1 //===- X86ISelDAGToDAG.cpp - A DAG pattern matching inst selector for X86 -===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines a DAG pattern matching instruction selector for X86,
11 // converting from a legalized dag to a X86 dag.
13 //===----------------------------------------------------------------------===//
16 #include "X86InstrBuilder.h"
17 #include "X86MachineFunctionInfo.h"
18 #include "X86RegisterInfo.h"
19 #include "X86Subtarget.h"
20 #include "X86TargetMachine.h"
21 #include "llvm/ADT/Statistic.h"
22 #include "llvm/CodeGen/MachineFrameInfo.h"
23 #include "llvm/CodeGen/MachineFunction.h"
24 #include "llvm/CodeGen/MachineInstrBuilder.h"
25 #include "llvm/CodeGen/MachineRegisterInfo.h"
26 #include "llvm/CodeGen/SelectionDAGISel.h"
27 #include "llvm/IR/Function.h"
28 #include "llvm/IR/Instructions.h"
29 #include "llvm/IR/Intrinsics.h"
30 #include "llvm/IR/Type.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/ErrorHandling.h"
33 #include "llvm/Support/MathExtras.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include "llvm/Target/TargetMachine.h"
36 #include "llvm/Target/TargetOptions.h"
40 #define DEBUG_TYPE "x86-isel"
42 STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor");
44 //===----------------------------------------------------------------------===//
45 // Pattern Matcher Implementation
46 //===----------------------------------------------------------------------===//
49 /// This corresponds to X86AddressMode, but uses SDValue's instead of register
50 /// numbers for the leaves of the matched tree.
51 struct X86ISelAddressMode {
57 // This is really a union, discriminated by BaseType!
65 const GlobalValue *GV;
67 const BlockAddress *BlockAddr;
71 unsigned Align; // CP alignment.
72 unsigned char SymbolFlags; // X86II::MO_*
75 : BaseType(RegBase), Base_FrameIndex(0), Scale(1), IndexReg(), Disp(0),
76 Segment(), GV(nullptr), CP(nullptr), BlockAddr(nullptr), ES(nullptr),
77 MCSym(nullptr), JT(-1), Align(0), SymbolFlags(X86II::MO_NO_FLAG) {}
79 bool hasSymbolicDisplacement() const {
80 return GV != nullptr || CP != nullptr || ES != nullptr ||
81 MCSym != nullptr || JT != -1 || BlockAddr != nullptr;
84 bool hasBaseOrIndexReg() const {
85 return BaseType == FrameIndexBase ||
86 IndexReg.getNode() != nullptr || Base_Reg.getNode() != nullptr;
89 /// Return true if this addressing mode is already RIP-relative.
90 bool isRIPRelative() const {
91 if (BaseType != RegBase) return false;
92 if (RegisterSDNode *RegNode =
93 dyn_cast_or_null<RegisterSDNode>(Base_Reg.getNode()))
94 return RegNode->getReg() == X86::RIP;
98 void setBaseReg(SDValue Reg) {
103 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
105 dbgs() << "X86ISelAddressMode " << this << '\n';
106 dbgs() << "Base_Reg ";
107 if (Base_Reg.getNode())
108 Base_Reg.getNode()->dump();
111 dbgs() << " Base.FrameIndex " << Base_FrameIndex << '\n'
112 << " Scale" << Scale << '\n'
114 if (IndexReg.getNode())
115 IndexReg.getNode()->dump();
118 dbgs() << " Disp " << Disp << '\n'
140 dbgs() << " JT" << JT << " Align" << Align << '\n';
147 //===--------------------------------------------------------------------===//
148 /// ISel - X86-specific code to select X86 machine instructions for
149 /// SelectionDAG operations.
151 class X86DAGToDAGISel final : public SelectionDAGISel {
152 /// Keep a pointer to the X86Subtarget around so that we can
153 /// make the right decision when generating code for different targets.
154 const X86Subtarget *Subtarget;
156 /// If true, selector should try to optimize for code size instead of
161 explicit X86DAGToDAGISel(X86TargetMachine &tm, CodeGenOpt::Level OptLevel)
162 : SelectionDAGISel(tm, OptLevel), OptForSize(false) {}
164 const char *getPassName() const override {
165 return "X86 DAG->DAG Instruction Selection";
168 bool runOnMachineFunction(MachineFunction &MF) override {
169 // Reset the subtarget each time through.
170 Subtarget = &MF.getSubtarget<X86Subtarget>();
171 SelectionDAGISel::runOnMachineFunction(MF);
175 void EmitFunctionEntryCode() override;
177 bool IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const override;
179 void PreprocessISelDAG() override;
181 inline bool immSext8(SDNode *N) const {
182 return isInt<8>(cast<ConstantSDNode>(N)->getSExtValue());
185 // True if the 64-bit immediate fits in a 32-bit sign-extended field.
186 inline bool i64immSExt32(SDNode *N) const {
187 uint64_t v = cast<ConstantSDNode>(N)->getZExtValue();
188 return (int64_t)v == (int32_t)v;
191 // Include the pieces autogenerated from the target description.
192 #include "X86GenDAGISel.inc"
195 SDNode *Select(SDNode *N) override;
196 SDNode *selectGather(SDNode *N, unsigned Opc);
197 SDNode *selectAtomicLoadArith(SDNode *Node, MVT NVT);
199 bool foldOffsetIntoAddress(uint64_t Offset, X86ISelAddressMode &AM);
200 bool matchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM);
201 bool matchWrapper(SDValue N, X86ISelAddressMode &AM);
202 bool matchAddress(SDValue N, X86ISelAddressMode &AM);
203 bool matchAdd(SDValue N, X86ISelAddressMode &AM, unsigned Depth);
204 bool matchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
206 bool matchAddressBase(SDValue N, X86ISelAddressMode &AM);
207 bool selectAddr(SDNode *Parent, SDValue N, SDValue &Base,
208 SDValue &Scale, SDValue &Index, SDValue &Disp,
210 bool selectVectorAddr(SDNode *Parent, SDValue N, SDValue &Base,
211 SDValue &Scale, SDValue &Index, SDValue &Disp,
213 bool selectMOV64Imm32(SDValue N, SDValue &Imm);
214 bool selectLEAAddr(SDValue N, SDValue &Base,
215 SDValue &Scale, SDValue &Index, SDValue &Disp,
217 bool selectLEA64_32Addr(SDValue N, SDValue &Base,
218 SDValue &Scale, SDValue &Index, SDValue &Disp,
220 bool selectTLSADDRAddr(SDValue N, SDValue &Base,
221 SDValue &Scale, SDValue &Index, SDValue &Disp,
223 bool selectScalarSSELoad(SDNode *Root, SDValue N,
224 SDValue &Base, SDValue &Scale,
225 SDValue &Index, SDValue &Disp,
227 SDValue &NodeWithChain);
229 bool tryFoldLoad(SDNode *P, SDValue N,
230 SDValue &Base, SDValue &Scale,
231 SDValue &Index, SDValue &Disp,
234 /// Implement addressing mode selection for inline asm expressions.
235 bool SelectInlineAsmMemoryOperand(const SDValue &Op,
236 unsigned ConstraintID,
237 std::vector<SDValue> &OutOps) override;
239 void emitSpecialCodeForMain();
241 inline void getAddressOperands(X86ISelAddressMode &AM, SDLoc DL,
242 SDValue &Base, SDValue &Scale,
243 SDValue &Index, SDValue &Disp,
245 Base = (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
246 ? CurDAG->getTargetFrameIndex(
248 TLI->getPointerTy(CurDAG->getDataLayout()))
250 Scale = getI8Imm(AM.Scale, DL);
252 // These are 32-bit even in 64-bit mode since RIP-relative offset
255 Disp = CurDAG->getTargetGlobalAddress(AM.GV, SDLoc(),
259 Disp = CurDAG->getTargetConstantPool(AM.CP, MVT::i32,
260 AM.Align, AM.Disp, AM.SymbolFlags);
262 assert(!AM.Disp && "Non-zero displacement is ignored with ES.");
263 Disp = CurDAG->getTargetExternalSymbol(AM.ES, MVT::i32, AM.SymbolFlags);
264 } else if (AM.MCSym) {
265 assert(!AM.Disp && "Non-zero displacement is ignored with MCSym.");
266 assert(AM.SymbolFlags == 0 && "oo");
267 Disp = CurDAG->getMCSymbol(AM.MCSym, MVT::i32);
268 } else if (AM.JT != -1) {
269 assert(!AM.Disp && "Non-zero displacement is ignored with JT.");
270 Disp = CurDAG->getTargetJumpTable(AM.JT, MVT::i32, AM.SymbolFlags);
271 } else if (AM.BlockAddr)
272 Disp = CurDAG->getTargetBlockAddress(AM.BlockAddr, MVT::i32, AM.Disp,
275 Disp = CurDAG->getTargetConstant(AM.Disp, DL, MVT::i32);
277 if (AM.Segment.getNode())
278 Segment = AM.Segment;
280 Segment = CurDAG->getRegister(0, MVT::i32);
283 // Utility function to determine whether we should avoid selecting
284 // immediate forms of instructions for better code size or not.
285 // At a high level, we'd like to avoid such instructions when
286 // we have similar constants used within the same basic block
287 // that can be kept in a register.
289 bool shouldAvoidImmediateInstFormsForSize(SDNode *N) const {
290 uint32_t UseCount = 0;
292 // Do not want to hoist if we're not optimizing for size.
293 // TODO: We'd like to remove this restriction.
294 // See the comment in X86InstrInfo.td for more info.
298 // Walk all the users of the immediate.
299 for (SDNode::use_iterator UI = N->use_begin(),
300 UE = N->use_end(); (UI != UE) && (UseCount < 2); ++UI) {
304 // This user is already selected. Count it as a legitimate use and
306 if (User->isMachineOpcode()) {
311 // We want to count stores of immediates as real uses.
312 if (User->getOpcode() == ISD::STORE &&
313 User->getOperand(1).getNode() == N) {
318 // We don't currently match users that have > 2 operands (except
319 // for stores, which are handled above)
320 // Those instruction won't match in ISEL, for now, and would
321 // be counted incorrectly.
322 // This may change in the future as we add additional instruction
324 if (User->getNumOperands() != 2)
327 // Immediates that are used for offsets as part of stack
328 // manipulation should be left alone. These are typically
329 // used to indicate SP offsets for argument passing and
330 // will get pulled into stores/pushes (implicitly).
331 if (User->getOpcode() == X86ISD::ADD ||
332 User->getOpcode() == ISD::ADD ||
333 User->getOpcode() == X86ISD::SUB ||
334 User->getOpcode() == ISD::SUB) {
336 // Find the other operand of the add/sub.
337 SDValue OtherOp = User->getOperand(0);
338 if (OtherOp.getNode() == N)
339 OtherOp = User->getOperand(1);
341 // Don't count if the other operand is SP.
342 RegisterSDNode *RegNode;
343 if (OtherOp->getOpcode() == ISD::CopyFromReg &&
344 (RegNode = dyn_cast_or_null<RegisterSDNode>(
345 OtherOp->getOperand(1).getNode())))
346 if ((RegNode->getReg() == X86::ESP) ||
347 (RegNode->getReg() == X86::RSP))
351 // ... otherwise, count this and move on.
355 // If we have more than 1 use, then recommend for hoisting.
356 return (UseCount > 1);
359 /// Return a target constant with the specified value of type i8.
360 inline SDValue getI8Imm(unsigned Imm, SDLoc DL) {
361 return CurDAG->getTargetConstant(Imm, DL, MVT::i8);
364 /// Return a target constant with the specified value, of type i32.
365 inline SDValue getI32Imm(unsigned Imm, SDLoc DL) {
366 return CurDAG->getTargetConstant(Imm, DL, MVT::i32);
369 /// Return an SDNode that returns the value of the global base register.
370 /// Output instructions required to initialize the global base register,
372 SDNode *getGlobalBaseReg();
374 /// Return a reference to the TargetMachine, casted to the target-specific
376 const X86TargetMachine &getTargetMachine() const {
377 return static_cast<const X86TargetMachine &>(TM);
380 /// Return a reference to the TargetInstrInfo, casted to the target-specific
382 const X86InstrInfo *getInstrInfo() const {
383 return Subtarget->getInstrInfo();
386 /// \brief Address-mode matching performs shift-of-and to and-of-shift
387 /// reassociation in order to expose more scaled addressing
389 bool ComplexPatternFuncMutatesDAG() const override {
397 X86DAGToDAGISel::IsProfitableToFold(SDValue N, SDNode *U, SDNode *Root) const {
398 if (OptLevel == CodeGenOpt::None) return false;
403 if (N.getOpcode() != ISD::LOAD)
406 // If N is a load, do additional profitability checks.
408 switch (U->getOpcode()) {
421 SDValue Op1 = U->getOperand(1);
423 // If the other operand is a 8-bit immediate we should fold the immediate
424 // instead. This reduces code size.
426 // movl 4(%esp), %eax
430 // addl 4(%esp), %eax
431 // The former is 2 bytes shorter. In case where the increment is 1, then
432 // the saving can be 4 bytes (by using incl %eax).
433 if (ConstantSDNode *Imm = dyn_cast<ConstantSDNode>(Op1))
434 if (Imm->getAPIntValue().isSignedIntN(8))
437 // If the other operand is a TLS address, we should fold it instead.
440 // leal i@NTPOFF(%eax), %eax
442 // movl $i@NTPOFF, %eax
444 // if the block also has an access to a second TLS address this will save
446 // FIXME: This is probably also true for non-TLS addresses.
447 if (Op1.getOpcode() == X86ISD::Wrapper) {
448 SDValue Val = Op1.getOperand(0);
449 if (Val.getOpcode() == ISD::TargetGlobalTLSAddress)
459 /// Replace the original chain operand of the call with
460 /// load's chain operand and move load below the call's chain operand.
