1 //===- ARMISelLowering.h - ARM DAG Lowering Interface -----------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the interfaces that ARM uses to lower LLVM code into a
10 // selection DAG.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_TARGET_ARM_ARMISELLOWERING_H
15 #define LLVM_LIB_TARGET_ARM_ARMISELLOWERING_H
16 
17 #include "MCTargetDesc/ARMBaseInfo.h"
18 #include "llvm/ADT/SmallVector.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/CodeGen/CallingConvLower.h"
21 #include "llvm/CodeGen/ISDOpcodes.h"
22 #include "llvm/CodeGen/MachineFunction.h"
23 #include "llvm/CodeGen/SelectionDAGNodes.h"
24 #include "llvm/CodeGen/TargetLowering.h"
25 #include "llvm/CodeGen/ValueTypes.h"
26 #include "llvm/IR/Attributes.h"
27 #include "llvm/IR/CallingConv.h"
28 #include "llvm/IR/Function.h"
29 #include "llvm/IR/IRBuilder.h"
30 #include "llvm/IR/InlineAsm.h"
31 #include "llvm/Support/CodeGen.h"
32 #include "llvm/Support/MachineValueType.h"
33 #include <utility>
34 
35 namespace llvm {
36 
37 class ARMSubtarget;
38 class DataLayout;
39 class FastISel;
40 class FunctionLoweringInfo;
41 class GlobalValue;
42 class InstrItineraryData;
43 class Instruction;
44 class MachineBasicBlock;
45 class MachineInstr;
46 class SelectionDAG;
47 class TargetLibraryInfo;
48 class TargetMachine;
49 class TargetRegisterInfo;
50 class VectorType;
51 
52   namespace ARMISD {
53 
54     // ARM Specific DAG Nodes
55     enum NodeType : unsigned {
56       // Start the numbering where the builtin ops and target ops leave off.
57       FIRST_NUMBER = ISD::BUILTIN_OP_END,
58 
59       Wrapper,      // Wrapper - A wrapper node for TargetConstantPool,
60                     // TargetExternalSymbol, and TargetGlobalAddress.
61       WrapperPIC,   // WrapperPIC - A wrapper node for TargetGlobalAddress in
62                     // PIC mode.
63       WrapperJT,    // WrapperJT - A wrapper node for TargetJumpTable
64 
65       // Add pseudo op to model memcpy for struct byval.
