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//===- VPlanValue.h - Represent Values in Vectorizer Plan -----------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
/// \file
/// This file contains the declarations of the entities induced by Vectorization
/// Plans, e.g. the instructions the VPlan intends to generate if executed.
/// VPlan models the following entities:
/// VPValue
/// |-- VPUser
/// | |-- VPInstruction
/// These are documented in docs/VectorizationPlan.rst.
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
// Forward declarations.
class VPUser;
// This is the base class of the VPlan Def/Use graph, used for modeling the data
// flow into, within and out of the VPlan. VPValues can stand for live-ins
// coming from the input IR, instructions which VPlan will generate if executed
// and live-outs which the VPlan will need to fix accordingly.
class VPValue {
friend class VPBuilder;
friend class VPlanHCFGTransforms;
friend class VPBasicBlock;
friend class VPInterleavedAccessInfo;
const unsigned char SubclassID; ///< Subclass identifier (for isa/dyn_cast).
SmallVector<VPUser *, 1> Users;
// Hold the underlying Value, if any, attached to this VPValue.
Value *UnderlyingVal;
VPValue(const unsigned char SC, Value *UV = nullptr)
: SubclassID(SC), UnderlyingVal(UV) {}
// DESIGN PRINCIPLE: Access to the underlying IR must be strictly limited to
// the front-end and back-end of VPlan so that the middle-end is as
// independent as possible of the underlying IR. We grant access to the
// underlying IR using friendship. In that way, we should be able to use VPlan
// for multiple underlying IRs (Polly?) by providing a new VPlan front-end,
// back-end and analysis information for the new IR.
/// Return the underlying Value attached to this VPValue.
Value *getUnderlyingValue() { return UnderlyingVal; }
// Set \p Val as the underlying Value of this VPValue.
void setUnderlyingValue(Value *Val) {
assert(!UnderlyingVal && "Underlying Value is already set.");
UnderlyingVal = Val;
/// An enumeration for keeping track of the concrete subclass of VPValue that
/// are actually instantiated. Values of this enumeration are kept in the
/// SubclassID field of the VPValue objects. They are used for concrete
/// type identification.
enum { VPValueSC, VPUserSC, VPInstructionSC };
VPValue(Value *UV = nullptr) : VPValue(VPValueSC, UV) {}
VPValue(const VPValue &) = delete;
VPValue &operator=(const VPValue &) = delete;
/// \return an ID for the concrete type of this object.
/// This is used to implement the classof checks. This should not be used
/// for any other purpose, as the values may change as LLVM evolves.
unsigned getVPValueID() const { return SubclassID; }
void printAsOperand(raw_ostream &OS) const {
OS << "%vp" << (unsigned short)(unsigned long long)this;
unsigned getNumUsers() const { return Users.size(); }
void addUser(VPUser &User) { Users.push_back(&User); }
typedef SmallVectorImpl<VPUser *>::iterator user_iterator;
typedef SmallVectorImpl<VPUser *>::const_iterator const_user_iterator;
typedef iterator_range<user_iterator> user_range;
typedef iterator_range<const_user_iterator> const_user_range;
user_iterator user_begin() { return Users.begin(); }
const_user_iterator user_begin() const { return Users.begin(); }
user_iterator user_end() { return Users.end(); }
const_user_iterator user_end() const { return Users.end(); }
user_range users() { return user_range(user_begin(), user_end()); }
const_user_range users() const {
return const_user_range(user_begin(), user_end());
/// Returns true if the value has more than one unique user.
bool hasMoreThanOneUniqueUser() {
if (getNumUsers() == 0)
return false;
// Check if all users match the first user.
auto Current = std::next(user_begin());
while (Current != user_end() && *user_begin() == *Current)
return Current != user_end();
void replaceAllUsesWith(VPValue *New);
typedef DenseMap<Value *, VPValue *> Value2VPValueTy;
typedef DenseMap<VPValue *, Value *> VPValue2ValueTy;
raw_ostream &operator<<(raw_ostream &OS, const VPValue &V);
/// This class augments VPValue with operands which provide the inverse def-use
/// edges from VPValue's users to their defs.
class VPUser : public VPValue {
SmallVector<VPValue *, 2> Operands;
VPUser(const unsigned char SC) : VPValue(SC) {}
VPUser(const unsigned char SC, ArrayRef<VPValue *> Operands) : VPValue(SC) {
for (VPValue *Operand : Operands)
VPUser() : VPValue(VPValue::VPUserSC) {}
VPUser(ArrayRef<VPValue *> Operands) : VPUser(VPValue::VPUserSC, Operands) {}
VPUser(std::initializer_list<VPValue *> Operands)
: VPUser(ArrayRef<VPValue *>(Operands)) {}
VPUser(const VPUser &) = delete;
VPUser &operator=(const VPUser &) = delete;
/// Method to support type inquiry through isa, cast, and dyn_cast.
static inline bool classof(const VPValue *V) {
return V->getVPValueID() >= VPUserSC &&
V->getVPValueID() <= VPInstructionSC;
void addOperand(VPValue *Operand) {
unsigned getNumOperands() const { return Operands.size(); }
inline VPValue *getOperand(unsigned N) const {
assert(N < Operands.size() && "Operand index out of bounds");
return Operands[N];
void setOperand(unsigned I, VPValue *New) { Operands[I] = New; }
typedef SmallVectorImpl<VPValue *>::iterator operand_iterator;
typedef SmallVectorImpl<VPValue *>::const_iterator const_operand_iterator;
typedef iterator_range<operand_iterator> operand_range;
typedef iterator_range<const_operand_iterator> const_operand_range;
operand_iterator op_begin() { return Operands.begin(); }
const_operand_iterator op_begin() const { return Operands.begin(); }
operand_iterator op_end() { return Operands.end(); }
const_operand_iterator op_end() const { return Operands.end(); }
operand_range operands() { return operand_range(op_begin(), op_end()); }
const_operand_range operands() const {
return const_operand_range(op_begin(), op_end());
} // namespace llvm