SSAUpdater.cpp revision db125cfaf57cc83e7dd7453de2d509bc8efd0e5e
193f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner//===- SSAUpdater.cpp - Unstructured SSA Update Tool ----------------------===// 293f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// 393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// The LLVM Compiler Infrastructure 493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// 593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// This file is distributed under the University of Illinois Open Source 693f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// License. See LICENSE.TXT for details. 793f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// 893f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner//===----------------------------------------------------------------------===// 993f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// 1093f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// This file implements the SSAUpdater class. 1193f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner// 1293f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner//===----------------------------------------------------------------------===// 1393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 1484bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson#define DEBUG_TYPE "ssaupdater" 15562b84b3aea359d1f918184e355da82bf05eb290Jay Foad#include "llvm/Constants.h" 1693f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner#include "llvm/Instructions.h" 17c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich#include "llvm/IntrinsicInst.h" 1893f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner#include "llvm/ADT/DenseMap.h" 19840635741f132a9a10f052cbf3b21e14bc74835aChris Lattner#include "llvm/ADT/TinyPtrVector.h" 20cdbd99262286e96729007ac535cd430ecb3d38acDuncan Sands#include "llvm/Analysis/InstructionSimplify.h" 2184bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson#include "llvm/Support/AlignOf.h" 2284bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson#include "llvm/Support/Allocator.h" 2393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner#include "llvm/Support/CFG.h" 2493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner#include "llvm/Support/Debug.h" 2593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner#include "llvm/Support/raw_ostream.h" 2640348e8d1ff564a23101d4fd37fe4dd03d9018abDevang Patel#include "llvm/Transforms/Utils/BasicBlockUtils.h" 27c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich#include "llvm/Transforms/Utils/Local.h" 284aad88d1fd88413029dd05255306b07cb19396eeBob Wilson#include "llvm/Transforms/Utils/SSAUpdater.h" 294aad88d1fd88413029dd05255306b07cb19396eeBob Wilson#include "llvm/Transforms/Utils/SSAUpdaterImpl.h" 3040348e8d1ff564a23101d4fd37fe4dd03d9018abDevang Patel 3193f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattnerusing namespace llvm; 3293f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 3384bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilsontypedef DenseMap<BasicBlock*, Value*> AvailableValsTy; 3493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattnerstatic AvailableValsTy &getAvailableVals(void *AV) { 3593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner return *static_cast<AvailableValsTy*>(AV); 3693f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner} 3793f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 38f5a1fb6b247611b92d9dec9476202b477661dbe8Chris LattnerSSAUpdater::SSAUpdater(SmallVectorImpl<PHINode*> *NewPHI) 39fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands : AV(0), ProtoType(0), ProtoName(), InsertedPHIs(NewPHI) {} 4093f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 4193f3bcf7f323069e40d9abb950da73d437b6f7daChris LattnerSSAUpdater::~SSAUpdater() { 4293f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner delete &getAvailableVals(AV); 4393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner} 4493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 4593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner/// Initialize - Reset this object to get ready for a new set of SSA 46fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands/// updates with type 'Ty'. PHI nodes get a name based on 'Name'. 47db125cfaf57cc83e7dd7453de2d509bc8efd0e5eChris Lattnervoid SSAUpdater::Initialize(Type *Ty, StringRef Name) { 4893f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner if (AV == 0) 4993f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner AV = new AvailableValsTy(); 5093f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner else 5193f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner getAvailableVals(AV).clear(); 52fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands ProtoType = Ty; 53fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands ProtoName = Name; 5493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner} 5593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 560bef562ea253878ee92a1eaf6db05b0c2edfa74cChris Lattner/// HasValueForBlock - Return true if the SSAUpdater already has a value for 570bef562ea253878ee92a1eaf6db05b0c2edfa74cChris Lattner/// the specified block. 580bef562ea253878ee92a1eaf6db05b0c2edfa74cChris Lattnerbool SSAUpdater::HasValueForBlock(BasicBlock *BB) const { 590bef562ea253878ee92a1eaf6db05b0c2edfa74cChris Lattner return getAvailableVals(AV).count(BB); 600bef562ea253878ee92a1eaf6db05b0c2edfa74cChris Lattner} 610bef562ea253878ee92a1eaf6db05b0c2edfa74cChris Lattner 6293f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner/// AddAvailableValue - Indicate that a rewritten value is available in the 6393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner/// specified block with the specified value. 