Ejemplo n.º 1
0
/*
 * users should call the integerSubtractAnalyser or integerSubtractAnalyserWithExplicitOperands APIs instead of calling this one directly 
 */
TR::Register* TR_X86SubtractAnalyser::integerSubtractAnalyserImpl(TR::Node     *root,
                                                                  TR::Node     *firstChild,
                                                                  TR::Node     *secondChild,
                                                                  TR_X86OpCodes regRegOpCode,
                                                                  TR_X86OpCodes regMemOpCode,
                                                                  TR_X86OpCodes copyOpCode,
                                                                  bool needsEflags, 
                                                                  TR::Node *borrow)  
   {
   TR::Register *targetRegister = NULL;
   TR::Register *firstRegister = firstChild->getRegister();
   TR::Register *secondRegister = secondChild->getRegister();
   setInputs(firstChild, firstRegister, secondChild, secondRegister);

   bool loadedConst = false;

   needsEflags = needsEflags || NEED_CC(root);

   if (getEvalChild1())
      {
      // if firstChild and secondChild are the same node, then we should
      // evaluate (take the else path) so that the evaluate for the secondChild
      // below will get the correct/already-allocated register.
      if (firstRegister == 0 && firstChild->getOpCodeValue() == TR::iconst && (firstChild != secondChild))
         {
	   // An iconst may have to be generated.  The iconst will be generated after the
	   //    secondChild is evaluated.  Set the loadedConst flag to true.
	   loadedConst = true;
         }
      else
         {
         firstRegister = _cg->evaluate(firstChild);
         }
      }

   if (getEvalChild2())
      {
      secondRegister = _cg->evaluate(secondChild);
      if (firstChild->getRegister())
         {
         firstRegister = firstChild->getRegister();
         }
      else if (!loadedConst)
         {
         firstRegister = _cg->evaluate(firstChild);
         }
      }

   if (loadedConst)
      {
      if (firstRegister == 0)
         {
         // firstchild is an inconst and it has not been evaluated.
         //   Generate the code for an iconst.
         firstRegister = _cg->allocateRegister();
         TR::TreeEvaluator::insertLoadConstant(firstChild, firstRegister, firstChild->getInt(), TR_RematerializableInt, _cg);
         }
      else
         {
         // firstchild was evaluated.  The code for an iconst does not need to be generated.
         //   Set the loadConst flag to false.
         loadedConst = false;
         }
      }

   if (borrow != 0)
      TR_X86ComputeCC::setCarryBorrow(borrow, true, _cg);

