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	Peephole optimization that generates a single conditional branch for csinc-branch sequences like in the examples below. This is possible when the csinc sets or clears a register based on a condition code and the branch checks that register. Also the condition code may not be modified between the csinc and the original branch. Examples: 1. Convert csinc w9, wzr, wzr, <CC>;tbnz w9, #0, 0x44 to b.<invCC> 2. Convert csinc w9, wzr, wzr, <CC>; tbz w9, #0, 0x44 to b.<CC> rdar://problem/18506500 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219742 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			1215 lines
		
	
	
		
			55 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			1215 lines
		
	
	
		
			55 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===-- llvm/Target/TargetInstrInfo.h - Instruction Info --------*- C++ -*-===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| //
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| // This file describes the target machine instruction set to the code generator.
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| //
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| //===----------------------------------------------------------------------===//
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| 
 | |
| #ifndef LLVM_TARGET_TARGETINSTRINFO_H
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| #define LLVM_TARGET_TARGETINSTRINFO_H
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| 
 | |
| #include "llvm/ADT/SmallSet.h"
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| #include "llvm/ADT/DenseMap.h"
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| #include "llvm/CodeGen/MachineFunction.h"
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| #include "llvm/CodeGen/MachineCombinerPattern.h"
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| #include "llvm/MC/MCInstrInfo.h"
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| #include "llvm/Target/TargetRegisterInfo.h"
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| 
 | |
| namespace llvm {
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| 
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| class InstrItineraryData;
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| class LiveVariables;
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| class MCAsmInfo;
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| class MachineMemOperand;
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| class MachineRegisterInfo;
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| class MDNode;
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| class MCInst;
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| struct MCSchedModel;
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| class MCSymbolRefExpr;
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| class SDNode;
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| class ScheduleHazardRecognizer;
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| class SelectionDAG;
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| class ScheduleDAG;
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| class TargetRegisterClass;
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| class TargetRegisterInfo;
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| class BranchProbability;
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| class TargetSubtargetInfo;
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| class DFAPacketizer;
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| 
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| template<class T> class SmallVectorImpl;
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| 
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| 
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| //---------------------------------------------------------------------------
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| ///
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| /// TargetInstrInfo - Interface to description of machine instruction set
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| ///
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| class TargetInstrInfo : public MCInstrInfo {
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|   TargetInstrInfo(const TargetInstrInfo &) LLVM_DELETED_FUNCTION;
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|   void operator=(const TargetInstrInfo &) LLVM_DELETED_FUNCTION;
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| public:
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|   TargetInstrInfo(int CFSetupOpcode = -1, int CFDestroyOpcode = -1)
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|     : CallFrameSetupOpcode(CFSetupOpcode),
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|       CallFrameDestroyOpcode(CFDestroyOpcode) {
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|   }
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| 
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|   virtual ~TargetInstrInfo();
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| 
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|   /// getRegClass - Givem a machine instruction descriptor, returns the register
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|   /// class constraint for OpNum, or NULL.
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|   const TargetRegisterClass *getRegClass(const MCInstrDesc &TID,
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|                                          unsigned OpNum,
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|                                          const TargetRegisterInfo *TRI,
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|                                          const MachineFunction &MF) const;
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| 
 | |
|   /// isTriviallyReMaterializable - Return true if the instruction is trivially
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|   /// rematerializable, meaning it has no side effects and requires no operands
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|   /// that aren't always available.
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|   bool isTriviallyReMaterializable(const MachineInstr *MI,
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|                                    AliasAnalysis *AA = nullptr) const {
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|     return MI->getOpcode() == TargetOpcode::IMPLICIT_DEF ||
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|            (MI->getDesc().isRematerializable() &&
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|             (isReallyTriviallyReMaterializable(MI, AA) ||
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|              isReallyTriviallyReMaterializableGeneric(MI, AA)));
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|   }
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| 
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| protected:
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|   /// isReallyTriviallyReMaterializable - For instructions with opcodes for
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|   /// which the M_REMATERIALIZABLE flag is set, this hook lets the target
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|   /// specify whether the instruction is actually trivially rematerializable,
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|   /// taking into consideration its operands. This predicate must return false
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|   /// if the instruction has any side effects other than producing a value, or
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|   /// if it requres any address registers that are not always available.
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|   virtual bool isReallyTriviallyReMaterializable(const MachineInstr *MI,
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|                                                  AliasAnalysis *AA) const {
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|     return false;
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|   }
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| 
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| private:
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|   /// isReallyTriviallyReMaterializableGeneric - For instructions with opcodes
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|   /// for which the M_REMATERIALIZABLE flag is set and the target hook
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|   /// isReallyTriviallyReMaterializable returns false, this function does
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|   /// target-independent tests to determine if the instruction is really
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|   /// trivially rematerializable.
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|   bool isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI,
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|                                                 AliasAnalysis *AA) const;
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| 
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| public:
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|   /// getCallFrameSetup/DestroyOpcode - These methods return the opcode of the
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|   /// frame setup/destroy instructions if they exist (-1 otherwise).  Some
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|   /// targets use pseudo instructions in order to abstract away the difference
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|   /// between operating with a frame pointer and operating without, through the
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|   /// use of these two instructions.
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|   ///
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|   int getCallFrameSetupOpcode() const { return CallFrameSetupOpcode; }
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|   int getCallFrameDestroyOpcode() const { return CallFrameDestroyOpcode; }
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| 
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|   /// isCoalescableExtInstr - Return true if the instruction is a "coalescable"
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|   /// extension instruction. That is, it's like a copy where it's legal for the
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|   /// source to overlap the destination. e.g. X86::MOVSX64rr32. If this returns
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|   /// true, then it's expected the pre-extension value is available as a subreg
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|   /// of the result register. This also returns the sub-register index in
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|   /// SubIdx.
 | |
|   virtual bool isCoalescableExtInstr(const MachineInstr &MI,
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|                                      unsigned &SrcReg, unsigned &DstReg,
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|                                      unsigned &SubIdx) const {
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|     return false;
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|   }
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| 
 | |
|   /// isLoadFromStackSlot - If the specified machine instruction is a direct
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|   /// load from a stack slot, return the virtual or physical register number of
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|   /// the destination along with the FrameIndex of the loaded stack slot.  If
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|   /// not, return 0.  This predicate must return 0 if the instruction has
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|   /// any side effects other than loading from the stack slot.
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|   virtual unsigned isLoadFromStackSlot(const MachineInstr *MI,
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|                                        int &FrameIndex) const {
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|     return 0;
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|   }
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| 
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|   /// isLoadFromStackSlotPostFE - Check for post-frame ptr elimination
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|   /// stack locations as well.  This uses a heuristic so it isn't
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|   /// reliable for correctness.
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|   virtual unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI,
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|                                              int &FrameIndex) const {
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|     return 0;
 | |
|   }
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| 
 | |
|   /// hasLoadFromStackSlot - If the specified machine instruction has
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|   /// a load from a stack slot, return true along with the FrameIndex
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|   /// of the loaded stack slot and the machine mem operand containing
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|   /// the reference.  If not, return false.  Unlike
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|   /// isLoadFromStackSlot, this returns true for any instructions that
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|   /// loads from the stack.  This is just a hint, as some cases may be
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|   /// missed.
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|   virtual bool hasLoadFromStackSlot(const MachineInstr *MI,
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|                                     const MachineMemOperand *&MMO,
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|                                     int &FrameIndex) const;
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| 
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|   /// isStoreToStackSlot - If the specified machine instruction is a direct
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|   /// store to a stack slot, return the virtual or physical register number of
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|   /// the source reg along with the FrameIndex of the loaded stack slot.  If
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|   /// not, return 0.  This predicate must return 0 if the instruction has
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|   /// any side effects other than storing to the stack slot.
