ArgumentPromotion.cpp revision 5eb6f6c829ddfe353f94623aa1009c72be930497
19e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner//===-- ArgumentPromotion.cpp - Promote by-reference arguments ------------===// 2ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 3ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// The LLVM Compiler Infrastructure 4ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 5ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// This file was developed by the LLVM research group and is distributed under 6ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// the University of Illinois Open Source License. See LICENSE.TXT for details. 7ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 8ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner//===----------------------------------------------------------------------===// 9ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 10ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// This pass promotes "by reference" arguments to be "by value" arguments. In 11ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// practice, this means looking for internal functions that have pointer 12ebeb0cba94e41b60f2095d4e7f09989f16233da4Chris Lattner// arguments. If we can prove, through the use of alias analysis, that an 13ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// argument is *only* loaded, then we can pass the value into the function 14ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// instead of the address of the value. This can cause recursive simplification 159e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner// of code and lead to the elimination of allocas (especially in C++ template 169e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner// code like the STL). 17ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 189440db886627161a8413e823797569fc7b10beafChris Lattner// This pass also handles aggregate arguments that are passed into a function, 199440db886627161a8413e823797569fc7b10beafChris Lattner// scalarizing them if the elements of the aggregate are only loaded. Note that 209440db886627161a8413e823797569fc7b10beafChris Lattner// we refuse to scalarize aggregates which would require passing in more than 219440db886627161a8413e823797569fc7b10beafChris Lattner// three operands to the function, because we don't want to pass thousands of 229e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner// operands for a large array or structure! 239440db886627161a8413e823797569fc7b10beafChris Lattner// 24ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// Note that this transformation could also be done for arguments that are only 25ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// stored to (returning the value instead), but we do not currently handle that 269440db886627161a8413e823797569fc7b10beafChris Lattner// case. This case would be best handled when and if we start supporting 279440db886627161a8413e823797569fc7b10beafChris Lattner// multiple return values from functions. 28ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner// 29ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner//===----------------------------------------------------------------------===// 30ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 319e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner#define DEBUG_TYPE "argpromotion" 32ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Transforms/IPO.h" 33ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Constants.h" 34ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/DerivedTypes.h" 35ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Module.h" 365eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner#include "llvm/CallGraphSCCPass.h" 37ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Instructions.h" 38ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Analysis/AliasAnalysis.h" 395eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner#include "llvm/Analysis/CallGraph.h" 40ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Target/TargetData.h" 41ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Support/CallSite.h" 42ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include "llvm/Support/CFG.h" 43551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 44551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/DepthFirstIterator.h" 45551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/Statistic.h" 46551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/ADT/StringExtras.h" 47ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner#include <set> 48ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattnerusing namespace llvm; 49ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 50ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattnernamespace { 51ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Statistic<> NumArgumentsPromoted("argpromotion", 52ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner "Number of pointer arguments promoted"); 539440db886627161a8413e823797569fc7b10beafChris Lattner Statistic<> NumAggregatesPromoted("argpromotion", 549440db886627161a8413e823797569fc7b10beafChris Lattner "Number of aggregate arguments promoted"); 55ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Statistic<> NumArgumentsDead("argpromotion", 56ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner "Number of dead pointer args eliminated"); 57ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 58ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner /// ArgPromotion - The 'by reference' to 'by value' argument promotion pass. 59ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner /// 605eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner struct ArgPromotion : public CallGraphSCCPass { 61ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 62ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner AU.addRequired<AliasAnalysis>(); 63ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner AU.addRequired<TargetData>(); 645eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner CallGraphSCCPass::getAnalysisUsage(AU); 65ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 66ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 675eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC); 68ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner private: 695eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner bool PromoteArguments(CallGraphNode *CGN); 70ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner