lib/VMCore/InstrTypes.cpp

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