1 //===- AArch64InstrInfo.h - AArch64 Instruction Information -----*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the AArch64 implementation of the TargetInstrInfo class.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #ifndef LLVM_LIB_TARGET_AARCH64_AARCH64INSTRINFO_H
15 #define LLVM_LIB_TARGET_AARCH64_AARCH64INSTRINFO_H
16
17 #include "AArch64.h"
18 #include "AArch64RegisterInfo.h"
19 #include "llvm/CodeGen/MachineCombinerPattern.h"
20 #include "llvm/Target/TargetInstrInfo.h"
21
22 #define GET_INSTRINFO_HEADER
23 #include "AArch64GenInstrInfo.inc"
24
25 namespace llvm {
26
27 class AArch64Subtarget;
28 class AArch64TargetMachine;
29
30 class AArch64InstrInfo : public AArch64GenInstrInfo {
31 // Reserve bits in the MachineMemOperand target hint flags, starting at 1.
32 // They will be shifted into MOTargetHintStart when accessed.
33 enum TargetMemOperandFlags {
34 MOSuppressPair = 1
35 };
36
37 const AArch64RegisterInfo RI;
38 const AArch64Subtarget &Subtarget;
39
40 public:
41 explicit AArch64InstrInfo(const AArch64Subtarget &STI);
42
43 /// getRegisterInfo - TargetInstrInfo is a superset of MRegister info. As
44 /// such, whenever a client has an instance of instruction info, it should
45 /// always be able to get register info as well (through this method).
getRegisterInfo()46 const AArch64RegisterInfo &getRegisterInfo() const { return RI; }
47
48 unsigned GetInstSizeInBytes(const MachineInstr *MI) const;
49
50 bool isAsCheapAsAMove(const MachineInstr *MI) const override;
51
52 bool isCoalescableExtInstr(const MachineInstr &MI, unsigned &SrcReg,
53 unsigned &DstReg, unsigned &SubIdx) const override;
54
55 bool
56 areMemAccessesTriviallyDisjoint(MachineInstr *MIa, MachineInstr *MIb,
57 AliasAnalysis *AA = nullptr) const override;
58
59 unsigned isLoadFromStackSlot(const MachineInstr *MI,
60 int &FrameIndex) const override;
61 unsigned isStoreToStackSlot(const MachineInstr *MI,
62 int &FrameIndex) const override;
63
64 /// Returns true if there is a shiftable register and that the shift value
65 /// is non-zero.
66 bool hasShiftedReg(const MachineInstr *MI) const;
67
68 /// Returns true if there is an extendable register and that the extending
69 /// value is non-zero.
70 bool hasExtendedReg(const MachineInstr *MI) const;
71
72 /// \brief Does this instruction set its full destination register to zero?
73 bool isGPRZero(const MachineInstr *MI) const;
74
75 /// \brief Does this instruction rename a GPR without modifying bits?
76 bool isGPRCopy(const MachineInstr *MI) const;
77
78 /// \brief Does this instruction rename an FPR without modifying bits?
79 bool isFPRCopy(const MachineInstr *MI) const;
80
81 /// Return true if this is load/store scales or extends its register offset.
82 /// This refers to scaling a dynamic index as opposed to scaled immediates.
83 /// MI should be a memory op that allows scaled addressing.
84 bool isScaledAddr(const MachineInstr *MI) const;
85
86 /// Return true if pairing the given load or store is hinted to be
87 /// unprofitable.
88 bool isLdStPairSuppressed(const MachineInstr *MI) const;
89
90 /// Hint that pairing the given load or store is unprofitable.
