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Fix a number of bugs in ipconstantprop, simplify the code, fit in 80 cols,
fix read after free bug (PR2238). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50141 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -152,20 +152,20 @@ bool IPCP::PropagateConstantReturn(Function &F) {
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for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
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if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
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unsigned RetValsSize = RetVals.size();
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assert (RetValsSize == RI->getNumOperands() && "Invalid ReturnInst operands!");
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for (unsigned i = 0; i < RetValsSize; ++i) {
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if (isa<UndefValue>(RI->getOperand(i))) {
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// Ignore
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} else if (Constant *C = dyn_cast<Constant>(RI->getOperand(i))) {
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Value *RV = RetVals[i];
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if (RV == 0)
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RetVals[i] = C;
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else if (RV != C)
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return false; // Does not return the same constant.
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} else {
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assert(RetVals.size() == RI->getNumOperands() &&
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"Invalid ReturnInst operands!");
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for (unsigned i = 0, e = RetVals.size(); i != e; ++i) {
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if (isa<UndefValue>(RI->getOperand(i)))
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continue; // Ignore
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Constant *C = dyn_cast<Constant>(RI->getOperand(i));
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if (C == 0)
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return false; // Does not return a constant.
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}
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Value *RV = RetVals[i];
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if (RV == 0)
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RetVals[i] = C;
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else if (RV != C)
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return false; // Does not return the same constant.
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}
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}
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@ -174,43 +174,41 @@ bool IPCP::PropagateConstantReturn(Function &F) {
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if (RetVals[i] == 0)
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RetVals[i] = UndefValue::get(STy->getElementType(i));
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} else {
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if (RetVals.size() == 1)
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if (RetVals[0] == 0)
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RetVals[0] = UndefValue::get(F.getReturnType());
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assert(RetVals.size() == 1);
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if (RetVals[0] == 0)
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RetVals[0] = UndefValue::get(F.getReturnType());
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}
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// If we got here, the function returns a constant value. Loop over all
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// users, replacing any uses of the return value with the returned constant.
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bool ReplacedAllUsers = true;
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bool MadeChange = false;
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for (Value::use_iterator I = F.use_begin(), E = F.use_end(); I != E; ++I)
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if (!isa<Instruction>(*I))
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for (Value::use_iterator UI = F.use_begin(), E = F.use_end(); UI != E; ++UI) {
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// Make sure this is an invoke or call and that the use is for the callee.
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if (!(isa<InvokeInst>(*UI) || isa<CallInst>(*UI)) ||
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UI.getOperandNo() != 0) {
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ReplacedAllUsers = false;
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else {
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CallSite CS = CallSite::get(cast<Instruction>(*I));
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if (CS.getInstruction() == 0 ||
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CS.getCalledFunction() != &F) {
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ReplacedAllUsers = false;
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} else {
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Instruction *Call = CS.getInstruction();
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if (!Call->use_empty()) {
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if (RetVals.size() == 1)
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Call->replaceAllUsesWith(RetVals[0]);
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else {
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for(Value::use_iterator CUI = Call->use_begin(), CUE = Call->use_end();
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CUI != CUE; ++CUI) {
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GetResultInst *GR = cast<GetResultInst>(CUI);
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if (RetVals[GR->getIndex()]) {
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GR->replaceAllUsesWith(RetVals[GR->getIndex()]);
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GR->eraseFromParent();
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}
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}
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}
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MadeChange = true;
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}
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}
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continue;
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}
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Instruction *Call = cast<Instruction>(*UI);
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if (Call->use_empty())
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continue;
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MadeChange = true;
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if (STy == 0) {
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Call->replaceAllUsesWith(RetVals[0]);
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continue;
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}
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while (!Call->use_empty()) {
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GetResultInst *GR = cast<GetResultInst>(Call->use_back());
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GR->replaceAllUsesWith(RetVals[GR->getIndex()]);
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GR->eraseFromParent();
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}
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}
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// If we replace all users with the returned constant, and there can be no
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// other callers of the function, replace the constant being returned in the
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// function with an undef value.
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