- Loads[0].POP.Offset);
+ Loads[0].POP.Offset.getSExtValue());
LoadInst *NewLoad = new LoadInst(
Builder->CreatePointerCast(
Ptr, PointerType::get(IntegerType::get(Ptr->getContext(), TotalSize),
@@ -221,7 +224,7 @@ bool LoadCombine::combineLoads(SmallVect
Value *V = Builder->CreateExtractInteger(
L.Load->getModule()->getDataLayout(), NewLoad,
cast<IntegerType>(L.Load->getType()),
- L.POP.Offset - Loads[0].POP.Offset, "combine.extract");
+ (L.POP.Offset - Loads[0].POP.Offset).getZExtValue(), "combine.extract");
L.Load->replaceAllUsesWith(V);
}
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