461 static void moveBelowOrigChain(SelectionDAG *CurDAG, SDValue Load,
462 SDValue Call, SDValue OrigChain) {
463 SmallVector<SDValue, 8> Ops;
464 SDValue Chain = OrigChain.getOperand(0);
465 if (Chain.getNode() == Load.getNode())
466 Ops.push_back(Load.getOperand(0));
468 assert(Chain.getOpcode() == ISD::TokenFactor &&
469 "Unexpected chain operand");
470 for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i)
471 if (Chain.getOperand(i).getNode() == Load.getNode())
472 Ops.push_back(Load.getOperand(0));
474 Ops.push_back(Chain.getOperand(i));
476 CurDAG->getNode(ISD::TokenFactor, SDLoc(Load), MVT::Other, Ops);
478 Ops.push_back(NewChain);
480 Ops.append(OrigChain->op_begin() + 1, OrigChain->op_end());
481 CurDAG->UpdateNodeOperands(OrigChain.getNode(), Ops);
482 CurDAG->UpdateNodeOperands(Load.getNode(), Call.getOperand(0),
483 Load.getOperand(1), Load.getOperand(2));
486 Ops.push_back(SDValue(Load.getNode(), 1));
487 Ops.append(Call->op_begin() + 1, Call->op_end());
488 CurDAG->UpdateNodeOperands(Call.getNode(), Ops);
491 /// Return true if call address is a load and it can be
492 /// moved below CALLSEQ_START and the chains leading up to the call.
493 /// Return the CALLSEQ_START by reference as a second output.
494 /// In the case of a tail call, there isn't a callseq node between the call
495 /// chain and the load.
496 static bool isCalleeLoad(SDValue Callee, SDValue &Chain, bool HasCallSeq) {
497 // The transformation is somewhat dangerous if the call's chain was glued to
498 // the call. After MoveBelowOrigChain the load is moved between the call and
499 // the chain, this can create a cycle if the load is not folded. So it is
500 // *really* important that we are sure the load will be folded.
501 if (Callee.getNode() == Chain.getNode() || !Callee.hasOneUse())
503 LoadSDNode *LD = dyn_cast<LoadSDNode>(Callee.getNode());
506 LD->getAddressingMode() != ISD::UNINDEXED ||
507 LD->getExtensionType() != ISD::NON_EXTLOAD)
510 // Now let's find the callseq_start.
511 while (HasCallSeq && Chain.getOpcode() != ISD::CALLSEQ_START) {
512 if (!Chain.hasOneUse())
514 Chain = Chain.getOperand(0);
517 if (!Chain.getNumOperands())
519 // Since we are not checking for AA here, conservatively abort if the chain
520 // writes to memory. It's not safe to move the callee (a load) across a store.
521 if (isa<MemSDNode>(Chain.getNode()) &&
522 cast<MemSDNode>(Chain.getNode())->writeMem())
524 if (Chain.getOperand(0).getNode() == Callee.getNode())
526 if (Chain.getOperand(0).getOpcode() == ISD::TokenFactor &&
527 Callee.getValue(1).isOperandOf(Chain.getOperand(0).getNode()) &&
528 Callee.getValue(1).hasOneUse())
533 void X86DAGToDAGISel::PreprocessISelDAG() {
534 // OptForSize is used in pattern predicates that isel is matching.
535 OptForSize = MF->getFunction()->optForSize();
537 for (SelectionDAG::allnodes_iterator I = CurDAG->allnodes_begin(),
538 E = CurDAG->allnodes_end(); I != E; ) {
539 SDNode *N = &*I++; // Preincrement iterator to avoid invalidation issues.
541 if (OptLevel != CodeGenOpt::None &&
542 // Only does this when target favors doesn't favor register indirect
544 ((N->getOpcode() == X86ISD::CALL && !Subtarget->callRegIndirect()) ||
545 (N->getOpcode() == X86ISD::TC_RETURN &&
546 // Only does this if load can be folded into TC_RETURN.
547 (Subtarget->is64Bit() ||
548 getTargetMachine().getRelocationModel() != Reloc::PIC_)))) {
549 /// Also try moving call address load from outside callseq_start to just
550 /// before the call to allow it to be folded.
568 bool HasCallSeq = N->getOpcode() == X86ISD::CALL;
569 SDValue Chain = N->getOperand(0);
570 SDValue Load = N->getOperand(1);
571 if (!isCalleeLoad(Load, Chain, HasCallSeq))
573 moveBelowOrigChain(CurDAG, Load, SDValue(N, 0), Chain);
578 // Lower fpround and fpextend nodes that target the FP stack to be store and
579 // load to the stack. This is a gross hack. We would like to simply mark
580 // these as being illegal, but when we do that, legalize produces these when
581 // it expands calls, then expands these in the same legalize pass. We would
582 // like dag combine to be able to hack on these between the call expansion
583 // and the node legalization. As such this pass basically does "really
584 // late" legalization of these inline with the X86 isel pass.
585 // FIXME: This should only happen when not compiled with -O0.
586 if (N->getOpcode() != ISD::FP_ROUND && N->getOpcode() != ISD::FP_EXTEND)
589 MVT SrcVT = N->getOperand(0).getSimpleValueType();
590 MVT DstVT = N->getSimpleValueType(0);
592 // If any of the sources are vectors, no fp stack involved.
593 if (SrcVT.isVector() || DstVT.isVector())
596 // If the source and destination are SSE registers, then this is a legal
597 // conversion that should not be lowered.
598 const X86TargetLowering *X86Lowering =
599 static_cast<const X86TargetLowering *>(TLI);
600 bool SrcIsSSE = X86Lowering->isScalarFPTypeInSSEReg(SrcVT);
601 bool DstIsSSE = X86Lowering->isScalarFPTypeInSSEReg(DstVT);
602 if (SrcIsSSE && DstIsSSE)
605 if (!SrcIsSSE && !DstIsSSE) {
606 // If this is an FPStack extension, it is a noop.
607 if (N->getOpcode() == ISD::FP_EXTEND)
609 // If this is a value-preserving FPStack truncation, it is a noop.
610 if (N->getConstantOperandVal(1))
614 // Here we could have an FP stack truncation or an FPStack <-> SSE convert.
615 // FPStack has extload and truncstore. SSE can fold direct loads into other
616 // operations. Based on this, decide what we want to do.
618 if (N->getOpcode() == ISD::FP_ROUND)
619 MemVT = DstVT; // FP_ROUND must use DstVT, we can't do a 'trunc load'.
621 MemVT = SrcIsSSE ? SrcVT : DstVT;
623 SDValue MemTmp = CurDAG->CreateStackTemporary(MemVT);
626 // FIXME: optimize the case where the src/dest is a load or store?
627 SDValue Store = CurDAG->getTruncStore(CurDAG->getEntryNode(), dl,
629 MemTmp, MachinePointerInfo(), MemVT,
631 SDValue Result = CurDAG->getExtLoad(ISD::EXTLOAD, dl, DstVT, Store, MemTmp,
632 MachinePointerInfo(),
633 MemVT, false, false, false, 0);
635 // We're about to replace all uses of the FP_ROUND/FP_EXTEND with the
636 // extload we created. This will cause general havok on the dag because
637 // anything below the conversion could be folded into other existing nodes.
638 // To avoid invalidating 'I', back it up to the convert node.
640 CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Result);
642 // Now that we did that, the node is dead. Increment the iterator to the
643 // next node to process, then delete N.
645 CurDAG->DeleteNode(N);
650 /// Emit any code that needs to be executed only in the main function.
651 void X86DAGToDAGISel::emitSpecialCodeForMain() {
652 if (Subtarget->isTargetCygMing()) {
653 TargetLowering::ArgListTy Args;
654 auto &DL = CurDAG->getDataLayout();
656 TargetLowering::CallLoweringInfo CLI(*CurDAG);
657 CLI.setChain(CurDAG->getRoot())
658 .setCallee(CallingConv::C, Type::getVoidTy(*CurDAG->getContext()),
659 CurDAG->getExternalSymbol("__main", TLI->getPointerTy(DL)),
661 const TargetLowering &TLI = CurDAG->getTargetLoweringInfo();
662 std::pair<SDValue, SDValue> Result = TLI.LowerCallTo(CLI);
663 CurDAG->setRoot(Result.second);
667 void X86DAGToDAGISel::EmitFunctionEntryCode() {
668 // If this is main, emit special code for main.
669 if (const Function *Fn = MF->getFunction())
670 if (Fn->hasExternalLinkage() && Fn->getName() == "main")
671 emitSpecialCodeForMain();
674 static bool isDispSafeForFrameIndex(int64_t Val) {
675 // On 64-bit platforms, we can run into an issue where a frame index
676 // includes a displacement that, when added to the explicit displacement,
677 // will overflow the displacement field. Assuming that the frame index
678 // displacement fits into a 31-bit integer (which is only slightly more
679 // aggressive than the current fundamental assumption that it fits into
680 // a 32-bit integer), a 31-bit disp should always be safe.
681 return isInt<31>(Val);
684 bool X86DAGToDAGISel::foldOffsetIntoAddress(uint64_t Offset,
685 X86ISelAddressMode &AM) {
686 // Cannot combine ExternalSymbol displacements with integer offsets.
687 if (Offset != 0 && (AM.ES || AM.MCSym))
689 int64_t Val = AM.Disp + Offset;
690 CodeModel::Model M = TM.getCodeModel();
691 if (Subtarget->is64Bit()) {
692 if (!X86::isOffsetSuitableForCodeModel(Val, M,
693 AM.hasSymbolicDisplacement()))
695 // In addition to the checks required for a register base, check that
696 // we do not try to use an unsafe Disp with a frame index.
697 if (AM.BaseType == X86ISelAddressMode::FrameIndexBase &&
698 !isDispSafeForFrameIndex(Val))
706 bool X86DAGToDAGISel::matchLoadInAddress(LoadSDNode *N, X86ISelAddressMode &AM){
707 SDValue Address = N->getOperand(1);
709 // load gs:0 -> GS segment register.
710 // load fs:0 -> FS segment register.
712 // This optimization is valid because the GNU TLS model defines that
713 // gs:0 (or fs:0 on X86-64) contains its own address.
714 // For more information see http://people.redhat.com/drepper/tls.pdf
715 if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Address))
716 if (C->getSExtValue() == 0 && AM.Segment.getNode() == nullptr &&
717 Subtarget->isTargetLinux())
718 switch (N->getPointerInfo().getAddrSpace()) {
720 AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
723 AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
730 /// Try to match X86ISD::Wrapper and X86ISD::WrapperRIP nodes into an addressing
731 /// mode. These wrap things that will resolve down into a symbol reference.
732 /// If no match is possible, this returns true, otherwise it returns false.
733 bool X86DAGToDAGISel::matchWrapper(SDValue N, X86ISelAddressMode &AM) {
734 // If the addressing mode already has a symbol as the displacement, we can
735 // never match another symbol.
736 if (AM.hasSymbolicDisplacement())
739 SDValue N0 = N.getOperand(0);
740 CodeModel::Model M = TM.getCodeModel();
742 // Handle X86-64 rip-relative addresses. We check this before checking direct
743 // folding because RIP is preferable to non-RIP accesses.
744 if (Subtarget->is64Bit() && N.getOpcode() == X86ISD::WrapperRIP &&
745 // Under X86-64 non-small code model, GV (and friends) are 64-bits, so
746 // they cannot be folded into immediate fields.
747 // FIXME: This can be improved for kernel and other models?
748 (M == CodeModel::Small || M == CodeModel::Kernel)) {
749 // Base and index reg must be 0 in order to use %rip as base.
750 if (AM.hasBaseOrIndexReg())
752 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
753 X86ISelAddressMode Backup = AM;
754 AM.GV = G->getGlobal();
755 AM.SymbolFlags = G->getTargetFlags();
756 if (foldOffsetIntoAddress(G->getOffset(), AM)) {
760 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
761 X86ISelAddressMode Backup = AM;
762 AM.CP = CP->getConstVal();
763 AM.Align = CP->getAlignment();
764 AM.SymbolFlags = CP->getTargetFlags();
765 if (foldOffsetIntoAddress(CP->getOffset(), AM)) {
769 } else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
770 AM.ES = S->getSymbol();
771 AM.SymbolFlags = S->getTargetFlags();
772 } else if (auto *S = dyn_cast<MCSymbolSDNode>(N0)) {
773 AM.MCSym = S->getMCSymbol();
774 } else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
775 AM.JT = J->getIndex();
776 AM.SymbolFlags = J->getTargetFlags();
777 } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(N0)) {
778 X86ISelAddressMode Backup = AM;
779 AM.BlockAddr = BA->getBlockAddress();
780 AM.SymbolFlags = BA->getTargetFlags();
781 if (foldOffsetIntoAddress(BA->getOffset(), AM)) {
786 llvm_unreachable("Unhandled symbol reference node.");
788 if (N.getOpcode() == X86ISD::WrapperRIP)
789 AM.setBaseReg(CurDAG->getRegister(X86::RIP, MVT::i64));
793 // Handle the case when globals fit in our immediate field: This is true for
794 // X86-32 always and X86-64 when in -mcmodel=small mode. In 64-bit
795 // mode, this only applies to a non-RIP-relative computation.
796 if (!Subtarget->is64Bit() ||
797 M == CodeModel::Small || M == CodeModel::Kernel) {
798 assert(N.getOpcode() != X86ISD::WrapperRIP &&
799 "RIP-relative addressing already handled");
800 if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(N0)) {
801 AM.GV = G->getGlobal();
802 AM.Disp += G->getOffset();
803 AM.SymbolFlags = G->getTargetFlags();
804 } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(N0)) {
805 AM.CP = CP->getConstVal();
806 AM.Align = CP->getAlignment();
807 AM.Disp += CP->getOffset();
808 AM.SymbolFlags = CP->getTargetFlags();
809 } else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(N0)) {
810 AM.ES = S->getSymbol();
811 AM.SymbolFlags = S->getTargetFlags();
812 } else if (auto *S = dyn_cast<MCSymbolSDNode>(N0)) {
813 AM.MCSym = S->getMCSymbol();
814 } else if (JumpTableSDNode *J = dyn_cast<JumpTableSDNode>(N0)) {
815 AM.JT = J->getIndex();
816 AM.SymbolFlags = J->getTargetFlags();
817 } else if (BlockAddressSDNode *BA = dyn_cast<BlockAddressSDNode>(N0)) {
818 AM.BlockAddr = BA->getBlockAddress();
819 AM.Disp += BA->getOffset();
820 AM.SymbolFlags = BA->getTargetFlags();
822 llvm_unreachable("Unhandled symbol reference node.");
829 /// Add the specified node to the specified addressing mode, returning true if
830 /// it cannot be done. This just pattern matches for the addressing mode.
