TR::Register *
TR::AMD64SystemLinkage::buildIndirectDispatch(TR::Node *callNode)
{
TR::SymbolReference *methodSymRef = callNode->getSymbolReference();
TR_ASSERT(methodSymRef->getSymbol()->castToMethodSymbol()->isComputed(), "system linkage only supports computed indirect call for now %p\n", callNode);
// Evaluate VFT
//
TR::Register *vftRegister;
TR::Node *vftNode = callNode->getFirstChild();
if (vftNode->getRegister())
{
vftRegister = vftNode->getRegister();
}
else
{
vftRegister = cg()->evaluate(vftNode);
}
// Allocate adequate register dependencies.
//
// pre = number of argument registers + 1 for VFT register
// post = number of volatile + VMThread + return register
//
uint32_t pre = getProperties().getNumIntegerArgumentRegisters() + getProperties().getNumFloatArgumentRegisters() + 1;
uint32_t post = getProperties().getNumVolatileRegisters() + 1 + (callNode->getDataType() == TR::NoType ? 0 : 1);
#if defined (PYTHON) && 0
// Treat all preserved GP regs as volatile until register map support available.
//
post += getProperties().getNumberOfPreservedGPRegisters();
#endif
TR::RegisterDependencyConditions *callDeps = generateRegisterDependencyConditions(pre, 1, cg());
TR::RealRegister::RegNum scratchRegIndex = getProperties().getIntegerScratchRegister(1);
callDeps->addPostCondition(vftRegister, scratchRegIndex, cg());
callDeps->stopAddingPostConditions();
// Evaluate outgoing arguments on the system stack and build pre-conditions.
//
int32_t memoryArgSize = buildArgs(callNode, callDeps);
// Dispatch
//
generateRegInstruction(CALLReg, callNode, vftRegister, callDeps, cg());
cg()->resetIsLeafMethod();
// Build label post-conditions
//
TR::RegisterDependencyConditions *postDeps = generateRegisterDependencyConditions(0, post, cg());
TR::Register *returnReg = buildVolatileAndReturnDependencies(callNode, postDeps);
postDeps->stopAddingPostConditions();
TR::LabelSymbol *postDepLabel = generateLabelSymbol(cg());
generateLabelInstruction(LABEL, callNode, postDepLabel, postDeps, cg());
return returnReg;
}
// Create a NoReg dependency for each child of a call that has been evaluated into a register.
// Ignore children that do not have a register since their live range should not persist outside of
// the helper call stream.
//
TR::RegisterDependencyConditions *TR_OutlinedInstructions::formEvaluatedArgumentDepList()
{
int32_t i, c=0;
for (i=_callNode->getFirstArgumentIndex(); i<_callNode->getNumChildren(); i++)
{
TR::Register *reg = _callNode->getChild(i)->getRegister();
if (reg)
{
TR::RegisterPair *regPair = reg->getRegisterPair();
c += regPair? 2 : 1;
}
}
TR::RegisterDependencyConditions *depConds = NULL;
if (c)
{
TR::Machine *machine = _cg->machine();
depConds = generateRegisterDependencyConditions(0, c, _cg);
for (i=_callNode->getFirstArgumentIndex(); i<_callNode->getNumChildren(); i++)
{
TR::Register *reg = _callNode->getChild(i)->getRegister();
if (reg)
{
TR::RegisterPair *regPair = reg->getRegisterPair();
if (regPair)
{
depConds->addPostCondition(regPair->getLowOrder(), TR::RealRegister::NoReg, _cg);
depConds->addPostCondition(regPair->getHighOrder(), TR::RealRegister::NoReg, _cg);
