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Split getDependency into getDependency and getDependencyFrom, the

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former does caching, the later doesn't.  This dramatically simplifies
the logic in getDependency and getDependencyFrom.

llvm-svn: 60234
This commit is contained in:
Chris Lattner 2008-11-29 03:47:00 +00:00
parent ed46ffe5c5
commit 96c72eef4b
4 changed files with 94 additions and 131 deletions
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17
include/llvm/Analysis/MemoryDependenceAnalysis.h
View File

@ -14,6 +14,7 @@
#ifndef LLVM_ANALYSIS_MEMORY_DEPENDENCE_H
#define LLVM_ANALYSIS_MEMORY_DEPENDENCE_H
#include "llvm/BasicBlock.h"
#include "llvm/Pass.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallPtrSet.h"
@ -156,9 +157,15 @@ namespace llvm {
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
/// getDependency - Return the instruction on which a memory operation
/// depends, starting with start.
MemDepResult getDependency(Instruction *query, Instruction *start = 0,
BasicBlock *block = 0);
/// depends.
MemDepResult getDependency(Instruction *QueryInst);
/// getDependencyFrom - Return the instruction on which the memory operation
/// 'QueryInst' depends. This starts scanning from the instruction before
/// the position indicated by ScanIt.
MemDepResult getDependencyFrom(Instruction *QueryInst,
BasicBlock::iterator ScanIt, BasicBlock *BB);
/// getNonLocalDependency - Fills the passed-in map with the non-local
/// dependencies of the queries. The map will contain NonLocal for
@ -199,8 +206,8 @@ namespace llvm {
/// in our internal data structures.
void verifyRemoved(Instruction *Inst) const;
MemDepResult getCallSiteDependency(CallSite C, Instruction* start,
BasicBlock* block);
MemDepResult getCallSiteDependency(CallSite C, BasicBlock::iterator ScanIt,
BasicBlock *BB);
void nonLocalHelper(Instruction* query, BasicBlock* block,
DenseMap<BasicBlock*, DepResultTy> &resp);
};

