LowerSwitch.cpp revision 333c40096561218bc3597cf153c0a3895274414c
114383485ac546e369b11797b42bc20831b6db57bChris Lattner//===- LowerSwitch.cpp - Eliminate Switch instructions --------------------===// 2fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 3b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// The LLVM Compiler Infrastructure 4b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell// 54ee451de366474b9c228b4e5fa573795a715216dChris Lattner// This file is distributed under the University of Illinois Open Source 64ee451de366474b9c228b4e5fa573795a715216dChris Lattner// License. See LICENSE.TXT for details. 7fd93908ae8b9684fe71c239e3c6cfe13ff6a2663Misha Brukman// 8b576c94c15af9a440f69d9d03c2afead7971118cJohn Criswell//===----------------------------------------------------------------------===// 914383485ac546e369b11797b42bc20831b6db57bChris Lattner// 10c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// The LowerSwitch transformation rewrites switch instructions with a sequence 11c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// of branches, which allows targets to get away with not implementing the 12c86b67742a3298c0a5a715b57a64f11107b8a3f2Gordon Henriksen// switch instruction until it is convenient. 1314383485ac546e369b11797b42bc20831b6db57bChris Lattner// 1414383485ac546e369b11797b42bc20831b6db57bChris Lattner//===----------------------------------------------------------------------===// 1514383485ac546e369b11797b42bc20831b6db57bChris Lattner 1614383485ac546e369b11797b42bc20831b6db57bChris Lattner#include "llvm/Transforms/Scalar.h" 178d89e7bdbcea38fe2ab3c85d91359712cd45714bChris Lattner#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h" 18ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner#include "llvm/Constants.h" 1914383485ac546e369b11797b42bc20831b6db57bChris Lattner#include "llvm/Function.h" 20d8e1eea678833cc2b15e4ea69a5a403ba9c3b013Misha Brukman#include "llvm/Instructions.h" 210a205a459884ec745df1c529396dd921f029dafdOwen Anderson#include "llvm/LLVMContext.h" 2214383485ac546e369b11797b42bc20831b6db57bChris Lattner#include "llvm/Pass.h" 23b61f2f061feefd79623fadd21eee4f195b0b8e56Dan Gohman#include "llvm/ADT/STLExtras.h" 24551ccae044b0ff658fe629dd67edd5ffe75d10e8Reid Spencer#include "llvm/Support/Debug.h" 25a4f0b3a084d120cfc5b5bb06f64b222f5cb72740Chris Lattner#include "llvm/Support/Compiler.h" 26944fac71e082cc2664cc71b4d3f6c72bab7143fbChris Lattner#include "llvm/Support/raw_ostream.h" 2720aa474f8fbebde588edc101b90e834df28ce4ceAlkis Evlogimenos#include <algorithm> 28d7456026629fc1760a45e6e955e9834246493147Chris Lattnerusing namespace llvm; 29d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 3014383485ac546e369b11797b42bc20831b6db57bChris Lattnernamespace { 3114383485ac546e369b11797b42bc20831b6db57bChris Lattner /// LowerSwitch Pass - Replace all SwitchInst instructions with chained branch 3214383485ac546e369b11797b42bc20831b6db57bChris Lattner /// instructions. Note that this cannot be a BasicBlock pass because it 3314383485ac546e369b11797b42bc20831b6db57bChris Lattner /// modifies the CFG! 34f4b546110c7b9f0c24be26cfe1eccdd570ee9feeChris Lattner class VISIBILITY_HIDDEN LowerSwitch : public FunctionPass { 35ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner public: 36ecd94c804a563f2a86572dcf1d2e81f397e19daaNick Lewycky static char ID; // Pass identification, replacement for typeid 37ae73dc1448d25b02cabc7c64c86c64371453dda8Dan Gohman LowerSwitch() : FunctionPass(&ID) {} 38794fd75c67a2cdc128d67342c6d88a504d186896Devang Patel 398d89e7bdbcea38fe2ab3c85d91359712cd45714bChris Lattner virtual bool runOnFunction(Function &F); 40ed96fe8c79b36a38bd9280438656ee539276fb41Chris Lattner 418d89e7bdbcea38fe2ab3c85d91359712cd45714bChris Lattner virtual void getAnalysisUsage(AnalysisUsage &AU) const { 42bed2946a96ecb15b0b636fa74cb26ce61b1c648eAnton Korobeynikov // This is a cluster of orthogonal Transforms 438d89e7bdbcea38fe2ab3c85d91359712cd45714bChris Lattner AU.addPreserved<UnifyFunctionExitNodes>(); 448d89e7bdbcea38fe2ab3c85d91359712cd45714bChris Lattner AU.addPreservedID(PromoteMemoryToRegisterID); 45ed96fe8c79b36a38bd9280438656ee539276fb41Chris Lattner AU.addPreservedID(LowerInvokePassID); 46ed96fe8c79b36a38bd9280438656ee539276fb41Chris Lattner AU.addPreservedID(LowerAllocationsID); 478d89e7bdbcea38fe2ab3c85d91359712cd45714bChris Lattner } 48e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 49e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov struct CaseRange { 50e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov Constant* Low; 51e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov Constant* High; 52e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov BasicBlock* BB; 53e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 54c4558fde76bdb17bff28375fe20ee02e027095b8Jeff