66       COPY_STRUCT_BYVAL,
67 
68       CALL,         // Function call.
69       CALL_PRED,    // Function call that's predicable.
70       CALL_NOLINK,  // Function call with branch not branch-and-link.
71       BRCOND,       // Conditional branch.
72       BR_JT,        // Jumptable branch.
73       BR2_JT,       // Jumptable branch (2 level - jumptable entry is a jump).
74       RET_FLAG,     // Return with a flag operand.
75       INTRET_FLAG,  // Interrupt return with an LR-offset and a flag operand.
76 
77       PIC_ADD,      // Add with a PC operand and a PIC label.
78 
79       ASRL,         // MVE long arithmetic shift right.
80       LSRL,         // MVE long shift right.
81       LSLL,         // MVE long shift left.
82 
83       CMP,          // ARM compare instructions.
84       CMN,          // ARM CMN instructions.
85       CMPZ,         // ARM compare that sets only Z flag.
86       CMPFP,        // ARM VFP compare instruction, sets FPSCR.
87       CMPFPE,       // ARM VFP signalling compare instruction, sets FPSCR.
88       CMPFPw0,      // ARM VFP compare against zero instruction, sets FPSCR.
89       CMPFPEw0,     // ARM VFP signalling compare against zero instruction, sets FPSCR.
90       FMSTAT,       // ARM fmstat instruction.
91 
92       CMOV,         // ARM conditional move instructions.
93       SUBS,         // Flag-setting subtraction.
94 
95       SSAT,         // Signed saturation
96       USAT,         // Unsigned saturation
97 
98       BCC_i64,
99 
100       SRL_FLAG,     // V,Flag = srl_flag X -> srl X, 1 + save carry out.
101       SRA_FLAG,     // V,Flag = sra_flag X -> sra X, 1 + save carry out.
102       RRX,          // V = RRX X, Flag     -> srl X, 1 + shift in carry flag.
103 
104       ADDC,         // Add with carry
105       ADDE,         // Add using carry
106       SUBC,         // Sub with carry
107       SUBE,         // Sub using carry
108       LSLS,         // Shift left producing carry
109 
110       VMOVRRD,      // double to two gprs.
111       VMOVDRR,      // Two gprs to double.
112       VMOVSR,       // move gpr to single, used for f32 literal constructed in a gpr
113 
114       EH_SJLJ_SETJMP,         // SjLj exception handling setjmp.
115       EH_SJLJ_LONGJMP,        // SjLj exception handling longjmp.
116       EH_SJLJ_SETUP_DISPATCH, // SjLj exception handling setup_dispatch.
117 
118       TC_RETURN,    // Tail call return pseudo.
119 
120       THREAD_POINTER,
121 
122       DYN_ALLOC,    // Dynamic allocation on the stack.
123 
124       MEMBARRIER_MCR, // Memory barrier (MCR)
125 
126       PRELOAD,      // Preload
127 
128       WIN__CHKSTK,  // Windows' __chkstk call to do stack probing.
129       WIN__DBZCHK,  // Windows' divide by zero check
130 
131       WLS,          // Low-overhead loops, While Loop Start
132       LOOP_DEC,     // Really a part of LE, performs the sub
133       LE,           // Low-overhead loops, Loop End
134 
135       PREDICATE_CAST, // Predicate cast for MVE i1 types
136 
137       VCMP,         // Vector compare.
138       VCMPZ,        // Vector compare to zero.
139       VTST,         // Vector test bits.
140 
141       // Vector shift by vector
142       VSHLs,        // ...left/right by signed
143       VSHLu,        // ...left/right by unsigned
144 
145       // Vector shift by immediate:
146       VSHLIMM,      // ...left
147       VSHRsIMM,     // ...right (signed)
148       VSHRuIMM,     // ...right (unsigned)
149 
150       // Vector rounding shift by immediate:
151       VRSHRsIMM,    // ...right (signed)
152       VRSHRuIMM,    // ...right (unsigned)
153       VRSHRNIMM,    // ...right narrow
154 
155       // Vector saturating shift by immediate:
156       VQSHLsIMM,    // ...left (signed)
157       VQSHLuIMM,    // ...left (unsigned)
158       VQSHLsuIMM,   // ...left (signed to unsigned)
159       VQSHRNsIMM,   // ...right narrow (signed)
160       VQSHRNuIMM,   // ...right narrow (unsigned)
161       VQSHRNsuIMM,  // ...right narrow (signed to unsigned)
162 
163       // Vector saturating rounding shift by immediate:
164       VQRSHRNsIMM,  // ...right narrow (signed)
165       VQRSHRNuIMM,  // ...right narrow (unsigned)
166       VQRSHRNsuIMM, // ...right narrow (signed to unsigned)
167 
168       // Vector shift and insert:
169       VSLIIMM,      // ...left
170       VSRIIMM,      // ...right
171 
172       // Vector get lane (VMOV scalar to ARM core register)
173       // (These are used for 8- and 16-bit element types only.)
174       VGETLANEu,    // zero-extend vector extract element
175       VGETLANEs,    // sign-extend vector extract element
176 
177       // Vector move immediate and move negated immediate:
178       VMOVIMM,
179       VMVNIMM,
180 
181       // Vector move f32 immediate:
182       VMOVFPIMM,
183 
184       // Move H <-> R, clearing top 16 bits
185       VMOVrh,
186       VMOVhr,
187 
188       // Vector duplicate:
189       VDUP,
190       VDUPLANE,
191 
192       // Vector shuffles:
193       VEXT,         // extract
194       VREV64,       // reverse elements within 64-bit doublewords
195       VREV32,       // reverse elements within 32-bit words
196       VREV16,       // reverse elements within 16-bit halfwords
197       VZIP,         // zip (interleave)
198       VUZP,         // unzip (deinterleave)
199       VTRN,         // transpose
200       VTBL1,        // 1-register shuffle with mask
201       VTBL2,        // 2-register shuffle with mask
202       VMOVN,        // MVE vmovn
203 
204       // Vector multiply long:
205       VMULLs,       // ...signed
206       VMULLu,       // ...unsigned
207 
208       SMULWB,       // Signed multiply word by half word, bottom
209       SMULWT,       // Signed multiply word by half word, top
210       UMLAL,        // 64bit Unsigned Accumulate Multiply
211       SMLAL,        // 64bit Signed Accumulate Multiply
212       UMAAL,        // 64-bit Unsigned Accumulate Accumulate Multiply
213       SMLALBB,      // 64-bit signed accumulate multiply bottom, bottom 16
214       SMLALBT,      // 64-bit signed accumulate multiply bottom, top 16
215       SMLALTB,      // 64-bit signed accumulate multiply top, bottom 16
216       SMLALTT,      // 64-bit signed accumulate multiply top, top 16
217       SMLALD,       // Signed multiply accumulate long dual
218       SMLALDX,      // Signed multiply accumulate long dual exchange
219       SMLSLD,       // Signed multiply subtract long dual
220       SMLSLDX,      // Signed multiply subtract long dual exchange
221       SMMLAR,       // Signed multiply long, round and add
222       SMMLSR,       // Signed multiply long, subtract and round
223 
224       // Single Lane QADD8 and QADD16. Only the bottom lane. That's what the b stands for.