   if (getCopyReg1())
      {
      if (firstChild->getReferenceCount() > 1)
         {
         TR::Register *thirdReg;
         if (firstChild->getOpCodeValue() == TR::iconst && loadedConst)
            {
            thirdReg = firstRegister;
            }
         else
            {
            if (secondChild->getReferenceCount() == 1 && secondRegister != 0 && !needsEflags && (borrow == 0))
               {
               // use one fewer registers if we negate the clobberable secondRegister and add
               // Don't do this though if condition codes are needed.  The sequence
               // depends on the carry flag being valid as if a sub was done.
               //
               bool nodeIs64Bit = TR_X86OpCode(regRegOpCode).hasLongSource();
               generateRegInstruction(NEGReg(nodeIs64Bit), secondChild, secondRegister, _cg);
               thirdReg       = secondRegister;
               secondRegister = firstRegister;
               regRegOpCode   = ADDRegReg(nodeIs64Bit);
               }
            else
               {
               thirdReg = _cg->allocateRegister();
               generateRegRegInstruction(copyOpCode, root, thirdReg, firstRegister, _cg);
               }
            }
         targetRegister = thirdReg;
         if (getSubReg3Reg2())
            {
            generateRegRegInstruction(regRegOpCode, root, thirdReg, secondRegister, _cg);
            }
         else // assert getSubReg3Mem2() == true
            {
            TR::MemoryReference  *tempMR = generateX86MemoryReference(secondChild, _cg);
            generateRegMemInstruction(regMemOpCode, root, thirdReg, tempMR, _cg);
            tempMR->decNodeReferenceCounts(_cg);
            }
         }
      else
         {
         if (getSubReg3Reg2())
            {
            generateRegRegInstruction(regRegOpCode, root, firstRegister, secondRegister, _cg);
            }
         else // assert getSubReg3Mem2() == true
            {
            TR::MemoryReference  *tempMR = generateX86MemoryReference(secondChild, _cg);
            generateRegMemInstruction(regMemOpCode, root, firstRegister, tempMR, _cg);
            tempMR->decNodeReferenceCounts(_cg);
            }
         targetRegister = firstRegister;
         }
      }
   else if (getSubReg1Reg2())
      {
      generateRegRegInstruction(regRegOpCode, root, firstRegister, secondRegister, _cg);
      targetRegister = firstRegister;
      }
   else // assert getSubReg1Mem2() == true
      {
      TR::MemoryReference  *tempMR = generateX86MemoryReference(secondChild, _cg);
      generateRegMemInstruction(regMemOpCode, root, firstRegister, tempMR, _cg);
      targetRegister = firstRegister;
      tempMR->decNodeReferenceCounts(_cg);
      }
   return targetRegister;
   }
Ejemplo n.º 2
0
void
TR_S390BinaryAnalyser::genericAnalyser(TR::Node * root,
                                       TR::InstOpCode::Mnemonic regToRegOpCode,
                                       TR::InstOpCode::Mnemonic memToRegOpCode,
                                       TR::InstOpCode::Mnemonic copyOpCode)
   {
   TR::Node * firstChild;
   TR::Node * secondChild;
   firstChild = root->getFirstChild();
   secondChild = root->getSecondChild();
   TR::Register * firstRegister = firstChild->getRegister();
   TR::Register * secondRegister = secondChild->getRegister();
   TR::Compilation *comp = TR::comp();

   TR::SymbolReference * firstReference = firstChild->getOpCode().hasSymbolReference() ? firstChild->getSymbolReference() : NULL;
   TR::SymbolReference * secondReference = secondChild->getOpCode().hasSymbolReference() ? secondChild->getSymbolReference() : NULL;

   setInputs(firstChild, firstRegister, secondChild, secondRegister,
             false, false, comp,
             (cg()->isAddressOfStaticSymRefWithLockedReg(firstReference) ||
              cg()->isAddressOfPrivateStaticSymRefWithLockedReg(firstReference)),
             (cg()->isAddressOfStaticSymRefWithLockedReg(secondReference) ||
              cg()->isAddressOfPrivateStaticSymRefWithLockedReg(secondReference)));

   /*
    * Check if SH or CH can be used to evaluate this integer subtract/compare node.
    * The second operand of SH/CH is a 16-bit number from memory. And using
    * these directly can save a load instruction.
    */
   bool is16BitMemory2Operand = false;
   if (secondChild->getOpCodeValue() == TR::s2i &&
       secondChild->getFirstChild()->getOpCodeValue() == TR::sloadi &&
       secondChild->isSingleRefUnevaluated() &&
       secondChild->getFirstChild()->isSingleRefUnevaluated())
      {
      bool supported = true;

      if (memToRegOpCode == TR::InstOpCode::S)
         {
         memToRegOpCode = TR::InstOpCode::SH;
         }
      else if (memToRegOpCode == TR::InstOpCode::C)
         {
         memToRegOpCode = TR::InstOpCode::CH;
         }
      else
         {
         supported = false;
         }

      if (supported)
         {
         setMem2();
         is16BitMemory2Operand = true;
         }
      }

   if (getEvalChild1())
      {
      firstRegister = cg()->evaluate(firstChild);
      }

   if (getEvalChild2())
      {
      secondRegister = cg()->evaluate(secondChild);
      }

   remapInputs(firstChild, firstRegister, secondChild, secondRegister);

   if (getCopyReg1())
      {
      TR::Register * thirdReg;
      bool done = false;

