ARMBaseInstrInfo.h revision 263508 
1//===-- ARMBaseInstrInfo.h - ARM Base 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 Base ARM implementation of the TargetInstrInfo class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef ARMBASEINSTRUCTIONINFO_H
15#define ARMBASEINSTRUCTIONINFO_H
16
17#include "ARM.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/SmallSet.h"
20#include "llvm/CodeGen/MachineInstrBuilder.h"
21#include "llvm/Target/TargetInstrInfo.h"
22
23#define GET_INSTRINFO_HEADER
24#include "ARMGenInstrInfo.inc"
25
26namespace llvm {
27  class ARMSubtarget;
28  class ARMBaseRegisterInfo;
29
30class ARMBaseInstrInfo : public ARMGenInstrInfo {
31  const ARMSubtarget &Subtarget;
32
33protected:
34  // Can be only subclassed.
35  explicit ARMBaseInstrInfo(const ARMSubtarget &STI);
36
37public:
38  // Return whether the target has an explicit NOP encoding.
39  bool hasNOP() const;
40
41  // Return the non-pre/post incrementing version of 'Opc'. Return 0
42  // if there is not such an opcode.
43  virtual unsigned getUnindexedOpcode(unsigned Opc) const =0;
44
45  virtual MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
46                                              MachineBasicBlock::iterator &MBBI,
47                                              LiveVariables *LV) const;
48
49  virtual const ARMBaseRegisterInfo &getRegisterInfo() const = 0;
50  const ARMSubtarget &getSubtarget() const { return Subtarget; }
51
52  ScheduleHazardRecognizer *
53  CreateTargetHazardRecognizer(const TargetMachine *TM,
54                               const ScheduleDAG *DAG) const;
55
56  ScheduleHazardRecognizer *
57  CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II,
58                                     const ScheduleDAG *DAG) const;
59
60  // Branch analysis.
61  virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
62                             MachineBasicBlock *&FBB,
63                             SmallVectorImpl<MachineOperand> &Cond,
64                             bool AllowModify = false) const;
65  virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const;
66  virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
67                                MachineBasicBlock *FBB,
68                                const SmallVectorImpl<MachineOperand> &Cond,
69                                DebugLoc DL) const;
70
71  virtual
72  bool ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const;
73
74  // Predication support.
75  bool isPredicated(const MachineInstr *MI) const;
76
77  ARMCC::CondCodes getPredicate(const MachineInstr *MI) const {
78    int PIdx = MI->findFirstPredOperandIdx();
79    return PIdx != -1 ? (ARMCC::CondCodes)MI->getOperand(PIdx).getImm()
80                      : ARMCC::AL;
81  }
82
83  virtual
84  bool PredicateInstruction(MachineInstr *MI,
85                            const SmallVectorImpl<MachineOperand> &Pred) const;
86
87  virtual
88  bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
89                         const SmallVectorImpl<MachineOperand> &Pred2) const;
90
91  virtual bool DefinesPredicate(MachineInstr *MI,
92                                std::vector<MachineOperand> &Pred) const;
93
94  virtual bool isPredicable(MachineInstr *MI) const;
95
96  /// GetInstSize - Returns the size of the specified MachineInstr.
97  ///
98  virtual unsigned GetInstSizeInBytes(const MachineInstr* MI) const;
99
100  virtual unsigned isLoadFromStackSlot(const MachineInstr *MI,
101                                       int &FrameIndex) const;
102  virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
103                                      int &FrameIndex) const;
104  virtual unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI,
105                                             int &FrameIndex) const;
106  virtual unsigned isStoreToStackSlotPostFE(const MachineInstr *MI,
107                                            int &FrameIndex) const;
108
109  virtual void copyPhysReg(MachineBasicBlock &MBB,
110                           MachineBasicBlock::iterator I, DebugLoc DL,
111                           unsigned DestReg, unsigned SrcReg,
112                           bool KillSrc) const;
113
114  virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
115                                   MachineBasicBlock::iterator MBBI,
116                                   unsigned SrcReg, bool isKill, int FrameIndex,
117                                   const TargetRegisterClass *RC,
118                                   const TargetRegisterInfo *TRI) const;
119
120  virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
121                                    MachineBasicBlock::iterator MBBI,
122                                    unsigned DestReg, int FrameIndex,
123                                    const TargetRegisterClass *RC,
124                                    const TargetRegisterInfo *TRI) const;
125
126  virtual bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const;
127
128  virtual void reMaterialize(MachineBasicBlock &MBB,
129                             MachineBasicBlock::iterator MI,
130                             unsigned DestReg, unsigned SubIdx,
131                             const MachineInstr *Orig,
132                             const TargetRegisterInfo &TRI) const;
133
134  MachineInstr *duplicate(MachineInstr *Orig, MachineFunction &MF) const;
135
136  MachineInstr *commuteInstruction(MachineInstr*, bool=false) const;
137
138  const MachineInstrBuilder &AddDReg(MachineInstrBuilder &MIB, unsigned Reg,
139                                     unsigned SubIdx, unsigned State,
140                                     const TargetRegisterInfo *TRI) const;
141
142  virtual bool produceSameValue(const MachineInstr *MI0,
143                                const MachineInstr *MI1,
144                                const MachineRegisterInfo *MRI) const;
145
146  /// areLoadsFromSameBasePtr - This is used by the pre-regalloc scheduler to
147  /// determine if two loads are loading from the same base address. It should
148  /// only return true if the base pointers are the same and the only
149  /// differences between the two addresses is the offset. It also returns the
150  /// offsets by reference.