225       QADD8b,
226       QSUB8b,
227       QADD16b,
228       QSUB16b,
229 
230       // Operands of the standard BUILD_VECTOR node are not legalized, which
231       // is fine if BUILD_VECTORs are always lowered to shuffles or other
232       // operations, but for ARM some BUILD_VECTORs are legal as-is and their
233       // operands need to be legalized.  Define an ARM-specific version of
234       // BUILD_VECTOR for this purpose.
235       BUILD_VECTOR,
236 
237       // Bit-field insert
238       BFI,
239 
240       // Vector OR with immediate
241       VORRIMM,
242       // Vector AND with NOT of immediate
243       VBICIMM,
244 
245       // Vector bitwise select
246       VBSL,
247 
248       // Pseudo-instruction representing a memory copy using ldm/stm
249       // instructions.
250       MEMCPY,
251 
252       // V8.1MMainline condition select
253       CSINV, // Conditional select invert.
254       CSNEG, // Conditional select negate.
255       CSINC, // Conditional select increment.
256 
257       // Vector load N-element structure to all lanes:
258       VLD1DUP = ISD::FIRST_TARGET_MEMORY_OPCODE,
259       VLD2DUP,
260       VLD3DUP,
261       VLD4DUP,
262 
263       // NEON loads with post-increment base updates:
264       VLD1_UPD,
265       VLD2_UPD,
266       VLD3_UPD,
267       VLD4_UPD,
268       VLD2LN_UPD,
269       VLD3LN_UPD,
270       VLD4LN_UPD,
271       VLD1DUP_UPD,
272       VLD2DUP_UPD,
273       VLD3DUP_UPD,
274       VLD4DUP_UPD,
275 
276       // NEON stores with post-increment base updates:
277       VST1_UPD,
278       VST2_UPD,
279       VST3_UPD,
280       VST4_UPD,
281       VST2LN_UPD,
282       VST3LN_UPD,
283       VST4LN_UPD
284     };
285 
286   } // end namespace ARMISD
287 
288   /// Define some predicates that are used for node matching.
289   namespace ARM {
290 
291     bool isBitFieldInvertedMask(unsigned v);
292 
293   } // end namespace ARM
294 
295   //===--------------------------------------------------------------------===//
296   //  ARMTargetLowering - ARM Implementation of the TargetLowering interface
297 
298   class ARMTargetLowering : public TargetLowering {
299   public:
300     explicit ARMTargetLowering(const TargetMachine &TM,
301                                const ARMSubtarget &STI);
302 
303     unsigned getJumpTableEncoding() const override;
304     bool useSoftFloat() const override;
305 
306     SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
307 
308     /// ReplaceNodeResults - Replace the results of node with an illegal result
309     /// type with new values built out of custom code.
310     void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue>&Results,
311                             SelectionDAG &DAG) const override;
312 
313     const char *getTargetNodeName(unsigned Opcode) const override;
314 
315     bool isSelectSupported(SelectSupportKind Kind) const override {
316       // ARM does not support scalar condition selects on vectors.
317       return (Kind != ScalarCondVectorVal);
318     }
319 
320     bool isReadOnly(const GlobalValue *GV) const;
321 
322     /// getSetCCResultType - Return the value type to use for ISD::SETCC.
323     EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
324                            EVT VT) const override;
325 
326     MachineBasicBlock *
327     EmitInstrWithCustomInserter(MachineInstr &MI,
328                                 MachineBasicBlock *MBB) const override;
329 
330     void AdjustInstrPostInstrSelection(MachineInstr &MI,
331                                        SDNode *Node) const override;
332 
333     SDValue PerformCMOVCombine(SDNode *N, SelectionDAG &DAG) const;
334     SDValue PerformBRCONDCombine(SDNode *N, SelectionDAG &DAG) const;
335     SDValue PerformCMOVToBFICombine(SDNode *N, SelectionDAG &DAG) const;
336     SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
337 
338     bool isDesirableToTransformToIntegerOp(unsigned Opc, EVT VT) const override;
339 
340     /// allowsMisalignedMemoryAccesses - Returns true if the target allows
341     /// unaligned memory accesses of the specified type. Returns whether it
342     /// is "fast" by reference in the second argument.
343     bool allowsMisalignedMemoryAccesses(EVT VT, unsigned AddrSpace,
344                                         unsigned Align,
345                                         MachineMemOperand::Flags Flags,
346                                         bool *Fast) const override;
347 
348     EVT getOptimalMemOpType(uint64_t Size,
349                             unsigned DstAlign, unsigned SrcAlign,
350                             bool IsMemset, bool ZeroMemset,
351                             bool MemcpyStrSrc,
352                             const AttributeList &FuncAttributes) const override;
353 
354     bool isTruncateFree(Type *SrcTy, Type *DstTy) const override;
355     bool isTruncateFree(EVT SrcVT, EVT DstVT) const override;
356     bool isZExtFree(SDValue Val, EVT VT2) const override;
357     bool shouldSinkOperands(Instruction *I,
358                             SmallVectorImpl<Use *> &Ops) const override;
359 
360     bool isFNegFree(EVT VT) const override;
361 
362     bool isVectorLoadExtDesirable(SDValue ExtVal) const override;
363 
364     bool allowTruncateForTailCall(Type *Ty1, Type *Ty2) const override;
365 
366 
367     /// isLegalAddressingMode - Return true if the addressing mode represented
368     /// by AM is legal for this target, for a load/store of the specified type.