831 bool X86DAGToDAGISel::matchAddress(SDValue N, X86ISelAddressMode &AM) {
832 if (matchAddressRecursively(N, AM, 0))
835 // Post-processing: Convert lea(,%reg,2) to lea(%reg,%reg), which has
836 // a smaller encoding and avoids a scaled-index.
838 AM.BaseType == X86ISelAddressMode::RegBase &&
839 AM.Base_Reg.getNode() == nullptr) {
840 AM.Base_Reg = AM.IndexReg;
844 // Post-processing: Convert foo to foo(%rip), even in non-PIC mode,
845 // because it has a smaller encoding.
846 // TODO: Which other code models can use this?
847 if (TM.getCodeModel() == CodeModel::Small &&
848 Subtarget->is64Bit() &&
850 AM.BaseType == X86ISelAddressMode::RegBase &&
851 AM.Base_Reg.getNode() == nullptr &&
852 AM.IndexReg.getNode() == nullptr &&
853 AM.SymbolFlags == X86II::MO_NO_FLAG &&
854 AM.hasSymbolicDisplacement())
855 AM.Base_Reg = CurDAG->getRegister(X86::RIP, MVT::i64);
860 bool X86DAGToDAGISel::matchAdd(SDValue N, X86ISelAddressMode &AM,
862 // Add an artificial use to this node so that we can keep track of
863 // it if it gets CSE'd with a different node.
864 HandleSDNode Handle(N);
866 X86ISelAddressMode Backup = AM;
867 if (!matchAddressRecursively(N.getOperand(0), AM, Depth+1) &&
868 !matchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1))
872 // Try again after commuting the operands.
873 if (!matchAddressRecursively(Handle.getValue().getOperand(1), AM, Depth+1) &&
874 !matchAddressRecursively(Handle.getValue().getOperand(0), AM, Depth+1))
878 // If we couldn't fold both operands into the address at the same time,
879 // see if we can just put each operand into a register and fold at least
881 if (AM.BaseType == X86ISelAddressMode::RegBase &&
882 !AM.Base_Reg.getNode() &&
883 !AM.IndexReg.getNode()) {
884 N = Handle.getValue();
885 AM.Base_Reg = N.getOperand(0);
886 AM.IndexReg = N.getOperand(1);
890 N = Handle.getValue();
894 // Insert a node into the DAG at least before the Pos node's position. This
895 // will reposition the node as needed, and will assign it a node ID that is <=
896 // the Pos node's ID. Note that this does *not* preserve the uniqueness of node
897 // IDs! The selection DAG must no longer depend on their uniqueness when this
899 static void insertDAGNode(SelectionDAG &DAG, SDValue Pos, SDValue N) {
900 if (N.getNode()->getNodeId() == -1 ||
901 N.getNode()->getNodeId() > Pos.getNode()->getNodeId()) {
902 DAG.RepositionNode(Pos.getNode()->getIterator(), N.getNode());
903 N.getNode()->setNodeId(Pos.getNode()->getNodeId());
907 // Transform "(X >> (8-C1)) & (0xff << C1)" to "((X >> 8) & 0xff) << C1" if
908 // safe. This allows us to convert the shift and and into an h-register
909 // extract and a scaled index. Returns false if the simplification is
911 static bool foldMaskAndShiftToExtract(SelectionDAG &DAG, SDValue N,
913 SDValue Shift, SDValue X,
914 X86ISelAddressMode &AM) {
915 if (Shift.getOpcode() != ISD::SRL ||
916 !isa<ConstantSDNode>(Shift.getOperand(1)) ||
920 int ScaleLog = 8 - Shift.getConstantOperandVal(1);
921 if (ScaleLog <= 0 || ScaleLog >= 4 ||
922 Mask != (0xffu << ScaleLog))
925 MVT VT = N.getSimpleValueType();
927 SDValue Eight = DAG.getConstant(8, DL, MVT::i8);
928 SDValue NewMask = DAG.getConstant(0xff, DL, VT);
929 SDValue Srl = DAG.getNode(ISD::SRL, DL, VT, X, Eight);
930 SDValue And = DAG.getNode(ISD::AND, DL, VT, Srl, NewMask);
931 SDValue ShlCount = DAG.getConstant(ScaleLog, DL, MVT::i8);
932 SDValue Shl = DAG.getNode(ISD::SHL, DL, VT, And, ShlCount);
934 // Insert the new nodes into the topological ordering. We must do this in
935 // a valid topological ordering as nothing is going to go back and re-sort
936 // these nodes. We continually insert before 'N' in sequence as this is
937 // essentially a pre-flattened and pre-sorted sequence of nodes. There is no
938 // hierarchy left to express.
939 insertDAGNode(DAG, N, Eight);
940 insertDAGNode(DAG, N, Srl);
941 insertDAGNode(DAG, N, NewMask);
942 insertDAGNode(DAG, N, And);
943 insertDAGNode(DAG, N, ShlCount);
944 insertDAGNode(DAG, N, Shl);
945 DAG.ReplaceAllUsesWith(N, Shl);
947 AM.Scale = (1 << ScaleLog);
951 // Transforms "(X << C1) & C2" to "(X & (C2>>C1)) << C1" if safe and if this
952 // allows us to fold the shift into this addressing mode. Returns false if the
953 // transform succeeded.
954 static bool foldMaskedShiftToScaledMask(SelectionDAG &DAG, SDValue N,
956 SDValue Shift, SDValue X,
957 X86ISelAddressMode &AM) {
958 if (Shift.getOpcode() != ISD::SHL ||
959 !isa<ConstantSDNode>(Shift.getOperand(1)))
962 // Not likely to be profitable if either the AND or SHIFT node has more
963 // than one use (unless all uses are for address computation). Besides,
964 // isel mechanism requires their node ids to be reused.
965 if (!N.hasOneUse() || !Shift.hasOneUse())
968 // Verify that the shift amount is something we can fold.
969 unsigned ShiftAmt = Shift.getConstantOperandVal(1);
970 if (ShiftAmt != 1 && ShiftAmt != 2 && ShiftAmt != 3)
973 MVT VT = N.getSimpleValueType();
975 SDValue NewMask = DAG.getConstant(Mask >> ShiftAmt, DL, VT);
976 SDValue NewAnd = DAG.getNode(ISD::AND, DL, VT, X, NewMask);
977 SDValue NewShift = DAG.getNode(ISD::SHL, DL, VT, NewAnd, Shift.getOperand(1));
979 // Insert the new nodes into the topological ordering. We must do this in
980 // a valid topological ordering as nothing is going to go back and re-sort
981 // these nodes. We continually insert before 'N' in sequence as this is
982 // essentially a pre-flattened and pre-sorted sequence of nodes. There is no
983 // hierarchy left to express.
984 insertDAGNode(DAG, N, NewMask);
985 insertDAGNode(DAG, N, NewAnd);
986 insertDAGNode(DAG, N, NewShift);
987 DAG.ReplaceAllUsesWith(N, NewShift);
989 AM.Scale = 1 << ShiftAmt;
990 AM.IndexReg = NewAnd;
994 // Implement some heroics to detect shifts of masked values where the mask can
995 // be replaced by extending the shift and undoing that in the addressing mode
996 // scale. Patterns such as (shl (srl x, c1), c2) are canonicalized into (and
997 // (srl x, SHIFT), MASK) by DAGCombines that don't know the shl can be done in
998 // the addressing mode. This results in code such as:
1000 // int f(short *y, int *lookup_table) {
1002 // return *y + lookup_table[*y >> 11];
1006 // movzwl (%rdi), %eax
1009 // addl (%rsi,%rcx,4), %eax
1012 // movzwl (%rdi), %eax
1016 // addl (%rsi,%rcx), %eax
1018 // Note that this function assumes the mask is provided as a mask *after* the
1019 // value is shifted. The input chain may or may not match that, but computing
1020 // such a mask is trivial.
1021 static bool foldMaskAndShiftToScale(SelectionDAG &DAG, SDValue N,
1023 SDValue Shift, SDValue X,
1024 X86ISelAddressMode &AM) {
1025 if (Shift.getOpcode() != ISD::SRL || !Shift.hasOneUse() ||
1026 !isa<ConstantSDNode>(Shift.getOperand(1)))
1029 unsigned ShiftAmt = Shift.getConstantOperandVal(1);
1030 unsigned MaskLZ = countLeadingZeros(Mask);
1031 unsigned MaskTZ = countTrailingZeros(Mask);
1033 // The amount of shift we're trying to fit into the addressing mode is taken
1034 // from the trailing zeros of the mask.
1035 unsigned AMShiftAmt = MaskTZ;
1037 // There is nothing we can do here unless the mask is removing some bits.
1038 // Also, the addressing mode can only represent shifts of 1, 2, or 3 bits.
1039 if (AMShiftAmt <= 0 || AMShiftAmt > 3) return true;
1041 // We also need to ensure that mask is a continuous run of bits.
1042 if (countTrailingOnes(Mask >> MaskTZ) + MaskTZ + MaskLZ != 64) return true;
1044 // Scale the leading zero count down based on the actual size of the value.
1045 // Also scale it down based on the size of the shift.
1046 MaskLZ -= (64 - X.getSimpleValueType().getSizeInBits()) + ShiftAmt;
1048 // The final check is to ensure that any masked out high bits of X are
1049 // already known to be zero. Otherwise, the mask has a semantic impact
1050 // other than masking out a couple of low bits. Unfortunately, because of
1051 // the mask, zero extensions will be removed from operands in some cases.
1052 // This code works extra hard to look through extensions because we can
1053 // replace them with zero extensions cheaply if necessary.
1054 bool ReplacingAnyExtend = false;
1055 if (X.getOpcode() == ISD::ANY_EXTEND) {
1056 unsigned ExtendBits = X.getSimpleValueType().getSizeInBits() -
1057 X.getOperand(0).getSimpleValueType().getSizeInBits();
1058 // Assume that we'll replace the any-extend with a zero-extend, and
1059 // narrow the search to the extended value.
1060 X = X.getOperand(0);
1061 MaskLZ = ExtendBits > MaskLZ ? 0 : MaskLZ - ExtendBits;
1062 ReplacingAnyExtend = true;
1064 APInt MaskedHighBits =
1065 APInt::getHighBitsSet(X.getSimpleValueType().getSizeInBits(), MaskLZ);
1066 APInt KnownZero, KnownOne;
1067 DAG.computeKnownBits(X, KnownZero, KnownOne);
1068 if (MaskedHighBits != KnownZero) return true;
1070 // We've identified a pattern that can be transformed into a single shift
1071 // and an addressing mode. Make it so.
1072 MVT VT = N.getSimpleValueType();
1073 if (ReplacingAnyExtend) {
1074 assert(X.getValueType() != VT);
1075 // We looked through an ANY_EXTEND node, insert a ZERO_EXTEND.
1076 SDValue NewX = DAG.getNode(ISD::ZERO_EXTEND, SDLoc(X), VT, X);
1077 insertDAGNode(DAG, N, NewX);
1081 SDValue NewSRLAmt = DAG.getConstant(ShiftAmt + AMShiftAmt, DL, MVT::i8);
1082 SDValue NewSRL = DAG.getNode(ISD::SRL, DL, VT, X, NewSRLAmt);
1083 SDValue NewSHLAmt = DAG.getConstant(AMShiftAmt, DL, MVT::i8);
1084 SDValue NewSHL = DAG.getNode(ISD::SHL, DL, VT, NewSRL, NewSHLAmt);
1086 // Insert the new nodes into the topological ordering. We must do this in
1087 // a valid topological ordering as nothing is going to go back and re-sort
1088 // these nodes. We continually insert before 'N' in sequence as this is
1089 // essentially a pre-flattened and pre-sorted sequence of nodes. There is no
1090 // hierarchy left to express.
1091 insertDAGNode(DAG, N, NewSRLAmt);
1092 insertDAGNode(DAG, N, NewSRL);
1093 insertDAGNode(DAG, N, NewSHLAmt);
1094 insertDAGNode(DAG, N, NewSHL);
1095 DAG.ReplaceAllUsesWith(N, NewSHL);
1097 AM.Scale = 1 << AMShiftAmt;
1098 AM.IndexReg = NewSRL;
1102 bool X86DAGToDAGISel::matchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
1106 dbgs() << "MatchAddress: ";
1111 return matchAddressBase(N, AM);
1113 // If this is already a %rip relative address, we can only merge immediates
1114 // into it. Instead of handling this in every case, we handle it here.
1115 // RIP relative addressing: %rip + 32-bit displacement!
1116 if (AM.isRIPRelative()) {
1117 // FIXME: JumpTable and ExternalSymbol address currently don't like
1118 // displacements. It isn't very important, but this should be fixed for
1120 if (!(AM.ES || AM.MCSym) && AM.JT != -1)
1123 if (ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(N))
1124 if (!foldOffsetIntoAddress(Cst->getSExtValue(), AM))
1129 switch (N.getOpcode()) {
1131 case ISD::LOCAL_RECOVER: {
1132 if (!AM.hasSymbolicDisplacement() && AM.Disp == 0)
1133 if (const auto *ESNode = dyn_cast<MCSymbolSDNode>(N.getOperand(0))) {
1134 // Use the symbol and don't prefix it.
1135 AM.MCSym = ESNode->getMCSymbol();
1140 case ISD::Constant: {
1141 uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
1142 if (!foldOffsetIntoAddress(Val, AM))
1147 case X86ISD::Wrapper:
1148 case X86ISD::WrapperRIP:
1149 if (!matchWrapper(N, AM))
1154 if (!matchLoadInAddress(cast<LoadSDNode>(N), AM))
1158 case ISD::FrameIndex:
1159 if (AM.BaseType == X86ISelAddressMode::RegBase &&
1160 AM.Base_Reg.getNode() == nullptr &&
1161 (!Subtarget->is64Bit() || isDispSafeForFrameIndex(AM.Disp))) {
1162 AM.BaseType = X86ISelAddressMode::FrameIndexBase;
1163 AM.Base_FrameIndex = cast<FrameIndexSDNode>(N)->getIndex();
1169 if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1)
1173 *CN = dyn_cast<ConstantSDNode>(N.getNode()->getOperand(1))) {
1174 unsigned Val = CN->getZExtValue();
1175 // Note that we handle x<<1 as (,x,2) rather than (x,x) here so
1176 // that the base operand remains free for further matching. If
1177 // the base doesn't end up getting used, a post-processing step
1178 // in MatchAddress turns (,x,2) into (x,x), which is cheaper.