151  virtual bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2,
152                                       int64_t &Offset1, int64_t &Offset2)const;
153
154  /// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
155  /// determine (in conjunction with areLoadsFromSameBasePtr) if two loads
156  /// should be scheduled togther. On some targets if two loads are loading from
157  /// addresses in the same cache line, it's better if they are scheduled
158  /// together. This function takes two integers that represent the load offsets
159  /// from the common base address. It returns true if it decides it's desirable
160  /// to schedule the two loads together. "NumLoads" is the number of loads that
161  /// have already been scheduled after Load1.
162  virtual bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2,
163                                       int64_t Offset1, int64_t Offset2,
164                                       unsigned NumLoads) const;
165
166  virtual bool isSchedulingBoundary(const MachineInstr *MI,
167                                    const MachineBasicBlock *MBB,
168                                    const MachineFunction &MF) const;
169
170  virtual bool isProfitableToIfCvt(MachineBasicBlock &MBB,
171                                   unsigned NumCycles, unsigned ExtraPredCycles,
172                                   const BranchProbability &Probability) const;
173
174  virtual bool isProfitableToIfCvt(MachineBasicBlock &TMBB,
175                                   unsigned NumT, unsigned ExtraT,
176                                   MachineBasicBlock &FMBB,
177                                   unsigned NumF, unsigned ExtraF,
178                                   const BranchProbability &Probability) const;
179
180  virtual bool isProfitableToDupForIfCvt(MachineBasicBlock &MBB,
181                                         unsigned NumCycles,
182                                         const BranchProbability
183                                         &Probability) const {
184    return NumCycles == 1;
185  }
186
187  virtual bool isProfitableToUnpredicate(MachineBasicBlock &TMBB,
188                                         MachineBasicBlock &FMBB) const;
189
190  /// analyzeCompare - For a comparison instruction, return the source registers
191  /// in SrcReg and SrcReg2 if having two register operands, and the value it
192  /// compares against in CmpValue. Return true if the comparison instruction
193  /// can be analyzed.
194  virtual bool analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
195                              unsigned &SrcReg2, int &CmpMask,
196                              int &CmpValue) const;
197
198  /// optimizeCompareInstr - Convert the instruction to set the zero flag so
199  /// that we can remove a "comparison with zero"; Remove a redundant CMP
200  /// instruction if the flags can be updated in the same way by an earlier
201  /// instruction such as SUB.
202  virtual bool optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg,
203                                    unsigned SrcReg2, int CmpMask, int CmpValue,
204                                    const MachineRegisterInfo *MRI) const;
205
206  virtual bool analyzeSelect(const MachineInstr *MI,
207                             SmallVectorImpl<MachineOperand> &Cond,
208                             unsigned &TrueOp, unsigned &FalseOp,
209                             bool &Optimizable) const;
210
211  virtual MachineInstr *optimizeSelect(MachineInstr *MI, bool) const;
212
213  /// FoldImmediate - 'Reg' is known to be defined by a move immediate
214  /// instruction, try to fold the immediate into the use instruction.
215  virtual bool FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI,
216                             unsigned Reg, MachineRegisterInfo *MRI) const;
217
218  virtual unsigned getNumMicroOps(const InstrItineraryData *ItinData,
219                                  const MachineInstr *MI) const;
220
221  virtual
222  int getOperandLatency(const InstrItineraryData *ItinData,
223                        const MachineInstr *DefMI, unsigned DefIdx,
224                        const MachineInstr *UseMI, unsigned UseIdx) const;
225  virtual
226  int getOperandLatency(const InstrItineraryData *ItinData,
227                        SDNode *DefNode, unsigned DefIdx,
228                        SDNode *UseNode, unsigned UseIdx) const;
229
230  /// VFP/NEON execution domains.
231  std::pair<uint16_t, uint16_t>
232  getExecutionDomain(const MachineInstr *MI) const;
233  void setExecutionDomain(MachineInstr *MI, unsigned Domain) const;
234
235  unsigned getPartialRegUpdateClearance(const MachineInstr*, unsigned,
236                                        const TargetRegisterInfo*) const;
237  void breakPartialRegDependency(MachineBasicBlock::iterator, unsigned,
238                                 const TargetRegisterInfo *TRI) const;
239  /// Get the number of addresses by LDM or VLDM or zero for unknown.
