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 using namespace llvm;
  22
  23 //===----------------------------------------------------------------------===//
  24 //                            TerminatorInst Class
  25 //===----------------------------------------------------------------------===//
  26
  27 TerminatorInst::TerminatorInst(Instruction::TermOps iType, Instruction *IB)
  28   : Instruction(Type::VoidTy, iType, "", IB) {
  29 }
  30
  31 TerminatorInst::TerminatorInst(Instruction::TermOps iType, BasicBlock *IAE)
  32   : Instruction(Type::VoidTy, iType, "", IAE) {
  33 }
  34
  35
  36
  37 //===----------------------------------------------------------------------===//
  38 //                               PHINode Class
  39 //===----------------------------------------------------------------------===//
  40
  41 PHINode::PHINode(const PHINode &PN)
  42   : Instruction(PN.getType(), Instruction::PHI) {
  43   Operands.reserve(PN.Operands.size());
  44   for (unsigned i = 0; i < PN.Operands.size(); i+=2) {
  45     Operands.push_back(Use(PN.Operands[i], this));
  46     Operands.push_back(Use(PN.Operands[i+1], this));
  47   }
  48 }
  49
  50 // removeIncomingValue - Remove an incoming value.  This is useful if a
  51 // predecessor basic block is deleted.
  52 Value *PHINode::removeIncomingValue(unsigned Idx, bool DeletePHIIfEmpty) {
  53   assert(Idx*2 < Operands.size() && "BB not in PHI node!");
  54   Value *Removed = Operands[Idx*2];
  55   Operands.erase(Operands.begin()+Idx*2,     // Erase Value and BasicBlock
  56                  Operands.begin()+Idx*2+2);
  57
  58   // If the PHI node is dead, because it has zero entries, nuke it now.
  59   if (getNumOperands() == 0 && DeletePHIIfEmpty) {
  60     // If anyone is using this PHI, make them use a dummy value instead...
  61     replaceAllUsesWith(Constant::getNullValue(getType()));
  62     getParent()->getInstList().erase(this);
  63   }
  64   return Removed;
  65 }