      if (firstRegister->getKind() == TR_GPR64)
         {
         thirdReg = cg()->allocate64bitRegister();
         }
      else if (firstRegister->getKind() == TR_VRF)
         {
         TR_ASSERT(false,"VRF: genericAnalyser unimplemented");
         }
      else if (firstRegister->getKind() != TR_FPR && firstRegister->getKind() != TR_VRF)
         {
         thirdReg = cg()->allocateRegister();
         }
      else
         {
         thirdReg = cg()->allocateRegister(TR_FPR);
         }

      if (cg()->getS390ProcessorInfo()->supportsArch(TR_S390ProcessorInfo::TR_z196))
         {
         if (getBinaryReg3Reg2() || secondRegister != NULL)
            {
            if (regToRegOpCode == TR::InstOpCode::SR)
               {
               generateRRRInstruction(cg(), TR::InstOpCode::SRK, root, thirdReg, firstRegister, secondRegister);
               done = true;
               }
            else if (regToRegOpCode == TR::InstOpCode::SLR)
               {
               generateRRRInstruction(cg(), TR::InstOpCode::SLRK, root, thirdReg, firstRegister, secondRegister);
               done = true;
               }
            else if (regToRegOpCode == TR::InstOpCode::SGR)
               {
               generateRRRInstruction(cg(), TR::InstOpCode::SGRK, root, thirdReg, firstRegister, secondRegister);
               done = true;
               }
            else if (regToRegOpCode == TR::InstOpCode::SLGR)
               {
               generateRRRInstruction(cg(), TR::InstOpCode::SLGRK, root, thirdReg, firstRegister, secondRegister);
               done = true;
               }
            }
         }

      if (!done)
         {
         generateRRInstruction(cg(), copyOpCode, root, thirdReg, firstRegister);
         if (getBinaryReg3Reg2() || (secondRegister != NULL))
            {
            generateRRInstruction(cg(), regToRegOpCode, root, thirdReg, secondRegister);
            }
         else
            {
            TR::Node* loadBaseAddr = is16BitMemory2Operand ? secondChild->getFirstChild() : secondChild;
            TR::MemoryReference * tempMR = generateS390MemoryReference(loadBaseAddr, cg());

            //floating-point arithmatics don't have RXY format instructions, so no long displacement
            if (secondChild->getOpCode().isFloatingPoint())
               {
               tempMR->enforce4KDisplacementLimit(secondChild, cg(), NULL);
               }

            generateRXInstruction(cg(), memToRegOpCode, root, thirdReg, tempMR);
            tempMR->stopUsingMemRefRegister(cg());
            if (is16BitMemory2Operand)
               {
               cg()->decReferenceCount(secondChild->getFirstChild());
               }
            }
         }

      root->setRegister(thirdReg);
      }
   else if (getBinaryReg1Reg2())
      {
      generateRRInstruction(cg(), regToRegOpCode, root, firstRegister, secondRegister);
      root->setRegister(firstRegister);
      }
   else // assert getBinaryReg1Mem2() == true
      {
      TR_ASSERT(  !getInvalid(), "TR_S390BinaryAnalyser::invalid case\n");

      TR::MemoryReference * tempMR = generateS390MemoryReference(is16BitMemory2Operand ? secondChild->getFirstChild() : secondChild, cg());
      //floating-point arithmatics don't have RXY format instructions, so no long displacement
      if (secondChild->getOpCode().isFloatingPoint())
         {
         tempMR->enforce4KDisplacementLimit(secondChild, cg(), NULL);
         }

      generateRXInstruction(cg(), memToRegOpCode, root, firstRegister, tempMR);
      tempMR->stopUsingMemRefRegister(cg());
      if (is16BitMemory2Operand)
         cg()->decReferenceCount(secondChild->getFirstChild());
      root->setRegister(firstRegister);
      }

   cg()->decReferenceCount(firstChild);
   cg()->decReferenceCount(secondChild);

   return;
   }
Ejemplo n.º 3
0
/*
 * users should call the longSubtractAnalyser or longSubtractAnalyserWithExplicitOperands APIs instead of calling this one directly 
 */
TR::Register* TR_X86SubtractAnalyser::longSubtractAnalyserImpl(TR::Node *root, TR::Node *&firstChild, TR::Node *&secondChild)
   {
   TR::Register *firstRegister  = firstChild->getRegister();
   TR::Register *secondRegister = secondChild->getRegister();
   TR::Register *targetRegister = NULL;

   bool firstHighZero      = false;
   bool secondHighZero     = false; bool useSecondHighOrder = false;

