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Simplify code a bit, and fix a bug that was breaking perlbmk

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llvm-svn: 12814
This commit is contained in:
Chris Lattner 2004-04-10 18:06:21 +00:00
parent f126f03878
commit 924b6c173c
1 changed files with 28 additions and 22 deletions
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50
lib/Transforms/Scalar/ADCE.cpp
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@ -43,7 +43,6 @@ namespace {
//
class ADCE : public FunctionPass {
Function *Func; // The function that we are working on
AliasAnalysis *AA; // Current AliasAnalysis object
std::vector<Instruction*> WorkList; // Instructions that just became live
std::set<Instruction*> LiveSet; // The set of live instructions
@ -55,7 +54,6 @@ public:
//
virtual bool runOnFunction(Function &F) {
Func = &F;
AA = &getAnalysis<AliasAnalysis>();
bool Changed = doADCE();
assert(WorkList.empty());
LiveSet.clear();
@ -184,6 +182,33 @@ TerminatorInst *ADCE::convertToUnconditionalBranch(TerminatorInst *TI) {
bool ADCE::doADCE() {
bool MadeChanges = false;
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
// Iterate over all invokes in the function, turning invokes into calls if
// they cannot throw.
for (Function::iterator BB = Func->begin(), E = Func->end(); BB != E; ++BB)
if (InvokeInst *II = dyn_cast<InvokeInst>(BB->getTerminator()))
if (Function *F = II->getCalledFunction())
if (AA.onlyReadsMemory(F)) {
// The function cannot unwind. Convert it to a call with a branch
// after it to the normal destination.
std::vector<Value*> Args(II->op_begin()+3, II->op_end());
std::string Name = II->getName(); II->setName("");
Instruction *NewCall = new CallInst(F, Args, Name, II);
II->replaceAllUsesWith(NewCall);
new BranchInst(II->getNormalDest(), II);
// Update PHI nodes in the unwind destination
II->getUnwindDest()->removePredecessor(BB);
BB->getInstList().erase(II);
if (NewCall->use_empty()) {
BB->getInstList().erase(NewCall);
++NumCallRemoved;
}
}
// Iterate over all of the instructions in the function, eliminating trivially
// dead instructions, and marking instructions live that are known to be
// needed. Perform the walk in depth first order so that we avoid marking any
@ -197,7 +222,7 @@ bool ADCE::doADCE() {
Instruction *I = II++;
if (CallInst *CI = dyn_cast<CallInst>(I)) {
Function *F = CI->getCalledFunction();
if (F && AA->onlyReadsMemory(F)) {
if (F && AA.onlyReadsMemory(F)) {
if (CI->use_empty()) {
BB->getInstList().erase(CI);
++NumCallRemoved;
@ -205,25 +230,6 @@ bool ADCE::doADCE() {
} else {
markInstructionLive(I);
}
} else if (InvokeInst *II = dyn_cast<InvokeInst>(I)) {
Function *F = II->getCalledFunction();
if (F && AA->onlyReadsMemory(F)) {
// The function cannot unwind. Convert it to a call with a branch
// after it to the normal destination.
std::vector<Value*> Args(II->op_begin()+3, II->op_end());
std::string Name = II->getName(); II->setName("");
Instruction *NewCall = new CallInst(F, Args, Name, II);
II->replaceAllUsesWith(NewCall);
new BranchInst(II->getNormalDest(), II);
BB->getInstList().erase(II);
if (NewCall->use_empty()) {
BB->getInstList().erase(NewCall);
++NumCallRemoved;
}
} else {
markInstructionLive(I);
}
} else if (I->mayWriteToMemory() || isa<ReturnInst>(I) ||
isa<UnwindInst>(I)) {
markInstructionLive(I);