369     bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM,
370                                Type *Ty, unsigned AS,
371                                Instruction *I = nullptr) const override;
372 
373     /// getScalingFactorCost - Return the cost of the scaling used in
374     /// addressing mode represented by AM.
375     /// If the AM is supported, the return value must be >= 0.
376     /// If the AM is not supported, the return value must be negative.
377     int getScalingFactorCost(const DataLayout &DL, const AddrMode &AM, Type *Ty,
378                              unsigned AS) const override;
379 
380     bool isLegalT2ScaledAddressingMode(const AddrMode &AM, EVT VT) const;
381 
382     /// Returns true if the addressing mode representing by AM is legal
383     /// for the Thumb1 target, for a load/store of the specified type.
384     bool isLegalT1ScaledAddressingMode(const AddrMode &AM, EVT VT) const;
385 
386     /// isLegalICmpImmediate - Return true if the specified immediate is legal
387     /// icmp immediate, that is the target has icmp instructions which can
388     /// compare a register against the immediate without having to materialize
389     /// the immediate into a register.
390     bool isLegalICmpImmediate(int64_t Imm) const override;
391 
392     /// isLegalAddImmediate - Return true if the specified immediate is legal
393     /// add immediate, that is the target has add instructions which can
394     /// add a register and the immediate without having to materialize
395     /// the immediate into a register.
396     bool isLegalAddImmediate(int64_t Imm) const override;
397 
398     /// getPreIndexedAddressParts - returns true by value, base pointer and
399     /// offset pointer and addressing mode by reference if the node's address
400     /// can be legally represented as pre-indexed load / store address.
401     bool getPreIndexedAddressParts(SDNode *N, SDValue &Base, SDValue &Offset,
402                                    ISD::MemIndexedMode &AM,
403                                    SelectionDAG &DAG) const override;
404 
405     /// getPostIndexedAddressParts - returns true by value, base pointer and
406     /// offset pointer and addressing mode by reference if this node can be
407     /// combined with a load / store to form a post-indexed load / store.
408     bool getPostIndexedAddressParts(SDNode *N, SDNode *Op, SDValue &Base,
409                                     SDValue &Offset, ISD::MemIndexedMode &AM,
410                                     SelectionDAG &DAG) const override;
411 
412     void computeKnownBitsForTargetNode(const SDValue Op, KnownBits &Known,
413                                        const APInt &DemandedElts,
414                                        const SelectionDAG &DAG,
415                                        unsigned Depth) const override;
416 
417     bool targetShrinkDemandedConstant(SDValue Op, const APInt &Demanded,
418                                       TargetLoweringOpt &TLO) const override;
419 
420 
421     bool ExpandInlineAsm(CallInst *CI) const override;
422 
423     ConstraintType getConstraintType(StringRef Constraint) const override;
424 
425     /// Examine constraint string and operand type and determine a weight value.
426     /// The operand object must already have been set up with the operand type.
427     ConstraintWeight getSingleConstraintMatchWeight(
428       AsmOperandInfo &info, const char *constraint) const override;
429 
430     std::pair<unsigned, const TargetRegisterClass *>
431     getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
432                                  StringRef Constraint, MVT VT) const override;
433 
434     const char *LowerXConstraint(EVT ConstraintVT) const override;
435 
436     /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
437     /// vector.  If it is invalid, don't add anything to Ops. If hasMemory is
438     /// true it means one of the asm constraint of the inline asm instruction
439     /// being processed is 'm'.
440     void LowerAsmOperandForConstraint(SDValue Op, std::string &Constraint,
441                                       std::vector<SDValue> &Ops,
442                                       SelectionDAG &DAG) const override;
443 
444     unsigned
445     getInlineAsmMemConstraint(StringRef ConstraintCode) const override {
446       if (ConstraintCode == "Q")
447         return InlineAsm::Constraint_Q;
448       else if (ConstraintCode == "o")
449         return InlineAsm::Constraint_o;
450       else if (ConstraintCode.size() == 2) {
451         if (ConstraintCode[0] == 'U') {
452           switch(ConstraintCode[1]) {
453           default:
454             break;
455           case 'm':
456             return InlineAsm::Constraint_Um;
457           case 'n':
458             return InlineAsm::Constraint_Un;
459           case 'q':
460             return InlineAsm::Constraint_Uq;
461           case 's':
462             return InlineAsm::Constraint_Us;
463           case 't':
464             return InlineAsm::Constraint_Ut;
465           case 'v':
466             return InlineAsm::Constraint_Uv;
467           case 'y':
468             return InlineAsm::Constraint_Uy;
469           }
470         }
471       }
472       return TargetLowering::getInlineAsmMemConstraint(ConstraintCode);
473     }
474 
475     const ARMSubtarget* getSubtarget() const {
476       return Subtarget;
477     }
478 
479     /// getRegClassFor - Return the register class that should be used for the
480     /// specified value type.