   TR_X86OpCodes regRegOpCode = SUB4RegReg;
   TR_X86OpCodes regMemOpCode = SUB4RegMem;

   bool needsEflags = NEED_CC(root) || (root->getOpCodeValue() == TR::lusubb);

   // Can generate better code for long adds when one or more children have a high order zero word
   // can avoid the evaluation when we don't need the result of such nodes for another parent.
   //
   if (firstChild->isHighWordZero() && !needsEflags)
      {
      firstHighZero = true;
      }

   if (secondChild->isHighWordZero() && !needsEflags)
      {
      secondHighZero = true;
      TR::ILOpCodes secondOp = secondChild->getOpCodeValue();
      if (secondChild->getReferenceCount() == 1 && secondRegister == 0)
         {
         if (secondOp == TR::iu2l || secondOp == TR::su2l ||
             secondOp == TR::bu2l ||
             (secondOp == TR::lushr &&
              secondChild->getSecondChild()->getOpCodeValue() == TR::iconst &&
              (secondChild->getSecondChild()->getInt() & TR::TreeEvaluator::shiftMask(true)) == 32))
            {
            secondChild    = secondChild->getFirstChild();
            secondRegister = secondChild->getRegister();
            if (secondOp == TR::lushr)
               {
               useSecondHighOrder = true;
               }
            }
         }
      }

   setInputs(firstChild, firstRegister, secondChild, secondRegister);

   if (isVolatileMemoryOperand(firstChild))
      resetMem1();

   if (isVolatileMemoryOperand(secondChild))
      resetMem2();

   if (getEvalChild1())
      {
      firstRegister = _cg->evaluate(firstChild);
      }

   if (getEvalChild2())
      {
      secondRegister = _cg->evaluate(secondChild);
      }

   if (secondHighZero && secondRegister && secondRegister->getRegisterPair())
      {
      if (!useSecondHighOrder)
         {
         secondRegister = secondRegister->getLowOrder();
         }
      else
         {
         secondRegister = secondRegister->getHighOrder();
         }
      }

   if (root->getOpCodeValue() == TR::lusubb &&
       TR_X86ComputeCC::setCarryBorrow(root->getChild(2), true, _cg))
      {
      // use SBB rather than SUB
      //
      regRegOpCode = SBB4RegReg;
      regMemOpCode = SBB4RegMem;
      }

   if (getCopyReg1())
      {
      TR::Register     *lowThird  = _cg->allocateRegister();
      TR::Register     *highThird = _cg->allocateRegister();
      TR::RegisterPair *thirdReg  = _cg->allocateRegisterPair(lowThird, highThird);
      targetRegister = thirdReg;
      generateRegRegInstruction(MOV4RegReg, root, lowThird, firstRegister->getLowOrder(), _cg);

      if (firstHighZero)
         {
         generateRegRegInstruction(XOR4RegReg, root, highThird, highThird, _cg);
         }
      else
         {
         generateRegRegInstruction(MOV4RegReg, root, highThird, firstRegister->getHighOrder(), _cg);
         }