}
else
{
depConds->addPostCondition(reg, TR::RealRegister::NoReg, _cg);
}
}
}
depConds->stopAddingConditions();
}
return depConds;
}
TR::Register *TR::IA32SystemLinkage::buildDirectDispatch(TR::Node *callNode, bool spillFPRegs)
{
TR::RealRegister *stackPointerReg = machine()->getX86RealRegister(TR::RealRegister::esp);
TR::SymbolReference *methodSymRef = callNode->getSymbolReference();
TR::MethodSymbol *methodSymbol = callNode->getSymbol()->castToMethodSymbol();
TR::ILOpCodes callOpCodeValue = callNode->getOpCodeValue();
if (!methodSymbol->isHelper())
diagnostic("Building call site for %s\n", methodSymbol->getMethod()->signature(trMemory()));
TR::RegisterDependencyConditions *deps;
deps = generateRegisterDependencyConditions((uint8_t)0, (uint8_t)6, cg());
TR::Register *returnReg = buildVolatileAndReturnDependencies(callNode, deps);
deps->stopAddingConditions();
TR::RegisterDependencyConditions *dummy = generateRegisterDependencyConditions((uint8_t)0, (uint8_t)0, cg());
uint32_t argSize = buildArgs(callNode, dummy);
TR::Register* targetAddressReg = NULL;
TR::MemoryReference* targetAddressMem = NULL;
// Call-out
int32_t stackAdjustment = cg()->getProperties().getCallerCleanup() ? 0 : -argSize;
TR::X86ImmInstruction* instr = generateImmSymInstruction(CALLImm4, callNode, (uintptr_t)methodSymbol->getMethodAddress(), methodSymRef, cg());
instr->setAdjustsFramePointerBy(stackAdjustment);
if (cg()->getProperties().getCallerCleanup() && argSize > 0)
{
// Clean up arguments
//
generateRegImmInstruction(
(argSize <= 127) ? ADD4RegImms : ADD4RegImm4,
callNode,
stackPointerReg,
argSize,
cg()
);
}
// Label denoting end of dispatch code sequence; dependencies are on
// this label rather than on the call
//
TR::LabelSymbol *endSystemCallSequence = generateLabelSymbol(cg());
generateLabelInstruction(LABEL, callNode, endSystemCallSequence, deps, cg());
// Stop using the killed registers that are not going to persist
//
if (deps)
stopUsingKilledRegisters(deps, returnReg);
// If the method returns a floating point value that is not used, insert a dummy store to
// eventually pop the value from the floating point stack.
//
if ((callNode->getDataType() == TR::Float ||
callNode->getDataType() == TR::Double) &&
callNode->getReferenceCount() == 1)
{
generateFPSTiST0RegRegInstruction(FSTRegReg, callNode, returnReg, returnReg, cg());
}
if (cg()->enableRegisterAssociations())
associatePreservedRegisters(deps, returnReg);
return returnReg;
}
TR::Register *OMR::X86::AMD64::TreeEvaluator::dbits2lEvaluator(TR::Node *node, TR::CodeGenerator *cg)
{
// TODO:AMD64: Peepholing
TR::Node *child = node->getFirstChild();
TR::Register *sreg = cg->evaluate(child);
TR::Register *treg = cg->allocateRegister(TR_GPR);
generateRegRegInstruction(MOVQReg8Reg, node, treg, sreg, cg);
if (node->normalizeNanValues())
{
static char *disableFastNormalizeNaNs = feGetEnv("TR_disableFastNormalizeNaNs");
if (disableFastNormalizeNaNs)
{
// This one is not clever, but it is simple, and it's based directly
// on the IA32 version which is known to work, so is safer.
