#define DEBUG_TYPE "adce"
#include "llvm/Transforms/Scalar.h"
+#include "llvm/BasicBlock.h"
#include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
#include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
+#include "llvm/Support/CFG.h"
#include "llvm/Support/InstIterator.h"
-#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/SmallPtrSet.h"
-
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
using namespace llvm;
STATISTIC(NumRemoved, "Number of instructions removed");
namespace {
- struct VISIBILITY_HIDDEN ADCE : public FunctionPass {
+ struct ADCE : public FunctionPass {
static char ID; // Pass identification, replacement for typeid
- ADCE() : FunctionPass((intptr_t)&ID) {}
+ ADCE() : FunctionPass(ID) {
+ initializeADCEPass(*PassRegistry::getPassRegistry());
+ }
virtual bool runOnFunction(Function& F);
}
char ADCE::ID = 0;
-static RegisterPass<ADCE> X("adce", "Aggressive Dead Code Elimination");
+INITIALIZE_PASS(ADCE, "adce", "Aggressive Dead Code Elimination", false, false)
bool ADCE::runOnFunction(Function& F) {
- SmallPtrSet<Instruction*, 32> alive;
- std::vector<Instruction*> 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()) ||
- I->mayWriteToMemory()) {
+ isa<DbgInfoIntrinsic>(I.getInstructionIterator()) ||
+ isa<LandingPadInst>(I.getInstructionIterator()) ||
+ I->mayHaveSideEffects()) {
alive.insert(I.getInstructionIterator());
worklist.push_back(I.getInstructionIterator());
}
// Propagate liveness backwards to operands.
while (!worklist.empty()) {
- Instruction* curr = worklist.back();
- worklist.pop_back();
-
+ 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))
// 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.
- SmallPtrSet<Instruction*, 32> dead;
+ // 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())) {
- dead.insert(I.getInstructionIterator());
+ worklist.push_back(I.getInstructionIterator());
I->dropAllReferences();
}
- for (SmallPtrSet<Instruction*, 32>::iterator I = dead.begin(),
- E = dead.end(); I != E; ++I) {
- NumRemoved++;
+ for (SmallVector<Instruction*, 1024>::iterator I = worklist.begin(),
+ E = worklist.end(); I != E; ++I) {
+ ++NumRemoved;
(*I)->eraseFromParent();
}
-
- return !dead.empty();
+
+ return !worklist.empty();
}
FunctionPass *llvm::createAggressiveDCEPass() {