204
lib/Analysis/MemoryDependenceAnalysis.cpp
View File

@ -87,74 +87,49 @@ void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
/// getCallSiteDependency - Private helper for finding the local dependencies
/// of a call site.
MemDepResult MemoryDependenceAnalysis::
getCallSiteDependency(CallSite C, Instruction *start, BasicBlock *block) {
DepResultTy &cachedResult = LocalDeps[C.getInstruction()];
getCallSiteDependency(CallSite C, BasicBlock::iterator ScanIt,
BasicBlock *BB) {
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
TargetData &TD = getAnalysis<TargetData>();
BasicBlock::iterator blockBegin = C.getInstruction()->getParent()->begin();
BasicBlock::iterator QI = C.getInstruction();
// If the starting point was specified, use it
if (start) {
QI = start;
blockBegin = start->getParent()->begin();
// If the starting point wasn't specified, but the block was, use it
} else if (!start && block) {
QI = block->end();
blockBegin = block->begin();
}
// Walk backwards through the block, looking for dependencies
while (QI != blockBegin) {
--QI;
while (ScanIt != BB->begin()) {
Instruction *Inst = --ScanIt;
// If this inst is a memory op, get the pointer it accessed
Value* pointer = 0;
uint64_t pointerSize = 0;
if (StoreInst* S = dyn_cast<StoreInst>(QI)) {
if (StoreInst* S = dyn_cast<StoreInst>(Inst)) {
pointer = S->getPointerOperand();
pointerSize = TD.getTypeStoreSize(S->getOperand(0)->getType());
} else if (AllocationInst* AI = dyn_cast<AllocationInst>(QI)) {
} else if (AllocationInst* AI = dyn_cast<AllocationInst>(Inst)) {
pointer = AI;
if (ConstantInt* C = dyn_cast<ConstantInt>(AI->getArraySize()))
pointerSize = C->getZExtValue() *
TD.getABITypeSize(AI->getAllocatedType());
else
pointerSize = ~0UL;
} else if (VAArgInst* V = dyn_cast<VAArgInst>(QI)) {
} else if (VAArgInst* V = dyn_cast<VAArgInst>(Inst)) {
pointer = V->getOperand(0);
pointerSize = TD.getTypeStoreSize(V->getType());
} else if (FreeInst* F = dyn_cast<FreeInst>(QI)) {
} else if (FreeInst* F = dyn_cast<FreeInst>(Inst)) {
pointer = F->getPointerOperand();
// FreeInsts erase the entire structure
pointerSize = ~0UL;
} else if (CallSite::get(QI).getInstruction() != 0) {
AliasAnalysis::ModRefBehavior result =
AA.getModRefBehavior(CallSite::get(QI));
if (result != AliasAnalysis::DoesNotAccessMemory) {
if (!start && !block) {
cachedResult = DepResultTy(QI, Normal);
reverseDep[QI].insert(C.getInstruction());
}
return MemDepResult::get(QI);
} else {
continue;
}
} else if (CallSite::get(Inst).getInstruction() != 0) {
if (AA.getModRefBehavior(CallSite::get(Inst)) !=
AliasAnalysis::DoesNotAccessMemory)
return MemDepResult::get(Inst);
continue;
} else
continue;
if (AA.getModRefInfo(C, pointer, pointerSize) != AliasAnalysis::NoModRef) {
if (!start && !block) {
cachedResult = DepResultTy(QI, Normal);
reverseDep[QI].insert(C.getInstruction());
}
return MemDepResult::get(QI);
}
if (AA.getModRefInfo(C, pointer, pointerSize) != AliasAnalysis::NoModRef)
return MemDepResult::get(Inst);
}
// No dependence found
cachedResult = DepResultTy(0, NonLocal);
// No dependence found.
return MemDepResult::getNonLocal();
}
@ -193,7 +168,7 @@ void MemoryDependenceAnalysis::nonLocalHelper(Instruction* query,
if (BB != block) {
visited.insert(BB);
MemDepResult localDep = getDependency(query, 0, BB);
MemDepResult localDep = getDependencyFrom(query, BB->end(), BB);
if (!localDep.isNonLocal()) {
resp.insert(std::make_pair(BB, ConvFromResult(localDep)));
stack.pop_back();
@ -205,7 +180,7 @@ void MemoryDependenceAnalysis::nonLocalHelper(Instruction* query,
} else if (BB == block) {
visited.insert(BB);
MemDepResult localDep = getDependency(query, 0, BB);
MemDepResult localDep = getDependencyFrom(query, BB->end(), BB);
if (localDep.getInst() != query)
resp.insert(std::make_pair(BB, ConvFromResult(localDep)));
@ -262,7 +237,7 @@ void MemoryDependenceAnalysis::getNonLocalDependency(Instruction* query,
for (SmallVector<BasicBlock*, 4>::iterator I = dirtied.begin(),
E = dirtied.end(); I != E; ++I) {
