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Fix several cache coherence bugs in MemDep/GVN that were found. Also add some (disabled) debugging code

Browse Source 
to make such problems easier to diagnose in the future, written by Duncan Sands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44695 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2007-12-08 01:37:09 +00:00
parent 1713d8bcff
commit 5fc4abac3d
3 changed files with 75 additions and 25 deletions
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2
include/llvm/Analysis/MemoryDependenceAnalysis.h
View File

@ -52,6 +52,8 @@ class MemoryDependenceAnalysis : public FunctionPass {
reverseDepMapType reverseDepNonLocal;
public:
void ping(Instruction* D);
// Special marker indicating that the query has no dependency
// in the specified block.
static Instruction* const NonLocal;

90
lib/Analysis/MemoryDependenceAnalysis.cpp
View File

@ -40,6 +40,31 @@ Instruction* const MemoryDependenceAnalysis::Dirty = (Instruction*)-5;
static RegisterPass<MemoryDependenceAnalysis> X("memdep",
"Memory Dependence Analysis");
void MemoryDependenceAnalysis::ping(Instruction *D) {
for (depMapType::iterator I = depGraphLocal.begin(), E = depGraphLocal.end();
I != E; ++I) {
assert(I->first != D);
assert(I->second.first != D);
}
for (nonLocalDepMapType::iterator I = depGraphNonLocal.begin(), E = depGraphNonLocal.end();
I != E; ++I) {
assert(I->first != D);
}
for (reverseDepMapType::iterator I = reverseDep.begin(), E = reverseDep.end();
I != E; ++I)
for (SmallPtrSet<Instruction*, 4>::iterator II = I->second.begin(), EE = I->second.end();
II != EE; ++II)
assert(*II != D);
for (reverseDepMapType::iterator I = reverseDepNonLocal.begin(), E = reverseDepNonLocal.end();
I != E; ++I)
for (SmallPtrSet<Instruction*, 4>::iterator II = I->second.begin(), EE = I->second.end();
II != EE; ++II)
assert(*II != D);
}
/// getAnalysisUsage - Does not modify anything. It uses Alias Analysis.
///
void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
@ -54,6 +79,8 @@ Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C,
Instruction* start,
BasicBlock* block) {
std::pair<Instruction*, bool>& cachedResult =
depGraphLocal[C.getInstruction()];
AliasAnalysis& AA = getAnalysis<AliasAnalysis>();
TargetData& TD = getAnalysis<TargetData>();
BasicBlock::iterator blockBegin = C.getInstruction()->getParent()->begin();
@ -100,8 +127,8 @@ Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C,
if (result != AliasAnalysis::DoesNotAccessMemory &&
result != AliasAnalysis::OnlyReadsMemory) {
if (!start && !block) {
depGraphLocal.insert(std::make_pair(C.getInstruction(),
std::make_pair(QI, true)));
cachedResult.first = QI;
cachedResult.second = true;
reverseDep[QI].insert(C.getInstruction());
}
return QI;
@ -113,8 +140,8 @@ Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C,
if (AA.getModRefInfo(C, pointer, pointerSize) != AliasAnalysis::NoModRef) {
if (!start && !block) {
depGraphLocal.insert(std::make_pair(C.getInstruction(),
std::make_pair(QI, true)));
cachedResult.first = QI;
cachedResult.second = true;
reverseDep[QI].insert(C.getInstruction());
}
return QI;
@ -122,8 +149,8 @@ Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C,
}
// No dependence found
depGraphLocal.insert(std::make_pair(C.getInstruction(),
std::make_pair(NonLocal, true)));
cachedResult.first = NonLocal;
cachedResult.second = true;
reverseDep[NonLocal].insert(C.getInstruction());
return NonLocal;
}
@ -265,13 +292,15 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query,
BasicBlock::iterator QI = query;
// Check for a cached result
std::pair<Instruction*, bool> cachedResult = depGraphLocal[query];
std::pair<Instruction*, bool>& cachedResult = depGraphLocal[query];
// If we have a _confirmed_ cached entry, return it
if (cachedResult.second)
return cachedResult.first;