6493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattnervoid SSAUpdater::AddAvailableValue(BasicBlock *BB, Value *V) { 65fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands assert(ProtoType != 0 && "Need to initialize SSAUpdater"); 66fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands assert(ProtoType == V->getType() && 6793f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner "All rewritten values must have the same type"); 6893f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner getAvailableVals(AV)[BB] = V; 6993f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner} 7093f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 71e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson/// IsEquivalentPHI - Check if PHI has the same incoming value as specified 72e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson/// in ValueMapping for each predecessor block. 7384bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilsonstatic bool IsEquivalentPHI(PHINode *PHI, 74e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson DenseMap<BasicBlock*, Value*> &ValueMapping) { 75e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson unsigned PHINumValues = PHI->getNumIncomingValues(); 76e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson if (PHINumValues != ValueMapping.size()) 77e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson return false; 78e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson 79e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson // Scan the phi to see if it matches. 80e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson for (unsigned i = 0, e = PHINumValues; i != e; ++i) 81e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson if (ValueMapping[PHI->getIncomingBlock(i)] != 82e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson PHI->getIncomingValue(i)) { 83e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson return false; 84e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson } 85e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson 86e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson return true; 87e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson} 88e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson 891a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// GetValueAtEndOfBlock - Construct SSA form, materializing a value that is 901a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// live at the end of the specified block. 915fb107287fd8d35b8fc39aa3e6b084fb2871a8ffChris LattnerValue *SSAUpdater::GetValueAtEndOfBlock(BasicBlock *BB) { 925fb107287fd8d35b8fc39aa3e6b084fb2871a8ffChris Lattner Value *Res = GetValueAtEndOfBlockInternal(BB); 9393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner return Res; 9493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner} 9593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 961a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// GetValueInMiddleOfBlock - Construct SSA form, materializing a value that 971a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// is live in the middle of the specified block. 981a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// 991a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// GetValueInMiddleOfBlock is the same as GetValueAtEndOfBlock except in one 1001a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// important case: if there is a definition of the rewritten value after the 1011a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// 'use' in BB. Consider code like this: 1021a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// 1031a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// X1 = ... 1041a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// SomeBB: 1051a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// use(X) 1061a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// X2 = ... 1071a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// br Cond, SomeBB, OutBB 1081a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// 1091a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// In this case, there are two values (X1 and X2) added to the AvailableVals 1101a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// set by the client of the rewriter, and those values are both live out of 1111a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// their respective blocks. However, the use of X happens in the *middle* of 1121a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// a block. Because of this, we need to insert a new PHI node in SomeBB to 1131a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// merge the appropriate values, and this value isn't live out of the block. 1141a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner/// 1151a8d4de397c360a76f1389d15e862eba265d71fdChris LattnerValue *SSAUpdater::GetValueInMiddleOfBlock(BasicBlock *BB) { 1161a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // If there is no definition of the renamed variable in this block, just use 1171a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // GetValueAtEndOfBlock to do our work. 11884bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson if (!HasValueForBlock(BB)) 1191a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner return GetValueAtEndOfBlock(BB); 120ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1211a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // Otherwise, we have the hard case. Get the live-in values for each 1221a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // predecessor. 1231a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner SmallVector<std::pair<BasicBlock*, Value*>, 8> PredValues; 1241a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner Value *SingularValue = 0; 125ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1261a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // We can get our predecessor info by walking the pred_iterator list, but it 1271a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // is relatively slow. If we already have PHI nodes in this block, walk one 1281a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // of them to get the predecessor list instead. 