1 //===-- SIISelLowering.h - SI 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 /// \file
10 /// SI DAG Lowering interface definition
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_TARGET_AMDGPU_SIISELLOWERING_H
15 #define LLVM_LIB_TARGET_AMDGPU_SIISELLOWERING_H
16 
17 #include "AMDGPUISelLowering.h"
18 #include "AMDGPUArgumentUsageInfo.h"
19 #include "SIInstrInfo.h"
20 
21 namespace llvm {
22 
23 class SITargetLowering final : public AMDGPUTargetLowering {
24 private:
25   const GCNSubtarget *Subtarget;
26 
27 public:
28   MVT getRegisterTypeForCallingConv(LLVMContext &Context,
29                                     CallingConv::ID CC,
30                                     EVT VT) const override;
31   unsigned getNumRegistersForCallingConv(LLVMContext &Context,
32                                          CallingConv::ID CC,
33                                          EVT VT) const override;
34 
35   unsigned getVectorTypeBreakdownForCallingConv(
36     LLVMContext &Context, CallingConv::ID CC, EVT VT, EVT &IntermediateVT,
37     unsigned &NumIntermediates, MVT &RegisterVT) const override;
38 
39 private:
40   SDValue lowerKernArgParameterPtr(SelectionDAG &DAG, const SDLoc &SL,
41                                    SDValue Chain, uint64_t Offset) const;
42   SDValue getImplicitArgPtr(SelectionDAG &DAG, const SDLoc &SL) const;
43   SDValue lowerKernargMemParameter(SelectionDAG &DAG, EVT VT, EVT MemVT,
44                                    const SDLoc &SL, SDValue Chain,
45                                    uint64_t Offset, unsigned Align, bool Signed,
46                                    const ISD::InputArg *Arg = nullptr) const;
47 
48   SDValue lowerStackParameter(SelectionDAG &DAG, CCValAssign &VA,
49                               const SDLoc &SL, SDValue Chain,
50                               const ISD::InputArg &Arg) const;
51   SDValue getPreloadedValue(SelectionDAG &DAG,
52                             const SIMachineFunctionInfo &MFI,
53                             EVT VT,
54                             AMDGPUFunctionArgInfo::PreloadedValue) const;
55 
56   SDValue LowerGlobalAddress(AMDGPUMachineFunction *MFI, SDValue Op,
57                              SelectionDAG &DAG) const override;
58   SDValue lowerImplicitZextParam(SelectionDAG &DAG, SDValue Op,
59                                  MVT VT, unsigned Offset) const;
60   SDValue lowerImage(SDValue Op, const AMDGPU::ImageDimIntrinsicInfo *Intr,
61                      SelectionDAG &DAG) const;
62   SDValue lowerSBuffer(EVT VT, SDLoc DL, SDValue Rsrc, SDValue Offset,
63                        SDValue GLC, SDValue DLC, SelectionDAG &DAG) const;
64 
65   SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) const;
66   SDValue LowerINTRINSIC_W_CHAIN(SDValue Op, SelectionDAG &DAG) const;
67   SDValue LowerINTRINSIC_VOID(SDValue Op, SelectionDAG &DAG) const;
68 
69   // The raw.tbuffer and struct.tbuffer intrinsics have two offset args: offset
70   // (the offset that is included in bounds checking and swizzling, to be split
71   // between the instruction's voffset and immoffset fields) and soffset (the
72   // offset that is excluded from bounds checking and swizzling, to go in the
73   // instruction's soffset field).  This function takes the first kind of
74   // offset and figures out how to split it between voffset and immoffset.