      if (getSubReg3Reg2())
         {
         if (secondHighZero)
            {
            generateRegRegInstruction(regRegOpCode, root, lowThird, secondRegister, _cg);
            generateRegImmInstruction(SBB4RegImms, root, highThird, 0, _cg);
            }
         else
            {
            generateRegRegInstruction(regRegOpCode, root, lowThird, secondRegister->getLowOrder(), _cg);
            generateRegRegInstruction(SBB4RegReg, root, highThird, secondRegister->getHighOrder(), _cg);
            }
         }
      else // assert getSubReg3Mem2() == true
         {
         TR::MemoryReference  *lowMR = generateX86MemoryReference(secondChild, _cg);
         /**
          * The below code is needed to ensure correct behaviour when the subtract analyser encounters a lushr bytecode that shifts
          * by 32 bits. This is the only case where the useSecondHighOrder bit is set.
          * When the first child of the lushr is in a register, code above handles the shift. When the first child of the lushr is in
          * memory, the below ensures that the upper part of the first child of the lushr is used as lowMR.
          */
         if (useSecondHighOrder)
            {
            TR_ASSERT(secondHighZero, "useSecondHighOrder should be consistent with secondHighZero. useSecondHighOrder subsumes secondHighZero");
        	   lowMR = generateX86MemoryReference(*lowMR, 4, _cg);
            }

         generateRegMemInstruction(regMemOpCode, root, lowThird, lowMR, _cg);
         if (secondHighZero)
            {
            generateRegImmInstruction(SBB4RegImms, root, highThird, 0, _cg);
            }
         else
            {
            TR::MemoryReference  *highMR = generateX86MemoryReference(*lowMR, 4, _cg);
            generateRegMemInstruction(SBB4RegMem, root, highThird, highMR, _cg);
            }
         lowMR->decNodeReferenceCounts(_cg);
         }
      }
   else if (getSubReg1Reg2())
      {
      if (secondHighZero)
         {
         generateRegRegInstruction(regRegOpCode, root, firstRegister->getLowOrder(), secondRegister, _cg);
         generateRegImmInstruction(SBB4RegImms, root, firstRegister->getHighOrder(), 0, _cg);
         }
      else
         {
         generateRegRegInstruction(regRegOpCode, root, firstRegister->getLowOrder(), secondRegister->getLowOrder(), _cg);
         generateRegRegInstruction(SBB4RegReg, root, firstRegister->getHighOrder(), secondRegister->getHighOrder(), _cg);
         }
      targetRegister = firstRegister;
      }
   else // assert getSubReg1Mem2() == true
      {
      TR::MemoryReference  *lowMR = generateX86MemoryReference(secondChild, _cg);
      /**
       * The below code is needed to ensure correct behaviour when the subtract analyser encounters a lushr bytecode that shifts
       * by 32 bits. This is the only case where the useSecondHighOrder bit is set.
       * When the first child of the lushr is in a register, code above handles the shift. When the first child of the lushr is in
       * memory, the below ensures that the upper part of the first child of the lushr is used as lowMR.
       */
      if (useSecondHighOrder)
     	 lowMR = generateX86MemoryReference(*lowMR, 4, _cg);

      generateRegMemInstruction(regMemOpCode, root, firstRegister->getLowOrder(), lowMR, _cg);

      if (secondHighZero)
         {
         generateRegImmInstruction(SBB4RegImms, root, firstRegister->getHighOrder(), 0, _cg);
         }
      else
         {
         TR::MemoryReference  *highMR = generateX86MemoryReference(*lowMR, 4, _cg);
         generateRegMemInstruction(SBB4RegMem, root, firstRegister->getHighOrder(), highMR, _cg);
         }

      targetRegister = firstRegister;
      lowMR->decNodeReferenceCounts(_cg);
      }

   return targetRegister;
   }
Ejemplo n.º 4
0
void
TR_S390BinaryAnalyser::longSubtractAnalyser(TR::Node * root)
   {
   TR::Node * firstChild;
   TR::Node * secondChild;
   TR::Instruction * cursor = NULL;
   TR::RegisterDependencyConditions * dependencies = NULL;
   bool setsOrReadsCC = NEED_CC(root) || (root->getOpCodeValue() == TR::lusubb);
   TR::InstOpCode::Mnemonic regToRegOpCode;
   TR::InstOpCode::Mnemonic memToRegOpCode;
   TR::Compilation *comp = TR::comp();