bool isSafeToPromoteArgument(Argument *Arg) const; 715eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *DoPromotion(Function *F, std::vector<Argument*> &ArgsToPromote); 72ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner }; 73ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 74ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner RegisterOpt<ArgPromotion> X("argpromotion", 75ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner "Promote 'by reference' arguments to scalars"); 76ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 77ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 78ed570a7dca45e001a6223e2a25d034b838934f88Chris LattnerPass *llvm::createArgumentPromotionPass() { 79ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return new ArgPromotion(); 80ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 81ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 825eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattnerbool ArgPromotion::runOnSCC(const std::vector<CallGraphNode *> &SCC) { 835eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner bool Changed = false, LocalChange; 84ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 855eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner do { 865eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner LocalChange = false; 875eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Attempt to promote arguments from all functions in this SCC. 885eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner for (unsigned i = 0, e = SCC.size(); i != e; ++i) 895eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner LocalChange |= PromoteArguments(SCC[i]); 905eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Changed |= LocalChange; // Remember that we changed something. 915eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner } while (LocalChange); 92ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 93ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return Changed; 94ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 95ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 969e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// PromoteArguments - This method checks the specified function to see if there 979e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// are any promotable arguments and if it is safe to promote the function (for 989e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// example, all callers are direct). If safe to promote some arguments, it 999e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// calls the DoPromotion method. 1009e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// 1015eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattnerbool ArgPromotion::PromoteArguments(CallGraphNode *CGN) { 1025eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *F = CGN->getFunction(); 1035eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner 1045eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Make sure that it is local to this module. 1055eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner if (!F || !F->hasInternalLinkage()) return false; 106ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 107ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // First check: see if there are any pointer arguments! If not, quick exit. 108ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<Argument*> PointerArgs; 109ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Function::aiterator I = F->abegin(), E = F->aend(); I != E; ++I) 110ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (isa<PointerType>(I->getType())) 111ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner PointerArgs.push_back(I); 112ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (PointerArgs.empty()) return false; 113ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 114ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Second check: make sure that all callers are direct callers. We can't 115ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // transform functions that have indirect callers. 116ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Value::use_iterator UI = F->use_begin(), E = F->use_end(); 1177db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner UI != E; ++UI) { 1187db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner CallSite CS = CallSite::get(*UI); 1199e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (!CS.getInstruction()) // "Taking the address" of the function 1209e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner return false; 1219e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 1229e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Ensure that this call site is CALLING the function, not passing it as 1239e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // an argument. 1249e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner for (CallSite::arg_iterator AI = CS.arg_begin(), E = CS.arg_end(); 1259e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AI != E; ++AI) 1269e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (*AI == F) return false; // Passing the function address in! 1277db5a6df78749bf0cd37870fcefe08b8849e38e6Chris Lattner } 128ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 129ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Check to see which arguments are promotable. If an argument is not 130ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // promotable, remove it from the PointerArgs vector. 131ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (unsigned i = 0; i != PointerArgs.size(); ++i) 132ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!isSafeToPromoteArgument(PointerArgs[i])) { 133ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::swap(PointerArgs[i--], PointerArgs.back()); 134ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner PointerArgs.pop_back(); 135ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 136ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 137ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // No promotable pointer arguments. 138ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (PointerArgs.empty()) return false; 139ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 140ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Okay, promote all of the arguments are rewrite the callees! 