diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/GVN.cpp | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index c966311c9e6..9a03c21593c 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -1593,6 +1593,11 @@ bool GVN::processInstruction(Instruction *I, ValueNumberedSet &currAvail, if (StoreInst *SI = dyn_cast<StoreInst>(I)) return processStore(SI, toErase); + // Allocations are always uniquely numbered, so we can save time and memory + // by fast failing them. + if (isa<AllocationInst>(I)) + return false; + if (MemCpyInst* M = dyn_cast<MemCpyInst>(I)) { MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>(); @@ -1692,6 +1697,7 @@ bool GVN::iterateOnFunction(Function &F) { SmallVector<Instruction*, 8> toErase; DenseMap<Value*, LoadInst*> lastSeenLoad; + DenseMap<DomTreeNode*, size_t> numChildrenVisited; // Top-down walk of the dominator tree for (df_iterator<DomTreeNode*> DI = df_begin(DT.getRootNode()), @@ -1704,8 +1710,16 @@ bool GVN::iterateOnFunction(Function &F) { BasicBlock* BB = DI->getBlock(); // A block inherits AVAIL_OUT from its dominator - if (DI->getIDom() != 0) + if (DI->getIDom() != 0) { currAvail = availableOut[DI->getIDom()->getBlock()]; + + numChildrenVisited[DI->getIDom()]++; + + if (numChildrenVisited[DI->getIDom()] == DI->getIDom()->getNumChildren()) { + availableOut.erase(DI->getIDom()->getBlock()); + numChildrenVisited.erase(DI->getIDom()); + } + } for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) { |