   if (TR::Compiler->target.is64Bit() || cg()->use64BitRegsOn32Bit())
      {
      if (!setsOrReadsCC)
         {
         regToRegOpCode = TR::InstOpCode::SGR;
         memToRegOpCode = TR::InstOpCode::SG;
         }
      else
         {
         regToRegOpCode = TR::InstOpCode::SLGR;
         memToRegOpCode = TR::InstOpCode::SLG;
         }
      }
   else
      {
      regToRegOpCode = TR::InstOpCode::SLR;
      memToRegOpCode = TR::InstOpCode::SL;
      }

   firstChild = root->getFirstChild();
   secondChild = root->getSecondChild();
   TR::Register * firstRegister = firstChild->getRegister();
   TR::Register * secondRegister = secondChild->getRegister();

   setInputs(firstChild, firstRegister, secondChild, secondRegister,
             false, false, comp);

   /**  Attempt to use SGH to subtract halfword (64 <- 16).
    * The second child is a halfword from memory */
   bool is16BitMemory2Operand = false;
   if (TR::Compiler->target.cpu.getS390SupportsZ14() &&
       secondChild->getOpCodeValue() == TR::s2l &&
       secondChild->getFirstChild()->getOpCodeValue() == TR::sloadi &&
       secondChild->isSingleRefUnevaluated() &&
       secondChild->getFirstChild()->isSingleRefUnevaluated())
      {
      setMem2();
      memToRegOpCode = TR::InstOpCode::SGH;
      is16BitMemory2Operand = true;
      }

   if (getEvalChild1())
      {
      firstRegister = cg()->evaluate(firstChild);
      }

   if (getEvalChild2())
      {
      secondRegister = cg()->evaluate(secondChild);
      }

   remapInputs(firstChild, firstRegister, secondChild, secondRegister);

   if ((root->getOpCodeValue() == TR::lusubb) &&
       TR_S390ComputeCC::setCarryBorrow(root->getChild(2), false, cg()))
      {
      // use SLBGR rather than SLGR/SGR
      //     SLBG rather than SLG/SG
      // or
      // use SLBR rather than SLR
      //     SLB rather than SL
      bool uses64bit = TR::Compiler->target.is64Bit() || cg()->use64BitRegsOn32Bit();
      regToRegOpCode = uses64bit ? TR::InstOpCode::SLBGR : TR::InstOpCode::SLBR;
      memToRegOpCode = uses64bit ? TR::InstOpCode::SLBG  : TR::InstOpCode::SLB;
      }

   if (TR::Compiler->target.is64Bit() || cg()->use64BitRegsOn32Bit())
      {
      if (getCopyReg1())
         {
         TR::Register * thirdReg = cg()->allocate64bitRegister();

         root->setRegister(thirdReg);
         generateRRInstruction(cg(), TR::InstOpCode::LGR, root, thirdReg, firstRegister);
         if (getBinaryReg3Reg2())
            {
            generateRRInstruction(cg(), regToRegOpCode, root, thirdReg, secondRegister);
            }
         else // assert getBinaryReg3Mem2() == true
            {
            TR::MemoryReference * longMR = generateS390MemoryReference(secondChild, cg());

            generateRXInstruction(cg(), memToRegOpCode, root, thirdReg, longMR);
            longMR->stopUsingMemRefRegister(cg());
            }
         }
      else if (getBinaryReg1Reg2())
         {
         generateRRInstruction(cg(), regToRegOpCode, root, firstRegister, secondRegister);

         root->setRegister(firstRegister);
         }
      else // assert getBinaryReg1Mem2() == true
         {
         TR_ASSERT(  !getInvalid(), "TR_S390BinaryAnalyser::invalid case\n");

         TR::Node* baseAddrNode = is16BitMemory2Operand ? secondChild->getFirstChild() : secondChild;
         TR::MemoryReference * longMR = generateS390MemoryReference(baseAddrNode, cg());

         generateRXInstruction(cg(), memToRegOpCode, root, firstRegister, longMR);

         longMR->stopUsingMemRefRegister(cg());
         root->setRegister(firstRegister);

         if(is16BitMemory2Operand)
            {
            cg()->decReferenceCount(secondChild->getFirstChild());
            }
         }

