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-rw-r--r--lib/Transforms/Scalar/MergedLoadStoreMotion.cpp292
1 files changed, 155 insertions, 137 deletions
diff --git a/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp b/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
index c812d618c16ac..30261b7550019 100644
--- a/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
+++ b/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
@@ -72,9 +72,7 @@
//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Transforms/Scalar/MergedLoadStoreMotion.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CFG.h"
@@ -82,51 +80,37 @@
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/PatternMatch.h"
-#include "llvm/Support/Allocator.h"
-#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/SSAUpdater.h"
-#include <vector>
using namespace llvm;
#define DEBUG_TYPE "mldst-motion"
+namespace {
//===----------------------------------------------------------------------===//
// MergedLoadStoreMotion Pass
//===----------------------------------------------------------------------===//
+class MergedLoadStoreMotion {
+ MemoryDependenceResults *MD = nullptr;
+ AliasAnalysis *AA = nullptr;
-namespace {
-class MergedLoadStoreMotion : public FunctionPass {
- AliasAnalysis *AA;
- MemoryDependenceAnalysis *MD;
+ // The mergeLoad/Store algorithms could have Size0 * Size1 complexity,
+ // where Size0 and Size1 are the #instructions on the two sides of
+ // the diamond. The constant chosen here is arbitrary. Compiler Time
+ // Control is enforced by the check Size0 * Size1 < MagicCompileTimeControl.
+ const int MagicCompileTimeControl = 250;
public:
- static char ID; // Pass identification, replacement for typeid
- MergedLoadStoreMotion()
- : FunctionPass(ID), MD(nullptr), MagicCompileTimeControl(250) {
- initializeMergedLoadStoreMotionPass(*PassRegistry::getPassRegistry());
- }
-
- bool runOnFunction(Function &F) override;
+ bool run(Function &F, MemoryDependenceResults *MD, AliasAnalysis &AA);
private:
- // This transformation requires dominator postdominator info
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.setPreservesCFG();
- AU.addRequired<TargetLibraryInfoWrapperPass>();
- AU.addRequired<AAResultsWrapperPass>();
- AU.addPreserved<GlobalsAAWrapperPass>();
- AU.addPreserved<MemoryDependenceAnalysis>();
- }
-
- // Helper routines
-
///
/// \brief Remove instruction from parent and update memory dependence
/// analysis.
@@ -135,9 +119,9 @@ private:
BasicBlock *getDiamondTail(BasicBlock *BB);
bool isDiamondHead(BasicBlock *BB);
// Routines for hoisting loads
- bool isLoadHoistBarrierInRange(const Instruction& Start,
- const Instruction& End,
- LoadInst* LI);
+ bool isLoadHoistBarrierInRange(const Instruction &Start,
+ const Instruction &End, LoadInst *LI,
+ bool SafeToLoadUnconditionally);
LoadInst *canHoistFromBlock(BasicBlock *BB, LoadInst *LI);
void hoistInstruction(BasicBlock *BB, Instruction *HoistCand,
Instruction *ElseInst);
@@ -151,31 +135,8 @@ private:
const Instruction &End, MemoryLocation Loc);
bool sinkStore(BasicBlock *BB, StoreInst *SinkCand, StoreInst *ElseInst);
bool mergeStores(BasicBlock *BB);
- // The mergeLoad/Store algorithms could have Size0 * Size1 complexity,
- // where Size0 and Size1 are the #instructions on the two sides of
- // the diamond. The constant chosen here is arbitrary. Compiler Time
- // Control is enforced by the check Size0 * Size1 < MagicCompileTimeControl.
- const int MagicCompileTimeControl;
};
-
-char MergedLoadStoreMotion::ID = 0;
-} // anonymous namespace
-
-///
-/// \brief createMergedLoadStoreMotionPass - The public interface to this file.