91 void suppressLdStPair(MachineInstr *MI) const;
92
93 bool getMemOpBaseRegImmOfs(MachineInstr *LdSt, unsigned &BaseReg,
94 unsigned &Offset,
95 const TargetRegisterInfo *TRI) const override;
96
97 bool getMemOpBaseRegImmOfsWidth(MachineInstr *LdSt, unsigned &BaseReg,
98 int &Offset, int &Width,
99 const TargetRegisterInfo *TRI) const;
100
enableClusterLoads()101 bool enableClusterLoads() const override { return true; }
102
103 bool shouldClusterLoads(MachineInstr *FirstLdSt, MachineInstr *SecondLdSt,
104 unsigned NumLoads) const override;
105
106 bool shouldScheduleAdjacent(MachineInstr *First,
107 MachineInstr *Second) const override;
108
109 MachineInstr *emitFrameIndexDebugValue(MachineFunction &MF, int FrameIx,
110 uint64_t Offset, const MDNode *Var,
111 const MDNode *Expr, DebugLoc DL) const;
112 void copyPhysRegTuple(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
113 DebugLoc DL, unsigned DestReg, unsigned SrcReg,
114 bool KillSrc, unsigned Opcode,
115 llvm::ArrayRef<unsigned> Indices) const;
116 void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator I,
117 DebugLoc DL, unsigned DestReg, unsigned SrcReg,
118 bool KillSrc) const override;
119
120 void storeRegToStackSlot(MachineBasicBlock &MBB,
121 MachineBasicBlock::iterator MBBI, unsigned SrcReg,
122 bool isKill, int FrameIndex,
123 const TargetRegisterClass *RC,
124 const TargetRegisterInfo *TRI) const override;
125
126 void loadRegFromStackSlot(MachineBasicBlock &MBB,
127 MachineBasicBlock::iterator MBBI, unsigned DestReg,
128 int FrameIndex, const TargetRegisterClass *RC,
129 const TargetRegisterInfo *TRI) const override;
130
131 using TargetInstrInfo::foldMemoryOperandImpl;
132 MachineInstr *foldMemoryOperandImpl(MachineFunction &MF, MachineInstr *MI,
133 ArrayRef<unsigned> Ops,
134 MachineBasicBlock::iterator InsertPt,
135 int FrameIndex) const override;
136
137 bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
138 MachineBasicBlock *&FBB,
139 SmallVectorImpl<MachineOperand> &Cond,
140 bool AllowModify = false) const override;
141 unsigned RemoveBranch(MachineBasicBlock &MBB) const override;
142 unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
143 MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
144 DebugLoc DL) const override;
145 bool
146 ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
147 bool canInsertSelect(const MachineBasicBlock &, ArrayRef<MachineOperand> Cond,
148 unsigned, unsigned, int &, int &, int &) const override;
149 void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
150 DebugLoc DL, unsigned DstReg, ArrayRef<MachineOperand> Cond,
151 unsigned TrueReg, unsigned FalseReg) const override;
152 void getNoopForMachoTarget(MCInst &NopInst) const override;
153
154 /// analyzeCompare - For a comparison instruction, return the source registers
155 /// in SrcReg and SrcReg2, and the value it compares against in CmpValue.
156 /// Return true if the comparison instruction can be analyzed.
157 bool analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
158 unsigned &SrcReg2, int &CmpMask,
159 int &CmpValue) const override;
160 /// optimizeCompareInstr - Convert the instruction supplying the argument to
161 /// the comparison into one that sets the zero bit in the flags register.
162 bool optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg,
163 unsigned SrcReg2, int CmpMask, int CmpValue,
164 const MachineRegisterInfo *MRI) const override;
165 bool optimizeCondBranch(MachineInstr *MI) const override;
166 /// Return true when there is potentially a faster code sequence
167 /// for an instruction chain ending in <Root>. All potential patterns are
168 /// listed in the <Patterns> array.
