1 //===- InstCombineWorklist.h - Worklist for InstCombine pass ----*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H 11 #define LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H 12 13 #include "llvm/ADT/DenseMap.h" 14 #include "llvm/ADT/STLExtras.h" 15 #include "llvm/ADT/SmallVector.h" 16 #include "llvm/IR/Instruction.h" 17 #include "llvm/Support/Compiler.h" 18 #include "llvm/Support/Debug.h" 19 #include "llvm/Support/raw_ostream.h" 20 21 #define DEBUG_TYPE "instcombine" 22 23 namespace llvm { 24 25 /// InstCombineWorklist - This is the worklist management logic for 26 /// InstCombine. 27 class InstCombineWorklist { 28 SmallVector<Instruction*, 256> Worklist; 29 DenseMap<Instruction*, unsigned> WorklistMap; 30 31 public: 32 InstCombineWorklist() = default; 33 34 InstCombineWorklist(InstCombineWorklist &&) = default; 35 InstCombineWorklist &operator=(InstCombineWorklist &&) = default; 36 37 bool isEmpty() const { return Worklist.empty(); } 38 39 /// Add - Add the specified instruction to the worklist if it isn't already 40 /// in it. 41 void Add(Instruction *I) { 42 if (WorklistMap.insert(std::make_pair(I, Worklist.size())).second) { 43 DEBUG(dbgs() << "IC: ADD: " << *I << '\n'); 44 Worklist.push_back(I); 45 } 46 } 47 48 void AddValue(Value *V) { 49 if (Instruction *I = dyn_cast<Instruction>(V)) 50 Add(I); 51 } 52 53 /// AddInitialGroup - Add the specified batch of stuff in reverse order. 54 /// which should only be done when the worklist is empty and when the group 55 /// has no duplicates. 56 void AddInitialGroup(ArrayRef<Instruction *> List) { 57 assert(Worklist.empty() && "Worklist must be empty to add initial group"); 58 Worklist.reserve(List.size()+16); 59 WorklistMap.reserve(List.size()); 60 DEBUG(dbgs() << "IC: ADDING: " << List.size() << " instrs to worklist\n"); 61 unsigned Idx = 0; 62 for (Instruction *I : reverse(List)) { 63 WorklistMap.insert(std::make_pair(I, Idx++)); 64 Worklist.push_back(I); 65 } 66 } 67 68 // Remove - remove I from the worklist if it exists. 69 void Remove(Instruction *I) { 70 DenseMap<Instruction*, unsigned>::iterator It = WorklistMap.find(I); 71 if (It == WorklistMap.end()) return; // Not in worklist. 72 73 // Don't bother moving everything down, just null out the slot. 74 Worklist[It->second] = nullptr; 75 76 WorklistMap.erase(It); 77 } 78 79 Instruction *RemoveOne() { 80 Instruction *I = Worklist.pop_back_val(); 81 WorklistMap.erase(I); 82 return I; 83 } 84 85 /// AddUsersToWorkList - When an instruction is simplified, add all users of 86 /// the instruction to the work lists because they might get more simplified 87 /// now. 88 /// 89 void AddUsersToWorkList(Instruction &I) { 90 for (User *U : I.users()) 91 Add(cast<Instruction>(U)); 92 } 93 94 95 /// Zap - check that the worklist is empty and nuke the backing store for 96 /// the map if it is large. 97 void Zap() { 98 assert(WorklistMap.empty() && "Worklist empty, but map not?"); 99 100 // Do an explicit clear, this shrinks the map if needed. 101 WorklistMap.clear(); 102 } 103 }; 104 105 } // end namespace llvm. 106 107 #undef DEBUG_TYPE 108 109 #endif 110