1179 if (Val == 1 || Val == 2 || Val == 3) {
1180 AM.Scale = 1 << Val;
1181 SDValue ShVal = N.getNode()->getOperand(0);
1183 // Okay, we know that we have a scale by now. However, if the scaled
1184 // value is an add of something and a constant, we can fold the
1185 // constant into the disp field here.
1186 if (CurDAG->isBaseWithConstantOffset(ShVal)) {
1187 AM.IndexReg = ShVal.getNode()->getOperand(0);
1188 ConstantSDNode *AddVal =
1189 cast<ConstantSDNode>(ShVal.getNode()->getOperand(1));
1190 uint64_t Disp = (uint64_t)AddVal->getSExtValue() << Val;
1191 if (!foldOffsetIntoAddress(Disp, AM))
1195 AM.IndexReg = ShVal;
1202 // Scale must not be used already.
1203 if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1) break;
1205 SDValue And = N.getOperand(0);
1206 if (And.getOpcode() != ISD::AND) break;
1207 SDValue X = And.getOperand(0);
1209 // We only handle up to 64-bit values here as those are what matter for
1210 // addressing mode optimizations.
1211 if (X.getSimpleValueType().getSizeInBits() > 64) break;
1213 // The mask used for the transform is expected to be post-shift, but we
1214 // found the shift first so just apply the shift to the mask before passing
1216 if (!isa<ConstantSDNode>(N.getOperand(1)) ||
1217 !isa<ConstantSDNode>(And.getOperand(1)))
1219 uint64_t Mask = And.getConstantOperandVal(1) >> N.getConstantOperandVal(1);
1221 // Try to fold the mask and shift into the scale, and return false if we
1223 if (!foldMaskAndShiftToScale(*CurDAG, N, Mask, N, X, AM))
1228 case ISD::SMUL_LOHI:
1229 case ISD::UMUL_LOHI:
1230 // A mul_lohi where we need the low part can be folded as a plain multiply.
1231 if (N.getResNo() != 0) break;
1234 case X86ISD::MUL_IMM:
1235 // X*[3,5,9] -> X+X*[2,4,8]
1236 if (AM.BaseType == X86ISelAddressMode::RegBase &&
1237 AM.Base_Reg.getNode() == nullptr &&
1238 AM.IndexReg.getNode() == nullptr) {
1240 *CN = dyn_cast<ConstantSDNode>(N.getNode()->getOperand(1)))
1241 if (CN->getZExtValue() == 3 || CN->getZExtValue() == 5 ||
1242 CN->getZExtValue() == 9) {
1243 AM.Scale = unsigned(CN->getZExtValue())-1;
1245 SDValue MulVal = N.getNode()->getOperand(0);
1248 // Okay, we know that we have a scale by now. However, if the scaled
1249 // value is an add of something and a constant, we can fold the
1250 // constant into the disp field here.
1251 if (MulVal.getNode()->getOpcode() == ISD::ADD && MulVal.hasOneUse() &&
1252 isa<ConstantSDNode>(MulVal.getNode()->getOperand(1))) {
1253 Reg = MulVal.getNode()->getOperand(0);
1254 ConstantSDNode *AddVal =
1255 cast<ConstantSDNode>(MulVal.getNode()->getOperand(1));
1256 uint64_t Disp = AddVal->getSExtValue() * CN->getZExtValue();
1257 if (foldOffsetIntoAddress(Disp, AM))
1258 Reg = N.getNode()->getOperand(0);
1260 Reg = N.getNode()->getOperand(0);
1263 AM.IndexReg = AM.Base_Reg = Reg;
1270 // Given A-B, if A can be completely folded into the address and
1271 // the index field with the index field unused, use -B as the index.
1272 // This is a win if a has multiple parts that can be folded into
1273 // the address. Also, this saves a mov if the base register has
1274 // other uses, since it avoids a two-address sub instruction, however
1275 // it costs an additional mov if the index register has other uses.
1277 // Add an artificial use to this node so that we can keep track of
1278 // it if it gets CSE'd with a different node.
1279 HandleSDNode Handle(N);
1281 // Test if the LHS of the sub can be folded.
1282 X86ISelAddressMode Backup = AM;
1283 if (matchAddressRecursively(N.getNode()->getOperand(0), AM, Depth+1)) {
1287 // Test if the index field is free for use.
1288 if (AM.IndexReg.getNode() || AM.isRIPRelative()) {
1294 SDValue RHS = Handle.getValue().getNode()->getOperand(1);
1295 // If the RHS involves a register with multiple uses, this
1296 // transformation incurs an extra mov, due to the neg instruction
1297 // clobbering its operand.
1298 if (!RHS.getNode()->hasOneUse() ||
1299 RHS.getNode()->getOpcode() == ISD::CopyFromReg ||
1300 RHS.getNode()->getOpcode() == ISD::TRUNCATE ||
1301 RHS.getNode()->getOpcode() == ISD::ANY_EXTEND ||
1302 (RHS.getNode()->getOpcode() == ISD::ZERO_EXTEND &&
1303 RHS.getNode()->getOperand(0).getValueType() == MVT::i32))
1305 // If the base is a register with multiple uses, this
1306 // transformation may save a mov.
1307 if ((AM.BaseType == X86ISelAddressMode::RegBase &&
1308 AM.Base_Reg.getNode() &&
1309 !AM.Base_Reg.getNode()->hasOneUse()) ||
1310 AM.BaseType == X86ISelAddressMode::FrameIndexBase)
1312 // If the folded LHS was interesting, this transformation saves
1313 // address arithmetic.
1314 if ((AM.hasSymbolicDisplacement() && !Backup.hasSymbolicDisplacement()) +
1315 ((AM.Disp != 0) && (Backup.Disp == 0)) +
1316 (AM.Segment.getNode() && !Backup.Segment.getNode()) >= 2)
1318 // If it doesn't look like it may be an overall win, don't do it.
1324 // Ok, the transformation is legal and appears profitable. Go for it.
1325 SDValue Zero = CurDAG->getConstant(0, dl, N.getValueType());
1326 SDValue Neg = CurDAG->getNode(ISD::SUB, dl, N.getValueType(), Zero, RHS);
1330 // Insert the new nodes into the topological ordering.
1331 insertDAGNode(*CurDAG, N, Zero);
1332 insertDAGNode(*CurDAG, N, Neg);
1337 if (!matchAdd(N, AM, Depth))
1342 // TODO: The bit-checking logic should be put into a helper function and
1343 // used by DAGCombiner.
1345 // We want to look through a transform in InstCombine and DAGCombiner that
1346 // turns 'add' into 'or', so we can treat this 'or' exactly like an 'add'.
1347 APInt LHSZero, LHSOne;
1348 APInt RHSZero, RHSOne;
1349 CurDAG->computeKnownBits(N.getOperand(0), LHSZero, LHSOne);
1350 CurDAG->computeKnownBits(N.getOperand(1), RHSZero, RHSOne);
1352 // If we know that there are no common bits set by the operands of this
1353 // 'or', it is equivalent to an 'add'. For example:
1354 // (or (and x, 1), (shl y, 3)) --> (add (and x, 1), (shl y, 3))
1355 // An 'lea' can then be used to match the shift (multiply) and add:
1357 // lea (%rsi, %rdi, 8), %rax
1358 if ((LHSZero | RHSZero).isAllOnesValue())
1359 if (!matchAdd(N, AM, Depth))
1366 // Perform some heroic transforms on an and of a constant-count shift
1367 // with a constant to enable use of the scaled offset field.
1369 // Scale must not be used already.
1370 if (AM.IndexReg.getNode() != nullptr || AM.Scale != 1) break;
1372 SDValue Shift = N.getOperand(0);
1373 if (Shift.getOpcode() != ISD::SRL && Shift.getOpcode() != ISD::SHL) break;
1374 SDValue X = Shift.getOperand(0);
1376 // We only handle up to 64-bit values here as those are what matter for
1377 // addressing mode optimizations.
1378 if (X.getSimpleValueType().getSizeInBits() > 64) break;
1380 if (!isa<ConstantSDNode>(N.getOperand(1)))
1382 uint64_t Mask = N.getConstantOperandVal(1);
1384 // Try to fold the mask and shift into an extract and scale.
1385 if (!foldMaskAndShiftToExtract(*CurDAG, N, Mask, Shift, X, AM))
1388 // Try to fold the mask and shift directly into the scale.
1389 if (!foldMaskAndShiftToScale(*CurDAG, N, Mask, Shift, X, AM))
1392 // Try to swap the mask and shift to place shifts which can be done as
1393 // a scale on the outside of the mask.
1394 if (!foldMaskedShiftToScaledMask(*CurDAG, N, Mask, Shift, X, AM))
1400 return matchAddressBase(N, AM);
1403 /// Helper for MatchAddress. Add the specified node to the
1404 /// specified addressing mode without any further recursion.
1405 bool X86DAGToDAGISel::matchAddressBase(SDValue N, X86ISelAddressMode &AM) {
1406 // Is the base register already occupied?
1407 if (AM.BaseType != X86ISelAddressMode::RegBase || AM.Base_Reg.getNode()) {
1408 // If so, check to see if the scale index register is set.
1409 if (!AM.IndexReg.getNode()) {
1415 // Otherwise, we cannot select it.
1419 // Default, generate it as a register.
1420 AM.BaseType = X86ISelAddressMode::RegBase;
1425 bool X86DAGToDAGISel::selectVectorAddr(SDNode *Parent, SDValue N, SDValue &Base,
1426 SDValue &Scale, SDValue &Index,
1427 SDValue &Disp, SDValue &Segment) {
1429 MaskedGatherScatterSDNode *Mgs = dyn_cast<MaskedGatherScatterSDNode>(Parent);
1432 X86ISelAddressMode AM;
1433 unsigned AddrSpace = Mgs->getPointerInfo().getAddrSpace();
1434 // AddrSpace 256 -> GS, 257 -> FS.
1435 if (AddrSpace == 256)
1436 AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
1437 if (AddrSpace == 257)
1438 AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
1441 Base = Mgs->getBasePtr();
1442 Index = Mgs->getIndex();
1443 unsigned ScalarSize = Mgs->getValue().getValueType().getScalarSizeInBits();
1444 Scale = getI8Imm(ScalarSize/8, DL);
1446 // If Base is 0, the whole address is in index and the Scale is 1
1447 if (isa<ConstantSDNode>(Base)) {
1448 assert(cast<ConstantSDNode>(Base)->isNullValue() &&
1449 "Unexpected base in gather/scatter");
1450 Scale = getI8Imm(1, DL);
1451 Base = CurDAG->getRegister(0, MVT::i32);
1453 if (AM.Segment.getNode())
1454 Segment = AM.Segment;
1456 Segment = CurDAG->getRegister(0, MVT::i32);
1457 Disp = CurDAG->getTargetConstant(0, DL, MVT::i32);
1461 /// Returns true if it is able to pattern match an addressing mode.
1462 /// It returns the operands which make up the maximal addressing mode it can
1463 /// match by reference.
1465 /// Parent is the parent node of the addr operand that is being matched. It
1466 /// is always a load, store, atomic node, or null. It is only null when
1467 /// checking memory operands for inline asm nodes.
1468 bool X86DAGToDAGISel::selectAddr(SDNode *Parent, SDValue N, SDValue &Base,
1469 SDValue &Scale, SDValue &Index,
1470 SDValue &Disp, SDValue &Segment) {
1471 X86ISelAddressMode AM;
1474 // This list of opcodes are all the nodes that have an "addr:$ptr" operand
1475 // that are not a MemSDNode, and thus don't have proper addrspace info.
1476 Parent->getOpcode() != ISD::INTRINSIC_W_CHAIN && // unaligned loads, fixme
1477 Parent->getOpcode() != ISD::INTRINSIC_VOID && // nontemporal stores
1478 Parent->getOpcode() != X86ISD::TLSCALL && // Fixme
1479 Parent->getOpcode() != X86ISD::EH_SJLJ_SETJMP && // setjmp
1480 Parent->getOpcode() != X86ISD::EH_SJLJ_LONGJMP) { // longjmp
1481 unsigned AddrSpace =
1482 cast<MemSDNode>(Parent)->getPointerInfo().getAddrSpace();
1483 // AddrSpace 256 -> GS, 257 -> FS.
1484 if (AddrSpace == 256)
1485 AM.Segment = CurDAG->getRegister(X86::GS, MVT::i16);
1486 if (AddrSpace == 257)
1487 AM.Segment = CurDAG->getRegister(X86::FS, MVT::i16);
1490 if (matchAddress(N, AM))
1493 MVT VT = N.getSimpleValueType();
1494 if (AM.BaseType == X86ISelAddressMode::RegBase) {
1495 if (!AM.Base_Reg.getNode())
1496 AM.Base_Reg = CurDAG->getRegister(0, VT);
1499 if (!AM.IndexReg.getNode())
1500 AM.IndexReg = CurDAG->getRegister(0, VT);
1502 getAddressOperands(AM, SDLoc(N), Base, Scale, Index, Disp, Segment);
1506 /// Match a scalar SSE load. In particular, we want to match a load whose top
1507 /// elements are either undef or zeros. The load flavor is derived from the
1508 /// type of N, which is either v4f32 or v2f64.
1511 /// PatternChainNode: this is the matched node that has a chain input and
1513 bool X86DAGToDAGISel::selectScalarSSELoad(SDNode *Root,
1514 SDValue N, SDValue &Base,
1515 SDValue &Scale, SDValue &Index,
1516 SDValue &Disp, SDValue &Segment,
1517 SDValue &PatternNodeWithChain) {
1518 if (N.getOpcode() == ISD::SCALAR_TO_VECTOR) {
1519 PatternNodeWithChain = N.getOperand(0);
1520 if (ISD::isNON_EXTLoad(PatternNodeWithChain.getNode()) &&
1521 PatternNodeWithChain.hasOneUse() &&
1522 IsProfitableToFold(N.getOperand(0), N.getNode(), Root) &&
1523 IsLegalToFold(N.getOperand(0), N.getNode(), Root, OptLevel)) {
1524 LoadSDNode *LD = cast<LoadSDNode>(PatternNodeWithChain);
1525 if (!selectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp, Segment))
1531 // Also handle the case where we explicitly require zeros in the top
1532 // elements. This is a vector shuffle from the zero vector.