75   std::pair<SDValue, SDValue> splitBufferOffsets(SDValue Offset,
76                                                  SelectionDAG &DAG) const;
77 
78   SDValue widenLoad(LoadSDNode *Ld, DAGCombinerInfo &DCI) const;
79   SDValue LowerLOAD(SDValue Op, SelectionDAG &DAG) const;
80   SDValue LowerSELECT(SDValue Op, SelectionDAG &DAG) const;
81   SDValue lowerFastUnsafeFDIV(SDValue Op, SelectionDAG &DAG) const;
82   SDValue lowerFDIV_FAST(SDValue Op, SelectionDAG &DAG) const;
83   SDValue LowerFDIV16(SDValue Op, SelectionDAG &DAG) const;
84   SDValue LowerFDIV32(SDValue Op, SelectionDAG &DAG) const;
85   SDValue LowerFDIV64(SDValue Op, SelectionDAG &DAG) const;
86   SDValue LowerFDIV(SDValue Op, SelectionDAG &DAG) const;
87   SDValue LowerINT_TO_FP(SDValue Op, SelectionDAG &DAG, bool Signed) const;
88   SDValue LowerSTORE(SDValue Op, SelectionDAG &DAG) const;
89   SDValue LowerTrig(SDValue Op, SelectionDAG &DAG) const;
90   SDValue LowerATOMIC_CMP_SWAP(SDValue Op, SelectionDAG &DAG) const;
91   SDValue LowerBRCOND(SDValue Op, SelectionDAG &DAG) const;
92   SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
93   SDValue adjustLoadValueType(unsigned Opcode, MemSDNode *M,
94                               SelectionDAG &DAG, ArrayRef<SDValue> Ops,
95                               bool IsIntrinsic = false) const;
96 
97   // Call DAG.getMemIntrinsicNode for a load, but first widen a dwordx3 type to
98   // dwordx4 if on SI.
99   SDValue getMemIntrinsicNode(unsigned Opcode, const SDLoc &DL, SDVTList VTList,
100                               ArrayRef<SDValue> Ops, EVT MemVT,
101                               MachineMemOperand *MMO, SelectionDAG &DAG) const;
102 
103   SDValue handleD16VData(SDValue VData, SelectionDAG &DAG) const;
104 
105   /// Converts \p Op, which must be of floating point type, to the
106   /// floating point type \p VT, by either extending or truncating it.
107   SDValue getFPExtOrFPTrunc(SelectionDAG &DAG,
108                             SDValue Op,
109                             const SDLoc &DL,
110                             EVT VT) const;
111 
112   SDValue convertArgType(
113     SelectionDAG &DAG, EVT VT, EVT MemVT, const SDLoc &SL, SDValue Val,
114     bool Signed, const ISD::InputArg *Arg = nullptr) const;
115 
116   /// Custom lowering for ISD::FP_ROUND for MVT::f16.
117   SDValue lowerFP_ROUND(SDValue Op, SelectionDAG &DAG) const;
118   SDValue lowerFMINNUM_FMAXNUM(SDValue Op, SelectionDAG &DAG) const;
119 
120   SDValue getSegmentAperture(unsigned AS, const SDLoc &DL,
121                              SelectionDAG &DAG) const;
122 
123   SDValue lowerADDRSPACECAST(SDValue Op, SelectionDAG &DAG) const;
124   SDValue lowerINSERT_SUBVECTOR(SDValue Op, SelectionDAG &DAG) const;
125   SDValue lowerINSERT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
126   SDValue lowerEXTRACT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
127   SDValue lowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) const;
128   SDValue lowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) const;
129   SDValue lowerTRAP(SDValue Op, SelectionDAG &DAG) const;
130   SDValue lowerDEBUGTRAP(SDValue Op, SelectionDAG &DAG) const;
131 
132   SDNode *adjustWritemask(MachineSDNode *&N, SelectionDAG &DAG) const;
133 
134   SDValue performUCharToFloatCombine(SDNode *N,
135                                      DAGCombinerInfo &DCI) const;
136   SDValue performSHLPtrCombine(SDNode *N,
137                                unsigned AS,
138                                EVT MemVT,
139                                DAGCombinerInfo &DCI) const;
