lib/VMCore/InstrTypes.cpp

   1 //===-- InstrTypes.cpp - Implement Instruction subclasses -------*- C++ -*-===//
   2 //
   3 // This file implements
   4 //
   5 //===----------------------------------------------------------------------===//
   6
   7 #include "llvm/iOther.h"
   8 #include "llvm/iPHINode.h"
   9 #include "llvm/Function.h"
  10 #include "llvm/SymbolTable.h"
  11 #include "llvm/Constant.h"
  12 #include "llvm/Type.h"
  13 #include <algorithm>  // find
  14
  15 //===----------------------------------------------------------------------===//
  16 //                            TerminatorInst Class
  17 //===----------------------------------------------------------------------===//
  18
  19 TerminatorInst::TerminatorInst(Instruction::TermOps iType, Instruction *IB)
  20   : Instruction(Type::VoidTy, iType, "", IB) {
  21 }
  22
  23 //===----------------------------------------------------------------------===//
  24 //                               PHINode Class
  25 //===----------------------------------------------------------------------===//
  26
  27 PHINode::PHINode(const PHINode &PN)
  28   : Instruction(PN.getType(), Instruction::PHINode) {
  29   Operands.reserve(PN.Operands.size());
  30   for (unsigned i = 0; i < PN.Operands.size(); i+=2) {
  31     Operands.push_back(Use(PN.Operands[i], this));
  32     Operands.push_back(Use(PN.Operands[i+1], this));
  33   }
  34 }
  35
  36 void PHINode::addIncoming(Value *D, BasicBlock *BB) {
  37   assert(getType() == D->getType() &&
  38          "All operands to PHI node must be the same type as the PHI node!");
  39   Operands.push_back(Use(D, this));
  40   Operands.push_back(Use(BB, this));
  41 }
  42
  43 // removeIncomingValue - Remove an incoming value.  This is useful if a
  44 // predecessor basic block is deleted.
  45 Value *PHINode::removeIncomingValue(const BasicBlock *BB,
  46                                     bool DeletePHIIfEmpty) {
  47   op_iterator Idx = find(Operands.begin(), Operands.end(), (const Value*)BB);
  48   assert(Idx != Operands.end() && "BB not in PHI node!");
  49   --Idx;  // Back up to value prior to Basic block
  50   Value *Removed = *Idx;
  51   Operands.erase(Idx, Idx+2);  // Erase Value and BasicBlock
  52
  53   // If the PHI node is dead, because it has zero entries, nuke it now.
  54   if (getNumOperands() == 0 && DeletePHIIfEmpty) {
  55     // If anyone is using this PHI, make them use a dummy value instead...
  56     replaceAllUsesWith(Constant::getNullValue(getType()));
  57     getParent()->getInstList().erase(this);
  58   }
  59   return Removed;
  60 }