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switch AddReachableCodeToWorklist from being recursive to being iterative.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35282 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-03-23 19:17:18 +00:00
parent b35ae0371a
commit 2c7718a539
1 changed files with 56 additions and 48 deletions
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104
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -9989,58 +9989,66 @@ static void AddReachableCodeToWorklist(BasicBlock *BB,
SmallPtrSet<BasicBlock*, 64> &Visited,
InstCombiner &IC,
const TargetData *TD) {
// We have now visited this block! If we've already been here, bail out.
if (!Visited.insert(BB)) return;
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
Instruction *Inst = BBI++;
// DCE instruction if trivially dead.
if (isInstructionTriviallyDead(Inst)) {
++NumDeadInst;
DOUT << "IC: DCE: " << *Inst;
Inst->eraseFromParent();
continue;
}
// ConstantProp instruction if trivially constant.
if (Constant *C = ConstantFoldInstruction(Inst, TD)) {
DOUT << "IC: ConstFold to: " << *C << " from: " << *Inst;
Inst->replaceAllUsesWith(C);
++NumConstProp;
Inst->eraseFromParent();
continue;
}
IC.AddToWorkList(Inst);
}
std::vector<BasicBlock*> Worklist;
Worklist.push_back(BB);
// Recursively visit successors. If this is a branch or switch on a constant,
// only visit the reachable successor.
TerminatorInst *TI = BB->getTerminator();
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
if (BI->isConditional() && isa<ConstantInt>(BI->getCondition())) {
bool CondVal = cast<ConstantInt>(BI->getCondition())->getZExtValue();
AddReachableCodeToWorklist(BI->getSuccessor(!CondVal), Visited, IC, TD);
return;
}
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
if (ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition())) {
// See if this is an explicit destination.
for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i)
if (SI->getCaseValue(i) == Cond) {
AddReachableCodeToWorklist(SI->getSuccessor(i), Visited, IC, TD);
return;
}
while (!Worklist.empty()) {
BB = Worklist.back();
Worklist.pop_back();
// We have now visited this block! If we've already been here, ignore it.
if (!Visited.insert(BB)) continue;
for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
Instruction *Inst = BBI++;
// Otherwise it is the default destination.
AddReachableCodeToWorklist(SI->getSuccessor(0), Visited, IC, TD);
return;
// DCE instruction if trivially dead.
if (isInstructionTriviallyDead(Inst)) {
++NumDeadInst;
DOUT << "IC: DCE: " << *Inst;
Inst->eraseFromParent();
continue;
}
// ConstantProp instruction if trivially constant.
if (Constant *C = ConstantFoldInstruction(Inst, TD)) {
DOUT << "IC: ConstFold to: " << *C << " from: " << *Inst;
Inst->replaceAllUsesWith(C);
++NumConstProp;
Inst->eraseFromParent();
continue;
}
IC.AddToWorkList(Inst);
}
// Recursively visit successors. If this is a branch or switch on a
// constant, only visit the reachable successor.
TerminatorInst *TI = BB->getTerminator();
if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
if (BI->isConditional() && isa<ConstantInt>(BI->getCondition())) {
bool CondVal = cast<ConstantInt>(BI->getCondition())->getZExtValue();
Worklist.push_back(BI->getSuccessor(!CondVal));
continue;
}
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
if (ConstantInt *Cond = dyn_cast<ConstantInt>(SI->getCondition())) {
// See if this is an explicit destination.
for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i)
if (SI->getCaseValue(i) == Cond) {
Worklist.push_back(SI->getSuccessor(i));
continue;
}
// Otherwise it is the default destination.
Worklist.push_back(SI->getSuccessor(0));
continue;
}
}
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
Worklist.push_back(TI->getSuccessor(i));
}
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
AddReachableCodeToWorklist(TI->getSuccessor(i), Visited, IC, TD);
}
bool InstCombiner::DoOneIteration(Function &F, unsigned Iteration) {