diff --git a/llvm/lib/Transforms/Scalar/RedundantLoadElimination.cpp b/llvm/lib/Transforms/Scalar/RedundantLoadElimination.cpp deleted file mode 100644 index 3b719df4f6e3..000000000000 --- a/llvm/lib/Transforms/Scalar/RedundantLoadElimination.cpp +++ /dev/null @@ -1,135 +0,0 @@ -//===- FastDLE.cpp - Fast Dead Load Elimination ---------------------------===// -// -// The LLVM Compiler Infrastructure -// -// This file was developed by Owen Anderson and is distributed under -// the University of Illinois Open Source License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements a trivial dead load elimination that only considers -// basic-block local redundant load. -// -// FIXME: This should eventually be extended to be a post-dominator tree -// traversal. Doing so would be pretty trivial. -// -//===----------------------------------------------------------------------===// - -#define DEBUG_TYPE "rle" -#include "llvm/Transforms/Scalar.h" -#include "llvm/Function.h" -#include "llvm/Instructions.h" -#include "llvm/Pass.h" -#include "llvm/ADT/SmallPtrSet.h" -#include "llvm/ADT/Statistic.h" -#include "llvm/Analysis/MemoryDependenceAnalysis.h" -#include "llvm/Transforms/Utils/Local.h" -#include "llvm/Support/Compiler.h" -using namespace llvm; - -STATISTIC(NumFastLoads, "Number of loads deleted"); - -namespace { - struct VISIBILITY_HIDDEN RLE : public FunctionPass { - static char ID; // Pass identification, replacement for typeid - RLE() : FunctionPass((intptr_t)&ID) {} - - virtual bool runOnFunction(Function &F) { - bool Changed = false; - for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) - Changed |= runOnBasicBlock(*I); - return Changed; - } - - bool runOnBasicBlock(BasicBlock &BB); - - // getAnalysisUsage - We require post dominance frontiers (aka Control - // Dependence Graph) - virtual void getAnalysisUsage(AnalysisUsage &AU) const { - AU.setPreservesCFG(); - AU.addRequired(); - AU.addPreserved(); - } - }; - char RLE::ID = 0; - RegisterPass X("rle", "Redundant Load Elimination"); -} - -FunctionPass *llvm::createRedundantLoadEliminationPass() { return new RLE(); } - -bool RLE::runOnBasicBlock(BasicBlock &BB) { - MemoryDependenceAnalysis& MD = getAnalysis(); - - // Record the last-seen load from this pointer - DenseMap lastLoad; - - bool MadeChange = false; - - // Do a top-down walk on the BB - for (BasicBlock::iterator BBI = BB.begin(), BBE = BB.end(); - BBI != BBE; ++BBI) { - // If we find a store or a free... - if (LoadInst* L = dyn_cast(BBI)) { - // We can't delete volatile loads - if (L->isVolatile()) { - lastLoad[L->getPointerOperand()] = L; - continue; - } - - Value* pointer = L->getPointerOperand(); - LoadInst*& last = lastLoad[pointer]; - - // ... to a pointer that has been loaded from before... - Instruction* dep = MD.getDependency(BBI); - bool deletedLoad = false; - - while (dep != MemoryDependenceAnalysis::None && - dep != MemoryDependenceAnalysis::NonLocal && - (isa(dep) || isa(dep))) { - // ... that depends on a store ... - if (StoreInst* S = dyn_cast(dep)) { - if (S->getPointerOperand() == pointer) { - // Remove it! - MD.removeInstruction(BBI); - - BBI--; - L->replaceAllUsesWith(S->getOperand(0)); - L->eraseFromParent(); - NumFastLoads++; - deletedLoad = true; - MadeChange = true; - } - - // Whether we removed it or not, we can't - // go any further - break; - } else if (!last) { - // If we don't depend on a store, and we haven't - // been loaded before, bail. - break; - } else if (dep == last) { - // Remove it! - MD.removeInstruction(BBI); - - BBI--; - L->replaceAllUsesWith(last); - L->eraseFromParent(); - deletedLoad = true; - NumFastLoads++; - MadeChange = true; - - break; - } else { - dep = MD.getDependency(BBI, dep); - } - } - - if (!deletedLoad) - last = L; - } - } - - return MadeChange; -} - -