//
TR::RegisterDependencyConditions *deps = generateRegisterDependencyConditions((uint8_t)0, (uint8_t)1, cg);
deps->addPostCondition(treg, TR::RealRegister::NoReg, cg);
TR::IA32ConstantDataSnippet *nan1Snippet = cg->findOrCreate8ByteConstant(node, DOUBLE_NAN_1_LOW);
TR::IA32ConstantDataSnippet *nan2Snippet = cg->findOrCreate8ByteConstant(node, DOUBLE_NAN_2_LOW);
TR::MemoryReference *nan1MR = generateX86MemoryReference(nan1Snippet, cg);
TR::MemoryReference *nan2MR = generateX86MemoryReference(nan2Snippet, cg);
TR::LabelSymbol *startLabel = TR::LabelSymbol::create(cg->trHeapMemory(),cg);
TR::LabelSymbol *normalizeLabel = TR::LabelSymbol::create(cg->trHeapMemory(),cg);
TR::LabelSymbol *endLabel = TR::LabelSymbol::create(cg->trHeapMemory(),cg);
startLabel->setStartInternalControlFlow();
endLabel ->setEndInternalControlFlow();
generateLabelInstruction( LABEL, node, startLabel, cg);
generateRegMemInstruction( CMP8RegMem, node, treg, nan1MR, cg);
generateLabelInstruction( JGE4, node, normalizeLabel, cg);
generateRegMemInstruction( CMP8RegMem, node, treg, nan2MR, cg);
generateLabelInstruction( JB4, node, endLabel, cg);
generateLabelInstruction( LABEL, node, normalizeLabel, cg);
generateRegImm64Instruction( MOV8RegImm64, node, treg, DOUBLE_NAN, cg);
generateLabelInstruction( LABEL, node, endLabel, deps, cg);
}
else
{
// A bunch of bookkeeping
//
uint64_t nanDetector = DOUBLE_NAN_2_LOW;
TR::RegisterDependencyConditions *internalControlFlowDeps = generateRegisterDependencyConditions((uint8_t)0, (uint8_t)1, cg);
internalControlFlowDeps->addPostCondition(treg, TR::RealRegister::NoReg, cg);
TR::RegisterDependencyConditions *helperDeps = generateRegisterDependencyConditions((uint8_t)1, (uint8_t)1, cg);
helperDeps->addPreCondition( treg, TR::RealRegister::eax, cg);
helperDeps->addPostCondition(treg, TR::RealRegister::eax, cg);
TR::IA32ConstantDataSnippet *nanDetectorSnippet = cg->findOrCreate8ByteConstant(node, nanDetector);
TR::MemoryReference *nanDetectorMR = generateX86MemoryReference(nanDetectorSnippet, cg);
TR::LabelSymbol *startLabel = TR::LabelSymbol::create(cg->trHeapMemory(),cg);
TR::LabelSymbol *slowPathLabel = TR::LabelSymbol::create(cg->trHeapMemory(),cg);
TR::LabelSymbol *normalizeLabel = TR::LabelSymbol::create(cg->trHeapMemory(),cg);
TR::LabelSymbol *endLabel = TR::LabelSymbol::create(cg->trHeapMemory(),cg);
startLabel->setStartInternalControlFlow();
endLabel ->setEndInternalControlFlow();
// Fast path: if subtracting nanDetector leaves CF=0 or OF=1, then it
// must be a NaN.
//
generateLabelInstruction( LABEL, node, startLabel, cg);
generateRegMemInstruction( CMP8RegMem, node, treg, nanDetectorMR, cg);
generateLabelInstruction( JAE4, node, slowPathLabel, cg);
generateLabelInstruction( JO4, node, slowPathLabel, cg);
// Slow path
//
TR_OutlinedInstructions *slowPath = new (cg->trHeapMemory()) TR_OutlinedInstructions(slowPathLabel, cg);
cg->getOutlinedInstructionsList().push_front(slowPath);
slowPath->swapInstructionListsWithCompilation();
generateLabelInstruction(NULL, LABEL, slowPathLabel, cg)->setNode(node);
generateRegImm64Instruction(MOV8RegImm64, node, treg, DOUBLE_NAN, cg);
generateLabelInstruction( JMP4, node, endLabel, cg);
slowPath->swapInstructionListsWithCompilation();
// Merge point
//
generateLabelInstruction(LABEL, node, endLabel, internalControlFlowDeps, cg);
}
}
node->setRegister(treg);
cg->decReferenceCount(child);
return treg;
}
TR::Register *TR::AMD64SystemLinkage::buildDirectDispatch(
TR::Node *callNode,
bool spillFPRegs)
{
TR::SymbolReference *methodSymRef = callNode->getSymbolReference();
TR::MethodSymbol *methodSymbol = methodSymRef->getSymbol()->castToMethodSymbol();
TR::Register *returnReg;
// Allocate adequate register dependencies.
//
// pre = number of argument registers
// post = number of volatile + return register
//
uint32_t pre = getProperties().getNumIntegerArgumentRegisters() + getProperties().getNumFloatArgumentRegisters();
uint32_t post = getProperties().getNumVolatileRegisters() + (callNode->getDataType() == TR::NoType ? 0 : 1);
#if defined (PYTHON) && 0
// Treat all preserved GP regs as volatile until register map support available.