169 bool getMachineCombinerPatterns(MachineInstr &Root,
170 SmallVectorImpl<MachineCombinerPattern> &Patterns)
171 const override;
172
173 /// When getMachineCombinerPatterns() finds patterns, this function generates
174 /// the instructions that could replace the original code sequence
175 void genAlternativeCodeSequence(
176 MachineInstr &Root, MachineCombinerPattern Pattern,
177 SmallVectorImpl<MachineInstr *> &InsInstrs,
178 SmallVectorImpl<MachineInstr *> &DelInstrs,
179 DenseMap<unsigned, unsigned> &InstrIdxForVirtReg) const override;
180 /// useMachineCombiner - AArch64 supports MachineCombiner
181 bool useMachineCombiner() const override;
182
183 bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const override;
184
185 std::pair<unsigned, unsigned>
186 decomposeMachineOperandsTargetFlags(unsigned TF) const override;
187 ArrayRef<std::pair<unsigned, const char *>>
188 getSerializableDirectMachineOperandTargetFlags() const override;
189 ArrayRef<std::pair<unsigned, const char *>>
190 getSerializableBitmaskMachineOperandTargetFlags() const override;
191
192 private:
193 void instantiateCondBranch(MachineBasicBlock &MBB, DebugLoc DL,
194 MachineBasicBlock *TBB,
195 ArrayRef<MachineOperand> Cond) const;
196 };
197
198 /// emitFrameOffset - Emit instructions as needed to set DestReg to SrcReg
199 /// plus Offset. This is intended to be used from within the prolog/epilog
200 /// insertion (PEI) pass, where a virtual scratch register may be allocated
201 /// if necessary, to be replaced by the scavenger at the end of PEI.
202 void emitFrameOffset(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
203 DebugLoc DL, unsigned DestReg, unsigned SrcReg, int Offset,
204 const TargetInstrInfo *TII,
205 MachineInstr::MIFlag = MachineInstr::NoFlags,
206 bool SetNZCV = false);
207
208 /// rewriteAArch64FrameIndex - Rewrite MI to access 'Offset' bytes from the
209 /// FP. Return false if the offset could not be handled directly in MI, and
210 /// return the left-over portion by reference.
211 bool rewriteAArch64FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
212 unsigned FrameReg, int &Offset,
213 const AArch64InstrInfo *TII);
214
215 /// \brief Use to report the frame offset status in isAArch64FrameOffsetLegal.
216 enum AArch64FrameOffsetStatus {
217 AArch64FrameOffsetCannotUpdate = 0x0, ///< Offset cannot apply.
218 AArch64FrameOffsetIsLegal = 0x1, ///< Offset is legal.
219 AArch64FrameOffsetCanUpdate = 0x2 ///< Offset can apply, at least partly.
220 };
221
222 /// \brief Check if the @p Offset is a valid frame offset for @p MI.
223 /// The returned value reports the validity of the frame offset for @p MI.
224 /// It uses the values defined by AArch64FrameOffsetStatus for that.
225 /// If result == AArch64FrameOffsetCannotUpdate, @p MI cannot be updated to
226 /// use an offset.eq
227 /// If result & AArch64FrameOffsetIsLegal, @p Offset can completely be
228 /// rewriten in @p MI.
229 /// If result & AArch64FrameOffsetCanUpdate, @p Offset contains the
230 /// amount that is off the limit of the legal offset.
231 /// If set, @p OutUseUnscaledOp will contain the whether @p MI should be
232 /// turned into an unscaled operator, which opcode is in @p OutUnscaledOp.
233 /// If set, @p EmittableOffset contains the amount that can be set in @p MI
234 /// (possibly with @p OutUnscaledOp if OutUseUnscaledOp is true) and that
235 /// is a legal offset.
236 int isAArch64FrameOffsetLegal(const MachineInstr &MI, int &Offset,
237 bool *OutUseUnscaledOp = nullptr,
238 unsigned *OutUnscaledOp = nullptr,
239 int *EmittableOffset = nullptr);
240
isUncondBranchOpcode(int Opc)241 static inline bool isUncondBranchOpcode(int Opc) { return Opc == AArch64::B; }
242
isCondBranchOpcode(int Opc)243 static inline bool isCondBranchOpcode(int Opc) {
244 switch (Opc) {
245 case AArch64::Bcc:
246 case AArch64::CBZW:
247 case AArch64::CBZX:
248 case AArch64::CBNZW:
249 case AArch64::CBNZX:
250 case AArch64::TBZW:
251 case AArch64::TBZX:
252 case AArch64::TBNZW:
253 case AArch64::TBNZX:
254 return true;
255 default:
256 return false;
257 }
258 }
259
isIndirectBranchOpcode(int Opc)260 static inline bool isIndirectBranchOpcode(int Opc) { return Opc == AArch64::BR; }
261
262 } // end namespace llvm
263
264 #endif
265