Cohen CaseRange() : Low(0), High(0), BB(0) { } 55c4558fde76bdb17bff28375fe20ee02e027095b8Jeff Cohen CaseRange(Constant* low, Constant* high, BasicBlock* bb) : 56c4558fde76bdb17bff28375fe20ee02e027095b8Jeff Cohen Low(low), High(high), BB(bb) { } 57e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov }; 58e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 59e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov typedef std::vector<CaseRange> CaseVector; 60e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov typedef std::vector<CaseRange>::iterator CaseItr; 61ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner private: 6214383485ac546e369b11797b42bc20831b6db57bChris Lattner void processSwitchInst(SwitchInst *SI); 63ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 64ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* switchConvert(CaseItr Begin, CaseItr End, Value* Val, 65ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* OrigBlock, BasicBlock* Default); 66e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov BasicBlock* newLeafBlock(CaseRange& Leaf, Value* Val, 67ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* OrigBlock, BasicBlock* Default); 68e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov unsigned Clusterify(CaseVector& Cases, SwitchInst *SI); 69ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner }; 70ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 71ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner /// The comparison function for sorting the switch case values in the vector. 72e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov /// WARNING: Case ranges should be disjoint! 73ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner struct CaseCmp { 74e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov bool operator () (const LowerSwitch::CaseRange& C1, 75e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov const LowerSwitch::CaseRange& C2) { 76ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 77e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov const ConstantInt* CI1 = cast<const ConstantInt>(C1.Low); 78e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov const ConstantInt* CI2 = cast<const ConstantInt>(C2.High); 79e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov return CI1->getValue().slt(CI2->getValue()); 80ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner } 8114383485ac546e369b11797b42bc20831b6db57bChris Lattner }; 8214383485ac546e369b11797b42bc20831b6db57bChris Lattner} 8314383485ac546e369b11797b42bc20831b6db57bChris Lattner 84844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanchar LowerSwitch::ID = 0; 85844731a7f1909f55935e3514c9e713a62d67662eDan Gohmanstatic RegisterPass<LowerSwitch> 86844731a7f1909f55935e3514c9e713a62d67662eDan GohmanX("lowerswitch", "Lower SwitchInst's to branches"); 87844731a7f1909f55935e3514c9e713a62d67662eDan Gohman 88b3674e475389b72939bf90965790d63e9fa24b95Chris Lattner// Publically exposed interface to pass... 896ddba2b933645d308428201e942abe1274fa5085Dan Gohmanconst PassInfo *const llvm::LowerSwitchID = &X; 9014383485ac546e369b11797b42bc20831b6db57bChris Lattner// createLowerSwitchPass - Interface to this file... 91d7456026629fc1760a45e6e955e9834246493147Chris LattnerFunctionPass *llvm::createLowerSwitchPass() { 9214383485ac546e369b11797b42bc20831b6db57bChris Lattner return new LowerSwitch(); 9314383485ac546e369b11797b42bc20831b6db57bChris Lattner} 9414383485ac546e369b11797b42bc20831b6db57bChris Lattner 9514383485ac546e369b11797b42bc20831b6db57bChris Lattnerbool LowerSwitch::runOnFunction(Function &F) { 9614383485ac546e369b11797b42bc20831b6db57bChris Lattner bool Changed = false; 9714383485ac546e369b11797b42bc20831b6db57bChris Lattner 9814383485ac546e369b11797b42bc20831b6db57bChris Lattner for (Function::iterator I = F.begin(), E = F.end(); I != E; ) { 9914383485ac546e369b11797b42bc20831b6db57bChris Lattner BasicBlock *Cur = I++; // Advance over block so we don't traverse new blocks 10014383485ac546e369b11797b42bc20831b6db57bChris Lattner 10114383485ac546e369b11797b42bc20831b6db57bChris Lattner if (SwitchInst *SI = dyn_cast<SwitchInst>(Cur->getTerminator())) { 10214383485ac546e369b11797b42bc20831b6db57bChris Lattner Changed = true; 10314383485ac546e369b11797b42bc20831b6db57bChris Lattner processSwitchInst(SI); 10414383485ac546e369b11797b42bc20831b6db57bChris Lattner } 10514383485ac546e369b11797b42bc20831b6db57bChris Lattner } 10614383485ac546e369b11797b42bc20831b6db57bChris Lattner 10714383485ac546e369b11797b42bc20831b6db57bChris Lattner return Changed; 10814383485ac546e369b11797b42bc20831b6db57bChris Lattner} 10914383485ac546e369b11797b42bc20831b6db57bChris Lattner 110ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// operator<< - Used for debugging purposes. 111ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// 112e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikovstatic std::ostream& operator<<(std::ostream &O, 113e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov const LowerSwitch::CaseVector &C) { 114ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner O << "["; 115ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 116e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov for (LowerSwitch::CaseVector::const_iterator B = C.begin(), 117d7456026629fc1760a45e6e955e9834246493147Chris Lattner E = C.end(); B != E; ) { 118e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov O << *B->Low << " -" << *B->High; 119ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner if (++B != E) O << ", "; 120ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner } 121ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 122ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner return O << "]"; 123ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner} 124e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 125e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikovstatic OStream& operator<<(OStream &O, const LowerSwitch::CaseVector &C) { 1265c7e326585f3a543388ba871c3425f7664cd9143Bill Wendling if (O.stream()) *O.stream() << C; 1275c7e326585f3a543388ba871c3425f7664cd9143Bill Wendling return O; 1285c7e326585f3a543388ba871c3425f7664cd9143Bill Wendling} 129ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 130ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// switchConvert - Convert the switch statement into a binary lookup of 131ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// the case values. The function recursively builds this tree. 132ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// 133ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris LattnerBasicBlock* LowerSwitch::switchConvert(CaseItr Begin, CaseItr End, 134ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner Value* Val, BasicBlock* OrigBlock, 135ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* Default) 136ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner{ 137ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner unsigned Size = End - Begin; 138ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 139ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner if (Size == 1) 140ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner return newLeafBlock(*Begin, Val, OrigBlock, Default); 141ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 142ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner unsigned Mid = Size / 2; 143e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov std::vector<CaseRange> LHS(Begin, Begin + Mid); 1440d45a096cff7de5b487f7f7aac17684945dd0b93Bill Wendling DOUT << "LHS: " << LHS << "\n"; 145e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov std::vector<CaseRange> RHS(Begin + Mid, End); 1460d45a096cff7de5b487f7f7aac17684945dd0b93Bill Wendling DOUT << "RHS: " << RHS << "\n"; 147ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 148e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov CaseRange& Pivot = *(Begin + Mid); 149944fac71e082cc2664cc71b4d3f6c72bab7143fbChris Lattner DEBUG(errs() << "Pivot ==> " 150944fac71e082cc2664cc71b4d3f6c72bab7143fbChris Lattner << cast<ConstantInt>(Pivot.Low)->getValue() << " -" 151f871ccb853a2ccbe8675c912330c041b318be8cdDan Gohman << cast<ConstantInt>(Pivot.High)->getValue() << "\n"); 152ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 153ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* LBranch = switchConvert(LHS.begin(), LHS.end(), Val, 154ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner OrigBlock, Default); 155ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* RBranch = switchConvert(RHS.begin(), RHS.end(), Val, 156ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner OrigBlock, Default); 157ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 158ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // Create a new node that checks if the value is < pivot. Go to the 159ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // left branch if it is and right branch if not. 160ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner Function* F = OrigBlock->getParent(); 161051a950000e21935165db56695e35bade668193bGabor Greif BasicBlock* NewNode = BasicBlock::Create("NodeBlock"); 162261cdfbe5e6e11d56ca1c49a75f26fece3b139c8Chris Lattner Function::iterator FI = OrigBlock; 163261cdfbe5e6e11d56ca1c49a75f26fece3b139c8Chris Lattner F->getBasicBlockList().insert(++FI, NewNode); 164ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 165333c40096561218bc3597cf153c0a3895274414cOwen Anderson ICmpInst* Comp = new ICmpInst(*Default->getContext(), ICmpInst::ICMP_SLT, 166333c40096561218bc3597cf153c0a3895274414cOwen