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|   virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
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|                                       int &FrameIndex) const {
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|     return 0;
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|   }
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| 
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|   /// isStoreToStackSlotPostFE - Check for post-frame ptr elimination
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|   /// stack locations as well.  This uses a heuristic so it isn't
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|   /// reliable for correctness.
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|   virtual unsigned isStoreToStackSlotPostFE(const MachineInstr *MI,
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|                                             int &FrameIndex) const {
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|     return 0;
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|   }
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| 
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|   /// hasStoreToStackSlot - If the specified machine instruction has a
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|   /// store to a stack slot, return true along with the FrameIndex of
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|   /// the loaded stack slot and the machine mem operand containing the
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|   /// reference.  If not, return false.  Unlike isStoreToStackSlot,
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|   /// this returns true for any instructions that stores to the
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|   /// stack.  This is just a hint, as some cases may be missed.
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|   virtual bool hasStoreToStackSlot(const MachineInstr *MI,
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|                                    const MachineMemOperand *&MMO,
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|                                    int &FrameIndex) const;
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| 
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|   /// isStackSlotCopy - Return true if the specified machine instruction
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|   /// is a copy of one stack slot to another and has no other effect.
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|   /// Provide the identity of the two frame indices.
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|   virtual bool isStackSlotCopy(const MachineInstr *MI, int &DestFrameIndex,
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|                                int &SrcFrameIndex) const {
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|     return false;
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|   }
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| 
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|   /// Compute the size in bytes and offset within a stack slot of a spilled
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|   /// register or subregister.
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|   ///
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|   /// \param [out] Size in bytes of the spilled value.
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|   /// \param [out] Offset in bytes within the stack slot.
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|   /// \returns true if both Size and Offset are successfully computed.
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|   ///
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|   /// Not all subregisters have computable spill slots. For example,
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|   /// subregisters registers may not be byte-sized, and a pair of discontiguous
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|   /// subregisters has no single offset.
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|   ///
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|   /// Targets with nontrivial bigendian implementations may need to override
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|   /// this, particularly to support spilled vector registers.
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|   virtual bool getStackSlotRange(const TargetRegisterClass *RC, unsigned SubIdx,
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|                                  unsigned &Size, unsigned &Offset,
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|                                  const TargetMachine *TM) const;
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| 
 | |
|   /// isAsCheapAsAMove - Return true if the instruction is as cheap as a move
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|   /// instruction.
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|   ///
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|   /// Targets for different archs need to override this, and different
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|   /// micro-architectures can also be finely tuned inside.
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|   virtual bool isAsCheapAsAMove(const MachineInstr *MI) const {
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|     return MI->isAsCheapAsAMove();
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|   }
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| 
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|   /// reMaterialize - Re-issue the specified 'original' instruction at the
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|   /// specific location targeting a new destination register.
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|   /// The register in Orig->getOperand(0).getReg() will be substituted by
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|   /// DestReg:SubIdx. Any existing subreg index is preserved or composed with
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|   /// SubIdx.
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|   virtual void reMaterialize(MachineBasicBlock &MBB,
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|                              MachineBasicBlock::iterator MI,
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|                              unsigned DestReg, unsigned SubIdx,
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|                              const MachineInstr *Orig,
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|                              const TargetRegisterInfo &TRI) const;
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| 
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|   /// duplicate - Create a duplicate of the Orig instruction in MF. This is like
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|   /// MachineFunction::CloneMachineInstr(), but the target may update operands
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|   /// that are required to be unique.
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|   ///
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|   /// The instruction must be duplicable as indicated by isNotDuplicable().
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|   virtual MachineInstr *duplicate(MachineInstr *Orig,
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|                                   MachineFunction &MF) const;
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| 
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|   /// convertToThreeAddress - This method must be implemented by targets that
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|   /// set the M_CONVERTIBLE_TO_3_ADDR flag.  When this flag is set, the target
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|   /// may be able to convert a two-address instruction into one or more true
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|   /// three-address instructions on demand.  This allows the X86 target (for
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|   /// example) to convert ADD and SHL instructions into LEA instructions if they
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|   /// would require register copies due to two-addressness.
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|   ///
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|   /// This method returns a null pointer if the transformation cannot be
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|   /// performed, otherwise it returns the last new instruction.
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|   ///
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|   virtual MachineInstr *
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|   convertToThreeAddress(MachineFunction::iterator &MFI,
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|                    MachineBasicBlock::iterator &MBBI, LiveVariables *LV) const {
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|     return nullptr;
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|   }
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| 
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|   /// commuteInstruction - If a target has any instructions that are
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|   /// commutable but require converting to different instructions or making
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|   /// non-trivial changes to commute them, this method can overloaded to do
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|   /// that.  The default implementation simply swaps the commutable operands.
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|   /// If NewMI is false, MI is modified in place and returned; otherwise, a
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|   /// new machine instruction is created and returned.  Do not call this
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|   /// method for a non-commutable instruction, but there may be some cases
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|   /// where this method fails and returns null.
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|   virtual MachineInstr *commuteInstruction(MachineInstr *MI,
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|                                            bool NewMI = false) const;
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| 
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|   /// findCommutedOpIndices - If specified MI is commutable, return the two
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|   /// operand indices that would swap value. Return false if the instruction
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|   /// is not in a form which this routine understands.
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|   virtual bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1,
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|                                      unsigned &SrcOpIdx2) const;
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| 
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|   /// A pair composed of a register and a sub-register index.
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|   /// Used to give some type checking when modeling Reg:SubReg.
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|   struct RegSubRegPair {
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|     unsigned Reg;
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|     unsigned SubReg;
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|     RegSubRegPair(unsigned Reg = 0, unsigned SubReg = 0)
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|         : Reg(Reg), SubReg(SubReg) {}
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|   };
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|   /// A pair composed of a pair of a register and a sub-register index,
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|   /// and another sub-register index.
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|   /// Used to give some type checking when modeling Reg:SubReg1, SubReg2.
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|   struct RegSubRegPairAndIdx : RegSubRegPair {
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|     unsigned SubIdx;
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|     RegSubRegPairAndIdx(unsigned Reg = 0, unsigned SubReg = 0,
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|                         unsigned SubIdx = 0)
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|         : RegSubRegPair(Reg, SubReg), SubIdx(SubIdx) {}
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|   };
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| 
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|   /// Build the equivalent inputs of a REG_SEQUENCE for the given \p MI
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|   /// and \p DefIdx.
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|   /// \p [out] InputRegs of the equivalent REG_SEQUENCE. Each element of
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|   /// the list is modeled as <Reg:SubReg, SubIdx>.
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|   /// E.g., REG_SEQUENCE vreg1:sub1, sub0, vreg2, sub1 would produce
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|   /// two elements:
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|   /// - vreg1:sub1, sub0
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|   /// - vreg2<:0>, sub1
 | |
|   ///
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|   /// \returns true if it is possible to build such an input sequence
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|   /// with the pair \p MI, \p DefIdx. False otherwise.
 | |
|   ///
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|   /// \pre MI.isRegSequence() or MI.isRegSequenceLike().
 | |
|   ///
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|   /// \note The generic implementation does not provide any support for
 | |
|   /// MI.isRegSequenceLike(). In other words, one has to override
 | |
|   /// getRegSequenceLikeInputs for target specific instructions.
 | |
|   bool
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|   getRegSequenceInputs(const MachineInstr &MI, unsigned DefIdx,
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|                        SmallVectorImpl<RegSubRegPairAndIdx> &InputRegs) const;
 | |
| 
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|   /// Build the equivalent inputs of a EXTRACT_SUBREG for the given \p MI
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|   /// and \p DefIdx.
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|   /// \p [out] InputReg of the equivalent EXTRACT_SUBREG.
