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Incorporate feedback. 

- Fix loop nest.
- Use RetVals.size()
- Check for null return value.

llvm-svn: 48605
This commit is contained in:
Devang Patel 2008-03-20 18:30:32 +00:00
parent b81777a354
commit 5ca2ea6479
1 changed files with 24 additions and 24 deletions
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48
llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
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@ -144,19 +144,17 @@ bool IPCP::PropagateConstantReturn(Function &F) {
// Check to see if this function returns a constant. // Check to see if this function returns a constant.
SmallVector<Value *,4> RetVals; SmallVector<Value *,4> RetVals;
unsigned N = 0;
const StructType *STy = dyn_cast<StructType>(F.getReturnType()); const StructType *STy = dyn_cast<StructType>(F.getReturnType());
if (STy) if (STy)
N = STy->getNumElements(); RetVals.assign(STy->getNumElements(), 0);
else else
N = 1;
for (unsigned i = 0; i < N; ++i)
RetVals.push_back(0); RetVals.push_back(0);
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) { if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
assert (N == RI->getNumOperands() && "Invalid ReturnInst operands!"); unsigned RetValsSize = RetVals.size();
for (unsigned i = 0; i < N; ++i) { assert (RetValsSize == RI->getNumOperands() && "Invalid ReturnInst operands!");
for (unsigned i = 0; i < RetValsSize; ++i) {
if (isa<UndefValue>(RI->getOperand(i))) { if (isa<UndefValue>(RI->getOperand(i))) {
// Ignore // Ignore
} else if (Constant *C = dyn_cast<Constant>(RI->getOperand(i))) { } else if (Constant *C = dyn_cast<Constant>(RI->getOperand(i))) {
@ -171,15 +169,14 @@ bool IPCP::PropagateConstantReturn(Function &F) {
} }
} }
if (N == 1) { if (STy) {
if (RetVals[0] == 0) for (unsigned i = 0, e = RetVals.size(); i < e; ++i)
RetVals[0] = UndefValue::get(F.getReturnType()); if (RetVals[i] == 0)
} else {
for (unsigned i = 0; i < N; ++i) {
Value *RetVal = RetVals[i];
if (RetVal == 0)
RetVals[i] = UndefValue::get(STy->getElementType(i)); RetVals[i] = UndefValue::get(STy->getElementType(i));
} } else {
if (RetVals.size() == 1)
if (RetVals[0] == 0)
RetVals[0] = UndefValue::get(F.getReturnType());
} }
// If we got here, the function returns a constant value. Loop over all // If we got here, the function returns a constant value. Loop over all
@ -197,14 +194,16 @@ bool IPCP::PropagateConstantReturn(Function &F) {
} else { } else {
Instruction *Call = CS.getInstruction(); Instruction *Call = CS.getInstruction();
if (!Call->use_empty()) { if (!Call->use_empty()) {
if (N == 1) if (RetVals.size() == 1)
Call->replaceAllUsesWith(RetVals[0]); Call->replaceAllUsesWith(RetVals[0]);
else { else {
for(Value::use_iterator CUI = Call->use_begin(), CUE = Call->use_end(); for(Value::use_iterator CUI = Call->use_begin(), CUE = Call->use_end();
CUI != CUE; ++CUI) { CUI != CUE; ++CUI) {
GetResultInst *GR = cast<GetResultInst>(CUI); GetResultInst *GR = cast<GetResultInst>(CUI);
GR->replaceAllUsesWith(RetVals[GR->getIndex()]); if (RetVals[GR->getIndex()]) {
GR->eraseFromParent(); GR->replaceAllUsesWith(RetVals[GR->getIndex()]);
GR->eraseFromParent();
}
} }
} }
MadeChange = true; MadeChange = true;
@ -216,18 +215,19 @@ bool IPCP::PropagateConstantReturn(Function &F) {
// other callers of the function, replace the constant being returned in the // other callers of the function, replace the constant being returned in the
// function with an undef value. // function with an undef value.
if (ReplacedAllUsers && F.hasInternalLinkage()) { if (ReplacedAllUsers && F.hasInternalLinkage()) {
for (unsigned i = 0; i < N; ++i) { for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
Value *RetVal = RetVals[i]; if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
if (isa<UndefValue>(RetVal)) for (unsigned i = 0, e = RetVals.size(); i < e; ++i) {
continue; Value *RetVal = RetVals[i];
Value *RV = UndefValue::get(RetVal->getType()); if (isa<UndefValue>(RetVal))
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) continue;
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) { Value *RV = UndefValue::get(RetVal->getType());
if (RI->getOperand(i) != RV) { if (RI->getOperand(i) != RV) {
RI->setOperand(i, RV); RI->setOperand(i, RV);
MadeChange = true; MadeChange = true;
} }
} }
}
} }
} }