-///
-FunctionPass *llvm::createMergedLoadStoreMotionPass() {
- return new MergedLoadStoreMotion();
-}
-
-INITIALIZE_PASS_BEGIN(MergedLoadStoreMotion, "mldst-motion",
- "MergedLoadStoreMotion", false, false)
-INITIALIZE_PASS_DEPENDENCY(MemoryDependenceAnalysis)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
-INITIALIZE_PASS_END(MergedLoadStoreMotion, "mldst-motion",
- "MergedLoadStoreMotion", false, false)
+} // end anonymous namespace
///
/// \brief Remove instruction from parent and update memory dependence analysis.
@@ -184,9 +145,9 @@ void MergedLoadStoreMotion::removeInstruction(Instruction *Inst) {
// Notify the memory dependence analysis.
if (MD) {
MD->removeInstruction(Inst);
- if (LoadInst *LI = dyn_cast<LoadInst>(Inst))
+ if (auto *LI = dyn_cast<LoadInst>(Inst))
MD->invalidateCachedPointerInfo(LI->getPointerOperand());
- if (Inst->getType()->getScalarType()->isPointerTy()) {
+ if (Inst->getType()->isPtrOrPtrVectorTy()) {
MD->invalidateCachedPointerInfo(Inst);
}
}
@@ -198,10 +159,7 @@ void MergedLoadStoreMotion::removeInstruction(Instruction *Inst) {
///
BasicBlock *MergedLoadStoreMotion::getDiamondTail(BasicBlock *BB) {
assert(isDiamondHead(BB) && "Basic block is not head of a diamond");
- BranchInst *BI = (BranchInst *)(BB->getTerminator());
- BasicBlock *Succ0 = BI->getSuccessor(0);
- BasicBlock *Tail = Succ0->getTerminator()->getSuccessor(0);
- return Tail;
+ return BB->getTerminator()->getSuccessor(0)->getSingleSuccessor();
}
///
@@ -210,25 +168,22 @@ BasicBlock *MergedLoadStoreMotion::getDiamondTail(BasicBlock *BB) {
bool MergedLoadStoreMotion::isDiamondHead(BasicBlock *BB) {
if (!BB)
return false;
- if (!isa<BranchInst>(BB->getTerminator()))
- return false;
- if (BB->getTerminator()->getNumSuccessors() != 2)
+ auto *BI = dyn_cast<BranchInst>(BB->getTerminator());
+ if (!BI || !BI->isConditional())
return false;
- BranchInst *BI = (BranchInst *)(BB->getTerminator());
BasicBlock *Succ0 = BI->getSuccessor(0);
BasicBlock *Succ1 = BI->getSuccessor(1);
- if (!Succ0->getSinglePredecessor() ||
- Succ0->getTerminator()->getNumSuccessors() != 1)
+ if (!Succ0->getSinglePredecessor())
return false;
- if (!Succ1->getSinglePredecessor() ||
- Succ1->getTerminator()->getNumSuccessors() != 1)
+ if (!Succ1->getSinglePredecessor())
return false;
- BasicBlock *Tail = Succ0->getTerminator()->getSuccessor(0);
+ BasicBlock *Succ0Succ = Succ0->getSingleSuccessor();
+ BasicBlock *Succ1Succ = Succ1->getSingleSuccessor();
// Ignore triangles.
- if (Succ1->getTerminator()->getSuccessor(0) != Tail)
+ if (!Succ0Succ || !Succ1Succ || Succ0Succ != Succ1Succ)
return false;
return true;
}
@@ -240,9 +195,14 @@ bool MergedLoadStoreMotion::isDiamondHead(BasicBlock *BB) {
/// being loaded or protect against the load from happening
/// it is considered a hoist barrier.