1533 if (N.getOpcode() == X86ISD::VZEXT_MOVL && N.getNode()->hasOneUse() &&
1534 // Check to see if the top elements are all zeros (or bitcast of zeros).
1535 N.getOperand(0).getOpcode() == ISD::SCALAR_TO_VECTOR &&
1536 N.getOperand(0).getNode()->hasOneUse() &&
1537 ISD::isNON_EXTLoad(N.getOperand(0).getOperand(0).getNode()) &&
1538 N.getOperand(0).getOperand(0).hasOneUse() &&
1539 IsProfitableToFold(N.getOperand(0), N.getNode(), Root) &&
1540 IsLegalToFold(N.getOperand(0), N.getNode(), Root, OptLevel)) {
1541 // Okay, this is a zero extending load. Fold it.
1542 LoadSDNode *LD = cast<LoadSDNode>(N.getOperand(0).getOperand(0));
1543 if (!selectAddr(LD, LD->getBasePtr(), Base, Scale, Index, Disp, Segment))
1545 PatternNodeWithChain = SDValue(LD, 0);
1552 bool X86DAGToDAGISel::selectMOV64Imm32(SDValue N, SDValue &Imm) {
1553 if (const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N)) {
1554 uint64_t ImmVal = CN->getZExtValue();
1555 if ((uint32_t)ImmVal != (uint64_t)ImmVal)
1558 Imm = CurDAG->getTargetConstant(ImmVal, SDLoc(N), MVT::i64);
1562 // In static codegen with small code model, we can get the address of a label
1563 // into a register with 'movl'. TableGen has already made sure we're looking
1564 // at a label of some kind.
1565 assert(N->getOpcode() == X86ISD::Wrapper &&
1566 "Unexpected node type for MOV32ri64");
1567 N = N.getOperand(0);
1569 if (N->getOpcode() != ISD::TargetConstantPool &&
1570 N->getOpcode() != ISD::TargetJumpTable &&
1571 N->getOpcode() != ISD::TargetGlobalAddress &&
1572 N->getOpcode() != ISD::TargetExternalSymbol &&
1573 N->getOpcode() != ISD::MCSymbol &&
1574 N->getOpcode() != ISD::TargetBlockAddress)
1578 return TM.getCodeModel() == CodeModel::Small;
1581 bool X86DAGToDAGISel::selectLEA64_32Addr(SDValue N, SDValue &Base,
1582 SDValue &Scale, SDValue &Index,
1583 SDValue &Disp, SDValue &Segment) {
1584 if (!selectLEAAddr(N, Base, Scale, Index, Disp, Segment))
1588 RegisterSDNode *RN = dyn_cast<RegisterSDNode>(Base);
1589 if (RN && RN->getReg() == 0)
1590 Base = CurDAG->getRegister(0, MVT::i64);
1591 else if (Base.getValueType() == MVT::i32 && !dyn_cast<FrameIndexSDNode>(Base)) {
1592 // Base could already be %rip, particularly in the x32 ABI.
1593 Base = SDValue(CurDAG->getMachineNode(
1594 TargetOpcode::SUBREG_TO_REG, DL, MVT::i64,
1595 CurDAG->getTargetConstant(0, DL, MVT::i64),
1597 CurDAG->getTargetConstant(X86::sub_32bit, DL, MVT::i32)),
1601 RN = dyn_cast<RegisterSDNode>(Index);
1602 if (RN && RN->getReg() == 0)
1603 Index = CurDAG->getRegister(0, MVT::i64);
1605 assert(Index.getValueType() == MVT::i32 &&
1606 "Expect to be extending 32-bit registers for use in LEA");
1607 Index = SDValue(CurDAG->getMachineNode(
1608 TargetOpcode::SUBREG_TO_REG, DL, MVT::i64,
1609 CurDAG->getTargetConstant(0, DL, MVT::i64),
1611 CurDAG->getTargetConstant(X86::sub_32bit, DL,
1619 /// Calls SelectAddr and determines if the maximal addressing
1620 /// mode it matches can be cost effectively emitted as an LEA instruction.
1621 bool X86DAGToDAGISel::selectLEAAddr(SDValue N,
1622 SDValue &Base, SDValue &Scale,
1623 SDValue &Index, SDValue &Disp,
1625 X86ISelAddressMode AM;
1627 // Set AM.Segment to prevent MatchAddress from using one. LEA doesn't support
1629 SDValue Copy = AM.Segment;
1630 SDValue T = CurDAG->getRegister(0, MVT::i32);
1632 if (matchAddress(N, AM))
1634 assert (T == AM.Segment);
1637 MVT VT = N.getSimpleValueType();
1638 unsigned Complexity = 0;
1639 if (AM.BaseType == X86ISelAddressMode::RegBase)
1640 if (AM.Base_Reg.getNode())
1643 AM.Base_Reg = CurDAG->getRegister(0, VT);
1644 else if (AM.BaseType == X86ISelAddressMode::FrameIndexBase)
1647 if (AM.IndexReg.getNode())
1650 AM.IndexReg = CurDAG->getRegister(0, VT);
1652 // Don't match just leal(,%reg,2). It's cheaper to do addl %reg, %reg, or with
1657 // FIXME: We are artificially lowering the criteria to turn ADD %reg, $GA
1658 // to a LEA. This is determined with some experimentation but is by no means
1659 // optimal (especially for code size consideration). LEA is nice because of
1660 // its three-address nature. Tweak the cost function again when we can run
1661 // convertToThreeAddress() at register allocation time.
1662 if (AM.hasSymbolicDisplacement()) {
1663 // For X86-64, always use LEA to materialize RIP-relative addresses.
1664 if (Subtarget->is64Bit())
1670 if (AM.Disp && (AM.Base_Reg.getNode() || AM.IndexReg.getNode()))
1673 // If it isn't worth using an LEA, reject it.
1674 if (Complexity <= 2)
1677 getAddressOperands(AM, SDLoc(N), Base, Scale, Index, Disp, Segment);
1681 /// This is only run on TargetGlobalTLSAddress nodes.
1682 bool X86DAGToDAGISel::selectTLSADDRAddr(SDValue N, SDValue &Base,
1683 SDValue &Scale, SDValue &Index,
1684 SDValue &Disp, SDValue &Segment) {
1685 assert(N.getOpcode() == ISD::TargetGlobalTLSAddress);
1686 const GlobalAddressSDNode *GA = cast<GlobalAddressSDNode>(N);
1688 X86ISelAddressMode AM;
1689 AM.GV = GA->getGlobal();
1690 AM.Disp += GA->getOffset();
1691 AM.Base_Reg = CurDAG->getRegister(0, N.getValueType());
1692 AM.SymbolFlags = GA->getTargetFlags();
1694 if (N.getValueType() == MVT::i32) {
1696 AM.IndexReg = CurDAG->getRegister(X86::EBX, MVT::i32);
1698 AM.IndexReg = CurDAG->getRegister(0, MVT::i64);
1701 getAddressOperands(AM, SDLoc(N), Base, Scale, Index, Disp, Segment);
1706 bool X86DAGToDAGISel::tryFoldLoad(SDNode *P, SDValue N,
1707 SDValue &Base, SDValue &Scale,
1708 SDValue &Index, SDValue &Disp,
1710 if (!ISD::isNON_EXTLoad(N.getNode()) ||
1711 !IsProfitableToFold(N, P, P) ||
1712 !IsLegalToFold(N, P, P, OptLevel))
1715 return selectAddr(N.getNode(),
1716 N.getOperand(1), Base, Scale, Index, Disp, Segment);
1719 /// Return an SDNode that returns the value of the global base register.
1720 /// Output instructions required to initialize the global base register,
1722 SDNode *X86DAGToDAGISel::getGlobalBaseReg() {
1723 unsigned GlobalBaseReg = getInstrInfo()->getGlobalBaseReg(MF);
1724 auto &DL = MF->getDataLayout();
1725 return CurDAG->getRegister(GlobalBaseReg, TLI->getPointerTy(DL)).getNode();
1728 /// Atomic opcode table
1756 static const uint16_t AtomicOpcTbl[AtomicOpcEnd][AtomicSzEnd] = {
1767 X86::LOCK_ADD64mi32,
1780 X86::LOCK_SUB64mi32,
1832 X86::LOCK_AND64mi32,
1845 X86::LOCK_XOR64mi32,
1850 // Return the target constant operand for atomic-load-op and do simple
1851 // translations, such as from atomic-load-add to lock-sub. The return value is
1852 // one of the following 3 cases:
1853 // + target-constant, the operand could be supported as a target constant.
1854 // + empty, the operand is not needed any more with the new op selected.
1855 // + non-empty, otherwise.
1856 static SDValue getAtomicLoadArithTargetConstant(SelectionDAG *CurDAG,
1858 enum AtomicOpc &Op, MVT NVT,
1860 const X86Subtarget *Subtarget) {
1861 if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Val)) {
1862 int64_t CNVal = CN->getSExtValue();
1863 // Quit if not 32-bit imm.
1864 if ((int32_t)CNVal != CNVal)
1866 // Quit if INT32_MIN: it would be negated as it is negative and overflow,
1867 // producing an immediate that does not fit in the 32 bits available for
1868 // an immediate operand to sub. However, it still fits in 32 bits for the
1869 // add (since it is not negated) so we can return target-constant.
1870 if (CNVal == INT32_MIN)
1871 return CurDAG->getTargetConstant(CNVal, dl, NVT);
1872 // For atomic-load-add, we could do some optimizations.
1874 // Translate to INC/DEC if ADD by 1 or -1.
1875 if (((CNVal == 1) || (CNVal == -1)) && !Subtarget->slowIncDec()) {
1876 Op = (CNVal == 1) ? INC : DEC;
1877 // No more constant operand after being translated into INC/DEC.
1880 // Translate to SUB if ADD by negative value.
1886 return CurDAG->getTargetConstant(CNVal, dl, NVT);
1889 // If the value operand is single-used, try to optimize it.
1890 if (Op == ADD && Val.hasOneUse()) {
1891 // Translate (atomic-load-add ptr (sub 0 x)) back to (lock-sub x).
1892 if (Val.getOpcode() == ISD::SUB && X86::isZeroNode(Val.getOperand(0))) {
1894 return Val.getOperand(1);
1896 // A special case for i16, which needs truncating as, in most cases, it's
1897 // promoted to i32. We will translate
1898 // (atomic-load-add (truncate (sub 0 x))) to (lock-sub (EXTRACT_SUBREG x))
1899 if (Val.getOpcode() == ISD::TRUNCATE && NVT == MVT::i16 &&
1900 Val.getOperand(0).getOpcode() == ISD::SUB &&
1901 X86::isZeroNode(Val.getOperand(0).getOperand(0))) {
1903 Val = Val.getOperand(0);
1904 return CurDAG->getTargetExtractSubreg(X86::sub_16bit, dl, NVT,
1912 SDNode *X86DAGToDAGISel::selectAtomicLoadArith(SDNode *Node, MVT NVT) {
1913 if (Node->hasAnyUseOfValue(0))
1918 // Optimize common patterns for __sync_or_and_fetch and similar arith
1919 // operations where the result is not used. This allows us to use the "lock"
1920 // version of the arithmetic instruction.
1921 SDValue Chain = Node->getOperand(0);
1922 SDValue Ptr = Node->getOperand(1);
1923 SDValue Val = Node->getOperand(2);
1924 SDValue Base, Scale, Index, Disp, Segment;
1925 if (!selectAddr(Node, Ptr, Base, Scale, Index, Disp, Segment))
1928 // Which index into the table.
1930 switch (Node->getOpcode()) {
1933 case ISD::ATOMIC_LOAD_OR:
1936 case ISD::ATOMIC_LOAD_AND:
1939 case ISD::ATOMIC_LOAD_XOR:
1942 case ISD::ATOMIC_LOAD_ADD:
1947 Val = getAtomicLoadArithTargetConstant(CurDAG, dl, Op, NVT, Val, Subtarget);
1948 bool isUnOp = !Val.getNode();
1949 bool isCN = Val.getNode() && (Val.getOpcode() == ISD::TargetConstant);
1952 switch (NVT.SimpleTy) {
1953 default: return nullptr;
1956 Opc = AtomicOpcTbl[Op][ConstantI8];
1958 Opc = AtomicOpcTbl[Op][I8];
1962 if (immSext8(Val.getNode()))
1963 Opc = AtomicOpcTbl[Op][SextConstantI16];
1965 Opc = AtomicOpcTbl[Op][ConstantI16];
1967 Opc = AtomicOpcTbl[Op][I16];
1971 if (immSext8(Val.getNode()))
1972 Opc = AtomicOpcTbl[Op][SextConstantI32];
1974 Opc = AtomicOpcTbl[Op][ConstantI32];
1976 Opc = AtomicOpcTbl[Op][I32];
1980 if (immSext8(Val.getNode()))
1981 Opc = AtomicOpcTbl[Op][SextConstantI64];
1982 else if (i64immSExt32(Val.getNode()))
1983 Opc = AtomicOpcTbl[Op][ConstantI64];
1985 llvm_unreachable("True 64 bits constant in SelectAtomicLoadArith");
1987 Opc = AtomicOpcTbl[Op][I64];
1991 assert(Opc != 0 && "Invalid arith lock transform!");
1993 // Building the new node.
1996 SDValue Ops[] = { Base, Scale, Index, Disp, Segment, Chain };
1997 Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops), 0);
1999 SDValue Ops[] = { Base, Scale, Index, Disp, Segment, Val, Chain };
2000 Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops), 0);
2003 // Copying the MachineMemOperand.
2004 MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
2005 MemOp[0] = cast<MemSDNode>(Node)->getMemOperand();
2006 cast<MachineSDNode>(Ret)->setMemRefs(MemOp, MemOp + 1);
2008 // We need to have two outputs as that is what the original instruction had.
2009 // So we add a dummy, undefined output. This is safe as we checked first
2010 // that no-one uses our output anyway.
2011 SDValue Undef = SDValue(CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF,
2013 SDValue RetVals[] = { Undef, Ret };
2014 return CurDAG->getMergeValues(RetVals, dl).getNode();
2017 /// Test whether the given X86ISD::CMP node has any uses which require the SF
2018 /// or OF bits to be accurate.
2019 static bool hasNoSignedComparisonUses(SDNode *N) {
2020 // Examine each user of the node.