//
post += getProperties().getNumberOfPreservedGPRegisters();
#endif
TR::RegisterDependencyConditions *preDeps = generateRegisterDependencyConditions(pre, 0, cg());
TR::RegisterDependencyConditions *postDeps = generateRegisterDependencyConditions(0, post, cg());
// Evaluate outgoing arguments on the system stack and build pre-conditions.
//
int32_t memoryArgSize = buildArgs(callNode, preDeps);
// Build post-conditions.
//
returnReg = buildVolatileAndReturnDependencies(callNode, postDeps);
postDeps->stopAddingPostConditions();
// Find the second scratch register in the post dependency list.
//
TR::Register *scratchReg = NULL;
TR::RealRegister::RegNum scratchRegIndex = getProperties().getIntegerScratchRegister(1);
for (int32_t i=0; i<post; i++)
{
if (postDeps->getPostConditions()->getRegisterDependency(i)->getRealRegister() == scratchRegIndex)
{
scratchReg = postDeps->getPostConditions()->getRegisterDependency(i)->getRegister();
break;
}
}
#if defined(PYTHON) && 0
// For Python, store the instruction that contains the GC map at this site into
// the frame object.
//
TR::SymbolReference *frameObjectSymRef =
comp()->getSymRefTab()->findOrCreateAutoSymbol(comp()->getMethodSymbol(), 0, TR::Address, true, false, true);
TR::Register *frameObjectRegister = cg()->allocateRegister();
generateRegMemInstruction(
L8RegMem,
callNode,
frameObjectRegister,
generateX86MemoryReference(frameObjectSymRef, cg()),
cg());
TR::RealRegister *espReal = cg()->machine()->getX86RealRegister(TR::RealRegister::esp);
TR::Register *gcMapPCRegister = cg()->allocateRegister();
generateRegMemInstruction(
LEA8RegMem,
callNode,
gcMapPCRegister,
generateX86MemoryReference(espReal, -8, cg()),
cg());
// Use "volatile" registers across the call. Once proper register map support
// is implemented, r14 and r15 will no longer be volatile and a different pair
// should be chosen.
//
TR::RegisterDependencyConditions *gcMapDeps = generateRegisterDependencyConditions(0, 2, cg());
gcMapDeps->addPostCondition(frameObjectRegister, TR::RealRegister::r14, cg());
gcMapDeps->addPostCondition(gcMapPCRegister, TR::RealRegister::r15, cg());
gcMapDeps->stopAddingPostConditions();
generateMemRegInstruction(
S8MemReg,
callNode,
generateX86MemoryReference(frameObjectRegister, fe()->getPythonGCMapPCOffsetInFrame(), cg()),
gcMapPCRegister,
gcMapDeps,
cg());
cg()->stopUsingRegister(frameObjectRegister);
cg()->stopUsingRegister(gcMapPCRegister);
#endif
TR::Instruction *instr;
if (methodSymbol->getMethodAddress())
{
TR_ASSERT(scratchReg, "could not find second scratch register");
auto LoadRegisterInstruction = generateRegImm64SymInstruction(
MOV8RegImm64,
callNode,
scratchReg,
(uintptr_t)methodSymbol->getMethodAddress(),
methodSymRef,
cg());
if (TR::Options::getCmdLineOptions()->getOption(TR_EmitRelocatableELFFile))
{
LoadRegisterInstruction->setReloKind(TR_NativeMethodAbsolute);
}
instr = generateRegInstruction(CALLReg, callNode, scratchReg, preDeps, cg());
}
else
{
instr = generateImmSymInstruction(CALLImm4, callNode, (uintptrj_t)methodSymbol->getMethodAddress(), methodSymRef, preDeps, cg());
}
cg()->resetIsLeafMethod();
instr->setNeedsGCMap(getProperties().getPreservedRegisterMapForGC());
cg()->stopUsingRegister(scratchReg);
TR::LabelSymbol *postDepLabel = generateLabelSymbol(cg());
generateLabelInstruction(LABEL, callNode, postDepLabel, postDeps, cg());
return returnReg;
}
TR::Register *TR::AMD64SystemLinkage::buildDirectDispatch(
TR::Node *callNode,
bool spillFPRegs)
{
TR::SymbolReference *methodSymRef = callNode->getSymbolReference();
TR::MethodSymbol *methodSymbol = methodSymRef->getSymbol()->castToMethodSymbol();
TR::Register *returnReg;
// Allocate adequate register dependencies.