///
-bool MergedLoadStoreMotion::isLoadHoistBarrierInRange(const Instruction& Start,
- const Instruction& End,
- LoadInst* LI) {
+bool MergedLoadStoreMotion::isLoadHoistBarrierInRange(
+ const Instruction &Start, const Instruction &End, LoadInst *LI,
+ bool SafeToLoadUnconditionally) {
+ if (!SafeToLoadUnconditionally)
+ for (const Instruction &Inst :
+ make_range(Start.getIterator(), End.getIterator()))
+ if (!isGuaranteedToTransferExecutionToSuccessor(&Inst))
+ return true;
MemoryLocation Loc = MemoryLocation::get(LI);
return AA->canInstructionRangeModRef(Start, End, Loc, MRI_Mod);
}
@@ -256,23 +216,28 @@ bool MergedLoadStoreMotion::isLoadHoistBarrierInRange(const Instruction& Start,
///
LoadInst *MergedLoadStoreMotion::canHoistFromBlock(BasicBlock *BB1,
LoadInst *Load0) {
-
+ BasicBlock *BB0 = Load0->getParent();
+ BasicBlock *Head = BB0->getSinglePredecessor();
+ bool SafeToLoadUnconditionally = isSafeToLoadUnconditionally(
+ Load0->getPointerOperand(), Load0->getAlignment(),
+ Load0->getModule()->getDataLayout(),
+ /*ScanFrom=*/Head->getTerminator());
for (BasicBlock::iterator BBI = BB1->begin(), BBE = BB1->end(); BBI != BBE;
++BBI) {
Instruction *Inst = &*BBI;
// Only merge and hoist loads when their result in used only in BB
- if (!isa<LoadInst>(Inst) || Inst->isUsedOutsideOfBlock(BB1))
+ auto *Load1 = dyn_cast<LoadInst>(Inst);
+ if (!Load1 || Inst->isUsedOutsideOfBlock(BB1))
continue;
- LoadInst *Load1 = dyn_cast<LoadInst>(Inst);
- BasicBlock *BB0 = Load0->getParent();
-
MemoryLocation Loc0 = MemoryLocation::get(Load0);
MemoryLocation Loc1 = MemoryLocation::get(Load1);
- if (AA->isMustAlias(Loc0, Loc1) && Load0->isSameOperationAs(Load1) &&
- !isLoadHoistBarrierInRange(BB1->front(), *Load1, Load1) &&
- !isLoadHoistBarrierInRange(BB0->front(), *Load0, Load0)) {
+ if (Load0->isSameOperationAs(Load1) && AA->isMustAlias(Loc0, Loc1) &&
+ !isLoadHoistBarrierInRange(BB1->front(), *Load1, Load1,
+ SafeToLoadUnconditionally) &&
+ !isLoadHoistBarrierInRange(BB0->front(), *Load0, Load0,
+ SafeToLoadUnconditionally)) {
return Load1;
}
}
@@ -319,11 +284,10 @@ void MergedLoadStoreMotion::hoistInstruction(BasicBlock *BB,
///
bool MergedLoadStoreMotion::isSafeToHoist(Instruction *I) const {
BasicBlock *Parent = I->getParent();
- for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
- Instruction *Instr = dyn_cast<Instruction>(I->getOperand(i));
- if (Instr && Instr->getParent() == Parent)
- return false;
- }
+ for (Use &U : I->operands())
+ if (auto *Instr = dyn_cast<Instruction>(&U))
+ if (Instr->getParent() == Parent)
+ return false;
return true;
}
@@ -333,8 +297,8 @@ bool MergedLoadStoreMotion::isSafeToHoist(Instruction *I) const {
bool MergedLoadStoreMotion::hoistLoad(BasicBlock *BB, LoadInst *L0,
LoadInst *L1) {
// Only one definition?