2021 for (SDNode::use_iterator UI = N->use_begin(),
2022 UE = N->use_end(); UI != UE; ++UI) {
2023 // Only examine CopyToReg uses.
2024 if (UI->getOpcode() != ISD::CopyToReg)
2026 // Only examine CopyToReg uses that copy to EFLAGS.
2027 if (cast<RegisterSDNode>(UI->getOperand(1))->getReg() !=
2030 // Examine each user of the CopyToReg use.
2031 for (SDNode::use_iterator FlagUI = UI->use_begin(),
2032 FlagUE = UI->use_end(); FlagUI != FlagUE; ++FlagUI) {
2033 // Only examine the Flag result.
2034 if (FlagUI.getUse().getResNo() != 1) continue;
2035 // Anything unusual: assume conservatively.
2036 if (!FlagUI->isMachineOpcode()) return false;
2037 // Examine the opcode of the user.
2038 switch (FlagUI->getMachineOpcode()) {
2039 // These comparisons don't treat the most significant bit specially.
2040 case X86::SETAr: case X86::SETAEr: case X86::SETBr: case X86::SETBEr:
2041 case X86::SETEr: case X86::SETNEr: case X86::SETPr: case X86::SETNPr:
2042 case X86::SETAm: case X86::SETAEm: case X86::SETBm: case X86::SETBEm:
2043 case X86::SETEm: case X86::SETNEm: case X86::SETPm: case X86::SETNPm:
2044 case X86::JA_1: case X86::JAE_1: case X86::JB_1: case X86::JBE_1:
2045 case X86::JE_1: case X86::JNE_1: case X86::JP_1: case X86::JNP_1:
2046 case X86::CMOVA16rr: case X86::CMOVA16rm:
2047 case X86::CMOVA32rr: case X86::CMOVA32rm:
2048 case X86::CMOVA64rr: case X86::CMOVA64rm:
2049 case X86::CMOVAE16rr: case X86::CMOVAE16rm:
2050 case X86::CMOVAE32rr: case X86::CMOVAE32rm:
2051 case X86::CMOVAE64rr: case X86::CMOVAE64rm:
2052 case X86::CMOVB16rr: case X86::CMOVB16rm:
2053 case X86::CMOVB32rr: case X86::CMOVB32rm:
2054 case X86::CMOVB64rr: case X86::CMOVB64rm:
2055 case X86::CMOVBE16rr: case X86::CMOVBE16rm:
2056 case X86::CMOVBE32rr: case X86::CMOVBE32rm:
2057 case X86::CMOVBE64rr: case X86::CMOVBE64rm:
2058 case X86::CMOVE16rr: case X86::CMOVE16rm:
2059 case X86::CMOVE32rr: case X86::CMOVE32rm:
2060 case X86::CMOVE64rr: case X86::CMOVE64rm:
2061 case X86::CMOVNE16rr: case X86::CMOVNE16rm:
2062 case X86::CMOVNE32rr: case X86::CMOVNE32rm:
2063 case X86::CMOVNE64rr: case X86::CMOVNE64rm:
2064 case X86::CMOVNP16rr: case X86::CMOVNP16rm:
2065 case X86::CMOVNP32rr: case X86::CMOVNP32rm:
2066 case X86::CMOVNP64rr: case X86::CMOVNP64rm:
2067 case X86::CMOVP16rr: case X86::CMOVP16rm:
2068 case X86::CMOVP32rr: case X86::CMOVP32rm:
2069 case X86::CMOVP64rr: case X86::CMOVP64rm:
2071 // Anything else: assume conservatively.
2072 default: return false;
2079 /// Check whether or not the chain ending in StoreNode is suitable for doing
2080 /// the {load; increment or decrement; store} to modify transformation.
2081 static bool isLoadIncOrDecStore(StoreSDNode *StoreNode, unsigned Opc,
2082 SDValue StoredVal, SelectionDAG *CurDAG,
2083 LoadSDNode* &LoadNode, SDValue &InputChain) {
2085 // is the value stored the result of a DEC or INC?
2086 if (!(Opc == X86ISD::DEC || Opc == X86ISD::INC)) return false;
2088 // is the stored value result 0 of the load?
2089 if (StoredVal.getResNo() != 0) return false;
2091 // are there other uses of the loaded value than the inc or dec?
2092 if (!StoredVal.getNode()->hasNUsesOfValue(1, 0)) return false;
2094 // is the store non-extending and non-indexed?
2095 if (!ISD::isNormalStore(StoreNode) || StoreNode->isNonTemporal())
2098 SDValue Load = StoredVal->getOperand(0);
2099 // Is the stored value a non-extending and non-indexed load?
2100 if (!ISD::isNormalLoad(Load.getNode())) return false;
2102 // Return LoadNode by reference.
2103 LoadNode = cast<LoadSDNode>(Load);
2104 // is the size of the value one that we can handle? (i.e. 64, 32, 16, or 8)
2105 EVT LdVT = LoadNode->getMemoryVT();
2106 if (LdVT != MVT::i64 && LdVT != MVT::i32 && LdVT != MVT::i16 &&
2110 // Is store the only read of the loaded value?
2111 if (!Load.hasOneUse())
2114 // Is the address of the store the same as the load?
2115 if (LoadNode->getBasePtr() != StoreNode->getBasePtr() ||
2116 LoadNode->getOffset() != StoreNode->getOffset())
2119 // Check if the chain is produced by the load or is a TokenFactor with
2120 // the load output chain as an operand. Return InputChain by reference.
2121 SDValue Chain = StoreNode->getChain();
2123 bool ChainCheck = false;
2124 if (Chain == Load.getValue(1)) {
2126 InputChain = LoadNode->getChain();
2127 } else if (Chain.getOpcode() == ISD::TokenFactor) {
2128 SmallVector<SDValue, 4> ChainOps;
2129 for (unsigned i = 0, e = Chain.getNumOperands(); i != e; ++i) {
2130 SDValue Op = Chain.getOperand(i);
2131 if (Op == Load.getValue(1)) {
2136 // Make sure using Op as part of the chain would not cause a cycle here.
2137 // In theory, we could check whether the chain node is a predecessor of
2138 // the load. But that can be very expensive. Instead visit the uses and
2139 // make sure they all have smaller node id than the load.
2140 int LoadId = LoadNode->getNodeId();
2141 for (SDNode::use_iterator UI = Op.getNode()->use_begin(),
2142 UE = UI->use_end(); UI != UE; ++UI) {
2143 if (UI.getUse().getResNo() != 0)
2145 if (UI->getNodeId() > LoadId)
2149 ChainOps.push_back(Op);
2153 // Make a new TokenFactor with all the other input chains except
2155 InputChain = CurDAG->getNode(ISD::TokenFactor, SDLoc(Chain),
2156 MVT::Other, ChainOps);
2164 /// Get the appropriate X86 opcode for an in-memory increment or decrement.
2165 /// Opc should be X86ISD::DEC or X86ISD::INC.
2166 static unsigned getFusedLdStOpcode(EVT &LdVT, unsigned Opc) {
2167 if (Opc == X86ISD::DEC) {
2168 if (LdVT == MVT::i64) return X86::DEC64m;
2169 if (LdVT == MVT::i32) return X86::DEC32m;
2170 if (LdVT == MVT::i16) return X86::DEC16m;
2171 if (LdVT == MVT::i8) return X86::DEC8m;
2173 assert(Opc == X86ISD::INC && "unrecognized opcode");
2174 if (LdVT == MVT::i64) return X86::INC64m;
2175 if (LdVT == MVT::i32) return X86::INC32m;
2176 if (LdVT == MVT::i16) return X86::INC16m;
2177 if (LdVT == MVT::i8) return X86::INC8m;
2179 llvm_unreachable("unrecognized size for LdVT");
2182 /// Customized ISel for GATHER operations.
2183 SDNode *X86DAGToDAGISel::selectGather(SDNode *Node, unsigned Opc) {
2184 // Operands of Gather: VSrc, Base, VIdx, VMask, Scale
2185 SDValue Chain = Node->getOperand(0);
2186 SDValue VSrc = Node->getOperand(2);
2187 SDValue Base = Node->getOperand(3);
2188 SDValue VIdx = Node->getOperand(4);
2189 SDValue VMask = Node->getOperand(5);
2190 ConstantSDNode *Scale = dyn_cast<ConstantSDNode>(Node->getOperand(6));
2194 SDVTList VTs = CurDAG->getVTList(VSrc.getValueType(), VSrc.getValueType(),
2199 // Memory Operands: Base, Scale, Index, Disp, Segment
2200 SDValue Disp = CurDAG->getTargetConstant(0, DL, MVT::i32);
2201 SDValue Segment = CurDAG->getRegister(0, MVT::i32);
2202 const SDValue Ops[] = { VSrc, Base, getI8Imm(Scale->getSExtValue(), DL), VIdx,
2203 Disp, Segment, VMask, Chain};
2204 SDNode *ResNode = CurDAG->getMachineNode(Opc, DL, VTs, Ops);
2205 // Node has 2 outputs: VDst and MVT::Other.
2206 // ResNode has 3 outputs: VDst, VMask_wb, and MVT::Other.
2207 // We replace VDst of Node with VDst of ResNode, and Other of Node with Other
2209 ReplaceUses(SDValue(Node, 0), SDValue(ResNode, 0));
2210 ReplaceUses(SDValue(Node, 1), SDValue(ResNode, 2));
2214 SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
2215 MVT NVT = Node->getSimpleValueType(0);
2217 unsigned Opcode = Node->getOpcode();
2220 DEBUG(dbgs() << "Selecting: "; Node->dump(CurDAG); dbgs() << '\n');
2222 if (Node->isMachineOpcode()) {
2223 DEBUG(dbgs() << "== "; Node->dump(CurDAG); dbgs() << '\n');
2224 Node->setNodeId(-1);
2225 return nullptr; // Already selected.
2231 if (Subtarget->isTargetNaCl())
2232 // NaCl has its own pass where jmp %r32 are converted to jmp %r64. We
2233 // leave the instruction alone.
2235 if (Subtarget->isTarget64BitILP32()) {
2236 // Converts a 32-bit register to a 64-bit, zero-extended version of
2237 // it. This is needed because x86-64 can do many things, but jmp %r32
2238 // ain't one of them.
2239 const SDValue &Target = Node->getOperand(1);
2240 assert(Target.getSimpleValueType() == llvm::MVT::i32);
2241 SDValue ZextTarget = CurDAG->getZExtOrTrunc(Target, dl, EVT(MVT::i64));
2242 SDValue Brind = CurDAG->getNode(ISD::BRIND, dl, MVT::Other,
2243 Node->getOperand(0), ZextTarget);
2244 ReplaceUses(SDValue(Node, 0), Brind);
2245 SelectCode(ZextTarget.getNode());
2246 SelectCode(Brind.getNode());
2251 case ISD::INTRINSIC_W_CHAIN: {
2252 unsigned IntNo = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue();
2255 case Intrinsic::x86_avx2_gather_d_pd:
2256 case Intrinsic::x86_avx2_gather_d_pd_256:
2257 case Intrinsic::x86_avx2_gather_q_pd:
2258 case Intrinsic::x86_avx2_gather_q_pd_256:
2259 case Intrinsic::x86_avx2_gather_d_ps:
2260 case Intrinsic::x86_avx2_gather_d_ps_256:
2261 case Intrinsic::x86_avx2_gather_q_ps:
2262 case Intrinsic::x86_avx2_gather_q_ps_256:
2263 case Intrinsic::x86_avx2_gather_d_q:
2264 case Intrinsic::x86_avx2_gather_d_q_256:
2265 case Intrinsic::x86_avx2_gather_q_q:
2266 case Intrinsic::x86_avx2_gather_q_q_256:
2267 case Intrinsic::x86_avx2_gather_d_d:
2268 case Intrinsic::x86_avx2_gather_d_d_256:
2269 case Intrinsic::x86_avx2_gather_q_d:
2270 case Intrinsic::x86_avx2_gather_q_d_256: {
2271 if (!Subtarget->hasAVX2())
2275 default: llvm_unreachable("Impossible intrinsic");
2276 case Intrinsic::x86_avx2_gather_d_pd: Opc = X86::VGATHERDPDrm; break;
2277 case Intrinsic::x86_avx2_gather_d_pd_256: Opc = X86::VGATHERDPDYrm; break;
2278 case Intrinsic::x86_avx2_gather_q_pd: Opc = X86::VGATHERQPDrm; break;
2279 case Intrinsic::x86_avx2_gather_q_pd_256: Opc = X86::VGATHERQPDYrm; break;
2280 case Intrinsic::x86_avx2_gather_d_ps: Opc = X86::VGATHERDPSrm; break;
2281 case Intrinsic::x86_avx2_gather_d_ps_256: Opc = X86::VGATHERDPSYrm; break;
2282 case Intrinsic::x86_avx2_gather_q_ps: Opc = X86::VGATHERQPSrm; break;
2283 case Intrinsic::x86_avx2_gather_q_ps_256: Opc = X86::VGATHERQPSYrm; break;
2284 case Intrinsic::x86_avx2_gather_d_q: Opc = X86::VPGATHERDQrm; break;
2285 case Intrinsic::x86_avx2_gather_d_q_256: Opc = X86::VPGATHERDQYrm; break;
2286 case Intrinsic::x86_avx2_gather_q_q: Opc = X86::VPGATHERQQrm; break;
2287 case Intrinsic::x86_avx2_gather_q_q_256: Opc = X86::VPGATHERQQYrm; break;
2288 case Intrinsic::x86_avx2_gather_d_d: Opc = X86::VPGATHERDDrm; break;
2289 case Intrinsic::x86_avx2_gather_d_d_256: Opc = X86::VPGATHERDDYrm; break;
2290 case Intrinsic::x86_avx2_gather_q_d: Opc = X86::VPGATHERQDrm; break;
2291 case Intrinsic::x86_avx2_gather_q_d_256: Opc = X86::VPGATHERQDYrm; break;
2293 SDNode *RetVal = selectGather(Node, Opc);
2295 // We already called ReplaceUses inside SelectGather.
2302 case X86ISD::GlobalBaseReg:
2303 return getGlobalBaseReg();
2305 case X86ISD::SHRUNKBLEND: {
2306 // SHRUNKBLEND selects like a regular VSELECT.
