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Diffstat (limited to 'contrib/llvm/lib/Transforms/Utils/Mem2Reg.cpp')
-rw-r--r-- | contrib/llvm/lib/Transforms/Utils/Mem2Reg.cpp | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Transforms/Utils/Mem2Reg.cpp b/contrib/llvm/lib/Transforms/Utils/Mem2Reg.cpp new file mode 100644 index 0000000..99203b6 --- /dev/null +++ b/contrib/llvm/lib/Transforms/Utils/Mem2Reg.cpp @@ -0,0 +1,90 @@ +//===- Mem2Reg.cpp - The -mem2reg pass, a wrapper around the Utils lib ----===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This pass is a simple pass wrapper around the PromoteMemToReg function call +// exposed by the Utils library. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "mem2reg" +#include "llvm/Transforms/Scalar.h" +#include "llvm/Transforms/Utils/PromoteMemToReg.h" +#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h" +#include "llvm/Analysis/Dominators.h" +#include "llvm/Instructions.h" +#include "llvm/Function.h" +#include "llvm/ADT/Statistic.h" +using namespace llvm; + +STATISTIC(NumPromoted, "Number of alloca's promoted"); + +namespace { + struct PromotePass : public FunctionPass { + static char ID; // Pass identification, replacement for typeid + PromotePass() : FunctionPass(&ID) {} + + // runOnFunction - To run this pass, first we calculate the alloca + // instructions that are safe for promotion, then we promote each one. + // + virtual bool runOnFunction(Function &F); + + // getAnalysisUsage - We need dominance frontiers + // + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.addRequired<DominatorTree>(); + AU.addRequired<DominanceFrontier>(); + AU.setPreservesCFG(); + // This is a cluster of orthogonal Transforms + AU.addPreserved<UnifyFunctionExitNodes>(); + AU.addPreservedID(LowerSwitchID); + AU.addPreservedID(LowerInvokePassID); + } + }; +} // end of anonymous namespace + +char PromotePass::ID = 0; +static RegisterPass<PromotePass> X("mem2reg", "Promote Memory to Register"); + +bool PromotePass::runOnFunction(Function &F) { + std::vector<AllocaInst*> Allocas; + + BasicBlock &BB = F.getEntryBlock(); // Get the entry node for the function + + bool Changed = false; + + DominatorTree &DT = getAnalysis<DominatorTree>(); + DominanceFrontier &DF = getAnalysis<DominanceFrontier>(); + + while (1) { + Allocas.clear(); + + // Find allocas that are safe to promote, by looking at all instructions in + // the entry node + for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I) + if (AllocaInst *AI = dyn_cast<AllocaInst>(I)) // Is it an alloca? + if (isAllocaPromotable(AI)) + Allocas.push_back(AI); + + if (Allocas.empty()) break; + + PromoteMemToReg(Allocas, DT, DF); + NumPromoted += Allocas.size(); + Changed = true; + } + + return Changed; +} + +// Publically exposed interface to pass... +const PassInfo *const llvm::PromoteMemoryToRegisterID = &X; +// createPromoteMemoryToRegister - Provide an entry point to create this pass. +// +FunctionPass *llvm::createPromoteMemoryToRegisterPass() { + return new PromotePass(); +} |