1 //===-- SystemZInstrInfo.h - SystemZ instruction information ----*- 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 contains the SystemZ implementation of the TargetInstrInfo class.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZINSTRINFO_H
14 #define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZINSTRINFO_H
15 
16 #include "SystemZ.h"
17 #include "SystemZRegisterInfo.h"
18 #include "llvm/ADT/ArrayRef.h"
19 #include "llvm/CodeGen/MachineBasicBlock.h"
20 #include "llvm/CodeGen/MachineFunction.h"
21 #include "llvm/CodeGen/MachineInstrBuilder.h"
22 #include "llvm/CodeGen/TargetInstrInfo.h"
23 #include <cstdint>
24 
25 #define GET_INSTRINFO_HEADER
26 #include "SystemZGenInstrInfo.inc"
27 
28 namespace llvm {
29 
30 class SystemZSubtarget;
31 
32 namespace SystemZII {
33 
34 enum {
35   // See comments in SystemZInstrFormats.td.
36   SimpleBDXLoad          = (1 << 0),
37   SimpleBDXStore         = (1 << 1),
38   Has20BitOffset         = (1 << 2),
39   HasIndex               = (1 << 3),
40   Is128Bit               = (1 << 4),
41   AccessSizeMask         = (31 << 5),
42   AccessSizeShift        = 5,
43   CCValuesMask           = (15 << 10),
44   CCValuesShift          = 10,
45   CompareZeroCCMaskMask  = (15 << 14),
46   CompareZeroCCMaskShift = 14,
47   CCMaskFirst            = (1 << 18),
48   CCMaskLast             = (1 << 19),
49   IsLogical              = (1 << 20),
50   CCIfNoSignedWrap       = (1 << 21)
51 };
52 
53 static inline unsigned getAccessSize(unsigned int Flags) {
54   return (Flags & AccessSizeMask) >> AccessSizeShift;
55 }
56 
57 static inline unsigned getCCValues(unsigned int Flags) {
58   return (Flags & CCValuesMask) >> CCValuesShift;
59 }
60 
61 static inline unsigned getCompareZeroCCMask(unsigned int Flags) {
62   return (Flags & CompareZeroCCMaskMask) >> CompareZeroCCMaskShift;
63 }
64 
65 // SystemZ MachineOperand target flags.
66 enum {
67   // Masks out the bits for the access model.
68   MO_SYMBOL_MODIFIER = (3 << 0),
69 
70   // @GOT (aka @GOTENT)
71   MO_GOT = (1 << 0),
72 
73   // @INDNTPOFF
74   MO_INDNTPOFF = (2 << 0)
75 };
76 
77 // Classifies a branch.
78 enum BranchType {
79   // An instruction that branches on the current value of CC.
80   BranchNormal,
81 
82   // An instruction that peforms a 32-bit signed comparison and branches
83   // on the result.
84   BranchC,
85 
86   // An instruction that peforms a 32-bit unsigned comparison and branches
87   // on the result.
88   BranchCL,
89 
90   // An instruction that peforms a 64-bit signed comparison and branches
91   // on the result.
92   BranchCG,
93 
94   // An instruction that peforms a 64-bit unsigned comparison and branches
95   // on the result.
96   BranchCLG,
97 
98   // An instruction that decrements a 32-bit register and branches if
99   // the result is nonzero.
100   BranchCT,
101 
102   // An instruction that decrements a 64-bit register and branches if
103   // the result is nonzero.
104   BranchCTG,
105 
106   // An instruction representing an asm goto statement.
107   AsmGoto
108 };
109 
110 // Information about a branch instruction.
111 class Branch {
112   // The target of the branch. In case of INLINEASM_BR, this is nullptr.
113   const MachineOperand *Target;
114 
115 public:
116   // The type of the branch.
117   BranchType Type;
118 
119   // CCMASK_<N> is set if CC might be equal to N.
120   unsigned CCValid;
121 
122   // CCMASK_<N> is set if the branch should be taken when CC == N.
123   unsigned CCMask;
124 
125   Branch(BranchType type, unsigned ccValid, unsigned ccMask,
126          const MachineOperand *target)
127     : Target(target), Type(type), CCValid(ccValid), CCMask(ccMask) {}
128 
129   bool isIndirect() { return Target != nullptr && Target->isReg(); }
130   bool hasMBBTarget() { return Target != nullptr && Target->isMBB(); }
131   MachineBasicBlock *getMBBTarget() {
132     return hasMBBTarget() ? Target->getMBB() : nullptr;
133   }
134 };
135 
136 // Kinds of fused compares in compare-and-* instructions.  Together with type
137 // of the converted compare, this identifies the compare-and-*
138 // instruction.
139 enum FusedCompareType {
140   // Relative branch - CRJ etc.
141   CompareAndBranch,
142 
143   // Indirect branch, used for return - CRBReturn etc.