Anderson Val, Pivot.Low, "Pivot"); 167ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner NewNode->getInstList().push_back(Comp); 168051a950000e21935165db56695e35bade668193bGabor Greif BranchInst::Create(LBranch, RBranch, Comp, NewNode); 169ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner return NewNode; 170ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner} 171ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 172ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// newLeafBlock - Create a new leaf block for the binary lookup tree. It 173ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// checks if the switch's value == the case's value. If not, then it 174ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// jumps to the default branch. At this point in the tree, the value 175ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// can't be another valid case value, so the jump to the "default" branch 176ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// is warranted. 177ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// 178e2ff29c17c1a7c121e22789cf1654d923467b472Anton KorobeynikovBasicBlock* LowerSwitch::newLeafBlock(CaseRange& Leaf, Value* Val, 179ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* OrigBlock, 180ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* Default) 181ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner{ 182ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner Function* F = OrigBlock->getParent(); 183051a950000e21935165db56695e35bade668193bGabor Greif BasicBlock* NewLeaf = BasicBlock::Create("LeafBlock"); 184261cdfbe5e6e11d56ca1c49a75f26fece3b139c8Chris Lattner Function::iterator FI = OrigBlock; 185261cdfbe5e6e11d56ca1c49a75f26fece3b139c8Chris Lattner F->getBasicBlockList().insert(++FI, NewLeaf); 186ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 187e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Emit comparison 188e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov ICmpInst* Comp = NULL; 189e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov if (Leaf.Low == Leaf.High) { 190e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Make the seteq instruction... 191333c40096561218bc3597cf153c0a3895274414cOwen Anderson Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_EQ, Val, 192333c40096561218bc3597cf153c0a3895274414cOwen Anderson Leaf.Low, "SwitchLeaf"); 193e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } else { 194e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Make range comparison 195e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov if (cast<ConstantInt>(Leaf.Low)->isMinValue(true /*isSigned*/)) { 196e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Val >= Min && Val <= Hi --> Val <= Hi 197333c40096561218bc3597cf153c0a3895274414cOwen Anderson Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_SLE, Val, Leaf.High, 198333c40096561218bc3597cf153c0a3895274414cOwen Anderson "SwitchLeaf"); 199e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } else if (cast<ConstantInt>(Leaf.Low)->isZero()) { 200e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Val >= 0 && Val <= Hi --> Val <=u Hi 201333c40096561218bc3597cf153c0a3895274414cOwen Anderson Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Val, Leaf.High, 202333c40096561218bc3597cf153c0a3895274414cOwen Anderson "SwitchLeaf"); 203e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } else { 204e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Emit V-Lo <=u Hi-Lo 2050a205a459884ec745df1c529396dd921f029dafdOwen Anderson Constant* NegLo = Context->getConstantExprNeg(Leaf.Low); 2067cbd8a3e92221437048b484d5ef9c0a22d0f8c58Gabor Greif Instruction* Add = BinaryOperator::CreateAdd(Val, NegLo, 207e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov Val->getName()+".off", 208e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov NewLeaf); 2090a205a459884ec745df1c529396dd921f029dafdOwen Anderson Constant *UpperBound = Context->getConstantExprAdd(NegLo, Leaf.High); 210333c40096561218bc3597cf153c0a3895274414cOwen Anderson Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Add, UpperBound, 211333c40096561218bc3597cf153c0a3895274414cOwen Anderson "SwitchLeaf"); 212e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } 213e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } 214ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 215ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // Make the conditional branch... 216e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov BasicBlock* Succ = Leaf.BB; 217051a950000e21935165db56695e35bade668193bGabor Greif BranchInst::Create(Succ, Default, Comp, NewLeaf); 218ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 219ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // If there were any PHI nodes in this successor, rewrite one entry 220ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // from OrigBlock to come from NewLeaf. 