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|   /// E.g., EXTRACT_SUBREG vreg1:sub1, sub0, sub1 would produce:
 | |
|   /// - vreg1:sub1, sub0
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|   ///
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|   /// \returns true if it is possible to build such an input sequence
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|   /// with the pair \p MI, \p DefIdx. False otherwise.
 | |
|   ///
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|   /// \pre MI.isExtractSubreg() or MI.isExtractSubregLike().
 | |
|   ///
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|   /// \note The generic implementation does not provide any support for
 | |
|   /// MI.isExtractSubregLike(). In other words, one has to override
 | |
|   /// getExtractSubregLikeInputs for target specific instructions.
 | |
|   bool
 | |
|   getExtractSubregInputs(const MachineInstr &MI, unsigned DefIdx,
 | |
|                          RegSubRegPairAndIdx &InputReg) const;
 | |
| 
 | |
|   /// Build the equivalent inputs of a INSERT_SUBREG for the given \p MI
 | |
|   /// and \p DefIdx.
 | |
|   /// \p [out] BaseReg and \p [out] InsertedReg contain
 | |
|   /// the equivalent inputs of INSERT_SUBREG.
 | |
|   /// E.g., INSERT_SUBREG vreg0:sub0, vreg1:sub1, sub3 would produce:
 | |
|   /// - BaseReg: vreg0:sub0
 | |
|   /// - InsertedReg: vreg1:sub1, sub3
 | |
|   ///
 | |
|   /// \returns true if it is possible to build such an input sequence
 | |
|   /// with the pair \p MI, \p DefIdx. False otherwise.
 | |
|   ///
 | |
|   /// \pre MI.isInsertSubreg() or MI.isInsertSubregLike().
 | |
|   ///
 | |
|   /// \note The generic implementation does not provide any support for
 | |
|   /// MI.isInsertSubregLike(). In other words, one has to override
 | |
|   /// getInsertSubregLikeInputs for target specific instructions.
 | |
|   bool
 | |
|   getInsertSubregInputs(const MachineInstr &MI, unsigned DefIdx,
 | |
|                         RegSubRegPair &BaseReg,
 | |
|                         RegSubRegPairAndIdx &InsertedReg) const;
 | |
| 
 | |
| 
 | |
|   /// produceSameValue - Return true if two machine instructions would produce
 | |
|   /// identical values. By default, this is only true when the two instructions
 | |
|   /// are deemed identical except for defs. If this function is called when the
 | |
|   /// IR is still in SSA form, the caller can pass the MachineRegisterInfo for
 | |
|   /// aggressive checks.
 | |
|   virtual bool produceSameValue(const MachineInstr *MI0,
 | |
|                                 const MachineInstr *MI1,
 | |
|                                 const MachineRegisterInfo *MRI = nullptr) const;
 | |
| 
 | |
|   /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning
 | |
|   /// true if it cannot be understood (e.g. it's a switch dispatch or isn't
 | |
|   /// implemented for a target).  Upon success, this returns false and returns
 | |
|   /// with the following information in various cases:
 | |
|   ///
 | |
|   /// 1. If this block ends with no branches (it just falls through to its succ)
 | |
|   ///    just return false, leaving TBB/FBB null.
 | |
|   /// 2. If this block ends with only an unconditional branch, it sets TBB to be
 | |
|   ///    the destination block.
 | |
|   /// 3. If this block ends with a conditional branch and it falls through to a
 | |
|   ///    successor block, it sets TBB to be the branch destination block and a
 | |
|   ///    list of operands that evaluate the condition. These operands can be
 | |
|   ///    passed to other TargetInstrInfo methods to create new branches.
 | |
|   /// 4. If this block ends with a conditional branch followed by an
 | |
|   ///    unconditional branch, it returns the 'true' destination in TBB, the
 | |
|   ///    'false' destination in FBB, and a list of operands that evaluate the
 | |
|   ///    condition.  These operands can be passed to other TargetInstrInfo
 | |
|   ///    methods to create new branches.
 | |
|   ///
 | |
|   /// Note that RemoveBranch and InsertBranch must be implemented to support
 | |
|   /// cases where this method returns success.
 | |
|   ///
 | |
|   /// If AllowModify is true, then this routine is allowed to modify the basic
 | |
|   /// block (e.g. delete instructions after the unconditional branch).
 | |
|   ///
 | |
|   virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
 | |
|                              MachineBasicBlock *&FBB,
 | |
|                              SmallVectorImpl<MachineOperand> &Cond,
 | |
|                              bool AllowModify = false) const {
 | |
|     return true;
 | |
|   }
 | |
| 
 | |
|   /// RemoveBranch - Remove the branching code at the end of the specific MBB.
 | |
|   /// This is only invoked in cases where AnalyzeBranch returns success. It
 | |
|   /// returns the number of instructions that were removed.
 | |
|   virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const {
 | |
|     llvm_unreachable("Target didn't implement TargetInstrInfo::RemoveBranch!");
 | |
|   }
 | |
| 
 | |
|   /// InsertBranch - Insert branch code into the end of the specified
 | |
|   /// MachineBasicBlock.  The operands to this method are the same as those
 | |
|   /// returned by AnalyzeBranch.  This is only invoked in cases where
 | |
|   /// AnalyzeBranch returns success. It returns the number of instructions
 | |
|   /// inserted.
 | |
|   ///
 | |
|   /// It is also invoked by tail merging to add unconditional branches in
 | |
|   /// cases where AnalyzeBranch doesn't apply because there was no original
 | |
|   /// branch to analyze.  At least this much must be implemented, else tail
 | |
|   /// merging needs to be disabled.
 | |
|   virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
 | |
|                                 MachineBasicBlock *FBB,
 | |
|                                 const SmallVectorImpl<MachineOperand> &Cond,
 | |
|                                 DebugLoc DL) const {
 | |
|     llvm_unreachable("Target didn't implement TargetInstrInfo::InsertBranch!");
 | |
|   }
 | |
| 
 | |
|   /// ReplaceTailWithBranchTo - Delete the instruction OldInst and everything
 | |
|   /// after it, replacing it with an unconditional branch to NewDest. This is
 | |
|   /// used by the tail merging pass.
 | |
|   virtual void ReplaceTailWithBranchTo(MachineBasicBlock::iterator Tail,
 | |
|                                        MachineBasicBlock *NewDest) const;
 | |
| 
 | |
|   /// getUnconditionalBranch - Get an instruction that performs an unconditional
 | |
|   /// branch to the given symbol.
 | |
|   virtual void
 | |
|   getUnconditionalBranch(MCInst &MI,
 | |
|                          const MCSymbolRefExpr *BranchTarget) const {
 | |
|     llvm_unreachable("Target didn't implement "
 | |
|                      "TargetInstrInfo::getUnconditionalBranch!");
 | |
|   }
 | |
| 
 | |
|   /// getTrap - Get a machine trap instruction
 | |
|   virtual void getTrap(MCInst &MI) const {
 | |
|     llvm_unreachable("Target didn't implement TargetInstrInfo::getTrap!");
 | |
|   }
 | |
| 
 | |
|   /// isLegalToSplitMBBAt - Return true if it's legal to split the given basic
 | |
|   /// block at the specified instruction (i.e. instruction would be the start
 | |
|   /// of a new basic block).
 | |
|   virtual bool isLegalToSplitMBBAt(MachineBasicBlock &MBB,
 | |
|                                    MachineBasicBlock::iterator MBBI) const {
 | |
|     return true;
 | |
|   }
 | |
| 
 | |
|   /// isProfitableToIfCvt - Return true if it's profitable to predicate
 | |
|   /// instructions with accumulated instruction latency of "NumCycles"
 | |
|   /// of the specified basic block, where the probability of the instructions
 | |
|   /// being executed is given by Probability, and Confidence is a measure
 | |
|   /// of our confidence that it will be properly predicted.