140 
141   SDValue performMemSDNodeCombine(MemSDNode *N, DAGCombinerInfo &DCI) const;
142 
143   SDValue splitBinaryBitConstantOp(DAGCombinerInfo &DCI, const SDLoc &SL,
144                                    unsigned Opc, SDValue LHS,
145                                    const ConstantSDNode *CRHS) const;
146 
147   SDValue performAndCombine(SDNode *N, DAGCombinerInfo &DCI) const;
148   SDValue performOrCombine(SDNode *N, DAGCombinerInfo &DCI) const;
149   SDValue performXorCombine(SDNode *N, DAGCombinerInfo &DCI) const;
150   SDValue performZeroExtendCombine(SDNode *N, DAGCombinerInfo &DCI) const;
151   SDValue performSignExtendInRegCombine(SDNode *N, DAGCombinerInfo &DCI) const;
152   SDValue performClassCombine(SDNode *N, DAGCombinerInfo &DCI) const;
153   SDValue getCanonicalConstantFP(SelectionDAG &DAG, const SDLoc &SL, EVT VT,
154                                  const APFloat &C) const;
155   SDValue performFCanonicalizeCombine(SDNode *N, DAGCombinerInfo &DCI) const;
156 
157   SDValue performFPMed3ImmCombine(SelectionDAG &DAG, const SDLoc &SL,
158                                   SDValue Op0, SDValue Op1) const;
159   SDValue performIntMed3ImmCombine(SelectionDAG &DAG, const SDLoc &SL,
160                                    SDValue Op0, SDValue Op1, bool Signed) const;
161   SDValue performMinMaxCombine(SDNode *N, DAGCombinerInfo &DCI) const;
162   SDValue performFMed3Combine(SDNode *N, DAGCombinerInfo &DCI) const;
163   SDValue performCvtPkRTZCombine(SDNode *N, DAGCombinerInfo &DCI) const;
164   SDValue performExtractVectorEltCombine(SDNode *N, DAGCombinerInfo &DCI) const;
165   SDValue performInsertVectorEltCombine(SDNode *N, DAGCombinerInfo &DCI) const;
166 
167   SDValue reassociateScalarOps(SDNode *N, SelectionDAG &DAG) const;
168   unsigned getFusedOpcode(const SelectionDAG &DAG,
169                           const SDNode *N0, const SDNode *N1) const;
170   SDValue performAddCombine(SDNode *N, DAGCombinerInfo &DCI) const;
171   SDValue performAddCarrySubCarryCombine(SDNode *N, DAGCombinerInfo &DCI) const;
172   SDValue performSubCombine(SDNode *N, DAGCombinerInfo &DCI) const;
173   SDValue performFAddCombine(SDNode *N, DAGCombinerInfo &DCI) const;
174   SDValue performFSubCombine(SDNode *N, DAGCombinerInfo &DCI) const;
175   SDValue performFMACombine(SDNode *N, DAGCombinerInfo &DCI) const;
176   SDValue performSetCCCombine(SDNode *N, DAGCombinerInfo &DCI) const;
177   SDValue performCvtF32UByteNCombine(SDNode *N, DAGCombinerInfo &DCI) const;
178   SDValue performClampCombine(SDNode *N, DAGCombinerInfo &DCI) const;
179   SDValue performRcpCombine(SDNode *N, DAGCombinerInfo &DCI) const;
180 
181   bool isLegalFlatAddressingMode(const AddrMode &AM) const;
182   bool isLegalMUBUFAddressingMode(const AddrMode &AM) const;
183 
184   unsigned isCFIntrinsic(const SDNode *Intr) const;
185 
186   /// \returns True if fixup needs to be emitted for given global value \p GV,
187   /// false otherwise.
188   bool shouldEmitFixup(const GlobalValue *GV) const;
189 
190   /// \returns True if GOT relocation needs to be emitted for given global value
191   /// \p GV, false otherwise.
192   bool shouldEmitGOTReloc(const GlobalValue *GV) const;
193 
194   /// \returns True if PC-relative relocation needs to be emitted for given
195   /// global value \p GV, false otherwise.
196   bool shouldEmitPCReloc(const GlobalValue *GV) const;
197 
198   // Analyze a combined offset from an amdgcn_buffer_ intrinsic and store the
199   // three offsets (voffset, soffset and instoffset) into the SDValue[3] array
200   // pointed to by Offsets.
