| //===-- ArgumentPromotion.cpp - Promote by-reference arguments ------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file was developed by the LLVM research group and is distributed under |
| // the University of Illinois Open Source License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass promotes "by reference" arguments to be "by value" arguments. In |
| // practice, this means looking for internal functions that have pointer |
| // arguments. If it can prove, through the use of alias analysis, that an |
| // argument is *only* loaded, then it can pass the value into the function |
| // instead of the address of the value. This can cause recursive simplification |
| // of code and lead to the elimination of allocas (especially in C++ template |
| // code like the STL). |
| // |
| // This pass also handles aggregate arguments that are passed into a function, |
| // scalarizing them if the elements of the aggregate are only loaded. Note that |
| // it refuses to scalarize aggregates which would require passing in more than |
| // three operands to the function, because passing thousands of operands for a |
| // large array or structure is unprofitable! |
| // |
| // Note that this transformation could also be done for arguments that are only |
| // stored to (returning the value instead), but does not currently. This case |
| // would be best handled when and if LLVM begins supporting multiple return |
| // values from functions. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "argpromotion" |
| #include "llvm/Transforms/IPO.h" |
| #include "llvm/Constants.h" |
| #include "llvm/DerivedTypes.h" |
| #include "llvm/Module.h" |
| #include "llvm/CallGraphSCCPass.h" |
| #include "llvm/Instructions.h" |
| #include "llvm/ParameterAttributes.h" |
| #include "llvm/Analysis/AliasAnalysis.h" |
| #include "llvm/Analysis/CallGraph.h" |
| #include "llvm/Target/TargetData.h" |
| #include "llvm/Support/CallSite.h" |
| #include "llvm/Support/CFG.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/ADT/DepthFirstIterator.h" |
| #include "llvm/ADT/Statistic.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/Support/Compiler.h" |
| #include <set> |
| using namespace llvm; |
| |
| STATISTIC(NumArgumentsPromoted , "Number of pointer arguments promoted"); |
| STATISTIC(NumAggregatesPromoted, "Number of aggregate arguments promoted"); |
| STATISTIC(NumArgumentsDead , "Number of dead pointer args eliminated"); |
| |
| namespace { |
| /// ArgPromotion - The 'by reference' to 'by value' argument promotion pass. |
| /// |
| struct VISIBILITY_HIDDEN ArgPromotion : public CallGraphSCCPass { |
| virtual void getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.addRequired<AliasAnalysis>(); |
| AU.addRequired<TargetData>(); |
| CallGraphSCCPass::getAnalysisUsage(AU); |
| } |
| |
| virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC); |
| static char ID; // Pass identification, replacement for typeid |
| ArgPromotion() : CallGraphSCCPass((intptr_t)&ID) {} |
| |
| private: |
| bool PromoteArguments(CallGraphNode *CGN); |
| bool isSafeToPromoteArgument(Argument *Arg) const; |
| Function *DoPromotion(Function *F, std::vector<Argument*> &ArgsToPromote); |
| }; |
| |
| char ArgPromotion::ID = 0; |
| RegisterPass<ArgPromotion> X("argpromotion", |
| "Promote 'by reference' arguments to scalars"); |
| } |
| |
| Pass *llvm::createArgumentPromotionPass() { |
| return new ArgPromotion(); |
| } |
| |
| bool ArgPromotion::runOnSCC(const std::vector<CallGraphNode *> &SCC) { |
| bool Changed = false, LocalChange; |
| |
| do { // Iterate until we stop promoting from this SCC. |
| LocalChange = false; |
| // Attempt to promote arguments from all functions in this SCC. |
| for (unsigned i = 0, e = SCC.size(); i != e; ++i) |
| LocalChange |= PromoteArguments(SCC[i]); |
| Changed |= LocalChange; // Remember that we changed something. |