2212da5c3dda6f5b9c4ec6d55008d33327764364bd4Reid Spencer for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) { 2222da5c3dda6f5b9c4ec6d55008d33327764364bd4Reid Spencer PHINode* PN = cast<PHINode>(I); 223e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Remove all but one incoming entries from the cluster 224e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov uint64_t Range = cast<ConstantInt>(Leaf.High)->getSExtValue() - 225e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov cast<ConstantInt>(Leaf.Low)->getSExtValue(); 226e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov for (uint64_t j = 0; j < Range; ++j) { 227e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov PN->removeIncomingValue(OrigBlock); 228e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } 229e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 230ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner int BlockIdx = PN->getBasicBlockIndex(OrigBlock); 231ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner assert(BlockIdx != -1 && "Switch didn't go to this successor??"); 232ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner PN->setIncomingBlock((unsigned)BlockIdx, NewLeaf); 233ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner } 234ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 235ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner return NewLeaf; 236ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner} 237ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 238e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov// Clusterify - Transform simple list of Cases into list of CaseRange's 239e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikovunsigned LowerSwitch::Clusterify(CaseVector& Cases, SwitchInst *SI) { 240e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov unsigned numCmps = 0; 241e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 242e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Start with "simple" cases 243e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov for (unsigned i = 1; i < SI->getNumSuccessors(); ++i) 244e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov Cases.push_back(CaseRange(SI->getSuccessorValue(i), 245e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov SI->getSuccessorValue(i), 246e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov SI->getSuccessor(i))); 247111c4f897eb9a42eac6aceea830b8e76058afd73Dan Gohman std::sort(Cases.begin(), Cases.end(), CaseCmp()); 248e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 249e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Merge case into clusters 250e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov if (Cases.size()>=2) 2519dfb11d32d302abfe8803d530138b38ddc567c60David Greene for (CaseItr I=Cases.begin(), J=next(Cases.begin()); J!=Cases.end(); ) { 252e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov int64_t nextValue = cast<ConstantInt>(J->Low)->getSExtValue(); 253e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov int64_t currentValue = cast<ConstantInt>(I->High)->getSExtValue(); 254e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov BasicBlock* nextBB = J->BB; 255e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov BasicBlock* currentBB = I->BB; 256e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 257e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // If the two neighboring cases go to the same destination, merge them 258e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // into a single case. 259e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov if ((nextValue-currentValue==1) && (currentBB == nextBB)) { 260e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov I->High = J->High; 261e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov J = Cases.erase(J); 262e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } else { 263e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov I = J++; 264e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } 265e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } 266e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 267e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov for (CaseItr I=Cases.begin(), E=Cases.end(); I!=E; ++I, ++numCmps) { 268e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov if (I->Low != I->High) 269e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // A range counts double, since it requires two compares. 