481     const TargetRegisterClass *
482     getRegClassFor(MVT VT, bool isDivergent = false) const override;
483 
484     /// Returns true if a cast between SrcAS and DestAS is a noop.
485     bool isNoopAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const override {
486       // Addrspacecasts are always noops.
487       return true;
488     }
489 
490     bool shouldAlignPointerArgs(CallInst *CI, unsigned &MinSize,
491                                 unsigned &PrefAlign) const override;
492 
493     /// createFastISel - This method returns a target specific FastISel object,
494     /// or null if the target does not support "fast" ISel.
495     FastISel *createFastISel(FunctionLoweringInfo &funcInfo,
496                              const TargetLibraryInfo *libInfo) const override;
497 
498     Sched::Preference getSchedulingPreference(SDNode *N) const override;
499 
500     bool
501     isShuffleMaskLegal(ArrayRef<int> M, EVT VT) const override;
502     bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const override;
503 
504     /// isFPImmLegal - Returns true if the target can instruction select the
505     /// specified FP immediate natively. If false, the legalizer will
506     /// materialize the FP immediate as a load from a constant pool.
507     bool isFPImmLegal(const APFloat &Imm, EVT VT,
508                       bool ForCodeSize = false) const override;
509 
510     bool getTgtMemIntrinsic(IntrinsicInfo &Info,
511                             const CallInst &I,
512                             MachineFunction &MF,
513                             unsigned Intrinsic) const override;
514 
515     /// Returns true if it is beneficial to convert a load of a constant
516     /// to just the constant itself.
517     bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
518                                            Type *Ty) const override;
519 
520     /// Return true if EXTRACT_SUBVECTOR is cheap for this result type
521     /// with this index.
522     bool isExtractSubvectorCheap(EVT ResVT, EVT SrcVT,
523                                  unsigned Index) const override;
524 
525     /// Returns true if an argument of type Ty needs to be passed in a
526     /// contiguous block of registers in calling convention CallConv.
527     bool functionArgumentNeedsConsecutiveRegisters(
528         Type *Ty, CallingConv::ID CallConv, bool isVarArg) const override;
529 
530     /// If a physical register, this returns the register that receives the
531     /// exception address on entry to an EH pad.
532     unsigned
533     getExceptionPointerRegister(const Constant *PersonalityFn) const override;
534 
535     /// If a physical register, this returns the register that receives the
536     /// exception typeid on entry to a landing pad.
537     unsigned
538     getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
539 
540     Instruction *makeDMB(IRBuilder<> &Builder, ARM_MB::MemBOpt Domain) const;
541     Value *emitLoadLinked(IRBuilder<> &Builder, Value *Addr,
542                           AtomicOrdering Ord) const override;
543     Value *emitStoreConditional(IRBuilder<> &Builder, Value *Val,
544                                 Value *Addr, AtomicOrdering Ord) const override;
545 
546     void emitAtomicCmpXchgNoStoreLLBalance(IRBuilder<> &Builder) const override;
547 
548     Instruction *emitLeadingFence(IRBuilder<> &Builder, Instruction *Inst,
549                                   AtomicOrdering Ord) const override;
550     Instruction *emitTrailingFence(IRBuilder<> &Builder, Instruction *Inst,
551                                    AtomicOrdering Ord) const override;
552 
553     unsigned getMaxSupportedInterleaveFactor() const override;
554 
555     bool lowerInterleavedLoad(LoadInst *LI,
556                               ArrayRef<ShuffleVectorInst *> Shuffles,
557                               ArrayRef<unsigned> Indices,
558                               unsigned Factor) const override;
559     bool lowerInterleavedStore(StoreInst *SI, ShuffleVectorInst *SVI,
560                                unsigned Factor) const override;
561 
562     bool shouldInsertFencesForAtomic(const Instruction *I) const override;
563     TargetLoweringBase::AtomicExpansionKind
564     shouldExpandAtomicLoadInIR(LoadInst *LI) const override;
565     bool shouldExpandAtomicStoreInIR(StoreInst *SI) const override;
566     TargetLoweringBase::AtomicExpansionKind
567     shouldExpandAtomicRMWInIR(AtomicRMWInst *AI) const override;
568     TargetLoweringBase::AtomicExpansionKind
569     shouldExpandAtomicCmpXchgInIR(AtomicCmpXchgInst *AI) const override;
570 
571     bool useLoadStackGuardNode() const override;
572 
573     void insertSSPDeclarations(Module &M) const override;
574     Value *getSDagStackGuard(const Module &M) const override;
575     Function *getSSPStackGuardCheck(const Module &M) const override;
576 
577     bool canCombineStoreAndExtract(Type *VectorTy, Value *Idx,
578                                    unsigned &Cost) const override;
579 
580     bool canMergeStoresTo(unsigned AddressSpace, EVT MemVT,
581                           const SelectionDAG &DAG) const override {
582       // Do not merge to larger than i32.