| } while (LocalChange); |
| |
| return Changed; |
| } |
| |
| /// PromoteArguments - This method checks the specified function to see if there |
| /// are any promotable arguments and if it is safe to promote the function (for |
| /// example, all callers are direct). If safe to promote some arguments, it |
| /// calls the DoPromotion method. |
| /// |
| bool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { |
| Function *F = CGN->getFunction(); |
| |
| // Make sure that it is local to this module. |
| if (!F || !F->hasInternalLinkage()) return false; |
| |
| // First check: see if there are any pointer arguments! If not, quick exit. |
| std::vector<Argument*> PointerArgs; |
| for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I) |
| if (isa<PointerType>(I->getType())) |
| PointerArgs.push_back(I); |
| if (PointerArgs.empty()) return false; |
| |
| // Second check: make sure that all callers are direct callers. We can't |
| // transform functions that have indirect callers. |
| for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); |
| UI != E; ++UI) { |
| CallSite CS = CallSite::get(*UI); |
| if (!CS.getInstruction()) // "Taking the address" of the function |
| return false; |
| |
| // Ensure that this call site is CALLING the function, not passing it as |
| // an argument. |
| for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end(); |
| AI != E; ++AI) |
| if (*AI == F) return false; // Passing the function address in! |
| } |
| |
| // Check to see which arguments are promotable. If an argument is not |
| // promotable, remove it from the PointerArgs vector. |
| for (unsigned i = 0; i != PointerArgs.size(); ++i) |
| if (!isSafeToPromoteArgument(PointerArgs[i])) { |
| std::swap(PointerArgs[i--], PointerArgs.back()); |
| PointerArgs.pop_back(); |
| } |
| |
| // No promotable pointer arguments. |
| if (PointerArgs.empty()) return false; |
| |
| // Okay, promote all of the arguments and rewrite the callees! |
| Function *NewF = DoPromotion(F, PointerArgs); |
| |
| // Update the call graph to know that the function has been transformed. |
| getAnalysis<CallGraph>().changeFunction(F, NewF); |
| return true; |
| } |
| |
| /// IsAlwaysValidPointer - Return true if the specified pointer is always legal |
| /// to load. |
| static bool IsAlwaysValidPointer(Value *V) { |
| if (isa<AllocaInst>(V) || isa<GlobalVariable>(V)) return true; |
| if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) |
| return IsAlwaysValidPointer(GEP->getOperand(0)); |
| if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) |
| if (CE->getOpcode() == Instruction::GetElementPtr) |
| return IsAlwaysValidPointer(CE->getOperand(0)); |
| |
| return false; |
| } |
| |
| /// AllCalleesPassInValidPointerForArgument - Return true if we can prove that |
| /// all callees pass in a valid pointer for the specified function argument. |
| static bool AllCalleesPassInValidPointerForArgument(Argument *Arg) { |
| Function *Callee = Arg->getParent(); |
| |
| unsigned ArgNo = std::distance(Callee->arg_begin(), |
| Function::arg_iterator(Arg)); |
| |
| // Look at all call sites of the function. At this pointer we know we only |
| // have direct callees. |
| for (Value::use_iterator UI = Callee->use_begin(), E = Callee->use_end(); |
| UI != E; ++UI) { |
| CallSite CS = CallSite::get(*UI); |
| assert(CS.getInstruction() && "Should only have direct calls!"); |
| |
| if (!IsAlwaysValidPointer(CS.getArgument(ArgNo))) |
| return false; |
| } |
| return true; |
| } |
| |
| |
| /// isSafeToPromoteArgument - As you might guess from the name of this method, |
| /// it checks to see if it is both safe and useful to promote the argument. |
| /// This method limits promotion of aggregates to only promote up to three |
| /// elements of the aggregate in order to avoid exploding the number of |
| /// arguments passed in. |
