diff options
Diffstat (limited to 'lib/Transforms/Scalar/ADCE.cpp')
-rw-r--r-- | lib/Transforms/Scalar/ADCE.cpp | 70 |
1 files changed, 34 insertions, 36 deletions
diff --git a/lib/Transforms/Scalar/ADCE.cpp b/lib/Transforms/Scalar/ADCE.cpp index 3d91984..d6fc916 100644 --- a/lib/Transforms/Scalar/ADCE.cpp +++ b/lib/Transforms/Scalar/ADCE.cpp @@ -32,19 +32,18 @@ using namespace llvm; STATISTIC(NumRemoved, "Number of instructions removed"); namespace { - struct ADCE : public FunctionPass { - static char ID; // Pass identification, replacement for typeid - ADCE() : FunctionPass(ID) { - initializeADCEPass(*PassRegistry::getPassRegistry()); - } - - bool runOnFunction(Function& F) override; +struct ADCE : public FunctionPass { + static char ID; // Pass identification, replacement for typeid + ADCE() : FunctionPass(ID) { + initializeADCEPass(*PassRegistry::getPassRegistry()); + } - void getAnalysisUsage(AnalysisUsage& AU) const override { - AU.setPreservesCFG(); - } + bool runOnFunction(Function& F) override; - }; + void getAnalysisUsage(AnalysisUsage& AU) const override { + AU.setPreservesCFG(); + } +}; } char ADCE::ID = 0; @@ -54,46 +53,45 @@ bool ADCE::runOnFunction(Function& F) { if (skipOptnoneFunction(F)) return false; - SmallPtrSet<Instruction*, 128> alive; - SmallVector<Instruction*, 128> worklist; + SmallPtrSet<Instruction*, 128> Alive; + SmallVector<Instruction*, 128> Worklist; // Collect the set of "root" instructions that are known live. - for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) - if (isa<TerminatorInst>(I.getInstructionIterator()) || - isa<DbgInfoIntrinsic>(I.getInstructionIterator()) || - isa<LandingPadInst>(I.getInstructionIterator()) || - I->mayHaveSideEffects()) { - alive.insert(I.getInstructionIterator()); - worklist.push_back(I.getInstructionIterator()); + for (Instruction &I : inst_range(F)) { + if (isa<TerminatorInst>(I) || isa<DbgInfoIntrinsic>(I) || + isa<LandingPadInst>(I) || I.mayHaveSideEffects()) { + Alive.insert(&I); + Worklist.push_back(&I); } + } // Propagate liveness backwards to operands. - while (!worklist.empty()) { - Instruction* curr = worklist.pop_back_val(); - for (Instruction::op_iterator OI = curr->op_begin(), OE = curr->op_end(); - OI != OE; ++OI) - if (Instruction* Inst = dyn_cast<Instruction>(OI)) - if (alive.insert(Inst).second) - worklist.push_back(Inst); + while (!Worklist.empty()) { + Instruction *Curr = Worklist.pop_back_val(); + for (Use &OI : Curr->operands()) { + if (Instruction *Inst = dyn_cast<Instruction>(OI)) + if (Alive.insert(Inst).second) + Worklist.push_back(Inst); + } } // The inverse of the live set is the dead set. These are those instructions // which have no side effects and do not influence the control flow or return // value of the function, and may therefore be deleted safely. - // NOTE: We reuse the worklist vector here for memory efficiency. - for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) - if (!alive.count(I.getInstructionIterator())) { - worklist.push_back(I.getInstructionIterator()); - I->dropAllReferences(); + // NOTE: We reuse the Worklist vector here for memory efficiency. + for (Instruction &I : inst_range(F)) { + if (!Alive.count(&I)) { + Worklist.push_back(&I); + I.dropAllReferences(); } + } - for (SmallVectorImpl<Instruction *>::iterator I = worklist.begin(), - E = worklist.end(); I != E; ++I) { + for (Instruction *&I : Worklist) { ++NumRemoved; - (*I)->eraseFromParent(); + I->eraseFromParent(); } - return !worklist.empty(); + return !Worklist.empty(); } FunctionPass *llvm::createAggressiveDCEPass() { |