diff --git a/include/llvm/Transforms/Utils/BasicBlockUtils.h b/include/llvm/Transforms/Utils/BasicBlockUtils.h index 2e8c335b372..6de8b850704 100644 --- a/include/llvm/Transforms/Utils/BasicBlockUtils.h +++ b/include/llvm/Transforms/Utils/BasicBlockUtils.h @@ -35,7 +35,7 @@ void DeleteDeadBlock(BasicBlock *BB); /// any single-entry PHI nodes in it, fold them away. This handles the case /// when all entries to the PHI nodes in a block are guaranteed equal, such as /// when the block has exactly one predecessor. -void FoldSingleEntryPHINodes(BasicBlock *BB); +void FoldSingleEntryPHINodes(BasicBlock *BB, Pass *P = 0); /// DeleteDeadPHIs - Examine each PHI in the given block and delete it if it /// is dead. Also recursively delete any operands that become dead as @@ -46,7 +46,7 @@ bool DeleteDeadPHIs(BasicBlock *BB); /// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor, /// if possible. The return value indicates success or failure. -bool MergeBlockIntoPredecessor(BasicBlock* BB, Pass* P = 0); +bool MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P = 0); // ReplaceInstWithValue - Replace all uses of an instruction (specified by BI) // with a value, then remove and delete the original instruction. diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp index b7fc9c30e06..a4bd7c1eb42 100644 --- a/lib/Transforms/Scalar/GVN.cpp +++ b/lib/Transforms/Scalar/GVN.cpp @@ -1741,8 +1741,8 @@ bool GVN::runOnFunction(Function& F) { // Merge unconditional branches, allowing PRE to catch more // optimization opportunities. for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ) { - BasicBlock *BB = FI; - ++FI; + BasicBlock *BB = FI++; + bool removedBlock = MergeBlockIntoPredecessor(BB, this); if (removedBlock) ++NumGVNBlocks; diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp index 3daa45cec36..40d33d15afc 100644 --- a/lib/Transforms/Utils/BasicBlockUtils.cpp +++ b/lib/Transforms/Utils/BasicBlockUtils.cpp @@ -19,8 +19,9 @@ #include "llvm/Constant.h" #include "llvm/Type.h" #include "llvm/Analysis/AliasAnalysis.h" -#include "llvm/Analysis/LoopInfo.h" #include "llvm/Analysis/DominanceFrontier.h" +#include "llvm/Analysis/LoopInfo.h" +#include "llvm/Analysis/MemoryDependenceAnalysis.h" #include "llvm/Target/TargetData.h" #include "llvm/Transforms/Utils/Local.h" #include "llvm/Transforms/Scalar.h" @@ -63,12 +64,27 @@ void llvm::DeleteDeadBlock(BasicBlock *BB) { /// any single-entry PHI nodes in it, fold them away. This handles the case /// when all entries to the PHI nodes in a block are guaranteed equal, such as /// when the block has exactly one predecessor. -void llvm::FoldSingleEntryPHINodes(BasicBlock *BB) { +void llvm::FoldSingleEntryPHINodes(BasicBlock *BB, Pass *P) { + if (!isa(BB->begin())) return; + + AliasAnalysis *AA = 0; + MemoryDependenceAnalysis *MemDep = 0; + if (P) { + AA = P->getAnalysisIfAvailable(); + MemDep = P->getAnalysisIfAvailable(); + } + while (PHINode *PN = dyn_cast(BB->begin())) { if (PN->getIncomingValue(0) != PN) PN->replaceAllUsesWith(PN->getIncomingValue(0)); else PN->replaceAllUsesWith(UndefValue::get(PN->getType())); + + if (MemDep) + MemDep->removeInstruction(PN); // Memdep updates AA itself. + else if (AA && isa(PN->getType())) + AA->deleteValue(PN); + PN->eraseFromParent(); } } @@ -132,7 +148,7 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) { // Begin by getting rid of unneeded PHIs. if (isa(BB->front())) - FoldSingleEntryPHINodes(BB); + FoldSingleEntryPHINodes(BB, P); // Delete the unconditional branch from the predecessor... PredBB->getInstList().pop_back();