| bool ArgPromotion::isSafeToPromoteArgument(Argument *Arg) const { |
| // We can only promote this argument if all of the uses are loads, or are GEP |
| // instructions (with constant indices) that are subsequently loaded. |
| bool HasLoadInEntryBlock = false; |
| BasicBlock *EntryBlock = Arg->getParent()->begin(); |
| std::vector<LoadInst*> Loads; |
| std::vector<std::vector<ConstantInt*> > GEPIndices; |
| for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end(); |
| UI != E; ++UI) |
| if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { |
| if (LI->isVolatile()) return false; // Don't hack volatile loads |
| Loads.push_back(LI); |
| HasLoadInEntryBlock |= LI->getParent() == EntryBlock; |
| } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { |
| if (GEP->use_empty()) { |
| // Dead GEP's cause trouble later. Just remove them if we run into |
| // them. |
| getAnalysis<AliasAnalysis>().deleteValue(GEP); |
| GEP->getParent()->getInstList().erase(GEP); |
| return isSafeToPromoteArgument(Arg); |
| } |
| // Ensure that all of the indices are constants. |
| std::vector<ConstantInt*> Operands; |
| for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i) |
| if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(i))) |
| Operands.push_back(C); |
| else |
| return false; // Not a constant operand GEP! |
| |
| // Ensure that the only users of the GEP are load instructions. |
| for (Value::use_iterator UI = GEP->use_begin(), E = GEP->use_end(); |
| UI != E; ++UI) |
| if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { |
| if (LI->isVolatile()) return false; // Don't hack volatile loads |
| Loads.push_back(LI); |
| HasLoadInEntryBlock |= LI->getParent() == EntryBlock; |
| } else { |
| return false; |
| } |
| |
| // See if there is already a GEP with these indices. If not, check to |
| // make sure that we aren't promoting too many elements. If so, nothing |
| // to do. |
| if (std::find(GEPIndices.begin(), GEPIndices.end(), Operands) == |
| GEPIndices.end()) { |
| if (GEPIndices.size() == 3) { |
| DOUT << "argpromotion disable promoting argument '" |
| << Arg->getName() << "' because it would require adding more " |
| << "than 3 arguments to the function.\n"; |
| // We limit aggregate promotion to only promoting up to three elements |
| // of the aggregate. |
| return false; |
| } |
| GEPIndices.push_back(Operands); |
| } |
| } else { |
| return false; // Not a load or a GEP. |
| } |
| |
| if (Loads.empty()) return true; // No users, this is a dead argument. |
| |
| // If we decide that we want to promote this argument, the value is going to |
| // be unconditionally loaded in all callees. This is only safe to do if the |
| // pointer was going to be unconditionally loaded anyway (i.e. there is a load |
| // of the pointer in the entry block of the function) or if we can prove that |
| // all pointers passed in are always to legal locations (for example, no null |
| // pointers are passed in, no pointers to free'd memory, etc). |
| if (!HasLoadInEntryBlock && !AllCalleesPassInValidPointerForArgument(Arg)) |
| return false; // Cannot prove that this is safe!! |
| |
| // Okay, now we know that the argument is only used by load instructions and |
| // it is safe to unconditionally load the pointer. Use alias analysis to |
| // check to see if the pointer is guaranteed to not be modified from entry of |
| // the function to each of the load instructions. |
| |
| // Because there could be several/many load instructions, remember which |
| // blocks we know to be transparent to the load. |
| std::set<BasicBlock*> TranspBlocks; |
| |
| AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); |
| TargetData &TD = getAnalysis<TargetData>(); |
| |
| for (unsigned i = 0, e = Loads.size(); i != e; ++i) { |
| // Check to see if the load is invalidated from the start of the block to |
| // the load itself. |