1291a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) { 1301a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner for (unsigned i = 0, e = SomePhi->getNumIncomingValues(); i != e; ++i) { 1311a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner BasicBlock *PredBB = SomePhi->getIncomingBlock(i); 1321a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner Value *PredVal = GetValueAtEndOfBlock(PredBB); 1331a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner PredValues.push_back(std::make_pair(PredBB, PredVal)); 134ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1351a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // Compute SingularValue. 1361a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner if (i == 0) 1371a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner SingularValue = PredVal; 1381a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner else if (PredVal != SingularValue) 1391a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner SingularValue = 0; 1401a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner } 1411a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner } else { 1421a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner bool isFirstPred = true; 1431a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) { 1441a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner BasicBlock *PredBB = *PI; 1451a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner Value *PredVal = GetValueAtEndOfBlock(PredBB); 1461a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner PredValues.push_back(std::make_pair(PredBB, PredVal)); 147ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1481a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // Compute SingularValue. 1491a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner if (isFirstPred) { 1501a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner SingularValue = PredVal; 1511a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner isFirstPred = false; 1521a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner } else if (PredVal != SingularValue) 1531a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner SingularValue = 0; 1541a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner } 1551a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner } 156ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1571a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // If there are no predecessors, just return undef. 1581a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner if (PredValues.empty()) 159fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands return UndefValue::get(ProtoType); 160ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1611a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // Otherwise, if all the merged values are the same, just use it. 1621a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner if (SingularValue != 0) 1631a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner return SingularValue; 164ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 16584bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson // Otherwise, we do need a PHI: check to see if we already have one available 16684bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson // in this block that produces the right value. 16784bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson if (isa<PHINode>(BB->begin())) { 16884bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson DenseMap<BasicBlock*, Value*> ValueMapping(PredValues.begin(), 16984bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson PredValues.end()); 17084bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson PHINode *SomePHI; 17184bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson for (BasicBlock::iterator It = BB->begin(); 17284bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson (SomePHI = dyn_cast<PHINode>(It)); ++It) { 17384bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson if (IsEquivalentPHI(SomePHI, ValueMapping)) 17484bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson return SomePHI; 17584bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 17684bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 177e98585eb36eff3b8c7da1cf7b044da6a05973074Bob Wilson 1784c1e3da0cdd2fd0df5188dea1988beb8bf6a0dc6Chris Lattner // Ok, we have no way out, insert a new one now. 1793ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad PHINode *InsertedPHI = PHINode::Create(ProtoType, PredValues.size(), 1803ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad ProtoName, &BB->front()); 181ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1821a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // Fill in all the predecessors of the PHI. 1831a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner for (unsigned i = 0, e = PredValues.size(); i != e; ++i) 1841a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner InsertedPHI->addIncoming(PredValues[i].second, PredValues[i].first); 185ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1861a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // See if the PHI node can be merged to a single value. This can happen in 1871a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner // loop cases when we get a PHI of itself and one other value. 188cdbd99262286e96729007ac535cd430ecb3d38acDuncan Sands if (Value *V = SimplifyInstruction(InsertedPHI)) { 1891a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner InsertedPHI->eraseFromParent(); 190cdbd99262286e96729007ac535cd430ecb3d38acDuncan Sands return V; 1911a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner } 192f5a1fb6b247611b92d9dec9476202b477661dbe8Chris Lattner 19340348e8d1ff564a23101d4fd37fe4dd03d9018abDevang Patel // Set DebugLoc. 