240  unsigned getNumLDMAddresses(const MachineInstr *MI) const;
241
242private:
243  unsigned getInstBundleLength(const MachineInstr *MI) const;
244
245  int getVLDMDefCycle(const InstrItineraryData *ItinData,
246                      const MCInstrDesc &DefMCID,
247                      unsigned DefClass,
248                      unsigned DefIdx, unsigned DefAlign) const;
249  int getLDMDefCycle(const InstrItineraryData *ItinData,
250                     const MCInstrDesc &DefMCID,
251                     unsigned DefClass,
252                     unsigned DefIdx, unsigned DefAlign) const;
253  int getVSTMUseCycle(const InstrItineraryData *ItinData,
254                      const MCInstrDesc &UseMCID,
255                      unsigned UseClass,
256                      unsigned UseIdx, unsigned UseAlign) const;
257  int getSTMUseCycle(const InstrItineraryData *ItinData,
258                     const MCInstrDesc &UseMCID,
259                     unsigned UseClass,
260                     unsigned UseIdx, unsigned UseAlign) const;
261  int getOperandLatency(const InstrItineraryData *ItinData,
262                        const MCInstrDesc &DefMCID,
263                        unsigned DefIdx, unsigned DefAlign,
264                        const MCInstrDesc &UseMCID,
265                        unsigned UseIdx, unsigned UseAlign) const;
266
267  unsigned getPredicationCost(const MachineInstr *MI) const;
268
269  unsigned getInstrLatency(const InstrItineraryData *ItinData,
270                           const MachineInstr *MI,
271                           unsigned *PredCost = 0) const;
272
273  int getInstrLatency(const InstrItineraryData *ItinData,
274                      SDNode *Node) const;
275
276  bool hasHighOperandLatency(const InstrItineraryData *ItinData,
277                             const MachineRegisterInfo *MRI,
278                             const MachineInstr *DefMI, unsigned DefIdx,
279                             const MachineInstr *UseMI, unsigned UseIdx) const;
280  bool hasLowDefLatency(const InstrItineraryData *ItinData,
281                        const MachineInstr *DefMI, unsigned DefIdx) const;
282
283  /// verifyInstruction - Perform target specific instruction verification.
284  bool verifyInstruction(const MachineInstr *MI, StringRef &ErrInfo) const;
285
286private:
287  /// Modeling special VFP / NEON fp MLA / MLS hazards.
288
289  /// MLxEntryMap - Map fp MLA / MLS to the corresponding entry in the internal
290  /// MLx table.
291  DenseMap<unsigned, unsigned> MLxEntryMap;
292
293  /// MLxHazardOpcodes - Set of add / sub and multiply opcodes that would cause
294  /// stalls when scheduled together with fp MLA / MLS opcodes.
295  SmallSet<unsigned, 16> MLxHazardOpcodes;
296
297public:
298  /// isFpMLxInstruction - Return true if the specified opcode is a fp MLA / MLS
299  /// instruction.
300  bool isFpMLxInstruction(unsigned Opcode) const {
301    return MLxEntryMap.count(Opcode);
302  }
303
304  /// isFpMLxInstruction - This version also returns the multiply opcode and the
305  /// addition / subtraction opcode to expand to. Return true for 'HasLane' for
306  /// the MLX instructions with an extra lane operand.
307  bool isFpMLxInstruction(unsigned Opcode, unsigned &MulOpc,
308                          unsigned &AddSubOpc, bool &NegAcc,
309                          bool &HasLane) const;
310
311  /// canCauseFpMLxStall - Return true if an instruction of the specified opcode
312  /// will cause stalls when scheduled after (within 4-cycle window) a fp
313  /// MLA / MLS instruction.
314  bool canCauseFpMLxStall(unsigned Opcode) const {
315    return MLxHazardOpcodes.count(Opcode);
316  }
317
318  /// Returns true if the instruction has a shift by immediate that can be
319  /// executed in one cycle less.