144   CompareAndReturn,
145 
146   // Indirect branch, used for sibcall - CRBCall etc.
147   CompareAndSibcall,
148 
149   // Trap
150   CompareAndTrap
151 };
152 
153 } // end namespace SystemZII
154 
155 namespace SystemZ {
156 int getTwoOperandOpcode(uint16_t Opcode);
157 int getTargetMemOpcode(uint16_t Opcode);
158 }
159 
160 class SystemZInstrInfo : public SystemZGenInstrInfo {
161   const SystemZRegisterInfo RI;
162   SystemZSubtarget &STI;
163 
164   void splitMove(MachineBasicBlock::iterator MI, unsigned NewOpcode) const;
165   void splitAdjDynAlloc(MachineBasicBlock::iterator MI) const;
166   void expandRIPseudo(MachineInstr &MI, unsigned LowOpcode, unsigned HighOpcode,
167                       bool ConvertHigh) const;
168   void expandRIEPseudo(MachineInstr &MI, unsigned LowOpcode,
169                        unsigned LowOpcodeK, unsigned HighOpcode) const;
170   void expandRXYPseudo(MachineInstr &MI, unsigned LowOpcode,
171                        unsigned HighOpcode) const;
172   void expandLOCPseudo(MachineInstr &MI, unsigned LowOpcode,
173                        unsigned HighOpcode) const;
174   void expandZExtPseudo(MachineInstr &MI, unsigned LowOpcode,
175                         unsigned Size) const;
176   void expandLoadStackGuard(MachineInstr *MI) const;
177 
178   MachineInstrBuilder
179   emitGRX32Move(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
180                 const DebugLoc &DL, unsigned DestReg, unsigned SrcReg,
181                 unsigned LowLowOpcode, unsigned Size, bool KillSrc,
182                 bool UndefSrc) const;
183 
184   virtual void anchor();
185 
186 protected:
187   /// Commutes the operands in the given instruction by changing the operands
188   /// order and/or changing the instruction's opcode and/or the immediate value
189   /// operand.
190   ///
191   /// The arguments 'CommuteOpIdx1' and 'CommuteOpIdx2' specify the operands
192   /// to be commuted.
193   ///
194   /// Do not call this method for a non-commutable instruction or
195   /// non-commutable operands.
196   /// Even though the instruction is commutable, the method may still
197   /// fail to commute the operands, null pointer is returned in such cases.
198   MachineInstr *commuteInstructionImpl(MachineInstr &MI, bool NewMI,
199                                        unsigned CommuteOpIdx1,
200                                        unsigned CommuteOpIdx2) const override;
201 
202 public:
203   explicit SystemZInstrInfo(SystemZSubtarget &STI);
204 
205   // Override TargetInstrInfo.
206   unsigned isLoadFromStackSlot(const MachineInstr &MI,
207                                int &FrameIndex) const override;
208   unsigned isStoreToStackSlot(const MachineInstr &MI,
209                               int &FrameIndex) const override;
210   bool isStackSlotCopy(const MachineInstr &MI, int &DestFrameIndex,
211                        int &SrcFrameIndex) const override;
212   bool analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
213                      MachineBasicBlock *&FBB,
214                      SmallVectorImpl<MachineOperand> &Cond,
215                      bool AllowModify) const override;
216   unsigned removeBranch(MachineBasicBlock &MBB,
217                         int *BytesRemoved = nullptr) const override;
218   unsigned insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
219                         MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
220                         const DebugLoc &DL,
221                         int *BytesAdded = nullptr) const override;
222   bool analyzeCompare(const MachineInstr &MI, unsigned &SrcReg,
223                       unsigned &SrcReg2, int &Mask, int &Value) const override;
224   bool canInsertSelect(const MachineBasicBlock &, ArrayRef<MachineOperand> Cond,
225                        unsigned, unsigned, unsigned, int &, int &,
226                        int &) const override;
227   void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
228                     const DebugLoc &DL, unsigned DstReg,
229                     ArrayRef<MachineOperand> Cond, unsigned TrueReg,
230                     unsigned FalseReg) const override;
231   bool FoldImmediate(MachineInstr &UseMI, MachineInstr &DefMI, unsigned Reg,
232                      MachineRegisterInfo *MRI) const override;
233   bool isPredicable(const MachineInstr &MI) const override;
234   bool isProfitableToIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
235                            unsigned ExtraPredCycles,
236                            BranchProbability Probability) const override;
237   bool isProfitableToIfCvt(MachineBasicBlock &TMBB,
238                            unsigned NumCyclesT, unsigned ExtraPredCyclesT,
239                            MachineBasicBlock &FMBB,
240                            unsigned NumCyclesF, unsigned ExtraPredCyclesF,
241                            BranchProbability Probability) const override;
242   bool isProfitableToDupForIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
243                             BranchProbability Probability) const override;
244   bool PredicateInstruction(MachineInstr &MI,
245                             ArrayRef<MachineOperand> Pred) const override;
