reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
//===- InstCombineWorklist.h - Worklist for InstCombine pass ----*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H
#define LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/Instruction.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"

#define DEBUG_TYPE "instcombine"

namespace llvm {

/// InstCombineWorklist - This is the worklist management logic for
/// InstCombine.
class InstCombineWorklist {
  SmallVector<Instruction*, 256> Worklist;
  DenseMap<Instruction*, unsigned> WorklistMap;

public:
  InstCombineWorklist() = default;

  InstCombineWorklist(InstCombineWorklist &&) = default;
  InstCombineWorklist &operator=(InstCombineWorklist &&) = default;

  bool isEmpty() const { return Worklist.empty(); }

  /// Add - Add the specified instruction to the worklist if it isn't already
  /// in it.
  void Add(Instruction *I) {
    if (WorklistMap.insert(std::make_pair(I, Worklist.size())).second) {
      LLVM_DEBUG(dbgs() << "IC: ADD: " << *I << '\n');
      Worklist.push_back(I);
    }
  }

  void AddValue(Value *V) {
    if (Instruction *I = dyn_cast<Instruction>(V))
      Add(I);
  }

  /// AddInitialGroup - Add the specified batch of stuff in reverse order.
  /// which should only be done when the worklist is empty and when the group
  /// has no duplicates.
  void AddInitialGroup(ArrayRef<Instruction *> List) {
    assert(Worklist.empty() && "Worklist must be empty to add initial group");
    Worklist.reserve(List.size()+16);
    WorklistMap.reserve(List.size());
    LLVM_DEBUG(dbgs() << "IC: ADDING: " << List.size()
                      << " instrs to worklist\n");
    unsigned Idx = 0;
    for (Instruction *I : reverse(List)) {
      WorklistMap.insert(std::make_pair(I, Idx++));
      Worklist.push_back(I);
    }
  }

  // Remove - remove I from the worklist if it exists.
  void Remove(Instruction *I) {
    DenseMap<Instruction*, unsigned>::iterator It = WorklistMap.find(I);
    if (It == WorklistMap.end()) return; // Not in worklist.

    // Don't bother moving everything down, just null out the slot.
    Worklist[It->second] = nullptr;

    WorklistMap.erase(It);
  }

  Instruction *RemoveOne() {
    Instruction *I = Worklist.pop_back_val();
    WorklistMap.erase(I);
    return I;
  }

  /// AddUsersToWorkList - When an instruction is simplified, add all users of
  /// the instruction to the work lists because they might get more simplified
  /// now.
  ///
  void AddUsersToWorkList(Instruction &I) {
    for (User *U : I.users())
      Add(cast<Instruction>(U));
  }


  /// Zap - check that the worklist is empty and nuke the backing store for
  /// the map if it is large.
  void Zap() {
    assert(WorklistMap.empty() && "Worklist empty, but map not?");

    // Do an explicit clear, this shrinks the map if needed.
    WorklistMap.clear();
  }
};

} // end namespace llvm.

#undef DEBUG_TYPE

#endif