- Instruction *A0 = dyn_cast<Instruction>(L0->getPointerOperand());
- Instruction *A1 = dyn_cast<Instruction>(L1->getPointerOperand());
+ auto *A0 = dyn_cast<Instruction>(L0->getPointerOperand());
+ auto *A1 = dyn_cast<Instruction>(L1->getPointerOperand());
if (A0 && A1 && A0->isIdenticalTo(A1) && isSafeToHoist(A0) &&
A0->hasOneUse() && (A0->getParent() == L0->getParent()) &&
A1->hasOneUse() && (A1->getParent() == L1->getParent()) &&
@@ -345,8 +309,8 @@ bool MergedLoadStoreMotion::hoistLoad(BasicBlock *BB, LoadInst *L0,
hoistInstruction(BB, A0, A1);
hoistInstruction(BB, L0, L1);
return true;
- } else
- return false;
+ }
+ return false;
}
///
@@ -358,7 +322,7 @@ bool MergedLoadStoreMotion::hoistLoad(BasicBlock *BB, LoadInst *L0,
bool MergedLoadStoreMotion::mergeLoads(BasicBlock *BB) {
bool MergedLoads = false;
assert(isDiamondHead(BB));
- BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
+ BranchInst *BI = cast<BranchInst>(BB->getTerminator());
BasicBlock *Succ0 = BI->getSuccessor(0);
BasicBlock *Succ1 = BI->getSuccessor(1);
// #Instructions in Succ1 for Compile Time Control
@@ -369,8 +333,8 @@ bool MergedLoadStoreMotion::mergeLoads(BasicBlock *BB) {
Instruction *I = &*BBI;
++BBI;
- // Only move non-simple (atomic, volatile) loads.
- LoadInst *L0 = dyn_cast<LoadInst>(I);
+ // Don't move non-simple (atomic, volatile) loads.
+ auto *L0 = dyn_cast<LoadInst>(I);
if (!L0 || !L0->isSimple() || L0->isUsedOutsideOfBlock(Succ0))
continue;
@@ -399,6 +363,10 @@ bool MergedLoadStoreMotion::mergeLoads(BasicBlock *BB) {
bool MergedLoadStoreMotion::isStoreSinkBarrierInRange(const Instruction &Start,
const Instruction &End,
MemoryLocation Loc) {
+ for (const Instruction &Inst :
+ make_range(Start.getIterator(), End.getIterator()))
+ if (Inst.mayThrow())
+ return true;
return AA->canInstructionRangeModRef(Start, End, Loc, MRI_ModRef);
}
@@ -411,22 +379,16 @@ StoreInst *MergedLoadStoreMotion::canSinkFromBlock(BasicBlock *BB1,
StoreInst *Store0) {
DEBUG(dbgs() << "can Sink? : "; Store0->dump(); dbgs() << "\n");
BasicBlock *BB0 = Store0->getParent();
- for (BasicBlock::reverse_iterator RBI = BB1->rbegin(), RBE = BB1->rend();
- RBI != RBE; ++RBI) {
- Instruction *Inst = &*RBI;
-
- if (!isa<StoreInst>(Inst))
- continue;
-
- StoreInst *Store1 = cast<StoreInst>(Inst);
+ for (Instruction &Inst : reverse(*BB1)) {
+ auto *Store1 = dyn_cast<StoreInst>(&Inst);
+ if (!Store1)
+ continue;
MemoryLocation Loc0 = MemoryLocation::get(Store0);
MemoryLocation Loc1 = MemoryLocation::get(Store1);
if (AA->isMustAlias(Loc0, Loc1) && Store0->isSameOperationAs(Store1) &&
- !isStoreSinkBarrierInRange(*(std::next(BasicBlock::iterator(Store1))),
- BB1->back(), Loc1) &&
- !isStoreSinkBarrierInRange(*(std::next(BasicBlock::iterator(Store0))),
- BB0->back(), Loc0)) {
+ !isStoreSinkBarrierInRange(*Store1->getNextNode(), BB1->back(), Loc1) &&
+ !isStoreSinkBarrierInRange(*Store0->getNextNode(), BB0->back(), Loc0)) {
return Store1;
}
}
@@ -439,17 +401,17 @@ StoreInst *MergedLoadStoreMotion::canSinkFromBlock(BasicBlock *BB1,
PHINode *MergedLoadStoreMotion::getPHIOperand(BasicBlock *BB, StoreInst *S0,
StoreInst *S1) {
// Create a phi if the values mismatch.