      }
   else    // if 32bit codegen...
      {
      bool zArchTrexsupported = performTransformation(comp, "O^O Use SL/SLB for long sub.");

      TR::Register * highDiff = NULL;
      TR::LabelSymbol * doneLSub = TR::LabelSymbol::create(cg()->trHeapMemory(),cg());
      if (getCopyReg1())
         {
         TR::Register * lowThird = cg()->allocateRegister();
         TR::Register * highThird = cg()->allocateRegister();

         TR::RegisterPair * thirdReg = cg()->allocateConsecutiveRegisterPair(lowThird, highThird);

         highDiff = highThird;

         dependencies = new (cg()->trHeapMemory()) TR::RegisterDependencyConditions(0, 9, cg());
         dependencies->addPostCondition(firstRegister, TR::RealRegister::EvenOddPair);
         dependencies->addPostCondition(firstRegister->getHighOrder(), TR::RealRegister::LegalEvenOfPair);
         dependencies->addPostCondition(firstRegister->getLowOrder(), TR::RealRegister::LegalOddOfPair);

         // If 2nd operand has ref count of 1 and can be accessed by a memory reference,
         // then second register will not be used.
         if(secondRegister == firstRegister && !setsOrReadsCC)
            {
            TR_ASSERT( false, "lsub with identical children - fix Simplifier");
            }
         if (secondRegister != NULL && firstRegister != secondRegister)
            {
            dependencies->addPostCondition(secondRegister, TR::RealRegister::EvenOddPair);
            dependencies->addPostCondition(secondRegister->getHighOrder(), TR::RealRegister::LegalEvenOfPair);
            dependencies->addPostCondition(secondRegister->getLowOrder(), TR::RealRegister::LegalOddOfPair);
            }
         dependencies->addPostCondition(highThird, TR::RealRegister::AssignAny);

         root->setRegister(thirdReg);
         generateRRInstruction(cg(), TR::InstOpCode::LR, root, highThird, firstRegister->getHighOrder());
         generateRRInstruction(cg(), TR::InstOpCode::LR, root, lowThird, firstRegister->getLowOrder());
         if (getBinaryReg3Reg2())
            {
            if ((ENABLE_ZARCH_FOR_32 && zArchTrexsupported) || setsOrReadsCC)
               {
               generateRRInstruction(cg(), regToRegOpCode, root, lowThird, secondRegister->getLowOrder());
               generateRRInstruction(cg(), TR::InstOpCode::SLBR, root, highThird, secondRegister->getHighOrder());
               }
            else
               {
               generateRRInstruction(cg(), TR::InstOpCode::SR, root, highThird, secondRegister->getHighOrder());
               generateRRInstruction(cg(), TR::InstOpCode::SLR, root, lowThird, secondRegister->getLowOrder());
               }
            }
         else // assert getBinaryReg3Mem2() == true
            {
            TR::MemoryReference * highMR = generateS390MemoryReference(secondChild, cg());
            TR::MemoryReference * lowMR = generateS390MemoryReference(*highMR, 4, cg());
            dependencies->addAssignAnyPostCondOnMemRef(highMR);

            if ((ENABLE_ZARCH_FOR_32 && zArchTrexsupported) || setsOrReadsCC)
               {
               generateRXInstruction(cg(), memToRegOpCode, root, lowThird, lowMR);
               generateRXInstruction(cg(), TR::InstOpCode::SLB, root, highThird, highMR);
               }
            else
               {
               generateRXInstruction(cg(), TR::InstOpCode::S, root, highThird, highMR);
               generateRXInstruction(cg(), TR::InstOpCode::SL, root, lowThird, lowMR);
               }
            highMR->stopUsingMemRefRegister(cg());
            lowMR->stopUsingMemRefRegister(cg());
            }
         }
      else if (getBinaryReg1Reg2())
         {
         dependencies = new (cg()->trHeapMemory()) TR::RegisterDependencyConditions(0, 6, cg());
         dependencies->addPostCondition(firstRegister, TR::RealRegister::EvenOddPair);
         dependencies->addPostCondition(firstRegister->getHighOrder(), TR::RealRegister::LegalEvenOfPair);
         dependencies->addPostCondition(firstRegister->getLowOrder(), TR::RealRegister::LegalOddOfPair);