19440348e8d1ff564a23101d4fd37fe4dd03d9018abDevang Patel InsertedPHI->setDebugLoc(GetFirstDebugLocInBasicBlock(BB)); 19540348e8d1ff564a23101d4fd37fe4dd03d9018abDevang Patel 196f5a1fb6b247611b92d9dec9476202b477661dbe8Chris Lattner // If the client wants to know about all new instructions, tell it. 197f5a1fb6b247611b92d9dec9476202b477661dbe8Chris Lattner if (InsertedPHIs) InsertedPHIs->push_back(InsertedPHI); 198ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 1991af40cacd4d162ffe9dfbafa1230e502e059be65David Greene DEBUG(dbgs() << " Inserted PHI: " << *InsertedPHI << "\n"); 2001a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner return InsertedPHI; 2011a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner} 2021a8d4de397c360a76f1389d15e862eba265d71fdChris Lattner 20393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner/// RewriteUse - Rewrite a use of the symbolic value. This handles PHI nodes, 20493f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner/// which use their value in the corresponding predecessor. 20593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattnervoid SSAUpdater::RewriteUse(Use &U) { 20693f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner Instruction *User = cast<Instruction>(U.getUser()); 20784bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson 20888a8624f8e104e1ba1ca21efa6ae23680b528a3eChris Lattner Value *V; 20988a8624f8e104e1ba1ca21efa6ae23680b528a3eChris Lattner if (PHINode *UserPN = dyn_cast<PHINode>(User)) 21088a8624f8e104e1ba1ca21efa6ae23680b528a3eChris Lattner V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U)); 21188a8624f8e104e1ba1ca21efa6ae23680b528a3eChris Lattner else 21288a8624f8e104e1ba1ca21efa6ae23680b528a3eChris Lattner V = GetValueInMiddleOfBlock(User->getParent()); 213ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 214f993327e71d826dcb852929a78881569ef83374dTorok Edwin U.set(V); 21593f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner} 21693f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner 217ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner/// RewriteUseAfterInsertions - Rewrite a use, just like RewriteUse. However, 218ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner/// this version of the method can rewrite uses in the same block as a 219ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner/// definition, because it assumes that all uses of a value are below any 220ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner/// inserted values. 221ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattnervoid SSAUpdater::RewriteUseAfterInsertions(Use &U) { 222ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner Instruction *User = cast<Instruction>(U.getUser()); 223ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner 224ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner Value *V; 225ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner if (PHINode *UserPN = dyn_cast<PHINode>(User)) 226ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner V = GetValueAtEndOfBlock(UserPN->getIncomingBlock(U)); 227ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner else 228ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner V = GetValueAtEndOfBlock(User->getParent()); 229ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner 230ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner U.set(V); 231ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner} 232ffd9beefb8d1fc854fc2863ad443a557be2b4196Chris Lattner 2334aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// PHIiter - Iterator for PHI operands. This is used for the PHI_iterator 2344aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// in the SSAUpdaterImpl template. 2354aad88d1fd88413029dd05255306b07cb19396eeBob Wilsonnamespace { 2364aad88d1fd88413029dd05255306b07cb19396eeBob Wilson class PHIiter { 2374aad88d1fd88413029dd05255306b07cb19396eeBob Wilson private: 2384aad88d1fd88413029dd05255306b07cb19396eeBob Wilson PHINode *PHI; 2394aad88d1fd88413029dd05255306b07cb19396eeBob Wilson unsigned idx; 2404aad88d1fd88413029dd05255306b07cb19396eeBob Wilson 2414aad88d1fd88413029dd05255306b07cb19396eeBob Wilson public: 2424aad88d1fd88413029dd05255306b07cb19396eeBob Wilson explicit PHIiter(PHINode *P) // begin iterator 2434aad88d1fd88413029dd05255306b07cb19396eeBob Wilson : PHI(P), idx(0) {} 2444aad88d1fd88413029dd05255306b07cb19396eeBob Wilson PHIiter(PHINode *P, bool) // end iterator 2454aad88d1fd88413029dd05255306b07cb19396eeBob Wilson : PHI(P), idx(PHI->getNumIncomingValues()) {} 2464aad88d1fd88413029dd05255306b07cb19396eeBob Wilson 2474aad88d1fd88413029dd05255306b07cb19396eeBob Wilson PHIiter &operator++() { ++idx; return *this; } 2484aad88d1fd88413029dd05255306b07cb19396eeBob Wilson bool operator==(const PHIiter& x) const { return idx == x.idx; } 2494aad88d1fd88413029dd05255306b07cb19396eeBob Wilson bool operator!=(const PHIiter& x) const { return !operator==(x); } 2504aad88d1fd88413029dd05255306b07cb19396eeBob Wilson Value *getIncomingValue() { return PHI->getIncomingValue(idx); } 2514aad88d1fd88413029dd05255306b07cb19396eeBob Wilson BasicBlock *getIncomingBlock() { return PHI->getIncomingBlock(idx); } 2524aad88d1fd88413029dd05255306b07cb19396eeBob Wilson }; 25384bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson} 25484bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson 2554aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// SSAUpdaterTraits<SSAUpdater> - Traits for the SSAUpdaterImpl template, 2564aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// specialized for SSAUpdater. 