201   void setBufferOffsets(SDValue CombinedOffset, SelectionDAG &DAG,
202                         SDValue *Offsets, unsigned Align = 4) const;
203 
204   // Handle 8 bit and 16 bit buffer loads
205   SDValue handleByteShortBufferLoads(SelectionDAG &DAG, EVT LoadVT, SDLoc DL,
206                                      ArrayRef<SDValue> Ops, MemSDNode *M) const;
207 
208   // Handle 8 bit and 16 bit buffer stores
209   SDValue handleByteShortBufferStores(SelectionDAG &DAG, EVT VDataType,
210                                       SDLoc DL, SDValue Ops[],
211                                       MemSDNode *M) const;
212 
213 public:
214   SITargetLowering(const TargetMachine &tm, const GCNSubtarget &STI);
215 
216   const GCNSubtarget *getSubtarget() const;
217 
218   bool isFPExtFoldable(unsigned Opcode, EVT DestVT, EVT SrcVT) const override;
219 
220   bool isShuffleMaskLegal(ArrayRef<int> /*Mask*/, EVT /*VT*/) const override;
221 
222   bool getTgtMemIntrinsic(IntrinsicInfo &, const CallInst &,
223                           MachineFunction &MF,
224                           unsigned IntrinsicID) const override;
225 
226   bool getAddrModeArguments(IntrinsicInst * /*I*/,
227                             SmallVectorImpl<Value*> &/*Ops*/,
228                             Type *&/*AccessTy*/) const override;
229 
230   bool isLegalGlobalAddressingMode(const AddrMode &AM) const;
231   bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM, Type *Ty,
232                              unsigned AS,
233                              Instruction *I = nullptr) const override;
234 
235   bool canMergeStoresTo(unsigned AS, EVT MemVT,
236                         const SelectionDAG &DAG) const override;
237 
238   bool allowsMisalignedMemoryAccesses(
239       EVT VT, unsigned AS, unsigned Align,
240       MachineMemOperand::Flags Flags = MachineMemOperand::MONone,
241       bool *IsFast = nullptr) const override;
242 
243   EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign,
244                           unsigned SrcAlign, bool IsMemset,
245                           bool ZeroMemset,
246                           bool MemcpyStrSrc,
247                           const AttributeList &FuncAttributes) const override;
248 
249   bool isMemOpUniform(const SDNode *N) const;
250   bool isMemOpHasNoClobberedMemOperand(const SDNode *N) const;
251   bool isNoopAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const override;
252   bool isFreeAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const override;
253 
254   TargetLoweringBase::LegalizeTypeAction
255   getPreferredVectorAction(MVT VT) const override;
256 
257   bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
258                                         Type *Ty) const override;
259 
260   bool isTypeDesirableForOp(unsigned Op, EVT VT) const override;
261 
262   bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const override;
263 
264   bool supportSplitCSR(MachineFunction *MF) const override;
265   void initializeSplitCSR(MachineBasicBlock *Entry) const override;
266   void insertCopiesSplitCSR(
267     MachineBasicBlock *Entry,
268     const SmallVectorImpl<MachineBasicBlock *> &Exits) const override;
269 
270   SDValue LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv,
271                                bool isVarArg,
272                                const SmallVectorImpl<ISD::InputArg> &Ins,
273                                const SDLoc &DL, SelectionDAG &DAG,
274                                SmallVectorImpl<SDValue> &InVals) const override;
275 
276   bool CanLowerReturn(CallingConv::ID CallConv,
277                       MachineFunction &MF, bool isVarArg,
278                       const SmallVectorImpl<ISD::OutputArg> &Outs,
279                       LLVMContext &Context) const override;
280 
281   SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
282                       const SmallVectorImpl<ISD::OutputArg> &Outs,
283                       const SmallVectorImpl<SDValue> &OutVals, const SDLoc &DL,
284                       SelectionDAG &DAG) const override;
285 
286   void passSpecialInputs(
287     CallLoweringInfo &CLI,
288     CCState &CCInfo,
289     const SIMachineFunctionInfo &Info,
290     SmallVectorImpl<std::pair<unsigned, SDValue>> &RegsToPass,
291     SmallVectorImpl<SDValue> &MemOpChains,
292     SDValue Chain) const;
293 