270e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov ++numCmps; 271e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov } 272e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 273e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov return numCmps; 274e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov} 275e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 27614383485ac546e369b11797b42bc20831b6db57bChris Lattner// processSwitchInst - Replace the specified switch instruction with a sequence 277ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner// of chained if-then insts in a balanced binary search. 27814383485ac546e369b11797b42bc20831b6db57bChris Lattner// 27914383485ac546e369b11797b42bc20831b6db57bChris Lattnervoid LowerSwitch::processSwitchInst(SwitchInst *SI) { 28014383485ac546e369b11797b42bc20831b6db57bChris Lattner BasicBlock *CurBlock = SI->getParent(); 28114383485ac546e369b11797b42bc20831b6db57bChris Lattner BasicBlock *OrigBlock = CurBlock; 28214383485ac546e369b11797b42bc20831b6db57bChris Lattner Function *F = CurBlock->getParent(); 28314383485ac546e369b11797b42bc20831b6db57bChris Lattner Value *Val = SI->getOperand(0); // The value we are switching on... 284ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* Default = SI->getDefaultDest(); 28514383485ac546e369b11797b42bc20831b6db57bChris Lattner 28644bb541c011bcae84759ed194ec7cb4139775fcbChris Lattner // If there is only the default destination, don't bother with the code below. 28744bb541c011bcae84759ed194ec7cb4139775fcbChris Lattner if (SI->getNumOperands() == 2) { 288051a950000e21935165db56695e35bade668193bGabor Greif BranchInst::Create(SI->getDefaultDest(), CurBlock); 289bf9eaddfb0642e49bc2f3835765a9782ff48c76eChris Lattner CurBlock->getInstList().erase(SI); 29044bb541c011bcae84759ed194ec7cb4139775fcbChris Lattner return; 29144bb541c011bcae84759ed194ec7cb4139775fcbChris Lattner } 29244bb541c011bcae84759ed194ec7cb4139775fcbChris Lattner 293ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // Create a new, empty default block so that the new hierarchy of 294ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // if-then statements go to this and the PHI nodes are happy. 295051a950000e21935165db56695e35bade668193bGabor Greif BasicBlock* NewDefault = BasicBlock::Create("NewDefault"); 296ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner F->getBasicBlockList().insert(Default, NewDefault); 29714383485ac546e369b11797b42bc20831b6db57bChris Lattner 298051a950000e21935165db56695e35bade668193bGabor Greif BranchInst::Create(Default, NewDefault); 29920af3222da5dea65246ecd9f64a53ea3e3cc1b8aChris Lattner 300ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // If there is an entry in any PHI nodes for the default edge, make sure 301ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // to update them as well. 3022da5c3dda6f5b9c4ec6d55008d33327764364bd4Reid Spencer for (BasicBlock::iterator I = Default->begin(); isa<PHINode>(I); ++I) { 3032da5c3dda6f5b9c4ec6d55008d33327764364bd4Reid Spencer PHINode *PN = cast<PHINode>(I); 304ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner int BlockIdx = PN->getBasicBlockIndex(OrigBlock); 305ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner assert(BlockIdx != -1 && "Switch didn't go to this successor??"); 306ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner PN->setIncomingBlock((unsigned)BlockIdx, NewDefault); 30714383485ac546e369b11797b42bc20831b6db57bChris Lattner } 30814383485ac546e369b11797b42bc20831b6db57bChris Lattner 309e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov // Prepare cases vector. 310e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov CaseVector Cases; 311e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov unsigned numCmps = Clusterify(Cases, SI); 312ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 313e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov DOUT << "Clusterify finished. Total clusters: " << Cases.size() 314e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov << ". Total compares: " << numCmps << "\n"; 3150d45a096cff7de5b487f7f7aac17684945dd0b93Bill Wendling DOUT << "Cases: " << Cases << "\n"; 316e2ff29c17c1a7c121e22789cf1654d923467b472Anton Korobeynikov 317ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner BasicBlock* SwitchBlock = switchConvert(Cases.begin(), Cases.end(), Val, 318ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner OrigBlock, NewDefault); 319ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 320ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner // Branch to our shiny new if-then stuff... 321051a950000e21935165db56695e35bade668193bGabor Greif BranchInst::Create(SwitchBlock, OrigBlock); 322ebbc1a5aa0c37ab29d14ae56c176b3bfd25658cbChris Lattner 32314383485ac546e369b11797b42bc20831b6db57bChris Lattner // We are now done with the switch instruction, delete it. 324bf9eaddfb0642e49bc2f3835765a9782ff48c76eChris Lattner CurBlock->getInstList().erase(SI); 32514383485ac546e369b11797b42bc20831b6db57bChris Lattner} 326