- PHINode *NewPN = nullptr;
Value *Opd1 = S0->getValueOperand();
Value *Opd2 = S1->getValueOperand();
- if (Opd1 != Opd2) {
- NewPN = PHINode::Create(Opd1->getType(), 2, Opd2->getName() + ".sink",
- &BB->front());
- NewPN->addIncoming(Opd1, S0->getParent());
- NewPN->addIncoming(Opd2, S1->getParent());
- if (MD && NewPN->getType()->getScalarType()->isPointerTy())
- MD->invalidateCachedPointerInfo(NewPN);
- }
+ if (Opd1 == Opd2)
+ return nullptr;
+
+ auto *NewPN = PHINode::Create(Opd1->getType(), 2, Opd2->getName() + ".sink",
+ &BB->front());
+ NewPN->addIncoming(Opd1, S0->getParent());
+ NewPN->addIncoming(Opd2, S1->getParent());
+ if (MD && NewPN->getType()->getScalarType()->isPointerTy())
+ MD->invalidateCachedPointerInfo(NewPN);
return NewPN;
}
@@ -461,8 +423,8 @@ PHINode *MergedLoadStoreMotion::getPHIOperand(BasicBlock *BB, StoreInst *S0,
bool MergedLoadStoreMotion::sinkStore(BasicBlock *BB, StoreInst *S0,
StoreInst *S1) {
// Only one definition?
- Instruction *A0 = dyn_cast<Instruction>(S0->getPointerOperand());
- Instruction *A1 = dyn_cast<Instruction>(S1->getPointerOperand());
+ auto *A0 = dyn_cast<Instruction>(S0->getPointerOperand());
+ auto *A1 = dyn_cast<Instruction>(S1->getPointerOperand());
if (A0 && A1 && A0->isIdenticalTo(A1) && A0->hasOneUse() &&
(A0->getParent() == S0->getParent()) && A1->hasOneUse() &&
(A1->getParent() == S1->getParent()) && isa<GetElementPtrInst>(A0)) {
@@ -476,7 +438,7 @@ bool MergedLoadStoreMotion::sinkStore(BasicBlock *BB, StoreInst *S0,
S0->dropUnknownNonDebugMetadata();
// Create the new store to be inserted at the join point.
- StoreInst *SNew = (StoreInst *)(S0->clone());
+ StoreInst *SNew = cast<StoreInst>(S0->clone());
Instruction *ANew = A0->clone();
SNew->insertBefore(&*InsertPt);
ANew->insertBefore(SNew);
@@ -484,9 +446,8 @@ bool MergedLoadStoreMotion::sinkStore(BasicBlock *BB, StoreInst *S0,
assert(S0->getParent() == A0->getParent());
assert(S1->getParent() == A1->getParent());
- PHINode *NewPN = getPHIOperand(BB, S0, S1);
// New PHI operand? Use it.
- if (NewPN)
+ if (PHINode *NewPN = getPHIOperand(BB, S0, S1))
SNew->setOperand(0, NewPN);
removeInstruction(S0);
removeInstruction(S1);
@@ -532,11 +493,9 @@ bool MergedLoadStoreMotion::mergeStores(BasicBlock *T) {
Instruction *I = &*RBI;
++RBI;
- // Sink move non-simple (atomic, volatile) stores
- if (!isa<StoreInst>(I))
- continue;
- StoreInst *S0 = (StoreInst *)I;
- if (!S0->isSimple())
+ // Don't sink non-simple (atomic, volatile) stores.