294   SDValue LowerCallResult(SDValue Chain, SDValue InFlag,
295                           CallingConv::ID CallConv, bool isVarArg,
296                           const SmallVectorImpl<ISD::InputArg> &Ins,
297                           const SDLoc &DL, SelectionDAG &DAG,
298                           SmallVectorImpl<SDValue> &InVals, bool isThisReturn,
299                           SDValue ThisVal) const;
300 
301   bool mayBeEmittedAsTailCall(const CallInst *) const override;
302 
303   bool isEligibleForTailCallOptimization(
304     SDValue Callee, CallingConv::ID CalleeCC, bool isVarArg,
305     const SmallVectorImpl<ISD::OutputArg> &Outs,
306     const SmallVectorImpl<SDValue> &OutVals,
307     const SmallVectorImpl<ISD::InputArg> &Ins, SelectionDAG &DAG) const;
308 
309   SDValue LowerCall(CallLoweringInfo &CLI,
310                     SmallVectorImpl<SDValue> &InVals) const override;
311 
312   unsigned getRegisterByName(const char* RegName, EVT VT,
313                              SelectionDAG &DAG) const override;
314 
315   MachineBasicBlock *splitKillBlock(MachineInstr &MI,
316                                     MachineBasicBlock *BB) const;
317 
318   MachineBasicBlock *emitGWSMemViolTestLoop(MachineInstr &MI,
319                                             MachineBasicBlock *BB) const;
320 
321   MachineBasicBlock *
322   EmitInstrWithCustomInserter(MachineInstr &MI,
323                               MachineBasicBlock *BB) const override;
324 
325   bool hasBitPreservingFPLogic(EVT VT) const override;
326   bool enableAggressiveFMAFusion(EVT VT) const override;
327   EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
328                          EVT VT) const override;
329   MVT getScalarShiftAmountTy(const DataLayout &, EVT) const override;
330   bool isFMAFasterThanFMulAndFAdd(EVT VT) const override;
331   SDValue splitUnaryVectorOp(SDValue Op, SelectionDAG &DAG) const;
332   SDValue splitBinaryVectorOp(SDValue Op, SelectionDAG &DAG) const;
333   SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
334 
335   void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue> &Results,
336                           SelectionDAG &DAG) const override;
337 
338   SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
339   SDNode *PostISelFolding(MachineSDNode *N, SelectionDAG &DAG) const override;
340   void AdjustInstrPostInstrSelection(MachineInstr &MI,
341                                      SDNode *Node) const override;
342 
343   SDNode *legalizeTargetIndependentNode(SDNode *Node, SelectionDAG &DAG) const;
344 
345   MachineSDNode *wrapAddr64Rsrc(SelectionDAG &DAG, const SDLoc &DL,
346                                 SDValue Ptr) const;
347   MachineSDNode *buildRSRC(SelectionDAG &DAG, const SDLoc &DL, SDValue Ptr,
348                            uint32_t RsrcDword1, uint64_t RsrcDword2And3) const;
349   std::pair<unsigned, const TargetRegisterClass *>
350   getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
351                                StringRef Constraint, MVT VT) const override;
352   ConstraintType getConstraintType(StringRef Constraint) const override;
353   SDValue copyToM0(SelectionDAG &DAG, SDValue Chain, const SDLoc &DL,
354                    SDValue V) const;
355 
356   void finalizeLowering(MachineFunction &MF) const override;
357 
358   void computeKnownBitsForFrameIndex(const SDValue Op,
359                                      KnownBits &Known,
360                                      const APInt &DemandedElts,
361                                      const SelectionDAG &DAG,
362                                      unsigned Depth = 0) const override;
363 
364   bool isSDNodeSourceOfDivergence(const SDNode *N,
365     FunctionLoweringInfo *FLI, LegacyDivergenceAnalysis *DA) const override;
366 
367   bool isCanonicalized(SelectionDAG &DAG, SDValue Op,
368                        unsigned MaxDepth = 5) const;
369   bool denormalsEnabledForType(EVT VT) const;
370 
371   bool isKnownNeverNaNForTargetNode(SDValue Op,
372                                     const SelectionDAG &DAG,
373                                     bool SNaN = false,
374                                     unsigned Depth = 0) const override;
375   AtomicExpansionKind shouldExpandAtomicRMWInIR(AtomicRMWInst *) const override;
376 
377   unsigned getPrefLoopAlignment(MachineLoop *ML) const override;
378 };
379 
380 } // End namespace llvm
381 
382 #endif
383