2574aad88d1fd88413029dd05255306b07cb19396eeBob Wilsonnamespace llvm { 2584aad88d1fd88413029dd05255306b07cb19396eeBob Wilsontemplate<> 2594aad88d1fd88413029dd05255306b07cb19396eeBob Wilsonclass SSAUpdaterTraits<SSAUpdater> { 2604aad88d1fd88413029dd05255306b07cb19396eeBob Wilsonpublic: 2614aad88d1fd88413029dd05255306b07cb19396eeBob Wilson typedef BasicBlock BlkT; 2624aad88d1fd88413029dd05255306b07cb19396eeBob Wilson typedef Value *ValT; 2634aad88d1fd88413029dd05255306b07cb19396eeBob Wilson typedef PHINode PhiT; 2644aad88d1fd88413029dd05255306b07cb19396eeBob Wilson 2654aad88d1fd88413029dd05255306b07cb19396eeBob Wilson typedef succ_iterator BlkSucc_iterator; 2664aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static BlkSucc_iterator BlkSucc_begin(BlkT *BB) { return succ_begin(BB); } 2674aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static BlkSucc_iterator BlkSucc_end(BlkT *BB) { return succ_end(BB); } 2684aad88d1fd88413029dd05255306b07cb19396eeBob Wilson 2694aad88d1fd88413029dd05255306b07cb19396eeBob Wilson typedef PHIiter PHI_iterator; 2704aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static inline PHI_iterator PHI_begin(PhiT *PHI) { return PHI_iterator(PHI); } 2714aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static inline PHI_iterator PHI_end(PhiT *PHI) { 2724aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return PHI_iterator(PHI, true); 27384bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 27449c283fd3f8f81e04b84dc848981b4bf17b2d706Bob Wilson 2754aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// FindPredecessorBlocks - Put the predecessors of Info->BB into the Preds 2764aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// vector, set Info->NumPreds, and allocate space in Info->Preds. 2774aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static void FindPredecessorBlocks(BasicBlock *BB, 2784aad88d1fd88413029dd05255306b07cb19396eeBob Wilson SmallVectorImpl<BasicBlock*> *Preds) { 2794aad88d1fd88413029dd05255306b07cb19396eeBob Wilson // We can get our predecessor info by walking the pred_iterator list, 2804aad88d1fd88413029dd05255306b07cb19396eeBob Wilson // but it is relatively slow. If we already have PHI nodes in this 2814aad88d1fd88413029dd05255306b07cb19396eeBob Wilson // block, walk one of them to get the predecessor list instead. 2824aad88d1fd88413029dd05255306b07cb19396eeBob Wilson if (PHINode *SomePhi = dyn_cast<PHINode>(BB->begin())) { 2834aad88d1fd88413029dd05255306b07cb19396eeBob Wilson for (unsigned PI = 0, E = SomePhi->getNumIncomingValues(); PI != E; ++PI) 2844aad88d1fd88413029dd05255306b07cb19396eeBob Wilson Preds->push_back(SomePhi->getIncomingBlock(PI)); 2854aad88d1fd88413029dd05255306b07cb19396eeBob Wilson } else { 2864aad88d1fd88413029dd05255306b07cb19396eeBob Wilson for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) 2874aad88d1fd88413029dd05255306b07cb19396eeBob Wilson Preds->push_back(*PI); 28884bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 28984bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 29084bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson 2914aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// GetUndefVal - Get an undefined value of the same type as the value 2924aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// being handled. 2934aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static Value *GetUndefVal(BasicBlock *BB, SSAUpdater *Updater) { 294fc6e29d4ab52b7d3efd83846ed495a9ca7e51e49Duncan Sands return UndefValue::get(Updater->ProtoType); 29584bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 29684bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson 2974aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// CreateEmptyPHI - Create a new PHI instruction in the specified block. 2984aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// Reserve space for the operands but do not fill them in yet. 2994aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static Value *CreateEmptyPHI(BasicBlock *BB, unsigned NumPreds, 3004aad88d1fd88413029dd05255306b07cb19396eeBob Wilson SSAUpdater *Updater) { 3013ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad PHINode *PHI = PHINode::Create(Updater->ProtoType, NumPreds, 3023ecfc861b4365f341c5c969b40e1afccde676e6fJay Foad Updater->ProtoName, &BB->front()); 3034aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return PHI; 304a0c6057061be055faa542d05b2213f2bd779e160Bob Wilson } 305a0c6057061be055faa542d05b2213f2bd779e160Bob Wilson 3064aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// AddPHIOperand - Add the specified value as an operand of the PHI for 3074aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// the specified predecessor block. 3084aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static void AddPHIOperand(PHINode *PHI, Value *Val, BasicBlock *Pred) { 3094aad88d1fd88413029dd05255306b07cb19396eeBob Wilson PHI->addIncoming(Val, Pred); 31084bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 311ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 3124aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// InstrIsPHI - Check if an instruction is a PHI. 3134aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// 3144aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static PHINode *InstrIsPHI(Instruction *I) { 3154aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return dyn_cast<PHINode>(I); 316a0c6057061be055faa542d05b2213f2bd779e160Bob Wilson } 31745305d4ff6bff8dfe62228c68b3cb61bb2d7254fChris Lattner 3184aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// ValueIsPHI - Check if a value is a PHI. 3194aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// 3204aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static PHINode *ValueIsPHI(Value *Val, SSAUpdater *Updater) { 3214aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return dyn_cast<PHINode>(Val); 32284bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 323ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 3244aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// ValueIsNewPHI - Like ValueIsPHI but also check if the PHI has no source 3254aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// operands, i.e., it was just added. 