583       return (MemVT.getSizeInBits() <= 32);
584     }
585 
586     bool isCheapToSpeculateCttz() const override;
587     bool isCheapToSpeculateCtlz() const override;
588 
589     bool convertSetCCLogicToBitwiseLogic(EVT VT) const override {
590       return VT.isScalarInteger();
591     }
592 
593     bool supportSwiftError() const override {
594       return true;
595     }
596 
597     bool hasStandaloneRem(EVT VT) const override {
598       return HasStandaloneRem;
599     }
600 
601     bool shouldExpandShift(SelectionDAG &DAG, SDNode *N) const override;
602 
603     CCAssignFn *CCAssignFnForCall(CallingConv::ID CC, bool isVarArg) const;
604     CCAssignFn *CCAssignFnForReturn(CallingConv::ID CC, bool isVarArg) const;
605 
606     /// Returns true if \p VecTy is a legal interleaved access type. This
607     /// function checks the vector element type and the overall width of the
608     /// vector.
609     bool isLegalInterleavedAccessType(unsigned Factor, VectorType *VecTy,
610                                       const DataLayout &DL) const;
611 
612     bool alignLoopsWithOptSize() const override;
613 
614     /// Returns the number of interleaved accesses that will be generated when
615     /// lowering accesses of the given type.
616     unsigned getNumInterleavedAccesses(VectorType *VecTy,
617                                        const DataLayout &DL) const;
618 
619     void finalizeLowering(MachineFunction &MF) const override;
620 
621     /// Return the correct alignment for the current calling convention.
622     Align getABIAlignmentForCallingConv(Type *ArgTy,
623                                         DataLayout DL) const override;
624 
625     bool isDesirableToCommuteWithShift(const SDNode *N,
626                                        CombineLevel Level) const override;
627 
628     bool shouldFoldConstantShiftPairToMask(const SDNode *N,
629                                            CombineLevel Level) const override;
630 
631     bool preferIncOfAddToSubOfNot(EVT VT) const override;
632 
633   protected:
634     std::pair<const TargetRegisterClass *, uint8_t>
635     findRepresentativeClass(const TargetRegisterInfo *TRI,
636                             MVT VT) const override;
637 
638   private:
639     /// Subtarget - Keep a pointer to the ARMSubtarget around so that we can
640     /// make the right decision when generating code for different targets.
641     const ARMSubtarget *Subtarget;
642 
643     const TargetRegisterInfo *RegInfo;
644 
645     const InstrItineraryData *Itins;
646 
647     /// ARMPCLabelIndex - Keep track of the number of ARM PC labels created.
648     unsigned ARMPCLabelIndex;
649 
650     // TODO: remove this, and have shouldInsertFencesForAtomic do the proper
651     // check.
652     bool InsertFencesForAtomic;
653 
654     bool HasStandaloneRem = true;
655 
656     void addTypeForNEON(MVT VT, MVT PromotedLdStVT, MVT PromotedBitwiseVT);
657     void addDRTypeForNEON(MVT VT);
658     void addQRTypeForNEON(MVT VT);
659     std::pair<SDValue, SDValue> getARMXALUOOp(SDValue Op, SelectionDAG &DAG, SDValue &ARMcc) const;
660 
661     using RegsToPassVector = SmallVector<std::pair<unsigned, SDValue>, 8>;
662 
663     void PassF64ArgInRegs(const SDLoc &dl, SelectionDAG &DAG, SDValue Chain,
664                           SDValue &Arg, RegsToPassVector &RegsToPass,
665                           CCValAssign &VA, CCValAssign &NextVA,
666                           SDValue &StackPtr,
667                           SmallVectorImpl<SDValue> &MemOpChains,
668                           ISD::ArgFlagsTy Flags) const;
669     SDValue GetF64FormalArgument(CCValAssign &VA, CCValAssign &NextVA,
670                                  SDValue &Root, SelectionDAG &DAG,
671                                  const SDLoc &dl) const;
672 
673     CallingConv::ID getEffectiveCallingConv(CallingConv::ID CC,
674                                             bool isVarArg) const;
675     CCAssignFn *CCAssignFnForNode(CallingConv::ID CC, bool Return,
676                                   bool isVarArg) const;
677     SDValue LowerMemOpCallTo(SDValue Chain, SDValue StackPtr, SDValue Arg,
678                              const SDLoc &dl, SelectionDAG &DAG,
679                              const CCValAssign &VA,
680                              ISD::ArgFlagsTy Flags) const;
681     SDValue LowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
682     SDValue LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
683     SDValue LowerEH_SJLJ_SETUP_DISPATCH(SDValue Op, SelectionDAG &DAG) const;
684     SDValue LowerINTRINSIC_VOID(SDValue Op, SelectionDAG &DAG,
685                                     const ARMSubtarget *Subtarget) const;
686     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG,
687                                     const ARMSubtarget *Subtarget) const;
688     SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
689     SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
690     SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
691     SDValue LowerGlobalAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
692     SDValue LowerGlobalAddressELF(SDValue Op, SelectionDAG &DAG) const;
693     SDValue LowerGlobalAddressWindows(SDValue Op, SelectionDAG &DAG) const;
694     SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