//
// pre = number of argument registers
// post = number of volatile + return register
//
uint32_t pre = getProperties().getNumIntegerArgumentRegisters() + getProperties().getNumFloatArgumentRegisters();
uint32_t post = getProperties().getNumVolatileRegisters() + (callNode->getDataType() == TR::NoType ? 0 : 1);
TR::RegisterDependencyConditions *preDeps = generateRegisterDependencyConditions(pre, 0, cg());
TR::RegisterDependencyConditions *postDeps = generateRegisterDependencyConditions(0, post, cg());
// Evaluate outgoing arguments on the system stack and build pre-conditions.
//
int32_t memoryArgSize = buildArgs(callNode, preDeps);
// Build post-conditions.
//
returnReg = buildVolatileAndReturnDependencies(callNode, postDeps);
postDeps->stopAddingPostConditions();
// Find the second scratch register in the post dependency list.
//
TR::Register *scratchReg = NULL;
TR::RealRegister::RegNum scratchRegIndex = getProperties().getIntegerScratchRegister(1);
for (int32_t i=0; i<post; i++)
{
if (postDeps->getPostConditions()->getRegisterDependency(i)->getRealRegister() == scratchRegIndex)
{
scratchReg = postDeps->getPostConditions()->getRegisterDependency(i)->getRegister();
break;
}
}
TR::Instruction *instr;
if (methodSymbol->getMethodAddress())
{
TR_ASSERT(scratchReg, "could not find second scratch register");
auto LoadRegisterInstruction = generateRegImm64SymInstruction(
MOV8RegImm64,
callNode,
scratchReg,
(uintptr_t)methodSymbol->getMethodAddress(),
methodSymRef,
cg());
if (comp()->getOption(TR_EmitRelocatableELFFile))
{
LoadRegisterInstruction->setReloKind(TR_NativeMethodAbsolute);
}
instr = generateRegInstruction(CALLReg, callNode, scratchReg, preDeps, cg());
}
else
{
instr = generateImmSymInstruction(CALLImm4, callNode, (uintptrj_t)methodSymbol->getMethodAddress(), methodSymRef, preDeps, cg());
}
cg()->resetIsLeafMethod();
instr->setNeedsGCMap(getProperties().getPreservedRegisterMapForGC());
cg()->stopUsingRegister(scratchReg);
TR::LabelSymbol *postDepLabel = generateLabelSymbol(cg());
generateLabelInstruction(LABEL, callNode, postDepLabel, postDeps, cg());
return returnReg;
}
TR::Register *TR_X86FPCompareAnalyser::fpCompareAnalyser(TR::Node *root,
TR_X86OpCodes cmpRegRegOpCode,
TR_X86OpCodes cmpRegMemOpCode,
TR_X86OpCodes cmpiRegRegOpCode,
bool useFCOMIInstructions)
{
TR::Node *firstChild,
*secondChild;
TR::ILOpCodes cmpOp = root->getOpCodeValue();
bool reverseMemOp = false;
bool reverseCmpOp = false;
TR::Compilation* comp = _cg->comp();
TR_X86OpCodes cmpInstr = useFCOMIInstructions ? cmpiRegRegOpCode : cmpRegRegOpCode;
// Some operators must have their operands swapped to improve the generated
// code needed to evaluate the result of the comparison.
//
bool mustSwapOperands = (cmpOp == TR::iffcmple ||
cmpOp == TR::ifdcmple ||
cmpOp == TR::iffcmpgtu ||
cmpOp == TR::ifdcmpgtu ||
cmpOp == TR::fcmple ||
cmpOp == TR::dcmple ||
cmpOp == TR::fcmpgtu ||
cmpOp == TR::dcmpgtu ||
(useFCOMIInstructions &&
(cmpOp == TR::iffcmplt ||
cmpOp == TR::ifdcmplt ||
cmpOp == TR::iffcmpgeu ||
cmpOp == TR::ifdcmpgeu ||
cmpOp == TR::fcmplt ||
cmpOp == TR::dcmplt ||
cmpOp == TR::fcmpgeu ||
cmpOp == TR::dcmpgeu))) ? true : false;
// Some operators should not have their operands swapped to improve the generated
// code needed to evaluate the result of the comparison.