| LoadInst *Load = Loads[i]; |
| BasicBlock *BB = Load->getParent(); |
| |
| const PointerType *LoadTy = |
| cast<PointerType>(Load->getOperand(0)->getType()); |
| unsigned LoadSize = (unsigned)TD.getTypeStoreSize(LoadTy->getElementType()); |
| |
| if (AA.canInstructionRangeModify(BB->front(), *Load, Arg, LoadSize)) |
| return false; // Pointer is invalidated! |
| |
| // Now check every path from the entry block to the load for transparency. |
| // To do this, we perform a depth first search on the inverse CFG from the |
| // loading block. |
| for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) |
| for (idf_ext_iterator<BasicBlock*> I = idf_ext_begin(*PI, TranspBlocks), |
| E = idf_ext_end(*PI, TranspBlocks); I != E; ++I) |
| if (AA.canBasicBlockModify(**I, Arg, LoadSize)) |
| return false; |
| } |
| |
| // If the path from the entry of the function to each load is free of |
| // instructions that potentially invalidate the load, we can make the |
| // transformation! |
| return true; |
| } |
| |
| namespace { |
| /// GEPIdxComparator - Provide a strong ordering for GEP indices. All Value* |
| /// elements are instances of ConstantInt. |
| /// |
| struct GEPIdxComparator { |
| bool operator()(const std::vector<Value*> &LHS, |
| const std::vector<Value*> &RHS) const { |
| unsigned idx = 0; |
| for (; idx < LHS.size() && idx < RHS.size(); ++idx) { |
| if (LHS[idx] != RHS[idx]) { |
| return cast<ConstantInt>(LHS[idx])->getZExtValue() < |
| cast<ConstantInt>(RHS[idx])->getZExtValue(); |
| } |
| } |
| |
| // Return less than if we ran out of stuff in LHS and we didn't run out of |
| // stuff in RHS. |
| return idx == LHS.size() && idx != RHS.size(); |
| } |
| }; |
| } |
| |
| |
| /// DoPromotion - This method actually performs the promotion of the specified |
| /// arguments, and returns the new function. At this point, we know that it's |
| /// safe to do so. |
| Function *ArgPromotion::DoPromotion(Function *F, |
| std::vector<Argument*> &Args2Prom) { |
| std::set<Argument*> ArgsToPromote(Args2Prom.begin(), Args2Prom.end()); |
| |
| // Start by computing a new prototype for the function, which is the same as |
| // the old function, but has modified arguments. |
| const FunctionType *FTy = F->getFunctionType(); |
| std::vector<const Type*> Params; |
| |
| typedef std::set<std::vector<Value*>, GEPIdxComparator> ScalarizeTable; |
| |
| // ScalarizedElements - If we are promoting a pointer that has elements |
| // accessed out of it, keep track of which elements are accessed so that we |
| // can add one argument for each. |
| // |
| // Arguments that are directly loaded will have a zero element value here, to |
| // handle cases where there are both a direct load and GEP accesses. |
| // |
| std::map<Argument*, ScalarizeTable> ScalarizedElements; |
| |
| // OriginalLoads - Keep track of a representative load instruction from the |
| // original function so that we can tell the alias analysis implementation |
| // what the new GEP/Load instructions we are inserting look like. |
| std::map<std::vector<Value*>, LoadInst*> OriginalLoads; |
| |
| // ParamAttrs - Keep track of the parameter attributes for the arguments |
| // that we are *not* promoting. For the ones that we do promote, the parameter |
| // attributes are lost |
| ParamAttrsVector ParamAttrsVec; |
| const ParamAttrsList *PAL = F->getParamAttrs(); |
| |
| unsigned index = 1; |
| for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; |
| ++I, ++index) |
| if (!ArgsToPromote.count(I)) { |
| Params.push_back(I->getType()); |
| if (PAL) { |
| unsigned attrs = PAL->getParamAttrs(index); |
| if (attrs) |
| ParamAttrsVec.push_back(ParamAttrsWithIndex::get(Params.size(), |
| attrs)); |
| } |
| } else if (I->use_empty()) { |
| ++NumArgumentsDead; |
| } else { |
| // Okay, this is being promoted. Check to see if there are any GEP uses |
