#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/MallocFreeHelper.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Support/Compiler.h"
using namespace llvm;
STATISTIC(NumFastStores, "Number of stores deleted");
STATISTIC(NumFastOther , "Number of other instrs removed");
namespace {
- struct VISIBILITY_HIDDEN DSE : public FunctionPass {
+ struct DSE : public FunctionPass {
+ TargetData *TD;
+
static char ID; // Pass identification, replacement for typeid
DSE() : FunctionPass(&ID) {}
}
bool runOnBasicBlock(BasicBlock &BB);
- bool handleFreeWithNonTrivialDependency(FreeInst *F, MemDepResult Dep);
+ bool handleFreeWithNonTrivialDependency(Instruction *F, MemDepResult Dep);
bool handleEndBlock(BasicBlock &BB);
bool RemoveUndeadPointers(Value* Ptr, uint64_t killPointerSize,
BasicBlock::iterator& BBI,
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addRequired<DominatorTree>();
- AU.addRequired<TargetData>();
AU.addRequired<AliasAnalysis>();
AU.addRequired<MemoryDependenceAnalysis>();
AU.addPreserved<DominatorTree>();
bool DSE::runOnBasicBlock(BasicBlock &BB) {
MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
- TargetData &TD = getAnalysis<TargetData>();
+ TD = getAnalysisIfAvailable<TargetData>();
bool MadeChange = false;
- // Do a top-down walk on the BB
+ // Do a top-down walk on the BB.
for (BasicBlock::iterator BBI = BB.begin(), BBE = BB.end(); BBI != BBE; ) {
Instruction *Inst = BBI++;
- // If we find a store or a free, get it's memory dependence.
- if (!isa<StoreInst>(Inst) && !isa<FreeInst>(Inst))
+ // If we find a store or a free, get its memory dependence.
+ if (!isa<StoreInst>(Inst) && !isFreeCall(Inst))
continue;
// Don't molest volatile stores or do queries that will return "clobber".
if (InstDep.isNonLocal()) continue;
// Handle frees whose dependencies are non-trivial.
- if (FreeInst *FI = dyn_cast<FreeInst>(Inst)) {
- MadeChange |= handleFreeWithNonTrivialDependency(FI, InstDep);
+ if (isFreeCall(Inst)) {
+ MadeChange |= handleFreeWithNonTrivialDependency(Inst, InstDep);
continue;
}
// If this is a store-store dependence, then the previous store is dead so
// long as this store is at least as big as it.
if (StoreInst *DepStore = dyn_cast<StoreInst>(InstDep.getInst()))
- if (TD.getTypeStoreSize(DepStore->getOperand(0)->getType()) <=
- TD.getTypeStoreSize(SI->getOperand(0)->getType())) {
+ if (TD &&
+ TD->getTypeStoreSize(DepStore->getOperand(0)->getType()) <=
+ TD->getTypeStoreSize(SI->getOperand(0)->getType())) {
// Delete the store and now-dead instructions that feed it.
DeleteDeadInstruction(DepStore);
NumFastStores++;
MadeChange = true;
-
+
+ // DeleteDeadInstruction can delete the current instruction in loop
+ // cases, reset BBI.
+ BBI = Inst;
if (BBI != BB.begin())
--BBI;
continue;
if (LoadInst *DepLoad = dyn_cast<LoadInst>(InstDep.getInst())) {
if (SI->getPointerOperand() == DepLoad->getPointerOperand() &&
SI->getOperand(0) == DepLoad) {
+ // DeleteDeadInstruction can delete the current instruction. Save BBI
+ // in case we need it.
+ WeakVH NextInst(BBI);
+
DeleteDeadInstruction(SI);
- if (BBI != BB.begin())
+
+ if (NextInst == 0) // Next instruction deleted.
+ BBI = BB.begin();
+ else if (BBI != BB.begin()) // Revisit this instruction if possible.
--BBI;
NumFastStores++;
MadeChange = true;
/// handleFreeWithNonTrivialDependency - Handle frees of entire structures whose
/// dependency is a store to a field of that structure.
-bool DSE::handleFreeWithNonTrivialDependency(FreeInst *F, MemDepResult Dep) {
+bool DSE::handleFreeWithNonTrivialDependency(Instruction *F, MemDepResult Dep) {
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
StoreInst *Dependency = dyn_cast_or_null<StoreInst>(Dep.getInst());
Value *DepPointer = Dependency->getPointerOperand()->getUnderlyingObject();
// Check for aliasing.
- if (AA.alias(F->getPointerOperand(), 1, DepPointer, 1) !=
+ if (AA.alias(F->getOperand(1), 1, DepPointer, 1) !=
AliasAnalysis::MustAlias)
return false;
/// store i32 1, i32* %A
/// ret void
bool DSE::handleEndBlock(BasicBlock &BB) {
- TargetData &TD = getAnalysis<TargetData>();
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
bool MadeChange = false;
// Get size information for the alloca
unsigned pointerSize = ~0U;
- if (AllocaInst* A = dyn_cast<AllocaInst>(*I)) {
- if (ConstantInt* C = dyn_cast<ConstantInt>(A->getArraySize()))
- pointerSize = C->getZExtValue() *
- TD.getABITypeSize(A->getAllocatedType());
- } else {
- const PointerType* PT = cast<PointerType>(
- cast<Argument>(*I)->getType());
- pointerSize = TD.getABITypeSize(PT->getElementType());
+ if (TD) {
+ if (AllocaInst* A = dyn_cast<AllocaInst>(*I)) {
+ if (ConstantInt* C = dyn_cast<ConstantInt>(A->getArraySize()))
+ pointerSize = C->getZExtValue() *
+ TD->getTypeAllocSize(A->getAllocatedType());
+ } else {
+ const PointerType* PT = cast<PointerType>(
+ cast<Argument>(*I)->getType());
+ pointerSize = TD->getTypeAllocSize(PT->getElementType());
+ }
}
// See if the call site touches it
bool DSE::RemoveUndeadPointers(Value* killPointer, uint64_t killPointerSize,
BasicBlock::iterator &BBI,
SmallPtrSet<Value*, 64>& deadPointers) {
- TargetData &TD = getAnalysis<TargetData>();
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
// If the kill pointer can be easily reduced to an alloca,
E = deadPointers.end(); I != E; ++I) {
// Get size information for the alloca.
unsigned pointerSize = ~0U;
- if (AllocaInst* A = dyn_cast<AllocaInst>(*I)) {
- if (ConstantInt* C = dyn_cast<ConstantInt>(A->getArraySize()))
- pointerSize = C->getZExtValue() *
- TD.getABITypeSize(A->getAllocatedType());
- } else {
- const PointerType* PT = cast<PointerType>(cast<Argument>(*I)->getType());
- pointerSize = TD.getABITypeSize(PT->getElementType());
+ if (TD) {
+ if (AllocaInst* A = dyn_cast<AllocaInst>(*I)) {
+ if (ConstantInt* C = dyn_cast<ConstantInt>(A->getArraySize()))
+ pointerSize = C->getZExtValue() *
+ TD->getTypeAllocSize(A->getAllocatedType());
+ } else {
+ const PointerType* PT = cast<PointerType>(cast<Argument>(*I)->getType());
+ pointerSize = TD->getTypeAllocSize(PT->getElementType());
+ }
}
// See if this pointer could alias it
projects / oota-llvm.git / blobdiff