1 //===-- llvm/iPHINode.h - PHI instruction definition -------------*- C++ -*--=//
3 // This file defines the PHINode class.
5 //===----------------------------------------------------------------------===//
7 #ifndef LLVM_IPHINODE_H
8 #define LLVM_IPHINODE_H
12 #include "llvm/Instruction.h"
15 //===----------------------------------------------------------------------===//
17 //===----------------------------------------------------------------------===//
19 // PHINode - The PHINode class is used to represent the magical mystical PHI
20 // node, that can not exist in nature, but can be synthesized in a computer
21 // scientist's overactive imagination.
23 class PHINode : public Instruction {
24 PHINode(const PHINode &PN);
26 PHINode(const Type *Ty, const std::string &Name = "",
27 Instruction *InsertBefore = 0)
28 : Instruction(Ty, Instruction::PHINode, Name, InsertBefore) {
31 virtual Instruction *clone() const { return new PHINode(*this); }
33 /// getNumIncomingValues - Return the number of incoming edges the PHI node
35 unsigned getNumIncomingValues() const { return Operands.size()/2; }
37 /// getIncomingValue - Return incoming value #x
38 Value *getIncomingValue(unsigned i) const {
39 assert(i*2 < Operands.size() && "Invalid value number!");
42 void setIncomingValue(unsigned i, Value *V) {
43 assert(i*2 < Operands.size() && "Invalid value number!");
46 inline unsigned getOperandNumForIncomingValue(unsigned i) {
50 /// getIncomingBlock - Return incoming basic block #x
51 BasicBlock *getIncomingBlock(unsigned i) const {
52 assert(i*2+1 < Operands.size() && "Invalid value number!");
53 return (BasicBlock*)Operands[i*2+1].get();
55 void setIncomingBlock(unsigned i, BasicBlock *BB) {
56 assert(i*2+1 < Operands.size() && "Invalid value number!");
57 Operands[i*2+1] = (Value*)BB;
59 unsigned getOperandNumForIncomingBlock(unsigned i) {
63 /// addIncoming - Add an incoming value to the end of the PHI list
64 void addIncoming(Value *D, BasicBlock *BB) {
65 assert(getType() == D->getType() &&
66 "All operands to PHI node must be the same type as the PHI node!");
67 Operands.push_back(Use(D, this));
68 Operands.push_back(Use((Value*)BB, this));
71 /// removeIncomingValue - Remove an incoming value. This is useful if a
72 /// predecessor basic block is deleted. The value removed is returned.
74 /// If the last incoming value for a PHI node is removed (and DeletePHIIfEmpty
75 /// is true), the PHI node is destroyed and any uses of it are replaced with
76 /// dummy values. The only time there should be zero incoming values to a PHI
77 /// node is when the block is dead, so this strategy is sound.
79 Value *removeIncomingValue(unsigned Idx, bool DeletePHIIfEmpty = true);
81 Value *removeIncomingValue(const BasicBlock *BB, bool DeletePHIIfEmpty =true){
82 int Idx = getBasicBlockIndex(BB);
83 assert(Idx >= 0 && "Invalid basic block argument to remove!");
84 return removeIncomingValue(Idx, DeletePHIIfEmpty);
87 /// getBasicBlockIndex - Return the first index of the specified basic
88 /// block in the value list for this PHI. Returns -1 if no instance.
90 int getBasicBlockIndex(const BasicBlock *BB) const {
91 for (unsigned i = 0; i < Operands.size()/2; ++i)
92 if (getIncomingBlock(i) == BB) return i;
96 Value *getIncomingValueForBlock(const BasicBlock *BB) const {
97 return getIncomingValue(getBasicBlockIndex(BB));
100 /// Methods for support type inquiry through isa, cast, and dyn_cast:
101 static inline bool classof(const PHINode *) { return true; }
102 static inline bool classof(const Instruction *I) {
103 return I->getOpcode() == Instruction::PHINode;
105 static inline bool classof(const Value *V) {
106 return isa<Instruction>(V) && classof(cast<Instruction>(V));