| // of the argument. |
| ScalarizeTable &ArgIndices = ScalarizedElements[I]; |
| for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; |
| ++UI) { |
| Instruction *User = cast<Instruction>(*UI); |
| assert(isa<LoadInst>(User) || isa<GetElementPtrInst>(User)); |
| std::vector<Value*> Indices(User->op_begin()+1, User->op_end()); |
| ArgIndices.insert(Indices); |
| LoadInst *OrigLoad; |
| if (LoadInst *L = dyn_cast<LoadInst>(User)) |
| OrigLoad = L; |
| else |
| OrigLoad = cast<LoadInst>(User->use_back()); |
| OriginalLoads[Indices] = OrigLoad; |
| } |
| |
| // Add a parameter to the function for each element passed in. |
| for (ScalarizeTable::iterator SI = ArgIndices.begin(), |
| E = ArgIndices.end(); SI != E; ++SI) |
| Params.push_back(GetElementPtrInst::getIndexedType(I->getType(), |
| SI->begin(), |
| SI->end())); |
| |
| if (ArgIndices.size() == 1 && ArgIndices.begin()->empty()) |
| ++NumArgumentsPromoted; |
| else |
| ++NumAggregatesPromoted; |
| } |
| |
| const Type *RetTy = FTy->getReturnType(); |
| |
| // Recompute the parameter attributes list based on the new arguments for |
| // the function. |
| if (ParamAttrsVec.empty()) |
| PAL = 0; |
| else |
| PAL = ParamAttrsList::get(ParamAttrsVec); |
| |
| // Work around LLVM bug PR56: the CWriter cannot emit varargs functions which |
| // have zero fixed arguments. |
| bool ExtraArgHack = false; |
| if (Params.empty() && FTy->isVarArg()) { |
| ExtraArgHack = true; |
| Params.push_back(Type::Int32Ty); |
| } |
| |
| // Construct the new function type using the new arguments. |
| FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); |
| |
| // Create the new function body and insert it into the module... |
| Function *NF = new Function(NFTy, F->getLinkage(), F->getName()); |
| NF->setCallingConv(F->getCallingConv()); |
| NF->setParamAttrs(PAL); |
| if (F->hasCollector()) |
| NF->setCollector(F->getCollector()); |
| F->getParent()->getFunctionList().insert(F, NF); |
| |
| // Get the alias analysis information that we need to update to reflect our |
| // changes. |
| AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); |
| |
| // Loop over all of the callers of the function, transforming the call sites |
| // to pass in the loaded pointers. |
| // |
| std::vector<Value*> Args; |
| while (!F->use_empty()) { |
| CallSite CS = CallSite::get(F->use_back()); |
| Instruction *Call = CS.getInstruction(); |
| |
| // Loop over the operands, inserting GEP and loads in the caller as |
| // appropriate. |
| CallSite::arg_iterator AI = CS.arg_begin(); |
| for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); |
| I != E; ++I, ++AI) |
| if (!ArgsToPromote.count(I)) |
| Args.push_back(*AI); // Unmodified argument |
| else if (!I->use_empty()) { |
| // Non-dead argument: insert GEPs and loads as appropriate. |
| ScalarizeTable &ArgIndices = ScalarizedElements[I]; |
| for (ScalarizeTable::iterator SI = ArgIndices.begin(), |
| E = ArgIndices.end(); SI != E; ++SI) { |
| Value *V = *AI; |
| LoadInst *OrigLoad = OriginalLoads[*SI]; |
| if (!SI->empty()) { |
| V = new GetElementPtrInst(V, SI->begin(), SI->end(), |
| V->getName()+".idx", Call); |
| AA.copyValue(OrigLoad->getOperand(0), V); |
| } |
| Args.push_back(new LoadInst(V, V->getName()+".val", Call)); |
| AA.copyValue(OrigLoad, Args.back()); |
| } |
| } |
| |
| if (ExtraArgHack) |
| Args.push_back(Constant::getNullValue(Type::Int32Ty)); |
| |
| // Push any varargs arguments on the list |
| for (; AI != CS.arg_end(); ++AI) |
| Args.push_back(*AI); |
| |
| Instruction *New; |
| if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { |
| New = new InvokeInst(NF, II->getNormalDest(), II->getUnwindDest(), |
| Args.begin(), Args.end(), "", Call); |
| cast<InvokeInst>(New)->setCallingConv(CS.getCallingConv()); |
| cast<InvokeInst>(New)->setParamAttrs(PAL); |
| } else { |
| New = new CallInst(NF, Args.begin(), Args.end(), "", Call); |