 | |
|   virtual
 | |
|   bool isProfitableToIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
 | |
|                            unsigned ExtraPredCycles,
 | |
|                            const BranchProbability &Probability) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// isProfitableToIfCvt - Second variant of isProfitableToIfCvt, this one
 | |
|   /// checks for the case where two basic blocks from true and false path
 | |
|   /// of a if-then-else (diamond) are predicated on mutally exclusive
 | |
|   /// predicates, where the probability of the true path being taken is given
 | |
|   /// by Probability, and Confidence is a measure of our confidence that it
 | |
|   /// will be properly predicted.
 | |
|   virtual bool
 | |
|   isProfitableToIfCvt(MachineBasicBlock &TMBB,
 | |
|                       unsigned NumTCycles, unsigned ExtraTCycles,
 | |
|                       MachineBasicBlock &FMBB,
 | |
|                       unsigned NumFCycles, unsigned ExtraFCycles,
 | |
|                       const BranchProbability &Probability) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// isProfitableToDupForIfCvt - Return true if it's profitable for
 | |
|   /// if-converter to duplicate instructions of specified accumulated
 | |
|   /// instruction latencies in the specified MBB to enable if-conversion.
 | |
|   /// The probability of the instructions being executed is given by
 | |
|   /// Probability, and Confidence is a measure of our confidence that it
 | |
|   /// will be properly predicted.
 | |
|   virtual bool
 | |
|   isProfitableToDupForIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
 | |
|                             const BranchProbability &Probability) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// isProfitableToUnpredicate - Return true if it's profitable to unpredicate
 | |
|   /// one side of a 'diamond', i.e. two sides of if-else predicated on mutually
 | |
|   /// exclusive predicates.
 | |
|   /// e.g.
 | |
|   ///   subeq  r0, r1, #1
 | |
|   ///   addne  r0, r1, #1
 | |
|   /// =>
 | |
|   ///   sub    r0, r1, #1
 | |
|   ///   addne  r0, r1, #1
 | |
|   ///
 | |
|   /// This may be profitable is conditional instructions are always executed.
 | |
|   virtual bool isProfitableToUnpredicate(MachineBasicBlock &TMBB,
 | |
|                                          MachineBasicBlock &FMBB) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// canInsertSelect - Return true if it is possible to insert a select
 | |
|   /// instruction that chooses between TrueReg and FalseReg based on the
 | |
|   /// condition code in Cond.
 | |
|   ///
 | |
|   /// When successful, also return the latency in cycles from TrueReg,
 | |
|   /// FalseReg, and Cond to the destination register. In most cases, a select
 | |
|   /// instruction will be 1 cycle, so CondCycles = TrueCycles = FalseCycles = 1
 | |
|   ///
 | |
|   /// Some x86 implementations have 2-cycle cmov instructions.
 | |
|   ///
 | |
|   /// @param MBB         Block where select instruction would be inserted.
 | |
|   /// @param Cond        Condition returned by AnalyzeBranch.
 | |
|   /// @param TrueReg     Virtual register to select when Cond is true.
 | |
|   /// @param FalseReg    Virtual register to select when Cond is false.
 | |
|   /// @param CondCycles  Latency from Cond+Branch to select output.
 | |
|   /// @param TrueCycles  Latency from TrueReg to select output.
 | |
|   /// @param FalseCycles Latency from FalseReg to select output.
 | |
|   virtual bool canInsertSelect(const MachineBasicBlock &MBB,
 | |
|                                const SmallVectorImpl<MachineOperand> &Cond,
 | |
|                                unsigned TrueReg, unsigned FalseReg,
 | |
|                                int &CondCycles,
 | |
|                                int &TrueCycles, int &FalseCycles) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// insertSelect - Insert a select instruction into MBB before I that will
 | |
|   /// copy TrueReg to DstReg when Cond is true, and FalseReg to DstReg when
 | |
|   /// Cond is false.
 | |
|   ///
 | |
|   /// This function can only be called after canInsertSelect() returned true.
 | |
|   /// The condition in Cond comes from AnalyzeBranch, and it can be assumed
 | |
|   /// that the same flags or registers required by Cond are available at the
 | |
|   /// insertion point.
 | |
|   ///
 | |
|   /// @param MBB      Block where select instruction should be inserted.
 | |
|   /// @param I        Insertion point.
 | |
|   /// @param DL       Source location for debugging.
 | |
|   /// @param DstReg   Virtual register to be defined by select instruction.
 | |
|   /// @param Cond     Condition as computed by AnalyzeBranch.
 | |
|   /// @param TrueReg  Virtual register to copy when Cond is true.
 | |
|   /// @param FalseReg Virtual register to copy when Cons is false.
 | |
|   virtual void insertSelect(MachineBasicBlock &MBB,
 | |
|                             MachineBasicBlock::iterator I, DebugLoc DL,
 | |
|                             unsigned DstReg,
 | |
|                             const SmallVectorImpl<MachineOperand> &Cond,
 | |
|                             unsigned TrueReg, unsigned FalseReg) const {
 | |
|     llvm_unreachable("Target didn't implement TargetInstrInfo::insertSelect!");
 | |
|   }
 | |
| 
 | |
|   /// analyzeSelect - Analyze the given select instruction, returning true if
 | |
|   /// it cannot be understood. It is assumed that MI->isSelect() is true.
 | |
|   ///
 | |
|   /// When successful, return the controlling condition and the operands that
 | |
|   /// determine the true and false result values.
 | |
|   ///
 | |
|   ///   Result = SELECT Cond, TrueOp, FalseOp
 | |
|   ///
 | |
|   /// Some targets can optimize select instructions, for example by predicating
 | |
|   /// the instruction defining one of the operands. Such targets should set
 | |
|   /// Optimizable.
 | |
|   ///
 | |
|   /// @param         MI Select instruction to analyze.
 | |
|   /// @param Cond    Condition controlling the select.
 | |
|   /// @param TrueOp  Operand number of the value selected when Cond is true.
 | |
|   /// @param FalseOp Operand number of the value selected when Cond is false.
 | |
|   /// @param Optimizable Returned as true if MI is optimizable.
 | |
|   /// @returns False on success.
 | |
|   virtual bool analyzeSelect(const MachineInstr *MI,
 | |
|                              SmallVectorImpl<MachineOperand> &Cond,
 | |
|                              unsigned &TrueOp, unsigned &FalseOp,
 | |
|                              bool &Optimizable) const {
 | |
|     assert(MI && MI->getDesc().isSelect() && "MI must be a select instruction");
 | |
|     return true;
 | |
|   }
 | |
| 
 | |
|   /// optimizeSelect - Given a select instruction that was understood by
 | |
|   /// analyzeSelect and returned Optimizable = true, attempt to optimize MI by
 | |
|   /// merging it with one of its operands. Returns NULL on failure.
 | |
|   ///
 | |
|   /// When successful, returns the new select instruction. The client is
 | |
|   /// responsible for deleting MI.
 | |
|   ///
 | |
|   /// If both sides of the select can be optimized, PreferFalse is used to pick
 | |
|   /// a side.
 | |
|   ///
 | |
|   /// @param MI          Optimizable select instruction.
 | |
|   /// @param PreferFalse Try to optimize FalseOp instead of TrueOp.
 | |
|   /// @returns Optimized instruction or NULL.
 | |
|   virtual MachineInstr *optimizeSelect(MachineInstr *MI,
 | |
|                                        bool PreferFalse = false) const {
 | |
|     // This function must be implemented if Optimizable is ever set.
 | |
|     llvm_unreachable("Target must implement TargetInstrInfo::optimizeSelect!");
 | |
|   }
 | |
| 
 | |
|   /// copyPhysReg - Emit instructions to copy a pair of physical registers.
 | |
|   ///
 | |
|   /// This function should support copies within any legal register class as
 | |
|   /// well as any cross-class copies created during instruction selection.