+ auto *S0 = dyn_cast<StoreInst>(I);
+ if (!S0 || !S0->isSimple())
continue;
++NStores;
@@ -551,22 +510,18 @@ bool MergedLoadStoreMotion::mergeStores(BasicBlock *T) {
// is likely stale at this point.
if (!Res)
break;
- else {
- RBI = Pred0->rbegin();
- RBE = Pred0->rend();
- DEBUG(dbgs() << "Search again\n"; Instruction *I = &*RBI; I->dump());
- }
+ RBI = Pred0->rbegin();
+ RBE = Pred0->rend();
+ DEBUG(dbgs() << "Search again\n"; Instruction *I = &*RBI; I->dump());
}
}
return MergedStores;
}
-///
-/// \brief Run the transformation for each function
-///
-bool MergedLoadStoreMotion::runOnFunction(Function &F) {
- MD = getAnalysisIfAvailable<MemoryDependenceAnalysis>();
- AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
+bool MergedLoadStoreMotion::run(Function &F, MemoryDependenceResults *MD,
+ AliasAnalysis &AA) {
+ this->MD = MD;
+ this->AA = &AA;
bool Changed = false;
DEBUG(dbgs() << "Instruction Merger\n");
@@ -585,3 +540,66 @@ bool MergedLoadStoreMotion::runOnFunction(Function &F) {
}
return Changed;
}
+
+namespace {
+class MergedLoadStoreMotionLegacyPass : public FunctionPass {
+public:
+ static char ID; // Pass identification, replacement for typeid
+ MergedLoadStoreMotionLegacyPass() : FunctionPass(ID) {
+ initializeMergedLoadStoreMotionLegacyPassPass(
+ *PassRegistry::getPassRegistry());
+ }
+
+ ///
+ /// \brief Run the transformation for each function
+ ///
+ bool runOnFunction(Function &F) override {
+ if (skipFunction(F))
+ return false;
+ MergedLoadStoreMotion Impl;
+ auto *MDWP = getAnalysisIfAvailable<MemoryDependenceWrapperPass>();
+ return Impl.run(F, MDWP ? &MDWP->getMemDep() : nullptr,
+ getAnalysis<AAResultsWrapperPass>().getAAResults());
+ }
+
+private:
+ // This transformation requires dominator postdominator info
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.setPreservesCFG();
+ AU.addRequired<AAResultsWrapperPass>();
+ AU.addPreserved<GlobalsAAWrapperPass>();
+ AU.addPreserved<MemoryDependenceWrapperPass>();
+ }
+};
+
+char MergedLoadStoreMotionLegacyPass::ID = 0;
+} // anonymous namespace
+
+///
+/// \brief createMergedLoadStoreMotionPass - The public interface to this file.
+///
+FunctionPass *llvm::createMergedLoadStoreMotionPass() {
+ return new MergedLoadStoreMotionLegacyPass();
+}
+
+INITIALIZE_PASS_BEGIN(MergedLoadStoreMotionLegacyPass, "mldst-motion",
+ "MergedLoadStoreMotion", false, false)
+INITIALIZE_PASS_DEPENDENCY(MemoryDependenceWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
+INITIALIZE_PASS_END(MergedLoadStoreMotionLegacyPass, "mldst-motion",
+ "MergedLoadStoreMotion", false, false)
+
+PreservedAnalyses
+MergedLoadStoreMotionPass::run(Function &F, AnalysisManager<Function> &AM) {
+ MergedLoadStoreMotion Impl;
+ auto *MD = AM.getCachedResult<MemoryDependenceAnalysis>(F);
+ auto &AA = AM.getResult<AAManager>(F);
+ if (!Impl.run(F, MD, AA))
+ return PreservedAnalyses::all();
+
+ // FIXME: This should also 'preserve the CFG'.
+ PreservedAnalyses PA;
+ PA.preserve<GlobalsAA>();
+ PA.preserve<MemoryDependenceAnalysis>();
+ return PA;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-16 14:57:15 +0000