3264aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static PHINode *ValueIsNewPHI(Value *Val, SSAUpdater *Updater) { 3274aad88d1fd88413029dd05255306b07cb19396eeBob Wilson PHINode *PHI = ValueIsPHI(Val, Updater); 3284aad88d1fd88413029dd05255306b07cb19396eeBob Wilson if (PHI && PHI->getNumIncomingValues() == 0) 3294aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return PHI; 3304aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return 0; 33184bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 33284bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson 3334aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// GetPHIValue - For the specified PHI instruction, return the value 3344aad88d1fd88413029dd05255306b07cb19396eeBob Wilson /// that it defines. 3354aad88d1fd88413029dd05255306b07cb19396eeBob Wilson static Value *GetPHIValue(PHINode *PHI) { 3364aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return PHI; 33784bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson } 3384aad88d1fd88413029dd05255306b07cb19396eeBob Wilson}; 33984bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson 3404aad88d1fd88413029dd05255306b07cb19396eeBob Wilson} // End llvm namespace 341ed90342d8ae0756305219e0f01e03e77599ebb41Duncan Sands 3424aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// GetValueAtEndOfBlockInternal - Check to see if AvailableVals has an entry 3434aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// for the specified BB and if so, return it. If not, construct SSA form by 3444aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// first calculating the required placement of PHIs and then inserting new 3454aad88d1fd88413029dd05255306b07cb19396eeBob Wilson/// PHIs where needed. 3464aad88d1fd88413029dd05255306b07cb19396eeBob WilsonValue *SSAUpdater::GetValueAtEndOfBlockInternal(BasicBlock *BB) { 34784bd6b0c31f41cdd1d859dab54b6bc1177c4c6bbBob Wilson AvailableValsTy &AvailableVals = getAvailableVals(AV); 3484aad88d1fd88413029dd05255306b07cb19396eeBob Wilson if (Value *V = AvailableVals[BB]) 3494aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return V; 3504aad88d1fd88413029dd05255306b07cb19396eeBob Wilson 3514aad88d1fd88413029dd05255306b07cb19396eeBob Wilson SSAUpdaterImpl<SSAUpdater> Impl(this, &AvailableVals, InsertedPHIs); 3524aad88d1fd88413029dd05255306b07cb19396eeBob Wilson return Impl.GetValue(BB); 35393f3bcf7f323069e40d9abb950da73d437b6f7daChris Lattner} 354a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 355a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner//===----------------------------------------------------------------------===// 356a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner// LoadAndStorePromoter Implementation 357a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner//===----------------------------------------------------------------------===// 358a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 359deaf55f69865bbc997a569c2a689ec5b0fbdefefChris LattnerLoadAndStorePromoter:: 360deaf55f69865bbc997a569c2a689ec5b0fbdefefChris LattnerLoadAndStorePromoter(const SmallVectorImpl<Instruction*> &Insts, 361231a5ab746ca12000aa57208869a98f78781aa6bDevang Patel SSAUpdater &S, StringRef BaseName) : SSA(S) { 362a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (Insts.empty()) return; 363a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 364deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Value *SomeVal; 365a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (LoadInst *LI = dyn_cast<LoadInst>(Insts[0])) 366deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SomeVal = LI; 367a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner else 368deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SomeVal = cast<StoreInst>(Insts[0])->getOperand(0); 369deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner 370deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner if (BaseName.empty()) 371deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner BaseName = SomeVal->getName(); 372deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SSA.Initialize(SomeVal->getType(), BaseName); 373deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner} 374deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner 375deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner 376deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattnervoid LoadAndStorePromoter:: 377deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattnerrun(const SmallVectorImpl<Instruction*> &Insts) const { 378a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 379a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // First step: bucket up uses of the alloca by the block they occur in. 380a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // This is important because we have to handle multiple defs/uses in a block 381a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // ourselves: SSAUpdater is purely for cross-block references. 382840635741f132a9a10f052cbf3b21e14bc74835aChris Lattner DenseMap<BasicBlock*, TinyPtrVector<Instruction*> > UsesByBlock; 383a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 384a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner for (unsigned i = 0, e = Insts.size(); i != e; ++i) { 385a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner Instruction *User = Insts[i]; 386a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner UsesByBlock[User->getParent()].push_back(User); 387a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 388a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 389a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Okay, now we can iterate over all the blocks in the function with uses, 390a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // processing them. Keep track of which loads are loading a live-in value. 391a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Walk the uses in the use-list order to be determinstic. 