320  bool isSwiftFastImmShift(const MachineInstr *MI) const;
321};
322
323static inline
324const MachineInstrBuilder &AddDefaultPred(const MachineInstrBuilder &MIB) {
325  return MIB.addImm((int64_t)ARMCC::AL).addReg(0);
326}
327
328static inline
329const MachineInstrBuilder &AddDefaultCC(const MachineInstrBuilder &MIB) {
330  return MIB.addReg(0);
331}
332
333static inline
334const MachineInstrBuilder &AddDefaultT1CC(const MachineInstrBuilder &MIB,
335                                          bool isDead = false) {
336  return MIB.addReg(ARM::CPSR, getDefRegState(true) | getDeadRegState(isDead));
337}
338
339static inline
340const MachineInstrBuilder &AddNoT1CC(const MachineInstrBuilder &MIB) {
341  return MIB.addReg(0);
342}
343
344static inline
345bool isUncondBranchOpcode(int Opc) {
346  return Opc == ARM::B || Opc == ARM::tB || Opc == ARM::t2B;
347}
348
349static inline
350bool isCondBranchOpcode(int Opc) {
351  return Opc == ARM::Bcc || Opc == ARM::tBcc || Opc == ARM::t2Bcc;
352}
353
354static inline
355bool isJumpTableBranchOpcode(int Opc) {
356  return Opc == ARM::BR_JTr || Opc == ARM::BR_JTm || Opc == ARM::BR_JTadd ||
357    Opc == ARM::tBR_JTr || Opc == ARM::t2BR_JT;
358}
359
360static inline
361bool isIndirectBranchOpcode(int Opc) {
362  return Opc == ARM::BX || Opc == ARM::MOVPCRX || Opc == ARM::tBRIND;
363}
364
365static inline bool isPopOpcode(int Opc) {
366  return Opc == ARM::tPOP_RET || Opc == ARM::LDMIA_RET ||
367         Opc == ARM::t2LDMIA_RET || Opc == ARM::tPOP || Opc == ARM::LDMIA_UPD ||
368         Opc == ARM::t2LDMIA_UPD || Opc == ARM::VLDMDIA_UPD;
369}
370
371static inline bool isPushOpcode(int Opc) {
372  return Opc == ARM::tPUSH || Opc == ARM::t2STMDB_UPD ||
373         Opc == ARM::STMDB_UPD || Opc == ARM::VSTMDDB_UPD;
374}
375
376/// getInstrPredicate - If instruction is predicated, returns its predicate
377/// condition, otherwise returns AL. It also returns the condition code
378/// register by reference.
379ARMCC::CondCodes getInstrPredicate(const MachineInstr *MI, unsigned &PredReg);
380
381int getMatchingCondBranchOpcode(int Opc);
382
383/// Determine if MI can be folded into an ARM MOVCC instruction, and return the
384/// opcode of the SSA instruction representing the conditional MI.
385unsigned canFoldARMInstrIntoMOVCC(unsigned Reg,
386                                  MachineInstr *&MI,
387                                  const MachineRegisterInfo &MRI);
388
389/// Map pseudo instructions that imply an 'S' bit onto real opcodes. Whether
390/// the instruction is encoded with an 'S' bit is determined by the optional
391/// CPSR def operand.
392unsigned convertAddSubFlagsOpcode(unsigned OldOpc);
393
394/// emitARMRegPlusImmediate / emitT2RegPlusImmediate - Emits a series of
395/// instructions to materializea destreg = basereg + immediate in ARM / Thumb2
396/// code.
397void emitARMRegPlusImmediate(MachineBasicBlock &MBB,
398                             MachineBasicBlock::iterator &MBBI, DebugLoc dl,
399                             unsigned DestReg, unsigned BaseReg, int NumBytes,
400                             ARMCC::CondCodes Pred, unsigned PredReg,
401                             const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
402
403void emitT2RegPlusImmediate(MachineBasicBlock &MBB,
404                            MachineBasicBlock::iterator &MBBI, DebugLoc dl,
405                            unsigned DestReg, unsigned BaseReg, int NumBytes,
406                            ARMCC::CondCodes Pred, unsigned PredReg,
407                            const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
408void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
409                               MachineBasicBlock::iterator &MBBI, DebugLoc dl,
410                               unsigned DestReg, unsigned BaseReg,
411                               int NumBytes, const TargetInstrInfo &TII,
412                               const ARMBaseRegisterInfo& MRI,
413                               unsigned MIFlags = 0);
414
415/// Tries to add registers to the reglist of a given base-updating
416/// push/pop instruction to adjust the stack by an additional
417/// NumBytes. This can save a few bytes per function in code-size, but
418/// obviously generates more memory traffic. As such, it only takes
419/// effect in functions being optimised for size.
420bool tryFoldSPUpdateIntoPushPop(MachineFunction &MF, MachineInstr *MI,
421                                unsigned NumBytes);
422
423/// rewriteARMFrameIndex / rewriteT2FrameIndex -
424/// Rewrite MI to access 'Offset' bytes from the FP. Return false if the
425/// offset could not be handled directly in MI, and return the left-over
426/// portion by reference.
427bool rewriteARMFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
428                          unsigned FrameReg, int &Offset,
429                          const ARMBaseInstrInfo &TII);
430
431bool rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
432                         unsigned FrameReg, int &Offset,
433                         const ARMBaseInstrInfo &TII);
434
435} // End llvm namespace
436
437#endif
438