2307 SDValue VSelect = CurDAG->getNode(
2308 ISD::VSELECT, SDLoc(Node), Node->getValueType(0), Node->getOperand(0),
2309 Node->getOperand(1), Node->getOperand(2));
2310 ReplaceUses(SDValue(Node, 0), VSelect);
2311 SelectCode(VSelect.getNode());
2312 // We already called ReplaceUses.
2316 case ISD::ATOMIC_LOAD_XOR:
2317 case ISD::ATOMIC_LOAD_AND:
2318 case ISD::ATOMIC_LOAD_OR:
2319 case ISD::ATOMIC_LOAD_ADD: {
2320 SDNode *RetVal = selectAtomicLoadArith(Node, NVT);
2328 // For operations of the form (x << C1) op C2, check if we can use a smaller
2329 // encoding for C2 by transforming it into (x op (C2>>C1)) << C1.
2330 SDValue N0 = Node->getOperand(0);
2331 SDValue N1 = Node->getOperand(1);
2333 if (N0->getOpcode() != ISD::SHL || !N0->hasOneUse())
2336 // i8 is unshrinkable, i16 should be promoted to i32.
2337 if (NVT != MVT::i32 && NVT != MVT::i64)
2340 ConstantSDNode *Cst = dyn_cast<ConstantSDNode>(N1);
2341 ConstantSDNode *ShlCst = dyn_cast<ConstantSDNode>(N0->getOperand(1));
2342 if (!Cst || !ShlCst)
2345 int64_t Val = Cst->getSExtValue();
2346 uint64_t ShlVal = ShlCst->getZExtValue();
2348 // Make sure that we don't change the operation by removing bits.
2349 // This only matters for OR and XOR, AND is unaffected.
2350 uint64_t RemovedBitsMask = (1ULL << ShlVal) - 1;
2351 if (Opcode != ISD::AND && (Val & RemovedBitsMask) != 0)
2354 unsigned ShlOp, AddOp, Op;
2357 // Check the minimum bitwidth for the new constant.
2358 // TODO: AND32ri is the same as AND64ri32 with zext imm.
2359 // TODO: MOV32ri+OR64r is cheaper than MOV64ri64+OR64rr
2360 // TODO: Using 16 and 8 bit operations is also possible for or32 & xor32.
2361 if (!isInt<8>(Val) && isInt<8>(Val >> ShlVal))
2363 else if (!isInt<32>(Val) && isInt<32>(Val >> ShlVal))
2366 // Bail if there is no smaller encoding.
2370 switch (NVT.SimpleTy) {
2371 default: llvm_unreachable("Unsupported VT!");
2373 assert(CstVT == MVT::i8);
2374 ShlOp = X86::SHL32ri;
2375 AddOp = X86::ADD32rr;
2378 default: llvm_unreachable("Impossible opcode");
2379 case ISD::AND: Op = X86::AND32ri8; break;
2380 case ISD::OR: Op = X86::OR32ri8; break;
2381 case ISD::XOR: Op = X86::XOR32ri8; break;
2385 assert(CstVT == MVT::i8 || CstVT == MVT::i32);
2386 ShlOp = X86::SHL64ri;
2387 AddOp = X86::ADD64rr;
2390 default: llvm_unreachable("Impossible opcode");
2391 case ISD::AND: Op = CstVT==MVT::i8? X86::AND64ri8 : X86::AND64ri32; break;
2392 case ISD::OR: Op = CstVT==MVT::i8? X86::OR64ri8 : X86::OR64ri32; break;
2393 case ISD::XOR: Op = CstVT==MVT::i8? X86::XOR64ri8 : X86::XOR64ri32; break;
2398 // Emit the smaller op and the shift.
2399 SDValue NewCst = CurDAG->getTargetConstant(Val >> ShlVal, dl, CstVT);
2400 SDNode *New = CurDAG->getMachineNode(Op, dl, NVT, N0->getOperand(0),NewCst);
2402 return CurDAG->SelectNodeTo(Node, AddOp, NVT, SDValue(New, 0),
2404 return CurDAG->SelectNodeTo(Node, ShlOp, NVT, SDValue(New, 0),
2405 getI8Imm(ShlVal, dl));
2408 case X86ISD::SMUL8: {
2409 SDValue N0 = Node->getOperand(0);
2410 SDValue N1 = Node->getOperand(1);
2412 Opc = (Opcode == X86ISD::SMUL8 ? X86::IMUL8r : X86::MUL8r);
2414 SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, X86::AL,
2415 N0, SDValue()).getValue(1);
2417 SDVTList VTs = CurDAG->getVTList(NVT, MVT::i32);
2418 SDValue Ops[] = {N1, InFlag};
2419 SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops);
2421 ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0));
2422 ReplaceUses(SDValue(Node, 1), SDValue(CNode, 1));
2426 case X86ISD::UMUL: {
2427 SDValue N0 = Node->getOperand(0);
2428 SDValue N1 = Node->getOperand(1);
2431 switch (NVT.SimpleTy) {
2432 default: llvm_unreachable("Unsupported VT!");
2433 case MVT::i8: LoReg = X86::AL; Opc = X86::MUL8r; break;
2434 case MVT::i16: LoReg = X86::AX; Opc = X86::MUL16r; break;
2435 case MVT::i32: LoReg = X86::EAX; Opc = X86::MUL32r; break;
2436 case MVT::i64: LoReg = X86::RAX; Opc = X86::MUL64r; break;
2439 SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, LoReg,
2440 N0, SDValue()).getValue(1);
2442 SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::i32);
2443 SDValue Ops[] = {N1, InFlag};
2444 SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops);
2446 ReplaceUses(SDValue(Node, 0), SDValue(CNode, 0));
2447 ReplaceUses(SDValue(Node, 1), SDValue(CNode, 1));
2448 ReplaceUses(SDValue(Node, 2), SDValue(CNode, 2));
2452 case ISD::SMUL_LOHI:
2453 case ISD::UMUL_LOHI: {
2454 SDValue N0 = Node->getOperand(0);
2455 SDValue N1 = Node->getOperand(1);
2457 bool isSigned = Opcode == ISD::SMUL_LOHI;
2458 bool hasBMI2 = Subtarget->hasBMI2();
2460 switch (NVT.SimpleTy) {
2461 default: llvm_unreachable("Unsupported VT!");
2462 case MVT::i8: Opc = X86::MUL8r; MOpc = X86::MUL8m; break;
2463 case MVT::i16: Opc = X86::MUL16r; MOpc = X86::MUL16m; break;
2464 case MVT::i32: Opc = hasBMI2 ? X86::MULX32rr : X86::MUL32r;
2465 MOpc = hasBMI2 ? X86::MULX32rm : X86::MUL32m; break;
2466 case MVT::i64: Opc = hasBMI2 ? X86::MULX64rr : X86::MUL64r;
2467 MOpc = hasBMI2 ? X86::MULX64rm : X86::MUL64m; break;
2470 switch (NVT.SimpleTy) {
2471 default: llvm_unreachable("Unsupported VT!");
2472 case MVT::i8: Opc = X86::IMUL8r; MOpc = X86::IMUL8m; break;
2473 case MVT::i16: Opc = X86::IMUL16r; MOpc = X86::IMUL16m; break;
2474 case MVT::i32: Opc = X86::IMUL32r; MOpc = X86::IMUL32m; break;
2475 case MVT::i64: Opc = X86::IMUL64r; MOpc = X86::IMUL64m; break;
2479 unsigned SrcReg, LoReg, HiReg;
2481 default: llvm_unreachable("Unknown MUL opcode!");
2484 SrcReg = LoReg = X86::AL; HiReg = X86::AH;
2488 SrcReg = LoReg = X86::AX; HiReg = X86::DX;
2492 SrcReg = LoReg = X86::EAX; HiReg = X86::EDX;
2496 SrcReg = LoReg = X86::RAX; HiReg = X86::RDX;
2499 SrcReg = X86::EDX; LoReg = HiReg = 0;
2502 SrcReg = X86::RDX; LoReg = HiReg = 0;
2506 SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
2507 bool foldedLoad = tryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
2508 // Multiply is commmutative.
2510 foldedLoad = tryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
2515 SDValue InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, SrcReg,
2516 N0, SDValue()).getValue(1);
2517 SDValue ResHi, ResLo;
2521 SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
2523 if (MOpc == X86::MULX32rm || MOpc == X86::MULX64rm) {
2524 SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::Other, MVT::Glue);
2525 SDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
2526 ResHi = SDValue(CNode, 0);
2527 ResLo = SDValue(CNode, 1);
2528 Chain = SDValue(CNode, 2);
2529 InFlag = SDValue(CNode, 3);
2531 SDVTList VTs = CurDAG->getVTList(MVT::Other, MVT::Glue);
2532 SDNode *CNode = CurDAG->getMachineNode(MOpc, dl, VTs, Ops);
2533 Chain = SDValue(CNode, 0);
2534 InFlag = SDValue(CNode, 1);
2537 // Update the chain.
2538 ReplaceUses(N1.getValue(1), Chain);
2540 SDValue Ops[] = { N1, InFlag };
2541 if (Opc == X86::MULX32rr || Opc == X86::MULX64rr) {
2542 SDVTList VTs = CurDAG->getVTList(NVT, NVT, MVT::Glue);
2543 SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops);
2544 ResHi = SDValue(CNode, 0);
2545 ResLo = SDValue(CNode, 1);
2546 InFlag = SDValue(CNode, 2);
2548 SDVTList VTs = CurDAG->getVTList(MVT::Glue);
2549 SDNode *CNode = CurDAG->getMachineNode(Opc, dl, VTs, Ops);
2550 InFlag = SDValue(CNode, 0);
2554 // Prevent use of AH in a REX instruction by referencing AX instead.
2555 if (HiReg == X86::AH && Subtarget->is64Bit() &&
2556 !SDValue(Node, 1).use_empty()) {
2557 SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
2558 X86::AX, MVT::i16, InFlag);
2559 InFlag = Result.getValue(2);
2560 // Get the low part if needed. Don't use getCopyFromReg for aliasing
2562 if (!SDValue(Node, 0).use_empty())
2563 ReplaceUses(SDValue(Node, 1),
2564 CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
2566 // Shift AX down 8 bits.
2567 Result = SDValue(CurDAG->getMachineNode(X86::SHR16ri, dl, MVT::i16,
2569 CurDAG->getTargetConstant(8, dl, MVT::i8)),
2571 // Then truncate it down to i8.
2572 ReplaceUses(SDValue(Node, 1),
2573 CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result));
2575 // Copy the low half of the result, if it is needed.
2576 if (!SDValue(Node, 0).use_empty()) {
2577 if (!ResLo.getNode()) {
2578 assert(LoReg && "Register for low half is not defined!");
2579 ResLo = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, LoReg, NVT,
2581 InFlag = ResLo.getValue(2);
2583 ReplaceUses(SDValue(Node, 0), ResLo);
2584 DEBUG(dbgs() << "=> "; ResLo.getNode()->dump(CurDAG); dbgs() << '\n');
2586 // Copy the high half of the result, if it is needed.
2587 if (!SDValue(Node, 1).use_empty()) {
2588 if (!ResHi.getNode()) {
2589 assert(HiReg && "Register for high half is not defined!");
2590 ResHi = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl, HiReg, NVT,
2592 InFlag = ResHi.getValue(2);
2594 ReplaceUses(SDValue(Node, 1), ResHi);
2595 DEBUG(dbgs() << "=> "; ResHi.getNode()->dump(CurDAG); dbgs() << '\n');
2603 case X86ISD::SDIVREM8_SEXT_HREG:
2604 case X86ISD::UDIVREM8_ZEXT_HREG: {
2605 SDValue N0 = Node->getOperand(0);
2606 SDValue N1 = Node->getOperand(1);
2608 bool isSigned = (Opcode == ISD::SDIVREM ||
2609 Opcode == X86ISD::SDIVREM8_SEXT_HREG);
2611 switch (NVT.SimpleTy) {
2612 default: llvm_unreachable("Unsupported VT!");
2613 case MVT::i8: Opc = X86::DIV8r; MOpc = X86::DIV8m; break;
2614 case MVT::i16: Opc = X86::DIV16r; MOpc = X86::DIV16m; break;
2615 case MVT::i32: Opc = X86::DIV32r; MOpc = X86::DIV32m; break;
2616 case MVT::i64: Opc = X86::DIV64r; MOpc = X86::DIV64m; break;
2619 switch (NVT.SimpleTy) {
2620 default: llvm_unreachable("Unsupported VT!");
2621 case MVT::i8: Opc = X86::IDIV8r; MOpc = X86::IDIV8m; break;
2622 case MVT::i16: Opc = X86::IDIV16r; MOpc = X86::IDIV16m; break;
2623 case MVT::i32: Opc = X86::IDIV32r; MOpc = X86::IDIV32m; break;
2624 case MVT::i64: Opc = X86::IDIV64r; MOpc = X86::IDIV64m; break;
2628 unsigned LoReg, HiReg, ClrReg;
2629 unsigned SExtOpcode;
2630 switch (NVT.SimpleTy) {
2631 default: llvm_unreachable("Unsupported VT!");
2633 LoReg = X86::AL; ClrReg = HiReg = X86::AH;
2634 SExtOpcode = X86::CBW;
2637 LoReg = X86::AX; HiReg = X86::DX;
2639 SExtOpcode = X86::CWD;
2642 LoReg = X86::EAX; ClrReg = HiReg = X86::EDX;
2643 SExtOpcode = X86::CDQ;
2646 LoReg = X86::RAX; ClrReg = HiReg = X86::RDX;
2647 SExtOpcode = X86::CQO;
2651 SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
2652 bool foldedLoad = tryFoldLoad(Node, N1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4);
2653 bool signBitIsZero = CurDAG->SignBitIsZero(N0);
2656 if (NVT == MVT::i8 && (!isSigned || signBitIsZero)) {
2657 // Special case for div8, just use a move with zero extension to AX to
2658 // clear the upper 8 bits (AH).
2659 SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Move, Chain;
2660 if (tryFoldLoad(Node, N0, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4)) {
2661 SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N0.getOperand(0) };
2663 SDValue(CurDAG->getMachineNode(X86::MOVZX32rm8, dl, MVT::i32,
2664 MVT::Other, Ops), 0);
2665 Chain = Move.getValue(1);
2666 ReplaceUses(N0.getValue(1), Chain);
2669 SDValue(CurDAG->getMachineNode(X86::MOVZX32rr8, dl, MVT::i32, N0),0);
2670 Chain = CurDAG->getEntryNode();
2672 Chain = CurDAG->getCopyToReg(Chain, dl, X86::EAX, Move, SDValue());
2673 InFlag = Chain.getValue(1);
2676 CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl,
2677 LoReg, N0, SDValue()).getValue(1);
2678 if (isSigned && !signBitIsZero) {
2679 // Sign extend the low part into the high part.