else if (cachedResult.first && cachedResult.first != NonLocal)
// If we have an unconfirmed cached entry, we can start our search from there
QI = cachedResult.first;
if (!block && !start) {
if (cachedResult.second)
return cachedResult.first;
else if (cachedResult.first && cachedResult.first != NonLocal)
// If we have an unconfirmed cached entry, we can start our search from there
QI = cachedResult.first;
}
if (start)
QI = start;
@ -322,7 +351,8 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query,
// All volatile loads/stores depend on each other
if (queryIsVolatile && S->isVolatile()) {
if (!start && !block) {
depGraphLocal.insert(std::make_pair(query, std::make_pair(S, true)));
cachedResult.first = S;
cachedResult.second = true;
reverseDep[S].insert(query);
}
@ -335,7 +365,8 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query,
// All volatile loads/stores depend on each other
if (queryIsVolatile && L->isVolatile()) {
if (!start && !block) {
depGraphLocal.insert(std::make_pair(query, std::make_pair(L, true)));
cachedResult.first = L;
cachedResult.second = true;
reverseDep[L].insert(query);
}
@ -370,8 +401,8 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query,
continue;
if (!start && !block) {
depGraphLocal.insert(std::make_pair(query,
std::make_pair(QI, true)));
cachedResult.first = QI;
cachedResult.second = true;
reverseDep[QI].insert(query);
}
@ -393,8 +424,8 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query,
continue;
if (!start && !block) {
depGraphLocal.insert(std::make_pair(query,
std::make_pair(QI, true)));
cachedResult.first = QI;
cachedResult.second = true;
reverseDep[QI].insert(query);
}
@ -405,8 +436,8 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query,
// If we found nothing, return the non-local flag
if (!start && !block) {
depGraphLocal.insert(std::make_pair(query,
std::make_pair(NonLocal, true)));
cachedResult.first = NonLocal;
cachedResult.second = true;
reverseDep[NonLocal].insert(query);
}
@ -420,6 +451,14 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction* rem) {
// Figure out the new dep for things that currently depend on rem
Instruction* newDep = NonLocal;
reverseDep[depGraphLocal[rem].first].erase(rem);
for (DenseMap<BasicBlock*, Value*>::iterator DI =
depGraphNonLocal[rem].begin(), DE = depGraphNonLocal[rem].end();
DI != DE; ++DI)
if (DI->second != None)
reverseDepNonLocal[DI->second].erase(rem);
depMapType::iterator depGraphEntry = depGraphLocal.find(rem);
if (depGraphEntry != depGraphLocal.end()) {
@ -449,10 +488,11 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction* rem) {
// Mark it as unconfirmed as long as it is not the non-local flag
depGraphLocal[*I] = std::make_pair(newDep, !newDep);
}
reverseDep.erase(rem);
}
depGraphLocal.erase(rem);
reverseDep.erase(rem);
if (reverseDepNonLocal.count(rem)) {
SmallPtrSet<Instruction*, 4>& set = reverseDepNonLocal[rem];
for (SmallPtrSet<Instruction*, 4>::iterator I = set.begin(), E = set.end();
@ -463,8 +503,12 @@ void MemoryDependenceAnalysis::removeInstruction(Instruction* rem) {
if (DI->second == rem)
DI->second = Dirty;
reverseDepNonLocal.erase(rem);
}
reverseDepNonLocal.erase(rem);
nonLocalDepMapType::iterator I = depGraphNonLocal.find(rem);
if (I != depGraphNonLocal.end())
depGraphNonLocal.erase(I);
getAnalysis<AliasAnalysis>().deleteValue(rem);
}

8
lib/Transforms/Scalar/GVN.cpp
View File

@ -1062,6 +1062,10 @@ bool GVN::processInstruction(Instruction* I,
}
}
// Remove it!
MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
MD.removeInstruction(I);
VN.erase(I);
I->replaceAllUsesWith(repl);
toErase.push_back(I);
@ -1128,11 +1132,11 @@ bool GVN::iterateOnFunction(Function &F) {
// Avoid iterator invalidation
++BI;
for (SmallVector<Instruction*, 4>::iterator I = toErase.begin(),
E = toErase.end(); I != E; ++I)
(*I)->eraseFromParent();
toErase.clear();
}
}