/// and zero out all the operands of this instruction. If any of them become
/// dead, delete them and the computation tree that feeds them.
///
-static void deleteDeadInstruction(Instruction *I, ScalarEvolution &SE,
+static void deleteDeadInstruction(Instruction *I,
const TargetLibraryInfo *TLI) {
- SmallVector<Instruction*, 32> NowDeadInsts;
-
- NowDeadInsts.push_back(I);
-
- // Before we touch this instruction, remove it from SE!
- do {
- Instruction *DeadInst = NowDeadInsts.pop_back_val();
-
- // This instruction is dead, zap it, in stages. Start by removing it from
- // SCEV.
- SE.forgetValue(DeadInst);
-
- for (unsigned op = 0, e = DeadInst->getNumOperands(); op != e; ++op) {
- Value *Op = DeadInst->getOperand(op);
- DeadInst->setOperand(op, nullptr);
-
- // If this operand just became dead, add it to the NowDeadInsts list.
- if (!Op->use_empty()) continue;
-
- if (Instruction *OpI = dyn_cast<Instruction>(Op))
- if (isInstructionTriviallyDead(OpI, TLI))
- NowDeadInsts.push_back(OpI);
- }
-
- DeadInst->eraseFromParent();
-
- } while (!NowDeadInsts.empty());
-}
-
-/// deleteIfDeadInstruction - If the specified value is a dead instruction,
-/// delete it and any recursively used instructions.
-static void deleteIfDeadInstruction(Value *V, ScalarEvolution &SE,
- const TargetLibraryInfo *TLI) {
- if (Instruction *I = dyn_cast<Instruction>(V))
- if (isInstructionTriviallyDead(I, TLI))
- deleteDeadInstruction(I, SE, TLI);
+ SmallVector<Value *, 16> Operands(I->value_op_begin(), I->value_op_end());
+ I->replaceAllUsesWith(UndefValue::get(I->getType()));
+ I->eraseFromParent();
+ for (Value *Op : Operands)
+ RecursivelyDeleteTriviallyDeadInstructions(Op, TLI);
}
//===----------------------------------------------------------------------===//
// the concern of breaking data dependence.
bool LIRUtil::isAlmostEmpty(BasicBlock *BB) {
if (BranchInst *Br = getBranch(BB)) {
- return Br->isUnconditional() && BB->size() == 1;
+ return Br->isUnconditional() && Br == BB->begin();
}
return false;
}
cast<ICmpInst>(Builder.CreateICmp(PreCond->getPredicate(), Opnd0, Opnd1));
PreCond->replaceAllUsesWith(NewPreCond);
- deleteDeadInstruction(PreCond, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(PreCond, TLI);
}
// Step 3: Note that the population count is exactly the trip count of the
// Step 4: All the references to the original population counter outside
// the loop are replaced with the NewCount -- the value returned from
// __builtin_ctpop().
- {
- SmallVector<Value *, 4> CntUses;
- for (User *U : CntInst->users())
- if (cast<Instruction>(U)->getParent() != Body)
- CntUses.push_back(U);
- for (unsigned Idx = 0; Idx < CntUses.size(); Idx++) {
- (cast<Instruction>(CntUses[Idx]))->replaceUsesOfWith(CntInst, NewCount);
- }
- }
+ CntInst->replaceUsesOutsideBlock(NewCount, Body);
// step 5: Forget the "non-computable" trip-count SCEV associated with the
// loop. The loop would otherwise not be deleted even if it becomes empty.
StoreSize, getAnalysis<AliasAnalysis>(), TheStore)) {
Expander.clear();
// If we generated new code for the base pointer, clean up.
- deleteIfDeadInstruction(BasePtr, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(BasePtr, TLI);
return false;
}
// Okay, the memset has been formed. Zap the original store and anything that
// feeds into it.
- deleteDeadInstruction(TheStore, *SE, TLI);
+ deleteDeadInstruction(TheStore, TLI);
++NumMemSet;
return true;
}
getAnalysis<AliasAnalysis>(), SI)) {
Expander.clear();
// If we generated new code for the base pointer, clean up.
- deleteIfDeadInstruction(StoreBasePtr, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(StoreBasePtr, TLI);
return false;
}
StoreSize, getAnalysis<AliasAnalysis>(), SI)) {
Expander.clear();
// If we generated new code for the base pointer, clean up.
- deleteIfDeadInstruction(LoadBasePtr, *SE, TLI);
- deleteIfDeadInstruction(StoreBasePtr, *SE, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(LoadBasePtr, TLI);
+ RecursivelyDeleteTriviallyDeadInstructions(StoreBasePtr, TLI);
return false;
}
// Okay, the memset has been formed. Zap the original store and anything that
// feeds into it.
- deleteDeadInstruction(SI, *SE, TLI);
+ deleteDeadInstruction(SI, TLI);
++NumMemCpy;
return true;
}