392a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner SmallVector<LoadInst*, 32> LiveInLoads; 393a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner DenseMap<Value*, Value*> ReplacedLoads; 394a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 395a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner for (unsigned i = 0, e = Insts.size(); i != e; ++i) { 396a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner Instruction *User = Insts[i]; 397a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner BasicBlock *BB = User->getParent(); 398840635741f132a9a10f052cbf3b21e14bc74835aChris Lattner TinyPtrVector<Instruction*> &BlockUses = UsesByBlock[BB]; 399a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 400a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // If this block has already been processed, ignore this repeat use. 401a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (BlockUses.empty()) continue; 402a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 403a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Okay, this is the first use in the block. If this block just has a 404a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // single user in it, we can rewrite it trivially. 405a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (BlockUses.size() == 1) { 406a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // If it is a store, it is a trivial def of the value in the block. 407c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich if (StoreInst *SI = dyn_cast<StoreInst>(User)) { 408231a5ab746ca12000aa57208869a98f78781aa6bDevang Patel updateDebugInfo(SI); 409deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SSA.AddAvailableValue(BB, SI->getOperand(0)); 410c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich } else 411a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Otherwise it is a load, queue it to rewrite as a live-in load. 412a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner LiveInLoads.push_back(cast<LoadInst>(User)); 413a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner BlockUses.clear(); 414a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner continue; 415a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 416a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 417a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Otherwise, check to see if this block is all loads. 418a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner bool HasStore = false; 419a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner for (unsigned i = 0, e = BlockUses.size(); i != e; ++i) { 420a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (isa<StoreInst>(BlockUses[i])) { 421a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner HasStore = true; 422a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner break; 423a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 424a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 425a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 426a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // If so, we can queue them all as live in loads. We don't have an 427a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // efficient way to tell which on is first in the block and don't want to 428a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // scan large blocks, so just add all loads as live ins. 429a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (!HasStore) { 430a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner for (unsigned i = 0, e = BlockUses.size(); i != e; ++i) 431a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner LiveInLoads.push_back(cast<LoadInst>(BlockUses[i])); 432a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner BlockUses.clear(); 433a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner continue; 434a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 435a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 436a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Otherwise, we have mixed loads and stores (or just a bunch of stores). 437a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Since SSAUpdater is purely for cross-block values, we need to determine 438a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // the order of these instructions in the block. If the first use in the 439a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // block is a load, then it uses the live in value. The last store defines 440a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // the live out value. We handle this by doing a linear scan of the block. 441a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner Value *StoredValue = 0; 442a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner for (BasicBlock::iterator II = BB->begin(), E = BB->end(); II != E; ++II) { 443a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (LoadInst *L = dyn_cast<LoadInst>(II)) { 444a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // If this is a load from an unrelated pointer, ignore it. 445a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (!isInstInList(L, Insts)) continue; 446a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 447a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // If we haven't seen a store yet, this is a live in use, otherwise 448a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // use the stored value. 