1415eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner Function *NewF = DoPromotion(F, PointerArgs); 1425eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner 1435eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Update the call graph to know that the old function is gone. 1445eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner getAnalysis<CallGraph>().changeFunction(F, NewF); 145ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return true; 146ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 147ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 1489e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 1499e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// isSafeToPromoteArgument - As you might guess from the name of this method, 1509e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// it checks to see if it is both safe and useful to promote the argument. 1519e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// This method limits promotion of aggregates to only promote up to three 1529e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// elements of the aggregate in order to avoid exploding the number of 1539e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// arguments passed in. 154ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattnerbool ArgPromotion::isSafeToPromoteArgument(Argument *Arg) const { 1559440db886627161a8413e823797569fc7b10beafChris Lattner // We can only promote this argument if all of the uses are loads, or are GEP 1569440db886627161a8413e823797569fc7b10beafChris Lattner // instructions (with constant indices) that are subsequently loaded. 157ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<LoadInst*> Loads; 158beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::vector<std::vector<ConstantInt*> > GEPIndices; 159ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Value::use_iterator UI = Arg->use_begin(), E = Arg->use_end(); 160ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner UI != E; ++UI) 161ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 162ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (LI->isVolatile()) return false; // Don't hack volatile loads 163ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Loads.push_back(LI); 1649440db886627161a8413e823797569fc7b10beafChris Lattner } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(*UI)) { 1659440db886627161a8413e823797569fc7b10beafChris Lattner if (GEP->use_empty()) { 1669440db886627161a8413e823797569fc7b10beafChris Lattner // Dead GEP's cause trouble later. Just remove them if we run into 1679440db886627161a8413e823797569fc7b10beafChris Lattner // them. 1689e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner getAnalysis<AliasAnalysis>().deleteValue(GEP); 1699440db886627161a8413e823797569fc7b10beafChris Lattner GEP->getParent()->getInstList().erase(GEP); 1709440db886627161a8413e823797569fc7b10beafChris Lattner return isSafeToPromoteArgument(Arg); 1719440db886627161a8413e823797569fc7b10beafChris Lattner } 1729440db886627161a8413e823797569fc7b10beafChris Lattner // Ensure that all of the indices are constants. 173beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::vector<ConstantInt*> Operands; 1749440db886627161a8413e823797569fc7b10beafChris Lattner for (unsigned i = 1, e = GEP->getNumOperands(); i != e; ++i) 175beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(i))) 1769440db886627161a8413e823797569fc7b10beafChris Lattner Operands.push_back(C); 1779440db886627161a8413e823797569fc7b10beafChris Lattner else 1789440db886627161a8413e823797569fc7b10beafChris Lattner return false; // Not a constant operand GEP! 1799440db886627161a8413e823797569fc7b10beafChris Lattner 1809440db886627161a8413e823797569fc7b10beafChris Lattner // Ensure that the only users of the GEP are load instructions. 1819440db886627161a8413e823797569fc7b10beafChris Lattner for (Value::use_iterator UI = GEP->use_begin(), E = GEP->use_end(); 1829440db886627161a8413e823797569fc7b10beafChris Lattner UI != E; ++UI) 1839440db886627161a8413e823797569fc7b10beafChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) { 1849440db886627161a8413e823797569fc7b10beafChris Lattner if (LI->isVolatile()) return false; // Don't hack volatile loads 1859440db886627161a8413e823797569fc7b10beafChris Lattner Loads.push_back(LI); 1869440db886627161a8413e823797569fc7b10beafChris Lattner } else { 1879440db886627161a8413e823797569fc7b10beafChris Lattner return false; 1889440db886627161a8413e823797569fc7b10beafChris Lattner } 189ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 1909e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // See if there is already a GEP with these indices. If not, check to 1919e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // make sure that we aren't promoting too many elements. If so, nothing 1929e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // to do. 1939440db886627161a8413e823797569fc7b10beafChris Lattner if (std::find(GEPIndices.begin(), GEPIndices.end(), Operands) == 1949440db886627161a8413e823797569fc7b10beafChris Lattner GEPIndices.end()) { 1959440db886627161a8413e823797569fc7b10beafChris Lattner if (GEPIndices.size() == 3) { 1969e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner DEBUG(std::cerr << "argpromotion disable promoting argument '" 1979e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner << Arg->getName() << "' because it would require adding more " 1989e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner << "than 3 arguments to the function.\n"); 1999440db886627161a8413e823797569fc7b10beafChris Lattner // We limit aggregate promotion to only promoting up to three elements 2009440db886627161a8413e823797569fc7b10beafChris Lattner // of the aggregate. 2019440db886627161a8413e823797569fc7b10beafChris Lattner return false; 2029440db886627161a8413e823797569fc7b10beafChris Lattner } 2039440db886627161a8413e823797569fc7b10beafChris Lattner GEPIndices.push_back(Operands); 2049440db886627161a8413e823797569fc7b10beafChris Lattner } 2059440db886627161a8413e823797569fc7b10beafChris Lattner } else { 2069440db886627161a8413e823797569fc7b10beafChris Lattner return false; // Not a load or a GEP. 2079440db886627161a8413e823797569fc7b10beafChris Lattner } 208ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 2099e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (Loads.empty()) return true; // No users, this is a dead argument. 210ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 2119e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Okay, now we know that the argument is only used by load instructions. Use 2129e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // alias analysis to check to see if the pointer is guaranteed to not be 2139e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // modified from entry of the function to each of the load instructions. 214ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Function &F = *Arg->getParent(); 215ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 216ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Because there could be several/many load instructions, remember which 217ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // blocks we know to be transparent to the load. 218ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::set<BasicBlock*> TranspBlocks; 219ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 220ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 2219440db886627161a8413e823797569fc7b10beafChris Lattner TargetData &TD = getAnalysis<TargetData>(); 222ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 223ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (unsigned i = 0, e = Loads.size(); i != e; ++i) { 224ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Check to see if the load is invalidated from the start of the block to 225ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the load itself. 226ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner LoadInst *Load = Loads[i]; 227ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner BasicBlock *BB = Load->getParent(); 2289440db886627161a8413e823797569fc7b10beafChris Lattner 2299440db886627161a8413e823797569fc7b10beafChris Lattner const PointerType *LoadTy = 2309440db886627161a8413e823797569fc7b10beafChris Lattner cast<PointerType>(Load->getOperand(0)->getType()); 2319440db886627161a8413e823797569fc7b10beafChris Lattner unsigned LoadSize = TD.getTypeSize(LoadTy->getElementType()); 2329440db886627161a8413e823797569fc7b10beafChris Lattner 233ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (AA.canInstructionRangeModify(BB->front(), *Load, Arg, LoadSize)) 234ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return false; // Pointer is invalidated! 235ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 236ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Now check every path from the entry block to the load for transparency. 237ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // To do this, we perform a depth first search on the inverse CFG from the 238ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // loading block. 239ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) 240ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (idf_ext_iterator<BasicBlock*> I = idf_ext_begin(*PI, TranspBlocks), 241ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner E = idf_ext_end(*PI, TranspBlocks); I != E; ++I) 242ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (AA.canBasicBlockModify(**I, Arg, LoadSize)) 243ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return false; 244ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 245ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 246ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // If the path from the entry of the function to each load is free of 247ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // instructions that potentially invalidate the load, we can make the 248ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // transformation! 249ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner return true; 250ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 251ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 252beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattnernamespace { 253beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// GEPIdxComparator - Provide a strong ordering for GEP indices. All Value* 254beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// elements are instances of ConstantInt. 255beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner /// 256beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner struct GEPIdxComparator { 257beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner bool operator()(const std::vector<Value*> &LHS, 258beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner const std::vector<Value*> &RHS) const { 259beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner unsigned idx = 0; 260beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (; idx < LHS.size() && idx < RHS.size(); ++idx) { 261beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner if (LHS[idx] != RHS[idx]) { 262beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner return cast<ConstantInt>(LHS[idx])->getRawValue() < 263beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner cast<ConstantInt>(RHS[idx])->getRawValue(); 264beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 265beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 266beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 267beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner // Return less than if we ran out of stuff in LHS and we didn't run out of 268beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner // stuff in RHS. 269beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner return idx == LHS.size() && idx != RHS.size(); 270beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner } 271beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner }; 272beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner} 273beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 274beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 2759e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner/// DoPromotion - This method actually performs the promotion of the specified 2765eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner/// arguments, and returns the new function. At this point, we know that it's 2775eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner/// safe to do so. 2785eb6f6c829ddfe353f94623aa1009c72be930497Chris LattnerFunction *ArgPromotion::DoPromotion(Function *F, 2795eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner std::vector<Argument*> &Args2Prom) { 280ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::set<Argument*> ArgsToPromote(Args2Prom.begin(), Args2Prom.end()); 281ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 282ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Start by computing a new prototype for the function, which is the same as 283ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the old function, but has modified arguments. 284ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner const FunctionType *FTy = F->getFunctionType(); 285ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<const Type*> Params; 286ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 287beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner typedef std::set<std::vector<Value*>, GEPIdxComparator> ScalarizeTable; 288beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner 2899440db886627161a8413e823797569fc7b10beafChris Lattner // ScalarizedElements - If we are promoting a pointer that has elements 2909440db886627161a8413e823797569fc7b10beafChris Lattner // accessed out of it, keep track of which elements are accessed so that we 2919440db886627161a8413e823797569fc7b10beafChris Lattner // can add one argument for each. 2929440db886627161a8413e823797569fc7b10beafChris Lattner // 2939440db886627161a8413e823797569fc7b10beafChris Lattner // Arguments that are directly loaded will have a zero element value here, to 2949440db886627161a8413e823797569fc7b10beafChris Lattner // handle cases where there are both a direct load and GEP accesses. 2959440db886627161a8413e823797569fc7b10beafChris Lattner // 296beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner std::map<Argument*, ScalarizeTable> ScalarizedElements; 2979440db886627161a8413e823797569fc7b10beafChris Lattner 2989e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // OriginalLoads - Keep track of a representative load instruction from the 2999e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // original function so that we can tell the alias analysis implementation 3009e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // what the new GEP/Load instructions we are inserting look like. 3019e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner std::map<std::vector<Value*>, LoadInst*> OriginalLoads; 3029e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 303ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Function::aiterator I = F->abegin(), E = F->aend(); I != E; ++I) 304ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) { 305ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Params.push_back(I->getType()); 3069e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else if (I->use_empty()) { 3079e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner ++NumArgumentsDead; 3089e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else { 3099440db886627161a8413e823797569fc7b10beafChris Lattner // Okay, this is being promoted. Check to see if there are any GEP uses 3109440db886627161a8413e823797569fc7b10beafChris Lattner // of the argument. 311beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 3129440db886627161a8413e823797569fc7b10beafChris Lattner for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E; 3139440db886627161a8413e823797569fc7b10beafChris Lattner ++UI) { 3149440db886627161a8413e823797569fc7b10beafChris Lattner Instruction *User = cast<Instruction>(*UI); 3159440db886627161a8413e823797569fc7b10beafChris Lattner assert(isa<LoadInst>(User) || isa<GetElementPtrInst>(User)); 3169e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner std::vector<Value*> Indices(User->op_begin()+1, User->op_end()); 3179e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner ArgIndices.insert(Indices); 3189e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner LoadInst *OrigLoad; 3199e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (LoadInst *L = dyn_cast<LoadInst>(User)) 3209e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner OrigLoad = L; 3219e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner else 3229e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner OrigLoad = cast<LoadInst>(User->use_back()); 3239e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner OriginalLoads[Indices] = OrigLoad; 3249440db886627161a8413e823797569fc7b10beafChris Lattner } 3259440db886627161a8413e823797569fc7b10beafChris Lattner 3269440db886627161a8413e823797569fc7b10beafChris Lattner // Add a parameter to the function for each element passed in. 327beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator SI = ArgIndices.begin(), 3289440db886627161a8413e823797569fc7b10beafChris Lattner E = ArgIndices.end(); SI != E; ++SI) 3299440db886627161a8413e823797569fc7b10beafChris Lattner Params.push_back(GetElementPtrInst::getIndexedType(I->getType(), *SI)); 3309440db886627161a8413e823797569fc7b10beafChris Lattner 3319440db886627161a8413e823797569fc7b10beafChris Lattner if (ArgIndices.size() == 1 && ArgIndices.begin()->empty()) 3329440db886627161a8413e823797569fc7b10beafChris Lattner ++NumArgumentsPromoted; 3339440db886627161a8413e823797569fc7b10beafChris Lattner else 3349440db886627161a8413e823797569fc7b10beafChris Lattner ++NumAggregatesPromoted; 335ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 336ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 337ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner const Type *RetTy = FTy->getReturnType(); 338ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 339ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Work around LLVM bug PR56: the CWriter cannot emit varargs functions which 340ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // have zero fixed arguments. 341ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner bool ExtraArgHack = false; 342ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (Params.empty() && FTy->isVarArg()) { 343ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner ExtraArgHack = true; 344ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Params.push_back(Type::IntTy); 345ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 346ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg()); 347ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 348ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Create the new function body and insert it into the module... 349ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Function *NF = new Function(NFTy, F->getLinkage(), F->getName()); 350ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner F->getParent()->getFunctionList().insert(F, NF); 3519e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 3529e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Get the alias analysis information that we need to update to reflect our 3539e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // changes. 