1 //===- InstCombineWorklist.h - Worklist for InstCombine pass ----*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H 10 #define LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H 11 12 #include "llvm/ADT/DenseMap.h" 13 #include "llvm/ADT/STLExtras.h" 14 #include "llvm/ADT/SetVector.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 /// These instructions will be added in reverse order after the current 31 /// combine has finished. This means that these instructions will be visited 32 /// in the order they have been added. 33 SmallSetVector<Instruction *, 16> Deferred; 34 35 public: 36 InstCombineWorklist() = default; 37 38 InstCombineWorklist(InstCombineWorklist &&) = default; 39 InstCombineWorklist &operator=(InstCombineWorklist &&) = default; 40 isEmpty()41 bool isEmpty() const { return Worklist.empty() && Deferred.empty(); } 42 43 /// Add instruction to the worklist. 44 /// Instructions will be visited in the order they are added. 45 /// You likely want to use this method. add(Instruction * I)46 void add(Instruction *I) { 47 if (Deferred.insert(I)) 48 LLVM_DEBUG(dbgs() << "IC: ADD DEFERRED: " << *I << '\n'); 49 } 50 51 /// Add value to the worklist if it is an instruction. 52 /// Instructions will be visited in the order they are added. addValue(Value * V)53 void addValue(Value *V) { 54 if (Instruction *I = dyn_cast<Instruction>(V)) 55 add(I); 56 } 57 58 /// Push the instruction onto the worklist stack. 59 /// Instructions that have been added first will be visited last. push(Instruction * I)60 void push(Instruction *I) { 61 assert(I); 62 assert(I->getParent() && "Instruction not inserted yet?"); 63 64 if (WorklistMap.insert(std::make_pair(I, Worklist.size())).second) { 65 LLVM_DEBUG(dbgs() << "IC: ADD: " << *I << '\n'); 66 Worklist.push_back(I); 67 } 68 } 69 pushValue(Value * V)70 void pushValue(Value *V) { 71 if (Instruction *I = dyn_cast<Instruction>(V)) 72 push(I); 73 } 74 popDeferred()75 Instruction *popDeferred() { 76 if (Deferred.empty()) 77 return nullptr; 78 return Deferred.pop_back_val(); 79 } 80 reserve(size_t Size)81 void reserve(size_t Size) { 82 Worklist.reserve(Size + 16); 83 WorklistMap.reserve(Size); 84 } 85 86 /// Remove I from the worklist if it exists. remove(Instruction * I)87 void remove(Instruction *I) { 88 DenseMap<Instruction*, unsigned>::iterator It = WorklistMap.find(I); 89 if (It != WorklistMap.end()) { 90 // Don't bother moving everything down, just null out the slot. 91 Worklist[It->second] = nullptr; 92 WorklistMap.erase(It); 93 } 94 95 Deferred.remove(I); 96 } 97 removeOne()98 Instruction *removeOne() { 99 if (Worklist.empty()) 100 return nullptr; 101 Instruction *I = Worklist.pop_back_val(); 102 WorklistMap.erase(I); 103 return I; 104 } 105 106 /// When an instruction is simplified, add all users of the instruction 107 /// to the work lists because they might get more simplified now. pushUsersToWorkList(Instruction & I)108 void pushUsersToWorkList(Instruction &I) { 109 for (User *U : I.users()) 110 push(cast<Instruction>(U)); 111 } 112 113 114 /// Check that the worklist is empty and nuke the backing store for the map. zap()115 void zap() { 116 assert(WorklistMap.empty() && "Worklist empty, but map not?"); 117 assert(Deferred.empty() && "Deferred instructions left over"); 118 119 // Do an explicit clear, this shrinks the map if needed. 120 WorklistMap.clear(); 121 } 122 }; 123 124 } // end namespace llvm. 125 126 #undef DEBUG_TYPE 127 128 #endif 129