         if(secondRegister == firstRegister)
            {
            TR_ASSERT( false, "lsub with identical children - fix Simplifier");
            }

         if (secondRegister != firstRegister)
            {
            dependencies->addPostCondition(secondRegister, TR::RealRegister::EvenOddPair);
            dependencies->addPostCondition(secondRegister->getHighOrder(), TR::RealRegister::LegalEvenOfPair);
            dependencies->addPostCondition(secondRegister->getLowOrder(), TR::RealRegister::LegalOddOfPair);
            }

         if ((ENABLE_ZARCH_FOR_32 && zArchTrexsupported) || setsOrReadsCC)
            {
            generateRRInstruction(cg(), regToRegOpCode, root, firstRegister->getLowOrder(), secondRegister->getLowOrder());
            generateRRInstruction(cg(), TR::InstOpCode::SLBR, root, firstRegister->getHighOrder(), secondRegister->getHighOrder());
            }
         else
            {
            generateRRInstruction(cg(), TR::InstOpCode::SR, root, firstRegister->getHighOrder(), secondRegister->getHighOrder());
            generateRRInstruction(cg(), TR::InstOpCode::SLR, root, firstRegister->getLowOrder(), secondRegister->getLowOrder());
            }

         highDiff = firstRegister->getHighOrder();
         root->setRegister(firstRegister);
         }
      else // assert getBinaryReg1Mem2() == true
         {
         TR_ASSERT(  !getInvalid(),"TR_S390BinaryAnalyser::invalid case\n");

         dependencies = new (cg()->trHeapMemory()) TR::RegisterDependencyConditions(0, 5, cg());
         dependencies->addPostCondition(firstRegister, TR::RealRegister::EvenOddPair);
         dependencies->addPostCondition(firstRegister->getHighOrder(), TR::RealRegister::LegalEvenOfPair);
         dependencies->addPostCondition(firstRegister->getLowOrder(), TR::RealRegister::LegalOddOfPair);

         TR::MemoryReference * highMR = generateS390MemoryReference(secondChild, cg());
         TR::MemoryReference * lowMR = generateS390MemoryReference(*highMR, 4, cg());
         dependencies->addAssignAnyPostCondOnMemRef(highMR);

         if ((ENABLE_ZARCH_FOR_32 && zArchTrexsupported) || setsOrReadsCC)
            {
            generateRXInstruction(cg(), memToRegOpCode, root, firstRegister->getLowOrder(), lowMR);
            generateRXInstruction(cg(), TR::InstOpCode::SLB, root, firstRegister->getHighOrder(), highMR);
            }
         else
            {
            generateRXInstruction(cg(), TR::InstOpCode::S, root, firstRegister->getHighOrder(), highMR);
            generateRXInstruction(cg(), TR::InstOpCode::SL, root, firstRegister->getLowOrder(), lowMR);
            }
         highDiff = firstRegister->getHighOrder();
         root->setRegister(firstRegister);
         highMR->stopUsingMemRefRegister(cg());
         lowMR->stopUsingMemRefRegister(cg());
         }

      if (!((ENABLE_ZARCH_FOR_32 && zArchTrexsupported) || setsOrReadsCC))
         {
         // Check for overflow in LS int. If overflow, we are done.
         generateS390BranchInstruction(cg(), TR::InstOpCode::BRC,TR::InstOpCode::COND_MASK3, root, doneLSub);

         // Increment MS int due to overflow in LS int
         generateRIInstruction(cg(), TR::InstOpCode::AHI, root, highDiff, -1);

         generateS390LabelInstruction(cg(), TR::InstOpCode::LABEL, root, doneLSub, dependencies);
         }
      }

   cg()->decReferenceCount(firstChild);
   cg()->decReferenceCount(secondChild);

   return;
   }