246   void copyPhysReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI,
247                    const DebugLoc &DL, MCRegister DestReg, MCRegister SrcReg,
248                    bool KillSrc) const override;
249   void storeRegToStackSlot(MachineBasicBlock &MBB,
250                            MachineBasicBlock::iterator MBBI,
251                            Register SrcReg, bool isKill, int FrameIndex,
252                            const TargetRegisterClass *RC,
253                            const TargetRegisterInfo *TRI) const override;
254   void loadRegFromStackSlot(MachineBasicBlock &MBB,
255                             MachineBasicBlock::iterator MBBI,
256                             Register DestReg, int FrameIdx,
257                             const TargetRegisterClass *RC,
258                             const TargetRegisterInfo *TRI) const override;
259   MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
260                                       MachineInstr &MI,
261                                       LiveVariables *LV) const override;
262   MachineInstr *
263   foldMemoryOperandImpl(MachineFunction &MF, MachineInstr &MI,
264                         ArrayRef<unsigned> Ops,
265                         MachineBasicBlock::iterator InsertPt, int FrameIndex,
266                         LiveIntervals *LIS = nullptr,
267                         VirtRegMap *VRM = nullptr) const override;
268   MachineInstr *foldMemoryOperandImpl(
269       MachineFunction &MF, MachineInstr &MI, ArrayRef<unsigned> Ops,
270       MachineBasicBlock::iterator InsertPt, MachineInstr &LoadMI,
271       LiveIntervals *LIS = nullptr) const override;
272   bool expandPostRAPseudo(MachineInstr &MBBI) const override;
273   bool reverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const
274     override;
275 
276   // Return the SystemZRegisterInfo, which this class owns.
277   const SystemZRegisterInfo &getRegisterInfo() const { return RI; }
278 
279   // Return the size in bytes of MI.
280   unsigned getInstSizeInBytes(const MachineInstr &MI) const override;
281 
282   // Return true if MI is a conditional or unconditional branch.
283   // When returning true, set Cond to the mask of condition-code
284   // values on which the instruction will branch, and set Target
285   // to the operand that contains the branch target.  This target
286   // can be a register or a basic block.
287   SystemZII::Branch getBranchInfo(const MachineInstr &MI) const;
288 
289   // Get the load and store opcodes for a given register class.
290   void getLoadStoreOpcodes(const TargetRegisterClass *RC,
291                            unsigned &LoadOpcode, unsigned &StoreOpcode) const;
292 
293   // Opcode is the opcode of an instruction that has an address operand,
294   // and the caller wants to perform that instruction's operation on an
295   // address that has displacement Offset.  Return the opcode of a suitable
296   // instruction (which might be Opcode itself) or 0 if no such instruction
297   // exists.
298   unsigned getOpcodeForOffset(unsigned Opcode, int64_t Offset) const;
299 
300   // If Opcode is a load instruction that has a LOAD AND TEST form,
301   // return the opcode for the testing form, otherwise return 0.
302   unsigned getLoadAndTest(unsigned Opcode) const;
303 
304   // Return true if ROTATE AND ... SELECTED BITS can be used to select bits
305   // Mask of the R2 operand, given that only the low BitSize bits of Mask are
306   // significant.  Set Start and End to the I3 and I4 operands if so.
307   bool isRxSBGMask(uint64_t Mask, unsigned BitSize,
308                    unsigned &Start, unsigned &End) const;
309 
310   // If Opcode is a COMPARE opcode for which an associated fused COMPARE AND *
311   // operation exists, return the opcode for the latter, otherwise return 0.
312   // MI, if nonnull, is the compare instruction.
313   unsigned getFusedCompare(unsigned Opcode,
314                            SystemZII::FusedCompareType Type,
315                            const MachineInstr *MI = nullptr) const;
316 
317   // If Opcode is a LOAD opcode for with an associated LOAD AND TRAP
318   // operation exists, returh the opcode for the latter, otherwise return 0.
319   unsigned getLoadAndTrap(unsigned Opcode) const;
320 
321   // Emit code before MBBI in MI to move immediate value Value into
322   // physical register Reg.
323   void loadImmediate(MachineBasicBlock &MBB,
324                      MachineBasicBlock::iterator MBBI,
325                      unsigned Reg, uint64_t Value) const;
326 
327   // Perform target specific instruction verification.
328   bool verifyInstruction(const MachineInstr &MI,
329                          StringRef &ErrInfo) const override;
330 
331   // Sometimes, it is possible for the target to tell, even without
332   // aliasing information, that two MIs access different memory
333   // addresses. This function returns true if two MIs access different
334   // memory addresses and false otherwise.
335   bool
336   areMemAccessesTriviallyDisjoint(const MachineInstr &MIa,
337                                   const MachineInstr &MIb) const override;
338 };
339 
340 } // end namespace llvm
341 
342 #endif // LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZINSTRINFO_H
343