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 // removeIncomingValue - Remove an incoming value.  This is useful if a
  37 // predecessor basic block is deleted.
  38 Value *PHINode::removeIncomingValue(unsigned Idx, bool DeletePHIIfEmpty) {
  39   assert(Idx*2 < Operands.size() && "BB not in PHI node!");
  40   Value *Removed = Operands[Idx*2];
  41   Operands.erase(Operands.begin()+Idx*2,     // Erase Value and BasicBlock
  42                  Operands.begin()+Idx*2+2);
  43
  44   // If the PHI node is dead, because it has zero entries, nuke it now.
  45   if (getNumOperands() == 0 && DeletePHIIfEmpty) {
  46     // If anyone is using this PHI, make them use a dummy value instead...
  47     replaceAllUsesWith(Constant::getNullValue(getType()));
  48     getParent()->getInstList().erase(this);
  49   }
  50   return Removed;
  51 }