| cast<CallInst>(New)->setCallingConv(CS.getCallingConv()); |
| cast<CallInst>(New)->setParamAttrs(PAL); |
| if (cast<CallInst>(Call)->isTailCall()) |
| cast<CallInst>(New)->setTailCall(); |
| } |
| Args.clear(); |
| |
| // Update the alias analysis implementation to know that we are replacing |
| // the old call with a new one. |
| AA.replaceWithNewValue(Call, New); |
| |
| if (!Call->use_empty()) { |
| Call->replaceAllUsesWith(New); |
| New->takeName(Call); |
| } |
| |
| // Finally, remove the old call from the program, reducing the use-count of |
| // F. |
| Call->getParent()->getInstList().erase(Call); |
| } |
| |
| // Since we have now created the new function, splice the body of the old |
| // function right into the new function, leaving the old rotting hulk of the |
| // function empty. |
| NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); |
| |
| // Loop over the argument list, transfering uses of the old arguments over to |
| // the new arguments, also transfering over the names as well. |
| // |
| for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(), |
| I2 = NF->arg_begin(); I != E; ++I) |
| if (!ArgsToPromote.count(I)) { |
| // If this is an unmodified argument, move the name and users over to the |
| // new version. |
| I->replaceAllUsesWith(I2); |
| I2->takeName(I); |
| AA.replaceWithNewValue(I, I2); |
| ++I2; |
| } else if (I->use_empty()) { |
| AA.deleteValue(I); |
| } else { |
| // Otherwise, if we promoted this argument, then all users are load |
| // instructions, and all loads should be using the new argument that we |
| // added. |
| ScalarizeTable &ArgIndices = ScalarizedElements[I]; |
| |
| while (!I->use_empty()) { |
| if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) { |
| assert(ArgIndices.begin()->empty() && |
| "Load element should sort to front!"); |
| I2->setName(I->getName()+".val"); |
| LI->replaceAllUsesWith(I2); |
| AA.replaceWithNewValue(LI, I2); |
| LI->getParent()->getInstList().erase(LI); |
| DOUT << "*** Promoted load of argument '" << I->getName() |
| << "' in function '" << F->getName() << "'\n"; |
| } else { |
| GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back()); |
| std::vector<Value*> Operands(GEP->op_begin()+1, GEP->op_end()); |
| |
| Function::arg_iterator TheArg = I2; |
| for (ScalarizeTable::iterator It = ArgIndices.begin(); |
| *It != Operands; ++It, ++TheArg) { |
| assert(It != ArgIndices.end() && "GEP not handled??"); |
| } |
| |
| std::string NewName = I->getName(); |
| for (unsigned i = 0, e = Operands.size(); i != e; ++i) |
| if (ConstantInt *CI = dyn_cast<ConstantInt>(Operands[i])) |
| NewName += "." + CI->getValue().toStringUnsigned(10); |
| else |
| NewName += ".x"; |
| TheArg->setName(NewName+".val"); |
| |
| DOUT << "*** Promoted agg argument '" << TheArg->getName() |
| << "' of function '" << F->getName() << "'\n"; |
| |
| // All of the uses must be load instructions. Replace them all with |
| // the argument specified by ArgNo. |
| while (!GEP->use_empty()) { |
| LoadInst *L = cast<LoadInst>(GEP->use_back()); |
| L->replaceAllUsesWith(TheArg); |
| AA.replaceWithNewValue(L, TheArg); |
| L->getParent()->getInstList().erase(L); |
| } |
| AA.deleteValue(GEP); |
| GEP->getParent()->getInstList().erase(GEP); |
| } |
| } |
| |
| // Increment I2 past all of the arguments added for this promoted pointer. |
| for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i) |
| ++I2; |
| } |
| |
| // Notify the alias analysis implementation that we inserted a new argument. |
| if (ExtraArgHack) |
| AA.copyValue(Constant::getNullValue(Type::Int32Ty), NF->arg_begin()); |
| |
| |
| // Tell the alias analysis that the old function is about to disappear. |
| AA.replaceWithNewValue(F, NF); |
| |
| // Now that the old function is dead, delete it. |
| F->getParent()->getFunctionList().erase(F); |
| return NF; |
| } |