3549e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); 3559e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 356ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Loop over all of the callers of the function, transforming the call sites 357ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // to pass in the loaded pointers. 358ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // 359ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::vector<Value*> Args; 360ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner while (!F->use_empty()) { 361ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner CallSite CS = CallSite::get(F->use_back()); 362ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Instruction *Call = CS.getInstruction(); 363ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 3649e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Loop over the operands, inserting GEP and loads in the caller as 3659e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // appropriate. 366ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner CallSite::arg_iterator AI = CS.arg_begin(); 367ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Function::aiterator I = F->abegin(), E = F->aend(); I != E; ++I, ++AI) 368ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) 369ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.push_back(*AI); // Unmodified argument 370ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner else if (!I->use_empty()) { 3719e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Non-dead argument: insert GEPs and loads as appropriate. 372beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 373beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator SI = ArgIndices.begin(), 3749440db886627161a8413e823797569fc7b10beafChris Lattner E = ArgIndices.end(); SI != E; ++SI) { 3759440db886627161a8413e823797569fc7b10beafChris Lattner Value *V = *AI; 3769e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner LoadInst *OrigLoad = OriginalLoads[*SI]; 3779e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (!SI->empty()) { 3789440db886627161a8413e823797569fc7b10beafChris Lattner V = new GetElementPtrInst(V, *SI, V->getName()+".idx", Call); 3799e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.copyValue(OrigLoad->getOperand(0), V); 3809e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } 3819440db886627161a8413e823797569fc7b10beafChris Lattner Args.push_back(new LoadInst(V, V->getName()+".val", Call)); 3829e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.copyValue(OrigLoad, Args.back()); 3839440db886627161a8413e823797569fc7b10beafChris Lattner } 384ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 385ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 386ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (ExtraArgHack) 387ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.push_back(Constant::getNullValue(Type::IntTy)); 388ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 389ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Push any varargs arguments on the list 390ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (; AI != CS.arg_end(); ++AI) 391ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.push_back(*AI); 392ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 393ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Instruction *New; 394ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) { 395ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner New = new InvokeInst(NF, II->getNormalDest(), II->getUnwindDest(), 396ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args, "", Call); 397ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } else { 398ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner New = new CallInst(NF, Args, "", Call); 399ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 400ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Args.clear(); 401ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 4029e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Update the alias analysis implementation to know that we are replacing 4039e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // the old call with a new one. 4049e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(Call, New); 4059e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 406ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!Call->use_empty()) { 407ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Call->replaceAllUsesWith(New); 408ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner std::string Name = Call->getName(); 409ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Call->setName(""); 410ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner New->setName(Name); 411ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 412ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 413ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Finally, remove the old call from the program, reducing the use-count of 414ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // F. 415ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner Call->getParent()->getInstList().erase(Call); 416ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 417ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 418ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Since we have now created the new function, splice the body of the old 419ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // function right into the new function, leaving the old rotting hulk of the 420ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // function empty. 421ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner NF->getBasicBlockList().splice(NF->begin(), F->getBasicBlockList()); 422ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 423ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Loop over the argument list, transfering uses of the old arguments over to 424ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // the new arguments, also transfering over the names as well. 425ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // 426ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner for (Function::aiterator I = F->abegin(), E = F->aend(), I2 = NF->abegin(); 427ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner I != E; ++I) 428ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner if (!ArgsToPromote.count(I)) { 429ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // If this is an unmodified argument, move the name and users over to the 430ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // new version. 431ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner I->replaceAllUsesWith(I2); 432ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner I2->setName(I->getName()); 4339e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(I, I2); 434ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner ++I2; 4359e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else if (I->use_empty()) { 4369e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.deleteValue(I); 4379e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner } else { 438ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Otherwise, if we promoted this argument, then all users are load 439ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // instructions, and all loads should be using the new argument that we 440ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // added. 441beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner ScalarizeTable &ArgIndices = ScalarizedElements[I]; 4429440db886627161a8413e823797569fc7b10beafChris Lattner 443ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner while (!I->use_empty()) { 4449440db886627161a8413e823797569fc7b10beafChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(I->use_back())) { 4459440db886627161a8413e823797569fc7b10beafChris Lattner assert(ArgIndices.begin()->empty() && 4469440db886627161a8413e823797569fc7b10beafChris Lattner "Load element should sort to front!"); 4479440db886627161a8413e823797569fc7b10beafChris Lattner I2->setName(I->getName()+".val"); 4489440db886627161a8413e823797569fc7b10beafChris Lattner LI->replaceAllUsesWith(I2); 4499e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(LI, I2); 4509440db886627161a8413e823797569fc7b10beafChris Lattner LI->getParent()->getInstList().erase(LI); 4519e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner DEBUG(std::cerr << "*** Promoted load of argument '" << I->getName() 4529e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner << "' in function '" << F->getName() << "'\n"); 4539440db886627161a8413e823797569fc7b10beafChris Lattner } else { 4549440db886627161a8413e823797569fc7b10beafChris Lattner GetElementPtrInst *GEP = cast<GetElementPtrInst>(I->use_back()); 4559440db886627161a8413e823797569fc7b10beafChris Lattner std::vector<Value*> Operands(GEP->op_begin()+1, GEP->op_end()); 4569440db886627161a8413e823797569fc7b10beafChris Lattner 4579440db886627161a8413e823797569fc7b10beafChris Lattner unsigned ArgNo = 0; 4589440db886627161a8413e823797569fc7b10beafChris Lattner Function::aiterator TheArg = I2; 459beabf45a6923b1748edae40d53e2b2c4362cc32fChris Lattner for (ScalarizeTable::iterator It = ArgIndices.begin(); 4609440db886627161a8413e823797569fc7b10beafChris Lattner *It != Operands; ++It, ++TheArg) { 4619440db886627161a8413e823797569fc7b10beafChris Lattner assert(It != ArgIndices.end() && "GEP not handled??"); 4629440db886627161a8413e823797569fc7b10beafChris Lattner } 4639440db886627161a8413e823797569fc7b10beafChris Lattner 4649440db886627161a8413e823797569fc7b10beafChris Lattner std::string NewName = I->getName(); 4659440db886627161a8413e823797569fc7b10beafChris Lattner for (unsigned i = 0, e = Operands.size(); i != e; ++i) 4669440db886627161a8413e823797569fc7b10beafChris Lattner if (ConstantInt *CI = dyn_cast<ConstantInt>(Operands[i])) 4679440db886627161a8413e823797569fc7b10beafChris Lattner NewName += "."+itostr((int64_t)CI->getRawValue()); 4689440db886627161a8413e823797569fc7b10beafChris Lattner else 4699440db886627161a8413e823797569fc7b10beafChris Lattner NewName += ".x"; 4709440db886627161a8413e823797569fc7b10beafChris Lattner TheArg->setName(NewName+".val"); 4719440db886627161a8413e823797569fc7b10beafChris Lattner 4729440db886627161a8413e823797569fc7b10beafChris Lattner DEBUG(std::cerr << "*** Promoted agg argument '" << TheArg->getName() 4739440db886627161a8413e823797569fc7b10beafChris Lattner << "' of function '" << F->getName() << "'\n"); 4749440db886627161a8413e823797569fc7b10beafChris Lattner 4759440db886627161a8413e823797569fc7b10beafChris Lattner // All of the uses must be load instructions. Replace them all with 4769440db886627161a8413e823797569fc7b10beafChris Lattner // the argument specified by ArgNo. 4779440db886627161a8413e823797569fc7b10beafChris Lattner while (!GEP->use_empty()) { 4789440db886627161a8413e823797569fc7b10beafChris Lattner LoadInst *L = cast<LoadInst>(GEP->use_back()); 4799440db886627161a8413e823797569fc7b10beafChris Lattner L->replaceAllUsesWith(TheArg); 4809e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(L, TheArg); 4819440db886627161a8413e823797569fc7b10beafChris Lattner L->getParent()->getInstList().erase(L); 4829440db886627161a8413e823797569fc7b10beafChris Lattner } 4839e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.deleteValue(GEP); 4849440db886627161a8413e823797569fc7b10beafChris Lattner GEP->getParent()->getInstList().erase(GEP); 4859440db886627161a8413e823797569fc7b10beafChris Lattner } 486ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 48786a734bd40857db9ef205234f3b58e550ee5959bChris Lattner 4885eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner // Increment I2 past all of the arguments added for this promoted pointer. 4895eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner for (unsigned i = 0, e = ArgIndices.size(); i != e; ++i) 4905eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner ++I2; 491ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner } 492ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner 4939e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Notify the alias analysis implementation that we inserted a new argument. 4949e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner if (ExtraArgHack) 4959e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.copyValue(Constant::getNullValue(Type::IntTy), NF->abegin()); 4969e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 4979e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 4989e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner // Tell the alias analysis that the old function is about to disappear. 4999e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner AA.replaceWithNewValue(F, NF); 5009e7cc2f0d42aa4127e3b8406e25907a96ce9ada0Chris Lattner 501ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner // Now that the old function is dead, delete it. 502ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner F->getParent()->getFunctionList().erase(F); 5035eb6f6c829ddfe353f94623aa1009c72be930497Chris Lattner return NF; 504ed570a7dca45e001a6223e2a25d034b838934f88Chris Lattner} 505