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author | Owen Anderson <resistor@mac.com> | 2007-07-16 21:52:50 +0000 |
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committer | Owen Anderson <resistor@mac.com> | 2007-07-16 21:52:50 +0000 |
commit | faac518ce0ae88a19f26b9aa9d34f6bf86ecb8c4 (patch) | |
tree | ec921ad0c2c4ec94bd031b3765b544bdd4b54ce4 /lib/Analysis/MemoryDependenceAnalysis.cpp | |
parent | 1629a1fa87f8c32d6d33173d6d6e77dc4ed1ca4f (diff) | |
download | external_llvm-faac518ce0ae88a19f26b9aa9d34f6bf86ecb8c4.zip external_llvm-faac518ce0ae88a19f26b9aa9d34f6bf86ecb8c4.tar.gz external_llvm-faac518ce0ae88a19f26b9aa9d34f6bf86ecb8c4.tar.bz2 |
Add support for walking up memory def chains, which enables finding many more
dead stores on 400.perlbench.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@39929 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/MemoryDependenceAnalysis.cpp')
-rw-r--r-- | lib/Analysis/MemoryDependenceAnalysis.cpp | 55 |
1 files changed, 37 insertions, 18 deletions
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp index fa43954..498e54c 100644 --- a/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -41,7 +41,8 @@ void MemoryDependenceAnalysis::getAnalysisUsage(AnalysisUsage &AU) const { } // Find the dependency of a CallSite -Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C, bool local) { +Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C, Instruction* start, + bool local) { assert(local && "Non-local memory dependence analysis not yet implemented"); AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); @@ -103,6 +104,7 @@ Instruction* MemoryDependenceAnalysis::getCallSiteDependency(CallSite C, bool lo /// depends. The local paramter indicates if the query should only /// evaluate dependencies within the same basic block. Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, + Instruction* start, bool local) { if (!local) assert(0 && "Non-local memory dependence is not yet supported."); @@ -119,6 +121,9 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, // If we have an unconfirmed cached entry, we can start our search from there QI = cachedResult.first; + if (start) + QI = start; + AliasAnalysis& AA = getAnalysis<AliasAnalysis>(); TargetData& TD = getAnalysis<TargetData>(); @@ -126,24 +131,24 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, Value* dependee = 0; uint64_t dependeeSize = 0; bool queryIsVolatile = false; - if (StoreInst* S = dyn_cast<StoreInst>(QI)) { + if (StoreInst* S = dyn_cast<StoreInst>(query)) { dependee = S->getPointerOperand(); dependeeSize = TD.getTypeSize(S->getOperand(0)->getType()); queryIsVolatile = S->isVolatile(); - } else if (LoadInst* L = dyn_cast<LoadInst>(QI)) { + } else if (LoadInst* L = dyn_cast<LoadInst>(query)) { dependee = L->getPointerOperand(); dependeeSize = TD.getTypeSize(L->getType()); queryIsVolatile = L->isVolatile(); - } else if (VAArgInst* V = dyn_cast<VAArgInst>(QI)) { + } else if (VAArgInst* V = dyn_cast<VAArgInst>(query)) { dependee = V->getOperand(0); dependeeSize = TD.getTypeSize(V->getType()); - } else if (FreeInst* F = dyn_cast<FreeInst>(QI)) { + } else if (FreeInst* F = dyn_cast<FreeInst>(query)) { dependee = F->getPointerOperand(); // FreeInsts erase the entire structure, not just a field dependeeSize = ~0UL; - } else if (CallSite::get(QI).getInstruction() != 0) - return getCallSiteDependency(CallSite::get(QI)); + } else if (CallSite::get(query).getInstruction() != 0) + return getCallSiteDependency(CallSite::get(query), start); else if (isa<AllocationInst>(query)) return None; else @@ -160,8 +165,11 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, if (StoreInst* S = dyn_cast<StoreInst>(QI)) { // All volatile loads/stores depend on each other if (queryIsVolatile && S->isVolatile()) { - depGraphLocal.insert(std::make_pair(query, std::make_pair(S, true))); - reverseDep.insert(std::make_pair(S, query)); + if (!start) { + depGraphLocal.insert(std::make_pair(query, std::make_pair(S, true))); + reverseDep.insert(std::make_pair(S, query)); + } + return S; } @@ -170,8 +178,11 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, } else if (LoadInst* L = dyn_cast<LoadInst>(QI)) { // All volatile loads/stores depend on each other if (queryIsVolatile && L->isVolatile()) { - depGraphLocal.insert(std::make_pair(query, std::make_pair(L, true))); - reverseDep.insert(std::make_pair(L, query)); + if (!start) { + depGraphLocal.insert(std::make_pair(query, std::make_pair(L, true))); + reverseDep.insert(std::make_pair(L, query)); + } + return L; } @@ -195,8 +206,11 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, // Call insts need special handling. Check is they can modify our pointer if (AA.getModRefInfo(CallSite::get(QI), dependee, dependeeSize) != AliasAnalysis::NoModRef) { - depGraphLocal.insert(std::make_pair(query, std::make_pair(QI, true))); - reverseDep.insert(std::make_pair(QI, query)); + if (!start) { + depGraphLocal.insert(std::make_pair(query, std::make_pair(QI, true))); + reverseDep.insert(std::make_pair(QI, query)); + } + return QI; } else { continue; @@ -209,17 +223,22 @@ Instruction* MemoryDependenceAnalysis::getDependency(Instruction* query, dependee, dependeeSize); if (R != AliasAnalysis::NoAlias) { - depGraphLocal.insert(std::make_pair(query, std::make_pair(QI, true))); - reverseDep.insert(std::make_pair(QI, query)); + if (!start) { + depGraphLocal.insert(std::make_pair(query, std::make_pair(QI, true))); + reverseDep.insert(std::make_pair(QI, query)); + } + return QI; } } } // If we found nothing, return the non-local flag - depGraphLocal.insert(std::make_pair(query, - std::make_pair(NonLocal, true))); - reverseDep.insert(std::make_pair(NonLocal, query)); + if (!start) { + depGraphLocal.insert(std::make_pair(query, + std::make_pair(NonLocal, true))); + reverseDep.insert(std::make_pair(NonLocal, query)); + } return NonLocal; } |