2681 SDValue(CurDAG->getMachineNode(SExtOpcode, dl, MVT::Glue, InFlag),0);
2683 // Zero out the high part, effectively zero extending the input.
2684 SDValue ClrNode = SDValue(CurDAG->getMachineNode(X86::MOV32r0, dl, NVT), 0);
2685 switch (NVT.SimpleTy) {
2688 SDValue(CurDAG->getMachineNode(
2689 TargetOpcode::EXTRACT_SUBREG, dl, MVT::i16, ClrNode,
2690 CurDAG->getTargetConstant(X86::sub_16bit, dl,
2698 SDValue(CurDAG->getMachineNode(
2699 TargetOpcode::SUBREG_TO_REG, dl, MVT::i64,
2700 CurDAG->getTargetConstant(0, dl, MVT::i64), ClrNode,
2701 CurDAG->getTargetConstant(X86::sub_32bit, dl,
2706 llvm_unreachable("Unexpected division source");
2709 InFlag = CurDAG->getCopyToReg(CurDAG->getEntryNode(), dl, ClrReg,
2710 ClrNode, InFlag).getValue(1);
2715 SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, N1.getOperand(0),
2718 CurDAG->getMachineNode(MOpc, dl, MVT::Other, MVT::Glue, Ops);
2719 InFlag = SDValue(CNode, 1);
2720 // Update the chain.
2721 ReplaceUses(N1.getValue(1), SDValue(CNode, 0));
2724 SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Glue, N1, InFlag), 0);
2727 // Prevent use of AH in a REX instruction by explicitly copying it to
2728 // an ABCD_L register.
2730 // The current assumption of the register allocator is that isel
2731 // won't generate explicit references to the GR8_ABCD_H registers. If
2732 // the allocator and/or the backend get enhanced to be more robust in
2733 // that regard, this can be, and should be, removed.
2734 if (HiReg == X86::AH && !SDValue(Node, 1).use_empty()) {
2735 SDValue AHCopy = CurDAG->getRegister(X86::AH, MVT::i8);
2736 unsigned AHExtOpcode =
2737 isSigned ? X86::MOVSX32_NOREXrr8 : X86::MOVZX32_NOREXrr8;
2739 SDNode *RNode = CurDAG->getMachineNode(AHExtOpcode, dl, MVT::i32,
2740 MVT::Glue, AHCopy, InFlag);
2741 SDValue Result(RNode, 0);
2742 InFlag = SDValue(RNode, 1);
2744 if (Opcode == X86ISD::UDIVREM8_ZEXT_HREG ||
2745 Opcode == X86ISD::SDIVREM8_SEXT_HREG) {
2746 if (Node->getValueType(1) == MVT::i64) {
2747 // It's not possible to directly movsx AH to a 64bit register, because
2748 // the latter needs the REX prefix, but the former can't have it.
2749 assert(Opcode != X86ISD::SDIVREM8_SEXT_HREG &&
2750 "Unexpected i64 sext of h-register");
2752 SDValue(CurDAG->getMachineNode(
2753 TargetOpcode::SUBREG_TO_REG, dl, MVT::i64,
2754 CurDAG->getTargetConstant(0, dl, MVT::i64), Result,
2755 CurDAG->getTargetConstant(X86::sub_32bit, dl,
2761 CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Result);
2763 ReplaceUses(SDValue(Node, 1), Result);
2764 DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
2766 // Copy the division (low) result, if it is needed.
2767 if (!SDValue(Node, 0).use_empty()) {
2768 SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
2769 LoReg, NVT, InFlag);
2770 InFlag = Result.getValue(2);
2771 ReplaceUses(SDValue(Node, 0), Result);
2772 DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
2774 // Copy the remainder (high) result, if it is needed.
2775 if (!SDValue(Node, 1).use_empty()) {
2776 SDValue Result = CurDAG->getCopyFromReg(CurDAG->getEntryNode(), dl,
2777 HiReg, NVT, InFlag);
2778 InFlag = Result.getValue(2);
2779 ReplaceUses(SDValue(Node, 1), Result);
2780 DEBUG(dbgs() << "=> "; Result.getNode()->dump(CurDAG); dbgs() << '\n');
2787 // Sometimes a SUB is used to perform comparison.
2788 if (Opcode == X86ISD::SUB && Node->hasAnyUseOfValue(0))
2789 // This node is not a CMP.
2791 SDValue N0 = Node->getOperand(0);
2792 SDValue N1 = Node->getOperand(1);
2794 if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse() &&
2795 hasNoSignedComparisonUses(Node))
2796 N0 = N0.getOperand(0);
2798 // Look for (X86cmp (and $op, $imm), 0) and see if we can convert it to
2799 // use a smaller encoding.
2800 // Look past the truncate if CMP is the only use of it.
2801 if ((N0.getNode()->getOpcode() == ISD::AND ||
2802 (N0.getResNo() == 0 && N0.getNode()->getOpcode() == X86ISD::AND)) &&
2803 N0.getNode()->hasOneUse() &&
2804 N0.getValueType() != MVT::i8 &&
2805 X86::isZeroNode(N1)) {
2806 ConstantSDNode *C = dyn_cast<ConstantSDNode>(N0.getNode()->getOperand(1));
2809 // For example, convert "testl %eax, $8" to "testb %al, $8"
2810 if ((C->getZExtValue() & ~UINT64_C(0xff)) == 0 &&
2811 (!(C->getZExtValue() & 0x80) ||
2812 hasNoSignedComparisonUses(Node))) {
2813 SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), dl, MVT::i8);
2814 SDValue Reg = N0.getNode()->getOperand(0);
2816 // On x86-32, only the ABCD registers have 8-bit subregisters.
2817 if (!Subtarget->is64Bit()) {
2818 const TargetRegisterClass *TRC;
2819 switch (N0.getSimpleValueType().SimpleTy) {
2820 case MVT::i32: TRC = &X86::GR32_ABCDRegClass; break;
2821 case MVT::i16: TRC = &X86::GR16_ABCDRegClass; break;
2822 default: llvm_unreachable("Unsupported TEST operand type!");
2824 SDValue RC = CurDAG->getTargetConstant(TRC->getID(), dl, MVT::i32);
2825 Reg = SDValue(CurDAG->getMachineNode(X86::COPY_TO_REGCLASS, dl,
2826 Reg.getValueType(), Reg, RC), 0);
2829 // Extract the l-register.
2830 SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl,
2834 SDNode *NewNode = CurDAG->getMachineNode(X86::TEST8ri, dl, MVT::i32,
2836 // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
2837 // one, do not call ReplaceAllUsesWith.
2838 ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
2839 SDValue(NewNode, 0));
2843 // For example, "testl %eax, $2048" to "testb %ah, $8".
2844 if ((C->getZExtValue() & ~UINT64_C(0xff00)) == 0 &&
2845 (!(C->getZExtValue() & 0x8000) ||
2846 hasNoSignedComparisonUses(Node))) {
2847 // Shift the immediate right by 8 bits.
2848 SDValue ShiftedImm = CurDAG->getTargetConstant(C->getZExtValue() >> 8,
2850 SDValue Reg = N0.getNode()->getOperand(0);
2852 // Put the value in an ABCD register.
2853 const TargetRegisterClass *TRC;
2854 switch (N0.getSimpleValueType().SimpleTy) {
2855 case MVT::i64: TRC = &X86::GR64_ABCDRegClass; break;
2856 case MVT::i32: TRC = &X86::GR32_ABCDRegClass; break;
2857 case MVT::i16: TRC = &X86::GR16_ABCDRegClass; break;
2858 default: llvm_unreachable("Unsupported TEST operand type!");
2860 SDValue RC = CurDAG->getTargetConstant(TRC->getID(), dl, MVT::i32);
2861 Reg = SDValue(CurDAG->getMachineNode(X86::COPY_TO_REGCLASS, dl,
2862 Reg.getValueType(), Reg, RC), 0);
2864 // Extract the h-register.
2865 SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_8bit_hi, dl,
2868 // Emit a testb. The EXTRACT_SUBREG becomes a COPY that can only
2869 // target GR8_NOREX registers, so make sure the register class is
2871 SDNode *NewNode = CurDAG->getMachineNode(X86::TEST8ri_NOREX, dl,
2872 MVT::i32, Subreg, ShiftedImm);
2873 // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
2874 // one, do not call ReplaceAllUsesWith.
2875 ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
2876 SDValue(NewNode, 0));
2880 // For example, "testl %eax, $32776" to "testw %ax, $32776".
2881 if ((C->getZExtValue() & ~UINT64_C(0xffff)) == 0 &&
2882 N0.getValueType() != MVT::i16 &&
2883 (!(C->getZExtValue() & 0x8000) ||
2884 hasNoSignedComparisonUses(Node))) {
2885 SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), dl,
2887 SDValue Reg = N0.getNode()->getOperand(0);
2889 // Extract the 16-bit subregister.
2890 SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_16bit, dl,
2894 SDNode *NewNode = CurDAG->getMachineNode(X86::TEST16ri, dl, MVT::i32,
2896 // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
2897 // one, do not call ReplaceAllUsesWith.
2898 ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
2899 SDValue(NewNode, 0));
2903 // For example, "testq %rax, $268468232" to "testl %eax, $268468232".
2904 if ((C->getZExtValue() & ~UINT64_C(0xffffffff)) == 0 &&
2905 N0.getValueType() == MVT::i64 &&
2906 (!(C->getZExtValue() & 0x80000000) ||
2907 hasNoSignedComparisonUses(Node))) {
2908 SDValue Imm = CurDAG->getTargetConstant(C->getZExtValue(), dl,
2910 SDValue Reg = N0.getNode()->getOperand(0);
2912 // Extract the 32-bit subregister.
2913 SDValue Subreg = CurDAG->getTargetExtractSubreg(X86::sub_32bit, dl,
2917 SDNode *NewNode = CurDAG->getMachineNode(X86::TEST32ri, dl, MVT::i32,
2919 // Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
2920 // one, do not call ReplaceAllUsesWith.
2921 ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
2922 SDValue(NewNode, 0));
2929 // Change a chain of {load; incr or dec; store} of the same value into
2930 // a simple increment or decrement through memory of that value, if the
2931 // uses of the modified value and its address are suitable.
2932 // The DEC64m tablegen pattern is currently not able to match the case where
2933 // the EFLAGS on the original DEC are used. (This also applies to
2934 // {INC,DEC}X{64,32,16,8}.)
2935 // We'll need to improve tablegen to allow flags to be transferred from a
2936 // node in the pattern to the result node. probably with a new keyword
2937 // for example, we have this
2938 // def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
2939 // [(store (add (loadi64 addr:$dst), -1), addr:$dst),
2940 // (implicit EFLAGS)]>;
2941 // but maybe need something like this
2942 // def DEC64m : RI<0xFF, MRM1m, (outs), (ins i64mem:$dst), "dec{q}\t$dst",
2943 // [(store (add (loadi64 addr:$dst), -1), addr:$dst),
2944 // (transferrable EFLAGS)]>;
2946 StoreSDNode *StoreNode = cast<StoreSDNode>(Node);
2947 SDValue StoredVal = StoreNode->getOperand(1);
2948 unsigned Opc = StoredVal->getOpcode();
2950 LoadSDNode *LoadNode = nullptr;
2952 if (!isLoadIncOrDecStore(StoreNode, Opc, StoredVal, CurDAG,
2953 LoadNode, InputChain))
2956 SDValue Base, Scale, Index, Disp, Segment;
2957 if (!selectAddr(LoadNode, LoadNode->getBasePtr(),
2958 Base, Scale, Index, Disp, Segment))
2961 MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(2);
2962 MemOp[0] = StoreNode->getMemOperand();
2963 MemOp[1] = LoadNode->getMemOperand();
2964 const SDValue Ops[] = { Base, Scale, Index, Disp, Segment, InputChain };
2965 EVT LdVT = LoadNode->getMemoryVT();
2966 unsigned newOpc = getFusedLdStOpcode(LdVT, Opc);
2967 MachineSDNode *Result = CurDAG->getMachineNode(newOpc,
2969 MVT::i32, MVT::Other, Ops);
2970 Result->setMemRefs(MemOp, MemOp + 2);
2972 ReplaceUses(SDValue(StoreNode, 0), SDValue(Result, 1));
2973 ReplaceUses(SDValue(StoredVal.getNode(), 1), SDValue(Result, 0));
2979 SDNode *ResNode = SelectCode(Node);
2981 DEBUG(dbgs() << "=> ";
2982 if (ResNode == nullptr || ResNode == Node)
2985 ResNode->dump(CurDAG);
2991 bool X86DAGToDAGISel::
2992 SelectInlineAsmMemoryOperand(const SDValue &Op, unsigned ConstraintID,
2993 std::vector<SDValue> &OutOps) {
2994 SDValue Op0, Op1, Op2, Op3, Op4;
2995 switch (ConstraintID) {
2997 llvm_unreachable("Unexpected asm memory constraint");
2998 case InlineAsm::Constraint_i:
2999 // FIXME: It seems strange that 'i' is needed here since it's supposed to
3000 // be an immediate and not a memory constraint.
3002 case InlineAsm::Constraint_o: // offsetable ??
3003 case InlineAsm::Constraint_v: // not offsetable ??
3004 case InlineAsm::Constraint_m: // memory
3005 case InlineAsm::Constraint_X:
3006 if (!selectAddr(nullptr, Op, Op0, Op1, Op2, Op3, Op4))
3011 OutOps.push_back(Op0);
3012 OutOps.push_back(Op1);
3013 OutOps.push_back(Op2);
3014 OutOps.push_back(Op3);
3015 OutOps.push_back(Op4);
3019 /// This pass converts a legalized DAG into a X86-specific DAG,
3020 /// ready for instruction scheduling.
3021 FunctionPass *llvm::createX86ISelDag(X86TargetMachine &TM,
3022 CodeGenOpt::Level OptLevel) {
3023 return new X86DAGToDAGISel(TM, OptLevel);