MemDepResult localDep = getDependency(query, 0, *I);
MemDepResult localDep = getDependencyFrom(query, (*I)->end(), *I);
if (!localDep.isNonLocal())
cached[*I] = ConvFromResult(localDep);
else {
@ -303,127 +278,86 @@ void MemoryDependenceAnalysis::getNonLocalDependency(Instruction* query,
/// evaluate dependencies within the same basic block.
/// FIXME: ELIMINATE START/BLOCK and make the caching happen in a higher level
/// METHOD.
MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *query,
Instruction *start,
BasicBlock *block) {
// Start looking for dependencies with the queried inst
BasicBlock::iterator QI = query;
// Check for a cached result
// FIXME: why do this when Block or Start is specified??
DepResultTy &cachedResult = LocalDeps[query];
if (start)
QI = start;
else if (block)
QI = block->end();
else if (cachedResult.getInt() != Dirty) {
// If we have a _confirmed_ cached entry, return it.
return ConvToResult(cachedResult);
} else if (Instruction *Inst = cachedResult.getPointer()) {
// If we have an unconfirmed cached entry, we can start our search from it.
QI = Inst;
}
AliasAnalysis& AA = getAnalysis<AliasAnalysis>();
TargetData& TD = getAnalysis<TargetData>();
MemDepResult MemoryDependenceAnalysis::
getDependencyFrom(Instruction *QueryInst, BasicBlock::iterator ScanIt,
BasicBlock *BB) {
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
TargetData &TD = getAnalysis<TargetData>();
// Get the pointer value for which dependence will be determined
Value* dependee = 0;
uint64_t dependeeSize = 0;
bool queryIsVolatile = false;
if (StoreInst* S = dyn_cast<StoreInst>(query)) {
if (StoreInst* S = dyn_cast<StoreInst>(QueryInst)) {
dependee = S->getPointerOperand();
dependeeSize = TD.getTypeStoreSize(S->getOperand(0)->getType());
queryIsVolatile = S->isVolatile();
} else if (LoadInst* L = dyn_cast<LoadInst>(query)) {
} else if (LoadInst* L = dyn_cast<LoadInst>(QueryInst)) {
dependee = L->getPointerOperand();
dependeeSize = TD.getTypeStoreSize(L->getType());
queryIsVolatile = L->isVolatile();
} else if (VAArgInst* V = dyn_cast<VAArgInst>(query)) {
} else if (VAArgInst* V = dyn_cast<VAArgInst>(QueryInst)) {
dependee = V->getOperand(0);
dependeeSize = TD.getTypeStoreSize(V->getType());
} else if (FreeInst* F = dyn_cast<FreeInst>(query)) {
} else if (FreeInst* F = dyn_cast<FreeInst>(QueryInst)) {
dependee = F->getPointerOperand();
// FreeInsts erase the entire structure, not just a field
dependeeSize = ~0UL;
} else if (CallSite::get(query).getInstruction() != 0)
return getCallSiteDependency(CallSite::get(query), start, block);
else if (isa<AllocationInst>(query))
return MemDepResult::getNone();
} else if (CallSite::get(QueryInst).getInstruction() != 0)
return getCallSiteDependency(CallSite::get(QueryInst), ScanIt, BB);
else
return MemDepResult::getNone();
BasicBlock::iterator blockBegin = block ? block->begin()
: query->getParent()->begin();
// Walk backwards through the basic block, looking for dependencies
while (QI != blockBegin) {
--QI;
while (ScanIt != BB->begin()) {
Instruction *Inst = --ScanIt;
// If this inst is a memory op, get the pointer it accessed
Value* pointer = 0;
uint64_t pointerSize = 0;
if (StoreInst* S = dyn_cast<StoreInst>(QI)) {
if (StoreInst* S = dyn_cast<StoreInst>(Inst)) {
// All volatile loads/stores depend on each other
if (queryIsVolatile && S->isVolatile()) {
if (!start && !block) {
cachedResult = DepResultTy(S, Normal);
reverseDep[S].insert(query);
}
if (queryIsVolatile && S->isVolatile())
return MemDepResult::get(S);
}
pointer = S->getPointerOperand();
pointerSize = TD.getTypeStoreSize(S->getOperand(0)->getType());
} else if (LoadInst* L = dyn_cast<LoadInst>(QI)) {
} else if (LoadInst* L = dyn_cast<LoadInst>(Inst)) {
// All volatile loads/stores depend on each other
if (queryIsVolatile && L->isVolatile()) {
if (!start && !block) {
cachedResult = DepResultTy(L, Normal);
reverseDep[L].insert(query);
}
if (queryIsVolatile && L->isVolatile())
return MemDepResult::get(L);
}
pointer = L->getPointerOperand();
