InstCombineWorklist.h revision 353358
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/SmallVector.h" 15#include "llvm/IR/Instruction.h" 16#include "llvm/Support/Compiler.h" 17#include "llvm/Support/Debug.h" 18#include "llvm/Support/raw_ostream.h" 19 20#define DEBUG_TYPE "instcombine" 21 22namespace llvm { 23 24/// InstCombineWorklist - This is the worklist management logic for 25/// InstCombine. 26class InstCombineWorklist { 27 SmallVector<Instruction*, 256> Worklist; 28 DenseMap<Instruction*, unsigned> WorklistMap; 29 30public: 31 InstCombineWorklist() = default; 32 33 InstCombineWorklist(InstCombineWorklist &&) = default; 34 InstCombineWorklist &operator=(InstCombineWorklist &&) = default; 35 36 bool isEmpty() const { return Worklist.empty(); } 37 38 /// Add - Add the specified instruction to the worklist if it isn't already 39 /// in it. 40 void Add(Instruction *I) { 41 if (WorklistMap.insert(std::make_pair(I, Worklist.size())).second) { 42 LLVM_DEBUG(dbgs() << "IC: ADD: " << *I << '\n'); 43 Worklist.push_back(I); 44 } 45 } 46 47 void AddValue(Value *V) { 48 if (Instruction *I = dyn_cast<Instruction>(V)) 49 Add(I); 50 } 51 52 /// AddInitialGroup - Add the specified batch of stuff in reverse order. 53 /// which should only be done when the worklist is empty and when the group 54 /// has no duplicates. 55 void AddInitialGroup(ArrayRef<Instruction *> List) { 56 assert(Worklist.empty() && "Worklist must be empty to add initial group"); 57 Worklist.reserve(List.size()+16); 58 WorklistMap.reserve(List.size()); 59 LLVM_DEBUG(dbgs() << "IC: ADDING: " << List.size() 60 << " 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