 | |
|   ///
 | |
|   /// The source and destination registers may overlap, which may require a
 | |
|   /// careful implementation when multiple copy instructions are required for
 | |
|   /// large registers. See for example the ARM target.
 | |
|   virtual void copyPhysReg(MachineBasicBlock &MBB,
 | |
|                            MachineBasicBlock::iterator MI, DebugLoc DL,
 | |
|                            unsigned DestReg, unsigned SrcReg,
 | |
|                            bool KillSrc) const {
 | |
|     llvm_unreachable("Target didn't implement TargetInstrInfo::copyPhysReg!");
 | |
|   }
 | |
| 
 | |
|   /// storeRegToStackSlot - Store the specified register of the given register
 | |
|   /// class to the specified stack frame index. The store instruction is to be
 | |
|   /// added to the given machine basic block before the specified machine
 | |
|   /// instruction. If isKill is true, the register operand is the last use and
 | |
|   /// must be marked kill.
 | |
|   virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
 | |
|                                    MachineBasicBlock::iterator MI,
 | |
|                                    unsigned SrcReg, bool isKill, int FrameIndex,
 | |
|                                    const TargetRegisterClass *RC,
 | |
|                                    const TargetRegisterInfo *TRI) const {
 | |
|     llvm_unreachable("Target didn't implement "
 | |
|                      "TargetInstrInfo::storeRegToStackSlot!");
 | |
|   }
 | |
| 
 | |
|   /// loadRegFromStackSlot - Load the specified register of the given register
 | |
|   /// class from the specified stack frame index. The load instruction is to be
 | |
|   /// added to the given machine basic block before the specified machine
 | |
|   /// instruction.
 | |
|   virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
 | |
|                                     MachineBasicBlock::iterator MI,
 | |
|                                     unsigned DestReg, int FrameIndex,
 | |
|                                     const TargetRegisterClass *RC,
 | |
|                                     const TargetRegisterInfo *TRI) const {
 | |
|     llvm_unreachable("Target didn't implement "
 | |
|                      "TargetInstrInfo::loadRegFromStackSlot!");
 | |
|   }
 | |
| 
 | |
|   /// expandPostRAPseudo - This function is called for all pseudo instructions
 | |
|   /// that remain after register allocation. Many pseudo instructions are
 | |
|   /// created to help register allocation. This is the place to convert them
 | |
|   /// into real instructions. The target can edit MI in place, or it can insert
 | |
|   /// new instructions and erase MI. The function should return true if
 | |
|   /// anything was changed.
 | |
|   virtual bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// foldMemoryOperand - Attempt to fold a load or store of the specified stack
 | |
|   /// slot into the specified machine instruction for the specified operand(s).
 | |
|   /// If this is possible, a new instruction is returned with the specified
 | |
|   /// operand folded, otherwise NULL is returned.
 | |
|   /// The new instruction is inserted before MI, and the client is responsible
 | |
|   /// for removing the old instruction.
 | |
|   MachineInstr* foldMemoryOperand(MachineBasicBlock::iterator MI,
 | |
|                                   const SmallVectorImpl<unsigned> &Ops,
 | |
|                                   int FrameIndex) const;
 | |
| 
 | |
|   /// foldMemoryOperand - Same as the previous version except it allows folding
 | |
|   /// of any load and store from / to any address, not just from a specific
 | |
|   /// stack slot.
 | |
|   MachineInstr* foldMemoryOperand(MachineBasicBlock::iterator MI,
 | |
|                                   const SmallVectorImpl<unsigned> &Ops,
 | |
|                                   MachineInstr* LoadMI) const;
 | |
| 
 | |
|   /// hasPattern - return true when there is potentially a faster code sequence
 | |
|   /// for an instruction chain ending in \p Root. All potential pattern are
 | |
|   /// returned in the \p Pattern vector. Pattern should be sorted in priority
 | |
|   /// order since the pattern evaluator stops checking as soon as it finds a
 | |
|   /// faster sequence.
 | |
|   /// \param Root - Instruction that could be combined with one of its operands
 | |
|   /// \param Pattern - Vector of possible combination pattern
 | |
| 
 | |
|   virtual bool hasPattern(
 | |
|       MachineInstr &Root,
 | |
|       SmallVectorImpl<MachineCombinerPattern::MC_PATTERN> &Pattern) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// genAlternativeCodeSequence - when hasPattern() finds a pattern this
 | |
|   /// function generates the instructions that could replace the original code
 | |
|   /// sequence. The client has to decide whether the actual replacementment is
 | |
|   /// beneficial or not.
 | |
|   /// \param Root - Instruction that could be combined with one of its operands
 | |
|   /// \param P - Combination pattern for Root
 | |
|   /// \param InsInstrs - Vector of new instructions that implement P
 | |
|   /// \param DelInstrs - Old instructions, including Root, that could be replaced
 | |
|   /// by InsInstr
 | |
|   /// \param InstrIdxForVirtReg - map of virtual register to instruction in
 | |
|   /// InsInstr that defines it
 | |
|   virtual void genAlternativeCodeSequence(
 | |
|       MachineInstr &Root, MachineCombinerPattern::MC_PATTERN P,
 | |
|       SmallVectorImpl<MachineInstr *> &InsInstrs,
 | |
|       SmallVectorImpl<MachineInstr *> &DelInstrs,
 | |
|       DenseMap<unsigned, unsigned> &InstrIdxForVirtReg) const {
 | |
|     return;
 | |
|   }
 | |
| 
 | |
|   /// useMachineCombiner - return true when a target supports MachineCombiner
 | |
|   virtual bool useMachineCombiner() const { return false; }
 | |
| 
 | |
| protected:
 | |
|   /// foldMemoryOperandImpl - Target-dependent implementation for
 | |
|   /// foldMemoryOperand. Target-independent code in foldMemoryOperand will
 | |
|   /// take care of adding a MachineMemOperand to the newly created instruction.
 | |
|   virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF,
 | |
|                                           MachineInstr* MI,
 | |
|                                           const SmallVectorImpl<unsigned> &Ops,
 | |
|                                           int FrameIndex) const {
 | |
|     return nullptr;
 | |
|   }
 | |
| 
 | |
|   /// foldMemoryOperandImpl - Target-dependent implementation for
 | |
|   /// foldMemoryOperand. Target-independent code in foldMemoryOperand will
 | |
|   /// take care of adding a MachineMemOperand to the newly created instruction.
 | |
|   virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF,
 | |
|                                               MachineInstr* MI,
 | |
|                                           const SmallVectorImpl<unsigned> &Ops,
 | |
|                                               MachineInstr* LoadMI) const {
 | |
|     return nullptr;
 | |
|   }
 | |
| 
 | |
|   /// \brief Target-dependent implementation of getRegSequenceInputs.
 | |
|   ///
 | |
|   /// \returns true if it is possible to build the equivalent
 | |
|   /// REG_SEQUENCE inputs with the pair \p MI, \p DefIdx. False otherwise.
 | |
|   ///
 | |
|   /// \pre MI.isRegSequenceLike().
 | |
|   ///
 | |
|   /// \see TargetInstrInfo::getRegSequenceInputs.
 | |
|   virtual bool getRegSequenceLikeInputs(
 | |
|       const MachineInstr &MI, unsigned DefIdx,
 | |
|       SmallVectorImpl<RegSubRegPairAndIdx> &InputRegs) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// \brief Target-dependent implementation of getExtractSubregInputs.
 | |
|   ///
 | |
|   /// \returns true if it is possible to build the equivalent
 | |
|   /// EXTRACT_SUBREG inputs with the pair \p MI, \p DefIdx. False otherwise.
 | |
|   ///
 | |
|   /// \pre MI.isExtractSubregLike().
 | |
|   ///
 | |
|   /// \see TargetInstrInfo::getExtractSubregInputs.