pointerSize = TD.getTypeStoreSize(L->getType());
} else if (AllocationInst* AI = dyn_cast<AllocationInst>(QI)) {
} else if (AllocationInst* AI = dyn_cast<AllocationInst>(Inst)) {
pointer = AI;
if (ConstantInt* C = dyn_cast<ConstantInt>(AI->getArraySize()))
pointerSize = C->getZExtValue() *
TD.getABITypeSize(AI->getAllocatedType());
else
pointerSize = ~0UL;
} else if (VAArgInst* V = dyn_cast<VAArgInst>(QI)) {
} else if (VAArgInst* V = dyn_cast<VAArgInst>(Inst)) {
pointer = V->getOperand(0);
pointerSize = TD.getTypeStoreSize(V->getType());
} else if (FreeInst* F = dyn_cast<FreeInst>(QI)) {
} else if (FreeInst* F = dyn_cast<FreeInst>(Inst)) {
pointer = F->getPointerOperand();
// FreeInsts erase the entire structure
pointerSize = ~0UL;
} else if (CallSite::get(QI).getInstruction() != 0) {
} else if (isa<CallInst>(Inst) || isa<InvokeInst>(Inst)) {
// Call insts need special handling. Check if they can modify our pointer
AliasAnalysis::ModRefResult MR = AA.getModRefInfo(CallSite::get(QI),
AliasAnalysis::ModRefResult MR = AA.getModRefInfo(CallSite::get(Inst),
dependee, dependeeSize);
if (MR != AliasAnalysis::NoModRef) {
// Loads don't depend on read-only calls
if (isa<LoadInst>(query) && MR == AliasAnalysis::Ref)
if (isa<LoadInst>(QueryInst) && MR == AliasAnalysis::Ref)
continue;
if (!start && !block) {
cachedResult = DepResultTy(QI, Normal);
reverseDep[QI].insert(query);
}
return MemDepResult::get(QI);
} else {
continue;
return MemDepResult::get(Inst);
}
continue;
}
// If we found a pointer, check if it could be the same as our pointer
@ -433,27 +367,49 @@ MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *query,
if (R != AliasAnalysis::NoAlias) {
// May-alias loads don't depend on each other
if (isa<LoadInst>(query) && isa<LoadInst>(QI) &&
if (isa<LoadInst>(QueryInst) && isa<LoadInst>(Inst) &&
R == AliasAnalysis::MayAlias)
continue;
if (!start && !block) {
cachedResult = DepResultTy(QI, Normal);
reverseDep[QI].insert(query);
}
return MemDepResult::get(QI);
return MemDepResult::get(Inst);
}
}
}
// If we found nothing, return the non-local flag
if (!start && !block)
cachedResult = DepResultTy(0, NonLocal);
// If we found nothing, return the non-local flag.
return MemDepResult::getNonLocal();
}
/// getDependency - Return the instruction on which a memory operation
/// depends.
MemDepResult MemoryDependenceAnalysis::getDependency(Instruction *QueryInst) {
Instruction *ScanPos = QueryInst;
// Check for a cached result
DepResultTy &LocalCache = LocalDeps[QueryInst];
// If the cached entry is non-dirty, just return it.
if (LocalCache.getInt() != Dirty)
return ConvToResult(LocalCache);
// Otherwise, if we have a dirty entry, we know we can start the scan at that
// instruction, which may save us some work.
if (Instruction *Inst = LocalCache.getPointer())
ScanPos = Inst;
// Do the scan.
MemDepResult Res =
getDependencyFrom(QueryInst, ScanPos, QueryInst->getParent());
// Remember the result!
// FIXME: Don't convert back and forth! Make a shared helper function.
LocalCache = ConvFromResult(Res);
if (Instruction *I = Res.getInst())
reverseDep[I].insert(QueryInst);
return Res;
}
/// dropInstruction - Remove an instruction from the analysis, making
/// absolutely conservative assumptions when updating the cache. This is
/// useful, for example when an instruction is changed rather than removed.

2
lib/Transforms/Scalar/DeadStoreElimination.cpp
View File

@ -116,7 +116,7 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) {
if (DepStore != last ||
TD.getTypeStoreSize(last->getOperand(0)->getType()) >
TD.getTypeStoreSize(Inst->getOperand(0)->getType())) {
dep = MD.getDependency(Inst, DepStore);
dep = MD.getDependencyFrom(Inst, DepStore, DepStore->getParent());
continue;
}

2
lib/Transforms/Scalar/GVN.cpp
View File

@ -990,7 +990,7 @@ bool GVN::processLoad(LoadInst *L, DenseMap<Value*, LoadInst*> &lastLoad,
break;
} else {
dep = MD.getDependency(L, DepInst);
dep = MD.getDependencyFrom(L, DepInst, DepInst->getParent());
}
}