695     SDValue LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,
696                                             SelectionDAG &DAG) const;
697     SDValue LowerToTLSExecModels(GlobalAddressSDNode *GA,
698                                  SelectionDAG &DAG,
699                                  TLSModel::Model model) const;
700     SDValue LowerGlobalTLSAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
701     SDValue LowerGlobalTLSAddressWindows(SDValue Op, SelectionDAG &DAG) const;
702     SDValue LowerGLOBAL_OFFSET_TABLE(SDValue Op, SelectionDAG &DAG) const;
703     SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
704     SDValue LowerSignedALUO(SDValue Op, SelectionDAG &DAG) const;
705     SDValue LowerUnsignedALUO(SDValue Op, SelectionDAG &DAG) const;
706     SDValue LowerSELECT(SDValue Op, SelectionDAG &DAG) const;
707     SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
708     SDValue LowerBRCOND(SDValue Op, SelectionDAG &DAG) const;
709     SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
710     SDValue LowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) const;
711     SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
712     SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
713     SDValue LowerShiftRightParts(SDValue Op, SelectionDAG &DAG) const;
714     SDValue LowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
715     SDValue LowerFLT_ROUNDS_(SDValue Op, SelectionDAG &DAG) const;
716     SDValue LowerConstantFP(SDValue Op, SelectionDAG &DAG,
717                             const ARMSubtarget *ST) const;
718     SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
719                               const ARMSubtarget *ST) const;
720     SDValue LowerINSERT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
721     SDValue LowerFSINCOS(SDValue Op, SelectionDAG &DAG) const;
722     SDValue LowerDivRem(SDValue Op, SelectionDAG &DAG) const;
723     SDValue LowerDIV_Windows(SDValue Op, SelectionDAG &DAG, bool Signed) const;
724     void ExpandDIV_Windows(SDValue Op, SelectionDAG &DAG, bool Signed,
725                            SmallVectorImpl<SDValue> &Results) const;
726     SDValue LowerWindowsDIVLibCall(SDValue Op, SelectionDAG &DAG, bool Signed,
727                                    SDValue &Chain) const;
728     SDValue LowerREM(SDNode *N, SelectionDAG &DAG) const;
729     SDValue LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const;
730     SDValue LowerFP_ROUND(SDValue Op, SelectionDAG &DAG) const;
731     SDValue LowerFP_EXTEND(SDValue Op, SelectionDAG &DAG) const;
732     SDValue LowerFP_TO_INT(SDValue Op, SelectionDAG &DAG) const;
733     SDValue LowerINT_TO_FP(SDValue Op, SelectionDAG &DAG) const;
734     SDValue LowerFSETCC(SDValue Op, SelectionDAG &DAG) const;
735     void lowerABS(SDNode *N, SmallVectorImpl<SDValue> &Results,
736                   SelectionDAG &DAG) const;
737 
738     Register getRegisterByName(const char* RegName, LLT VT,
739                                const MachineFunction &MF) const override;
740 
741     SDValue BuildSDIVPow2(SDNode *N, const APInt &Divisor, SelectionDAG &DAG,
742                           SmallVectorImpl<SDNode *> &Created) const override;
743 
744     bool isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,
745                                     EVT VT) const override;
746 
747     SDValue ReconstructShuffle(SDValue Op, SelectionDAG &DAG) const;
748 
749     SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
750                             CallingConv::ID CallConv, bool isVarArg,
751                             const SmallVectorImpl<ISD::InputArg> &Ins,
752                             const SDLoc &dl, SelectionDAG &DAG,
753                             SmallVectorImpl<SDValue> &InVals, bool isThisReturn,
754                             SDValue ThisVal) const;
755 
756     bool supportSplitCSR(MachineFunction *MF) const override {
757       return MF->getFunction().getCallingConv() == CallingConv::CXX_FAST_TLS &&
758           MF->getFunction().hasFnAttribute(Attribute::NoUnwind);
759     }
760 
761     void initializeSplitCSR(MachineBasicBlock *Entry) const override;
762     void insertCopiesSplitCSR(
763       MachineBasicBlock *Entry,
764       const SmallVectorImpl<MachineBasicBlock *> &Exits) const override;
765 
766     SDValue
767     LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
768                          const SmallVectorImpl<ISD::InputArg> &Ins,
769                          const SDLoc &dl, SelectionDAG &DAG,
770                          SmallVectorImpl<SDValue> &InVals) const override;
771 
772     int StoreByValRegs(CCState &CCInfo, SelectionDAG &DAG, const SDLoc &dl,
773                        SDValue &Chain, const Value *OrigArg,
774                        unsigned InRegsParamRecordIdx, int ArgOffset,
775                        unsigned ArgSize) const;
776 
777     void VarArgStyleRegisters(CCState &CCInfo, SelectionDAG &DAG,
778                               const SDLoc &dl, SDValue &Chain,
779                               unsigned ArgOffset, unsigned TotalArgRegsSaveSize,
780                               bool ForceMutable = false) const;
781 
782     SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
783                       SmallVectorImpl<SDValue> &InVals) const override;
784 
785     /// HandleByVal - Target-specific cleanup for ByVal support.