 | |
|   virtual bool getExtractSubregLikeInputs(
 | |
|       const MachineInstr &MI, unsigned DefIdx,
 | |
|       RegSubRegPairAndIdx &InputReg) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// \brief Target-dependent implementation of getInsertSubregInputs.
 | |
|   ///
 | |
|   /// \returns true if it is possible to build the equivalent
 | |
|   /// INSERT_SUBREG inputs with the pair \p MI, \p DefIdx. False otherwise.
 | |
|   ///
 | |
|   /// \pre MI.isInsertSubregLike().
 | |
|   ///
 | |
|   /// \see TargetInstrInfo::getInsertSubregInputs.
 | |
|   virtual bool
 | |
|   getInsertSubregLikeInputs(const MachineInstr &MI, unsigned DefIdx,
 | |
|                             RegSubRegPair &BaseReg,
 | |
|                             RegSubRegPairAndIdx &InsertedReg) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
| public:
 | |
|   /// canFoldMemoryOperand - Returns true for the specified load / store if
 | |
|   /// folding is possible.
 | |
|   virtual
 | |
|   bool canFoldMemoryOperand(const MachineInstr *MI,
 | |
|                             const SmallVectorImpl<unsigned> &Ops) const;
 | |
| 
 | |
|   /// unfoldMemoryOperand - Separate a single instruction which folded a load or
 | |
|   /// a store or a load and a store into two or more instruction. If this is
 | |
|   /// possible, returns true as well as the new instructions by reference.
 | |
|   virtual bool unfoldMemoryOperand(MachineFunction &MF, MachineInstr *MI,
 | |
|                                 unsigned Reg, bool UnfoldLoad, bool UnfoldStore,
 | |
|                                  SmallVectorImpl<MachineInstr*> &NewMIs) const{
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   virtual bool unfoldMemoryOperand(SelectionDAG &DAG, SDNode *N,
 | |
|                                    SmallVectorImpl<SDNode*> &NewNodes) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// getOpcodeAfterMemoryUnfold - Returns the opcode of the would be new
 | |
|   /// instruction after load / store are unfolded from an instruction of the
 | |
|   /// specified opcode. It returns zero if the specified unfolding is not
 | |
|   /// possible. If LoadRegIndex is non-null, it is filled in with the operand
 | |
|   /// index of the operand which will hold the register holding the loaded
 | |
|   /// value.
 | |
|   virtual unsigned getOpcodeAfterMemoryUnfold(unsigned Opc,
 | |
|                                       bool UnfoldLoad, bool UnfoldStore,
 | |
|                                       unsigned *LoadRegIndex = nullptr) const {
 | |
|     return 0;
 | |
|   }
 | |
| 
 | |
|   /// areLoadsFromSameBasePtr - This is used by the pre-regalloc scheduler
 | |
|   /// to determine if two loads are loading from the same base address. It
 | |
|   /// should only return true if the base pointers are the same and the
 | |
|   /// only differences between the two addresses are the offset. It also returns
 | |
|   /// the offsets by reference.
 | |
|   virtual bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2,
 | |
|                                     int64_t &Offset1, int64_t &Offset2) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
 | |
|   /// determine (in conjunction with areLoadsFromSameBasePtr) if two loads should
 | |
|   /// be scheduled togther. On some targets if two loads are loading from
 | |
|   /// addresses in the same cache line, it's better if they are scheduled
 | |
|   /// together. This function takes two integers that represent the load offsets
 | |
|   /// from the common base address. It returns true if it decides it's desirable
 | |
|   /// to schedule the two loads together. "NumLoads" is the number of loads that
 | |
|   /// have already been scheduled after Load1.
 | |
|   virtual bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2,
 | |
|                                        int64_t Offset1, int64_t Offset2,
 | |
|                                        unsigned NumLoads) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// \brief Get the base register and byte offset of a load/store instr.
 | |
|   virtual bool getLdStBaseRegImmOfs(MachineInstr *LdSt,
 | |
|                                     unsigned &BaseReg, unsigned &Offset,
 | |
|                                     const TargetRegisterInfo *TRI) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   virtual bool enableClusterLoads() const { return false; }
 | |
| 
 | |
|   virtual bool shouldClusterLoads(MachineInstr *FirstLdSt,
 | |
|                                   MachineInstr *SecondLdSt,
 | |
|                                   unsigned NumLoads) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// \brief Can this target fuse the given instructions if they are scheduled
 | |
|   /// adjacent.
 | |
|   virtual bool shouldScheduleAdjacent(MachineInstr* First,
 | |
|                                       MachineInstr *Second) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// ReverseBranchCondition - Reverses the branch condition of the specified
 | |
|   /// condition list, returning false on success and true if it cannot be
 | |
|   /// reversed.
 | |
|   virtual
 | |
|   bool ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const {
 | |
|     return true;
 | |
|   }
 | |
| 
 | |
|   /// insertNoop - Insert a noop into the instruction stream at the specified
 | |
|   /// point.
 | |
|   virtual void insertNoop(MachineBasicBlock &MBB,
 | |
|                           MachineBasicBlock::iterator MI) const;
 | |
| 
 | |
| 
 | |
|   /// Return the noop instruction to use for a noop.
 | |
|   virtual void getNoopForMachoTarget(MCInst &NopInst) const;
 | |
| 
 | |
| 
 | |
|   /// isPredicated - Returns true if the instruction is already predicated.
 | |
|   ///
 | |
|   virtual bool isPredicated(const MachineInstr *MI) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// isUnpredicatedTerminator - Returns true if the instruction is a
 | |
|   /// terminator instruction that has not been predicated.
 | |
|   virtual bool isUnpredicatedTerminator(const MachineInstr *MI) const;
 | |
| 
 | |
|   /// PredicateInstruction - Convert the instruction into a predicated
 | |
|   /// instruction. It returns true if the operation was successful.
 | |
|   virtual
 | |
|   bool PredicateInstruction(MachineInstr *MI,
 | |
|                         const SmallVectorImpl<MachineOperand> &Pred) const;
 | |
| 
 | |
|   /// SubsumesPredicate - Returns true if the first specified predicate
 | |
|   /// subsumes the second, e.g. GE subsumes GT.
 | |
|   virtual
 | |
|   bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
 | |
|                          const SmallVectorImpl<MachineOperand> &Pred2) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// DefinesPredicate - If the specified instruction defines any predicate
 | |
|   /// or condition code register(s) used for predication, returns true as well
 | |
|   /// as the definition predicate(s) by reference.
 | |
|   virtual bool DefinesPredicate(MachineInstr *MI,
 | |
|                                 std::vector<MachineOperand> &Pred) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// isPredicable - Return true if the specified instruction can be predicated.
 | |
|   /// By default, this returns true for every instruction with a
 | |
|   /// PredicateOperand.
 | |
|   virtual bool isPredicable(MachineInstr *MI) const {
 | |
|     return MI->getDesc().isPredicable();
 | |
|   }
 | |
| 
 | |
|   /// isSafeToMoveRegClassDefs - Return true if it's safe to move a machine
 | |
|   /// instruction that defines the specified register class.
 | |
|   virtual bool isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const {
 | |
|     return true;
 | |
|   }
 | |
| 
 | |
|   /// isSchedulingBoundary - Test if the given instruction should be
 | |
|   /// considered a scheduling boundary. This primarily includes labels and
 | |
|   /// terminators.
 | |
|   virtual bool isSchedulingBoundary(const MachineInstr *MI,
 | |
|                                     const MachineBasicBlock *MBB,
 | |
|                                     const MachineFunction &MF) const;
 | |
| 
 | |
|   /// Measure the specified inline asm to determine an approximation of its
 | |
|   /// length.