//
bool preventOperandSwapping = (cmpOp == TR::iffcmpltu ||
cmpOp == TR::ifdcmpltu ||
cmpOp == TR::iffcmpge ||
cmpOp == TR::ifdcmpge ||
cmpOp == TR::fcmpltu ||
cmpOp == TR::dcmpltu ||
cmpOp == TR::fcmpge ||
cmpOp == TR::dcmpge ||
(useFCOMIInstructions &&
(cmpOp == TR::iffcmpgt ||
cmpOp == TR::ifdcmpgt ||
cmpOp == TR::iffcmpleu ||
cmpOp == TR::ifdcmpleu ||
cmpOp == TR::fcmpgt ||
cmpOp == TR::dcmpgt ||
cmpOp == TR::fcmpleu ||
cmpOp == TR::dcmpleu))) ? true : false;
// For correctness, don't swap operands of these operators.
//
if (cmpOp == TR::fcmpg || cmpOp == TR::fcmpl ||
cmpOp == TR::dcmpg || cmpOp == TR::dcmpl)
{
preventOperandSwapping = true;
}
// Initial operand evaluation ordering.
//
if (preventOperandSwapping || (!mustSwapOperands && _cg->whichChildToEvaluate(root) == 0))
{
firstChild = root->getFirstChild();
secondChild = root->getSecondChild();
setReversedOperands(false);
}
else
{
firstChild = root->getSecondChild();
secondChild = root->getFirstChild();
setReversedOperands(true);
}
TR::Register *firstRegister = firstChild->getRegister();
TR::Register *secondRegister = secondChild->getRegister();
setInputs(firstChild,
firstRegister,
secondChild,
secondRegister,
useFCOMIInstructions,
// If either 'preventOperandSwapping' or 'mustSwapOperands' is set then the
// initial operand ordering set above must be maintained.
//
preventOperandSwapping || mustSwapOperands);
// Make sure any required operand ordering is respected.
//
if ((getCmpReg2Reg1() || getCmpReg2Mem1()) &&
(mustSwapOperands || preventOperandSwapping))
{
reverseCmpOp = getCmpReg2Reg1() ? true : false;
reverseMemOp = getCmpReg2Mem1() ? true : false;
}
// If we are not comparing with a memory operand, one of them evaluates
// to a zero, and the zero is not already on the stack, then we can use
// FTST to save a register.
//
// (With a memory operand, either the constant zero needs to be loaded
// to use FCOM, or the memory operand needs to be loaded to use FTST,
// so there is no gain in using FTST.)
//
// If the constant zero is in the target register, using FTST means the
// comparison will be reversed. We cannot do this if the initial ordering
// of the operands must be maintained.
//
// Finally, if FTST is used and this is the last use of the target, the
// target register may need to be explicitly popped.
//
TR::Register *targetRegisterForFTST = NULL;
TR::Node *targetChildForFTST = NULL;
if (getEvalChild1() && isUnevaluatedZero(firstChild)) // do we need getEvalChild1() here?
{
if ( ((getCmpReg1Reg2() || reverseCmpOp) && !(preventOperandSwapping || mustSwapOperands)) ||
(getCmpReg2Reg1() && !reverseCmpOp))
{
if (getEvalChild2())
{
secondRegister = _cg->evaluate(secondChild);
}
targetRegisterForFTST = secondRegister;
targetChildForFTST = secondChild;
notReversedOperands();
}
}
else if (getEvalChild2() && isUnevaluatedZero(secondChild)) // do we need getEvalChild2() here?
{
if ( (getCmpReg1Reg2() || reverseCmpOp) ||
(getCmpReg2Reg1() && !reverseCmpOp && !(preventOperandSwapping || mustSwapOperands)) )
{
if (getEvalChild1())
{
firstRegister = _cg->evaluate(firstChild);
}
targetRegisterForFTST = firstRegister;
targetChildForFTST = firstChild;
}
}
if (!targetRegisterForFTST)
{
// If we have a choice, evaluate the target operand last. By doing so, we
// help out the register assigner because the target must be TOS. This
// avoids an unneccessary FXCH for the target.