786     void HandleByVal(CCState *, unsigned &, unsigned) const override;
787 
788     /// IsEligibleForTailCallOptimization - Check whether the call is eligible
789     /// for tail call optimization. Targets which want to do tail call
790     /// optimization should implement this function.
791     bool IsEligibleForTailCallOptimization(
792         SDValue Callee, CallingConv::ID CalleeCC, bool isVarArg,
793         bool isCalleeStructRet, bool isCallerStructRet,
794         const SmallVectorImpl<ISD::OutputArg> &Outs,
795         const SmallVectorImpl<SDValue> &OutVals,
796         const SmallVectorImpl<ISD::InputArg> &Ins, SelectionDAG &DAG,
797         const bool isIndirect) const;
798 
799     bool CanLowerReturn(CallingConv::ID CallConv,
800                         MachineFunction &MF, bool isVarArg,
801                         const SmallVectorImpl<ISD::OutputArg> &Outs,
802                         LLVMContext &Context) const override;
803 
804     SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
805                         const SmallVectorImpl<ISD::OutputArg> &Outs,
806                         const SmallVectorImpl<SDValue> &OutVals,
807                         const SDLoc &dl, SelectionDAG &DAG) const override;
808 
809     bool isUsedByReturnOnly(SDNode *N, SDValue &Chain) const override;
810 
811     bool mayBeEmittedAsTailCall(const CallInst *CI) const override;
812 
813     bool shouldConsiderGEPOffsetSplit() const override { return true; }
814 
815     bool isUnsupportedFloatingType(EVT VT) const;
816 
817     SDValue getCMOV(const SDLoc &dl, EVT VT, SDValue FalseVal, SDValue TrueVal,
818                     SDValue ARMcc, SDValue CCR, SDValue Cmp,
819                     SelectionDAG &DAG) const;
820     SDValue getARMCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
821                       SDValue &ARMcc, SelectionDAG &DAG, const SDLoc &dl) const;
822     SDValue getVFPCmp(SDValue LHS, SDValue RHS, SelectionDAG &DAG,
823                       const SDLoc &dl, bool Signaling = false) const;
824     SDValue duplicateCmp(SDValue Cmp, SelectionDAG &DAG) const;
825 
826     SDValue OptimizeVFPBrcond(SDValue Op, SelectionDAG &DAG) const;
827 
828     void SetupEntryBlockForSjLj(MachineInstr &MI, MachineBasicBlock *MBB,
829                                 MachineBasicBlock *DispatchBB, int FI) const;
830 
831     void EmitSjLjDispatchBlock(MachineInstr &MI, MachineBasicBlock *MBB) const;
832 
833     bool RemapAddSubWithFlags(MachineInstr &MI, MachineBasicBlock *BB) const;
834 
835     MachineBasicBlock *EmitStructByval(MachineInstr &MI,
836                                        MachineBasicBlock *MBB) const;
837 
838     MachineBasicBlock *EmitLowered__chkstk(MachineInstr &MI,
839                                            MachineBasicBlock *MBB) const;
840     MachineBasicBlock *EmitLowered__dbzchk(MachineInstr &MI,
841                                            MachineBasicBlock *MBB) const;
842     void addMVEVectorTypes(bool HasMVEFP);
843     void addAllExtLoads(const MVT From, const MVT To, LegalizeAction Action);
844     void setAllExpand(MVT VT);
845   };
846 
847   enum VMOVModImmType {
848     VMOVModImm,
849     VMVNModImm,
850     MVEVMVNModImm,
851     OtherModImm
852   };
853 
854   namespace ARM {
855 
856     FastISel *createFastISel(FunctionLoweringInfo &funcInfo,
857                              const TargetLibraryInfo *libInfo);
858 
859   } // end namespace ARM
860 
861 } // end namespace llvm
862 
863 #endif // LLVM_LIB_TARGET_ARM_ARMISELLOWERING_H
864