 | |
|   virtual unsigned getInlineAsmLength(const char *Str,
 | |
|                                       const MCAsmInfo &MAI) const;
 | |
| 
 | |
|   /// CreateTargetHazardRecognizer - Allocate and return a hazard recognizer to
 | |
|   /// use for this target when scheduling the machine instructions before
 | |
|   /// register allocation.
 | |
|   virtual ScheduleHazardRecognizer*
 | |
|   CreateTargetHazardRecognizer(const TargetSubtargetInfo *STI,
 | |
|                                const ScheduleDAG *DAG) const;
 | |
| 
 | |
|   /// CreateTargetMIHazardRecognizer - Allocate and return a hazard recognizer
 | |
|   /// to use for this target when scheduling the machine instructions before
 | |
|   /// register allocation.
 | |
|   virtual ScheduleHazardRecognizer*
 | |
|   CreateTargetMIHazardRecognizer(const InstrItineraryData*,
 | |
|                                  const ScheduleDAG *DAG) const;
 | |
| 
 | |
|   /// CreateTargetPostRAHazardRecognizer - Allocate and return a hazard
 | |
|   /// recognizer to use for this target when scheduling the machine instructions
 | |
|   /// after register allocation.
 | |
|   virtual ScheduleHazardRecognizer*
 | |
|   CreateTargetPostRAHazardRecognizer(const InstrItineraryData*,
 | |
|                                      const ScheduleDAG *DAG) const;
 | |
| 
 | |
|   /// Provide a global flag for disabling the PreRA hazard recognizer that
 | |
|   /// targets may choose to honor.
 | |
|   bool usePreRAHazardRecognizer() const;
 | |
| 
 | |
|   /// analyzeCompare - For a comparison instruction, return the source registers
 | |
|   /// in SrcReg and SrcReg2 if having two register operands, and the value it
 | |
|   /// compares against in CmpValue. Return true if the comparison instruction
 | |
|   /// can be analyzed.
 | |
|   virtual bool analyzeCompare(const MachineInstr *MI,
 | |
|                               unsigned &SrcReg, unsigned &SrcReg2,
 | |
|                               int &Mask, int &Value) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// optimizeCompareInstr - See if the comparison instruction can be converted
 | |
|   /// into something more efficient. E.g., on ARM most instructions can set the
 | |
|   /// flags register, obviating the need for a separate CMP.
 | |
|   virtual bool optimizeCompareInstr(MachineInstr *CmpInstr,
 | |
|                                     unsigned SrcReg, unsigned SrcReg2,
 | |
|                                     int Mask, int Value,
 | |
|                                     const MachineRegisterInfo *MRI) const {
 | |
|     return false;
 | |
|   }
 | |
|   virtual bool optimizeCondBranch(MachineInstr *MI) const { return false; }
 | |
| 
 | |
|   /// optimizeLoadInstr - Try to remove the load by folding it to a register
 | |
|   /// operand at the use. We fold the load instructions if and only if the
 | |
|   /// def and use are in the same BB. We only look at one load and see
 | |
|   /// whether it can be folded into MI. FoldAsLoadDefReg is the virtual register
 | |
|   /// defined by the load we are trying to fold. DefMI returns the machine
 | |
|   /// instruction that defines FoldAsLoadDefReg, and the function returns
 | |
|   /// the machine instruction generated due to folding.
 | |
|   virtual MachineInstr* optimizeLoadInstr(MachineInstr *MI,
 | |
|                         const MachineRegisterInfo *MRI,
 | |
|                         unsigned &FoldAsLoadDefReg,
 | |
|                         MachineInstr *&DefMI) const {
 | |
|     return nullptr;
 | |
|   }
 | |
| 
 | |
|   /// FoldImmediate - 'Reg' is known to be defined by a move immediate
 | |
|   /// instruction, try to fold the immediate into the use instruction.
 | |
|   /// If MRI->hasOneNonDBGUse(Reg) is true, and this function returns true,
 | |
|   /// then the caller may assume that DefMI has been erased from its parent
 | |
|   /// block. The caller may assume that it will not be erased by this
 | |
|   /// function otherwise.
 | |
|   virtual bool FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI,
 | |
|                              unsigned Reg, MachineRegisterInfo *MRI) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// getNumMicroOps - Return the number of u-operations the given machine
 | |
|   /// instruction will be decoded to on the target cpu. The itinerary's
 | |
|   /// IssueWidth is the number of microops that can be dispatched each
 | |
|   /// cycle. An instruction with zero microops takes no dispatch resources.
 | |
|   virtual unsigned getNumMicroOps(const InstrItineraryData *ItinData,
 | |
|                                   const MachineInstr *MI) const;
 | |
| 
 | |
|   /// isZeroCost - Return true for pseudo instructions that don't consume any
 | |
|   /// machine resources in their current form. These are common cases that the
 | |
|   /// scheduler should consider free, rather than conservatively handling them
 | |
|   /// as instructions with no itinerary.
 | |
|   bool isZeroCost(unsigned Opcode) const {
 | |
|     return Opcode <= TargetOpcode::COPY;
 | |
|   }
 | |
| 
 | |
|   virtual int getOperandLatency(const InstrItineraryData *ItinData,
 | |
|                                 SDNode *DefNode, unsigned DefIdx,
 | |
|                                 SDNode *UseNode, unsigned UseIdx) const;
 | |
| 
 | |
|   /// getOperandLatency - Compute and return the use operand latency of a given
 | |
|   /// pair of def and use.
 | |
|   /// In most cases, the static scheduling itinerary was enough to determine the
 | |
|   /// operand latency. But it may not be possible for instructions with variable
 | |
|   /// number of defs / uses.
 | |
|   ///
 | |
|   /// This is a raw interface to the itinerary that may be directly overriden by
 | |
|   /// a target. Use computeOperandLatency to get the best estimate of latency.
 | |
|   virtual int getOperandLatency(const InstrItineraryData *ItinData,
 | |
|                                 const MachineInstr *DefMI, unsigned DefIdx,
 | |
|                                 const MachineInstr *UseMI,
 | |
|                                 unsigned UseIdx) const;
 | |
| 
 | |
|   /// computeOperandLatency - Compute and return the latency of the given data
 | |
|   /// dependent def and use when the operand indices are already known.
 | |
|   unsigned computeOperandLatency(const InstrItineraryData *ItinData,
 | |
|                                  const MachineInstr *DefMI, unsigned DefIdx,
 | |
|                                  const MachineInstr *UseMI, unsigned UseIdx)
 | |
|     const;
 | |
| 
 | |
|   /// getInstrLatency - Compute the instruction latency of a given instruction.
 | |
|   /// If the instruction has higher cost when predicated, it's returned via
 | |
|   /// PredCost.
 | |
|   virtual unsigned getInstrLatency(const InstrItineraryData *ItinData,
 | |
|                                    const MachineInstr *MI,
 | |
|                                    unsigned *PredCost = nullptr) const;
 | |
| 
 | |
|   virtual unsigned getPredicationCost(const MachineInstr *MI) const;
 | |
| 
 | |
|   virtual int getInstrLatency(const InstrItineraryData *ItinData,
 | |
|                               SDNode *Node) const;
 | |
| 
 | |
|   /// Return the default expected latency for a def based on it's opcode.
 | |
|   unsigned defaultDefLatency(const MCSchedModel &SchedModel,
 | |
|                              const MachineInstr *DefMI) const;
 | |
| 
 | |
|   int computeDefOperandLatency(const InstrItineraryData *ItinData,
 | |
|                                const MachineInstr *DefMI) const;
 | |
| 
 | |
|   /// isHighLatencyDef - Return true if this opcode has high latency to its
 | |
|   /// result.
 | |
|   virtual bool isHighLatencyDef(int opc) const { return false; }
 | |
| 
 | |
|   /// hasHighOperandLatency - Compute operand latency between a def of 'Reg'
 | |
|   /// and an use in the current loop, return true if the target considered
 | |
|   /// it 'high'. This is used by optimization passes such as machine LICM to
 | |
|   /// determine whether it makes sense to hoist an instruction out even in
 | |
|   /// high register pressure situation.
