aboutsummaryrefslogtreecommitdiffstats
path: root/lib/Transforms/Scalar/ADCE.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/Transforms/Scalar/ADCE.cpp')
-rw-r--r--lib/Transforms/Scalar/ADCE.cpp70
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() {