//
if (getEvalChild1() && getEvalChild2())
{
if (getCmpReg1Reg2() || getCmpReg1Mem2())
{
secondRegister = _cg->evaluate(secondChild);
firstRegister = _cg->evaluate(firstChild);
}
else
{
firstRegister = _cg->evaluate(firstChild);
secondRegister = _cg->evaluate(secondChild);
}
}
else
{
if (getEvalChild1())
{
firstRegister = _cg->evaluate(firstChild);
}
if (getEvalChild2())
{
secondRegister = _cg->evaluate(secondChild);
}
}
}
// Adjust the FP precision of feeding operands.
//
if (firstRegister &&
(firstRegister->needsPrecisionAdjustment() ||
comp->getOption(TR_StrictFPCompares) ||
(firstRegister->mayNeedPrecisionAdjustment() && secondChild->getOpCode().isLoadConst()) ||
(firstRegister->mayNeedPrecisionAdjustment() && !secondRegister)))
{
TR::TreeEvaluator::insertPrecisionAdjustment(firstRegister, root, _cg);
}
if (secondRegister &&
(secondRegister->needsPrecisionAdjustment() ||
comp->getOption(TR_StrictFPCompares) ||
(secondRegister->mayNeedPrecisionAdjustment() && firstChild->getOpCode().isLoadConst()) ||
(secondRegister->mayNeedPrecisionAdjustment() && !firstRegister)))
{
TR::TreeEvaluator::insertPrecisionAdjustment(secondRegister, root, _cg);
}
// Generate the compare instruction.
//
if (targetRegisterForFTST)
{
generateFPRegInstruction(FTSTReg, root, targetRegisterForFTST, _cg);
}
else if (!useFCOMIInstructions && (getCmpReg1Mem2() || reverseMemOp))
{
TR::MemoryReference *tempMR = generateX86MemoryReference(secondChild, _cg);
generateFPRegMemInstruction(cmpRegMemOpCode, root, firstRegister, tempMR, _cg);
tempMR->decNodeReferenceCounts(_cg);
}
else if (!useFCOMIInstructions && getCmpReg2Mem1())
{
TR::MemoryReference *tempMR = generateX86MemoryReference(firstChild, _cg);
generateFPRegMemInstruction(cmpRegMemOpCode, root, secondRegister, tempMR, _cg);
notReversedOperands();
tempMR->decNodeReferenceCounts(_cg);
}
else if (getCmpReg1Reg2() || reverseCmpOp)
{
generateFPCompareRegRegInstruction(cmpInstr, root, firstRegister, secondRegister, _cg);
}
else if (getCmpReg2Reg1())
{
generateFPCompareRegRegInstruction(cmpInstr, root, secondRegister, firstRegister, _cg);
notReversedOperands();
}
_cg->decReferenceCount(firstChild);
_cg->decReferenceCount(secondChild);
// Evaluate the comparison.
//
if (getReversedOperands())
{
cmpOp = TR::ILOpCode(cmpOp).getOpCodeForSwapChildren();
TR::Node::recreate(root, cmpOp);
}
if (useFCOMIInstructions && !targetRegisterForFTST)
{
return NULL;
}
// We must manually move the FP condition flags to the EFLAGS register if we don't
// use the FCOMI instructions.
//
TR::Register *accRegister = _cg->allocateRegister();
TR::RegisterDependencyConditions *dependencies = generateRegisterDependencyConditions((uint8_t)1, 1, _cg);
dependencies->addPreCondition(accRegister, TR::RealRegister::eax, _cg);
dependencies->addPostCondition(accRegister, TR::RealRegister::eax, _cg);
generateRegInstruction(STSWAcc, root, accRegister, dependencies, _cg);
// Pop the FTST target register if it is not used any more.
//
if (targetRegisterForFTST &&
targetChildForFTST && targetChildForFTST->getReferenceCount() == 0)
{
generateFPSTiST0RegRegInstruction(FSTRegReg, root, targetRegisterForFTST, targetRegisterForFTST, _cg);
}
return accRegister;
}