449a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (StoredValue) { 450deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner replaceLoadWithValue(L, StoredValue); 451a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner L->replaceAllUsesWith(StoredValue); 452a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner ReplacedLoads[L] = StoredValue; 453a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } else { 454a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner LiveInLoads.push_back(L); 455a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 456a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner continue; 457a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 458a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 459c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich if (StoreInst *SI = dyn_cast<StoreInst>(II)) { 460a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // If this is a store to an unrelated pointer, ignore it. 461c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich if (!isInstInList(SI, Insts)) continue; 462231a5ab746ca12000aa57208869a98f78781aa6bDevang Patel updateDebugInfo(SI); 463c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich 464a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Remember that this is the active value in the block. 465c827939046670a9800659b83e2048f1d3a79a531Cameron Zwarich StoredValue = SI->getOperand(0); 466a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 467a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 468a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 469a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // The last stored value that happened is the live-out for the block. 470a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner assert(StoredValue && "Already checked that there is a store in block"); 471deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner SSA.AddAvailableValue(BB, StoredValue); 472a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner BlockUses.clear(); 473a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 474a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 475a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Okay, now we rewrite all loads that use live-in values in the loop, 476a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // inserting PHI nodes as necessary. 477a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner for (unsigned i = 0, e = LiveInLoads.size(); i != e; ++i) { 478a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner LoadInst *ALoad = LiveInLoads[i]; 479deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner Value *NewVal = SSA.GetValueInMiddleOfBlock(ALoad->getParent()); 480deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner replaceLoadWithValue(ALoad, NewVal); 481867be59684afef29f058385c6618ec7753596ffcChris Lattner 482867be59684afef29f058385c6618ec7753596ffcChris Lattner // Avoid assertions in unreachable code. 483867be59684afef29f058385c6618ec7753596ffcChris Lattner if (NewVal == ALoad) NewVal = UndefValue::get(NewVal->getType()); 484a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner ALoad->replaceAllUsesWith(NewVal); 485a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner ReplacedLoads[ALoad] = NewVal; 486a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 487a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 488deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner // Allow the client to do stuff before we start nuking things. 489deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner doExtraRewritesBeforeFinalDeletion(); 490deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner 491a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Now that everything is rewritten, delete the old instructions from the 492a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // function. They should all be dead now. 493a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner for (unsigned i = 0, e = Insts.size(); i != e; ++i) { 494a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner Instruction *User = Insts[i]; 495a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 496a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // If this is a load that still has uses, then the load must have been added 497a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // as a live value in the SSAUpdate data structure for a block (e.g. because 498a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // the loaded value was stored later). In this case, we need to recursively 499a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // propagate the updates until we get to the real value. 500a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner if (!User->use_empty()) { 501a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner Value *NewVal = ReplacedLoads[User]; 502a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner assert(NewVal && "not a replaced load?"); 503a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 504a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // Propagate down to the ultimate replacee. The intermediately loads 505a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // could theoretically already have been deleted, so we don't want to 506a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner // dereference the Value*'s. 507a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner DenseMap<Value*, Value*>::iterator RLI = ReplacedLoads.find(NewVal); 508a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner while (RLI != ReplacedLoads.end()) { 509a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner NewVal = RLI->second; 510a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner RLI = ReplacedLoads.find(NewVal); 511a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 512a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 513deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner replaceLoadWithValue(cast<LoadInst>(User), NewVal); 514a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner User->replaceAllUsesWith(NewVal); 515a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 516a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner 517deaf55f69865bbc997a569c2a689ec5b0fbdefefChris Lattner instructionDeleted(User); 518a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner User->eraseFromParent(); 519a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner } 520a2d845a3ff0b11ca7de6dd0485aa23edef7d149aChris Lattner} 521