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Fix a number of bugs in ipconstantprop, simplify the code, fit in 80 cols,

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fix read after free bug (PR2238).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50141 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-04-23 05:59:23 +00:00
parent c6ee00b8ee
commit e9625c6c88
1 changed files with 39 additions and 41 deletions
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80
lib/Transforms/IPO/IPConstantPropagation.cpp
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@ -152,20 +152,20 @@ bool IPCP::PropagateConstantReturn(Function &F) {
for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
unsigned RetValsSize = RetVals.size();
assert (RetValsSize == RI->getNumOperands() && "Invalid ReturnInst operands!");
for (unsigned i = 0; i < RetValsSize; ++i) {
if (isa<UndefValue>(RI->getOperand(i))) {
// Ignore
} else if (Constant *C = dyn_cast<Constant>(RI->getOperand(i))) {
Value *RV = RetVals[i];
if (RV == 0)
RetVals[i] = C;
else if (RV != C)
return false; // Does not return the same constant.
} else {
assert(RetVals.size() == RI->getNumOperands() &&
"Invalid ReturnInst operands!");
for (unsigned i = 0, e = RetVals.size(); i != e; ++i) {
if (isa<UndefValue>(RI->getOperand(i)))
continue; // Ignore
Constant *C = dyn_cast<Constant>(RI->getOperand(i));
if (C == 0)
return false; // Does not return a constant.
}
Value *RV = RetVals[i];
if (RV == 0)
RetVals[i] = C;
else if (RV != C)
return false; // Does not return the same constant.
}
}
@ -174,43 +174,41 @@ bool IPCP::PropagateConstantReturn(Function &F) {
if (RetVals[i] == 0)
RetVals[i] = UndefValue::get(STy->getElementType(i));
} else {
if (RetVals.size() == 1)
if (RetVals[0] == 0)
RetVals[0] = UndefValue::get(F.getReturnType());
assert(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
// users, replacing any uses of the return value with the returned constant.
bool ReplacedAllUsers = true;
bool MadeChange = false;
for (Value::use_iterator I = F.use_begin(), E = F.use_end(); I != E; ++I)
if (!isa<Instruction>(*I))
for (Value::use_iterator UI = F.use_begin(), E = F.use_end(); UI != E; ++UI) {
// Make sure this is an invoke or call and that the use is for the callee.
if (!(isa<InvokeInst>(*UI) || isa<CallInst>(*UI)) ||
UI.getOperandNo() != 0) {
ReplacedAllUsers = false;
else {
CallSite CS = CallSite::get(cast<Instruction>(*I));
if (CS.getInstruction() == 0 ||
CS.getCalledFunction() != &F) {
ReplacedAllUsers = false;
} else {
Instruction *Call = CS.getInstruction();
if (!Call->use_empty()) {
if (RetVals.size() == 1)
Call->replaceAllUsesWith(RetVals[0]);
else {
for(Value::use_iterator CUI = Call->use_begin(), CUE = Call->use_end();
CUI != CUE; ++CUI) {
GetResultInst *GR = cast<GetResultInst>(CUI);
if (RetVals[GR->getIndex()]) {
GR->replaceAllUsesWith(RetVals[GR->getIndex()]);
GR->eraseFromParent();
}
}
}
MadeChange = true;
}
}
continue;
}
Instruction *Call = cast<Instruction>(*UI);
if (Call->use_empty())
continue;
MadeChange = true;
if (STy == 0) {
Call->replaceAllUsesWith(RetVals[0]);
continue;
}
while (!Call->use_empty()) {
GetResultInst *GR = cast<GetResultInst>(Call->use_back());
GR->replaceAllUsesWith(RetVals[GR->getIndex()]);
GR->eraseFromParent();
}
}
// If we replace all users with the returned constant, and there can be no
// other callers of the function, replace the constant being returned in the
// function with an undef value.