1//===- VPlanValue.h - Represent Values in Vectorizer Plan -----------------===//
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/// \file
10/// This file contains the declarations of the entities induced by Vectorization
11/// Plans, e.g. the instructions the VPlan intends to generate if executed.
12/// VPlan models the following entities:
13/// VPValue
14///  |-- VPUser
15///  |    |-- VPInstruction
16/// These are documented in docs/VectorizationPlan.rst.
17///
18//===----------------------------------------------------------------------===//
19
20#ifndef LLVM_TRANSFORMS_VECTORIZE_VPLAN_VALUE_H
21#define LLVM_TRANSFORMS_VECTORIZE_VPLAN_VALUE_H
22
23#include "llvm/ADT/DenseMap.h"
24#include "llvm/ADT/SmallVector.h"
25#include "llvm/IR/Value.h"
26#include "llvm/Support/Debug.h"
27#include "llvm/Support/raw_ostream.h"
28
29namespace llvm {
30
31// Forward declarations.
32class VPUser;
33
34// This is the base class of the VPlan Def/Use graph, used for modeling the data
35// flow into, within and out of the VPlan. VPValues can stand for live-ins
36// coming from the input IR, instructions which VPlan will generate if executed
37// and live-outs which the VPlan will need to fix accordingly.
38class VPValue {
39  friend class VPBuilder;
40  friend class VPlanTransforms;
41  friend class VPBasicBlock;
42  friend class VPInterleavedAccessInfo;
43
44private:
45  const unsigned char SubclassID; ///< Subclass identifier (for isa/dyn_cast).
46
47  SmallVector<VPUser *, 1> Users;
48
49protected:
50  // Hold the underlying Value, if any, attached to this VPValue.
51  Value *UnderlyingVal;
52
53  VPValue(const unsigned char SC, Value *UV = nullptr)
54      : SubclassID(SC), UnderlyingVal(UV) {}
55
56  // DESIGN PRINCIPLE: Access to the underlying IR must be strictly limited to
57  // the front-end and back-end of VPlan so that the middle-end is as
58  // independent as possible of the underlying IR. We grant access to the
59  // underlying IR using friendship. In that way, we should be able to use VPlan
60  // for multiple underlying IRs (Polly?) by providing a new VPlan front-end,
61  // back-end and analysis information for the new IR.
62
63  /// Return the underlying Value attached to this VPValue.
64  Value *getUnderlyingValue() { return UnderlyingVal; }
65
66  // Set \p Val as the underlying Value of this VPValue.
67  void setUnderlyingValue(Value *Val) {
68    assert(!UnderlyingVal && "Underlying Value is already set.");
69    UnderlyingVal = Val;
70  }
71
72public:
73  /// An enumeration for keeping track of the concrete subclass of VPValue that
74  /// are actually instantiated. Values of this enumeration are kept in the
75  /// SubclassID field of the VPValue objects. They are used for concrete
76  /// type identification.
77  enum { VPValueSC, VPUserSC, VPInstructionSC };
78
79  VPValue(Value *UV = nullptr) : VPValue(VPValueSC, UV) {}
80  VPValue(const VPValue &) = delete;
81  VPValue &operator=(const VPValue &) = delete;
82
83  /// \return an ID for the concrete type of this object.
84  /// This is used to implement the classof checks. This should not be used
85  /// for any other purpose, as the values may change as LLVM evolves.
86  unsigned getVPValueID() const { return SubclassID; }
87
88  void printAsOperand(raw_ostream &OS) const {
89    OS << "%vp" << (unsigned short)(unsigned long long)this;
90  }
91
92  unsigned getNumUsers() const { return Users.size(); }
93  void addUser(VPUser &User) { Users.push_back(&User); }
94
95  typedef SmallVectorImpl<VPUser *>::iterator user_iterator;
96  typedef SmallVectorImpl<VPUser *>::const_iterator const_user_iterator;
97  typedef iterator_range<user_iterator> user_range;
98  typedef iterator_range<const_user_iterator> const_user_range;
99
100  user_iterator user_begin() { return Users.begin(); }
101  const_user_iterator user_begin() const { return Users.begin(); }
102  user_iterator user_end() { return Users.end(); }
103  const_user_iterator user_end() const { return Users.end(); }
104  user_range users() { return user_range(user_begin(), user_end()); }
105  const_user_range users() const {
106    return const_user_range(user_begin(), user_end());
107  }
108
109  /// Returns true if the value has more than one unique user.
110  bool hasMoreThanOneUniqueUser() {
111    if (getNumUsers() == 0)
112      return false;
113
114    // Check if all users match the first user.
115    auto Current = std::next(user_begin());
116    while (Current != user_end() && *user_begin() == *Current)
117      Current++;
118    return Current != user_end();
119  }
120
121  void replaceAllUsesWith(VPValue *New);
122};
123
124typedef DenseMap<Value *, VPValue *> Value2VPValueTy;
125typedef DenseMap<VPValue *, Value *> VPValue2ValueTy;
126
127raw_ostream &operator<<(raw_ostream &OS, const VPValue &V);
128
129/// This class augments VPValue with operands which provide the inverse def-use
130/// edges from VPValue's users to their defs.
131class VPUser : public VPValue {
132private:
133  SmallVector<VPValue *, 2> Operands;
134
135protected:
136  VPUser(const unsigned char SC) : VPValue(SC) {}
137  VPUser(const unsigned char SC, ArrayRef<VPValue *> Operands) : VPValue(SC) {
138    for (VPValue *Operand : Operands)
139      addOperand(Operand);
140  }
141
142public:
143  VPUser() : VPValue(VPValue::VPUserSC) {}
144  VPUser(ArrayRef<VPValue *> Operands) : VPUser(VPValue::VPUserSC, Operands) {}
145  VPUser(std::initializer_list<VPValue *> Operands)
146      : VPUser(ArrayRef<VPValue *>(Operands)) {}
147  VPUser(const VPUser &) = delete;
148  VPUser &operator=(const VPUser &) = delete;
149
150  /// Method to support type inquiry through isa, cast, and dyn_cast.
151  static inline bool classof(const VPValue *V) {
152    return V->getVPValueID() >= VPUserSC &&
153           V->getVPValueID() <= VPInstructionSC;
154  }
155
156  void addOperand(VPValue *Operand) {
157    Operands.push_back(Operand);
158    Operand->addUser(*this);
159  }
160
161  unsigned getNumOperands() const { return Operands.size(); }
162  inline VPValue *getOperand(unsigned N) const {
163    assert(N < Operands.size() && "Operand index out of bounds");
164    return Operands[N];
165  }
166
167  void setOperand(unsigned I, VPValue *New) { Operands[I] = New; }
168
169  typedef SmallVectorImpl<VPValue *>::iterator operand_iterator;
170  typedef SmallVectorImpl<VPValue *>::const_iterator const_operand_iterator;
171  typedef iterator_range<operand_iterator> operand_range;
172  typedef iterator_range<const_operand_iterator> const_operand_range;
173
174  operand_iterator op_begin() { return Operands.begin(); }
175  const_operand_iterator op_begin() const { return Operands.begin(); }
176  operand_iterator op_end() { return Operands.end(); }
177  const_operand_iterator op_end() const { return Operands.end(); }
178  operand_range operands() { return operand_range(op_begin(), op_end()); }
179  const_operand_range operands() const {
180    return const_operand_range(op_begin(), op_end());
181  }
182};
183
184} // namespace llvm
185
186#endif // LLVM_TRANSFORMS_VECTORIZE_VPLAN_VALUE_H
187