 | |
|   virtual
 | |
|   bool hasHighOperandLatency(const InstrItineraryData *ItinData,
 | |
|                              const MachineRegisterInfo *MRI,
 | |
|                              const MachineInstr *DefMI, unsigned DefIdx,
 | |
|                              const MachineInstr *UseMI, unsigned UseIdx) const {
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
|   /// hasLowDefLatency - Compute operand latency of a def of 'Reg', return true
 | |
|   /// if the target considered it 'low'.
 | |
|   virtual
 | |
|   bool hasLowDefLatency(const InstrItineraryData *ItinData,
 | |
|                         const MachineInstr *DefMI, unsigned DefIdx) const;
 | |
| 
 | |
|   /// verifyInstruction - Perform target specific instruction verification.
 | |
|   virtual
 | |
|   bool verifyInstruction(const MachineInstr *MI, StringRef &ErrInfo) const {
 | |
|     return true;
 | |
|   }
 | |
| 
 | |
|   /// getExecutionDomain - Return the current execution domain and bit mask of
 | |
|   /// possible domains for instruction.
 | |
|   ///
 | |
|   /// Some micro-architectures have multiple execution domains, and multiple
 | |
|   /// opcodes that perform the same operation in different domains.  For
 | |
|   /// example, the x86 architecture provides the por, orps, and orpd
 | |
|   /// instructions that all do the same thing.  There is a latency penalty if a
 | |
|   /// register is written in one domain and read in another.
 | |
|   ///
 | |
|   /// This function returns a pair (domain, mask) containing the execution
 | |
|   /// domain of MI, and a bit mask of possible domains.  The setExecutionDomain
 | |
|   /// function can be used to change the opcode to one of the domains in the
 | |
|   /// bit mask.  Instructions whose execution domain can't be changed should
 | |
|   /// return a 0 mask.
 | |
|   ///
 | |
|   /// The execution domain numbers don't have any special meaning except domain
 | |
|   /// 0 is used for instructions that are not associated with any interesting
 | |
|   /// execution domain.
 | |
|   ///
 | |
|   virtual std::pair<uint16_t, uint16_t>
 | |
|   getExecutionDomain(const MachineInstr *MI) const {
 | |
|     return std::make_pair(0, 0);
 | |
|   }
 | |
| 
 | |
|   /// setExecutionDomain - Change the opcode of MI to execute in Domain.
 | |
|   ///
 | |
|   /// The bit (1 << Domain) must be set in the mask returned from
 | |
|   /// getExecutionDomain(MI).
 | |
|   ///
 | |
|   virtual void setExecutionDomain(MachineInstr *MI, unsigned Domain) const {}
 | |
| 
 | |
| 
 | |
|   /// getPartialRegUpdateClearance - Returns the preferred minimum clearance
 | |
|   /// before an instruction with an unwanted partial register update.
 | |
|   ///
 | |
|   /// Some instructions only write part of a register, and implicitly need to
 | |
|   /// read the other parts of the register.  This may cause unwanted stalls
 | |
|   /// preventing otherwise unrelated instructions from executing in parallel in
 | |
|   /// an out-of-order CPU.
 | |
|   ///
 | |
|   /// For example, the x86 instruction cvtsi2ss writes its result to bits
 | |
|   /// [31:0] of the destination xmm register. Bits [127:32] are unaffected, so
 | |
|   /// the instruction needs to wait for the old value of the register to become
 | |
|   /// available:
 | |
|   ///
 | |
|   ///   addps %xmm1, %xmm0
 | |
|   ///   movaps %xmm0, (%rax)
 | |
|   ///   cvtsi2ss %rbx, %xmm0
 | |
|   ///
 | |
|   /// In the code above, the cvtsi2ss instruction needs to wait for the addps
 | |
|   /// instruction before it can issue, even though the high bits of %xmm0
 | |
|   /// probably aren't needed.
 | |
|   ///
 | |
|   /// This hook returns the preferred clearance before MI, measured in
 | |
|   /// instructions.  Other defs of MI's operand OpNum are avoided in the last N
 | |
|   /// instructions before MI.  It should only return a positive value for
 | |
|   /// unwanted dependencies.  If the old bits of the defined register have
 | |
|   /// useful values, or if MI is determined to otherwise read the dependency,
 | |
|   /// the hook should return 0.
 | |
|   ///
 | |
|   /// The unwanted dependency may be handled by:
 | |
|   ///
 | |
|   /// 1. Allocating the same register for an MI def and use.  That makes the
 | |
|   ///    unwanted dependency identical to a required dependency.
 | |
|   ///
 | |
|   /// 2. Allocating a register for the def that has no defs in the previous N
 | |
|   ///    instructions.
 | |
|   ///
 | |
|   /// 3. Calling breakPartialRegDependency() with the same arguments.  This
 | |
|   ///    allows the target to insert a dependency breaking instruction.
 | |
|   ///
 | |
|   virtual unsigned
 | |
|   getPartialRegUpdateClearance(const MachineInstr *MI, unsigned OpNum,
 | |
|                                const TargetRegisterInfo *TRI) const {
 | |
|     // The default implementation returns 0 for no partial register dependency.
 | |
|     return 0;
 | |
|   }
 | |
| 
 | |
|   /// \brief Return the minimum clearance before an instruction that reads an
 | |
|   /// unused register.
 | |
|   ///
 | |
|   /// For example, AVX instructions may copy part of an register operand into
 | |
|   /// the unused high bits of the destination register.
 | |
|   ///
 | |
|   /// vcvtsi2sdq %rax, %xmm0<undef>, %xmm14
 | |
|   ///
 | |
|   /// In the code above, vcvtsi2sdq copies %xmm0[127:64] into %xmm14 creating a
 | |
|   /// false dependence on any previous write to %xmm0.
 | |
|   ///
 | |
|   /// This hook works similarly to getPartialRegUpdateClearance, except that it
 | |
|   /// does not take an operand index. Instead sets \p OpNum to the index of the
 | |
|   /// unused register.
 | |
|   virtual unsigned getUndefRegClearance(const MachineInstr *MI, unsigned &OpNum,
 | |
|                                         const TargetRegisterInfo *TRI) const {
 | |
|     // The default implementation returns 0 for no undef register dependency.
 | |
|     return 0;
 | |
|   }
 | |
| 
 | |
|   /// breakPartialRegDependency - Insert a dependency-breaking instruction
 | |
|   /// before MI to eliminate an unwanted dependency on OpNum.
 | |
|   ///
 | |
|   /// If it wasn't possible to avoid a def in the last N instructions before MI
 | |
|   /// (see getPartialRegUpdateClearance), this hook will be called to break the
 | |
|   /// unwanted dependency.
 | |
|   ///
 | |
|   /// On x86, an xorps instruction can be used as a dependency breaker:
 | |
|   ///
 | |
|   ///   addps %xmm1, %xmm0
 | |
|   ///   movaps %xmm0, (%rax)
 | |
|   ///   xorps %xmm0, %xmm0
 | |
|   ///   cvtsi2ss %rbx, %xmm0
 | |
|   ///
 | |
|   /// An <imp-kill> operand should be added to MI if an instruction was
 | |
|   /// inserted.  This ties the instructions together in the post-ra scheduler.
 | |
|   ///
 | |
|   virtual void
 | |
|   breakPartialRegDependency(MachineBasicBlock::iterator MI, unsigned OpNum,
 | |
|                             const TargetRegisterInfo *TRI) const {}
 | |
| 
 | |
|   /// Create machine specific model for scheduling.
 | |
|   virtual DFAPacketizer *
 | |
|   CreateTargetScheduleState(const TargetSubtargetInfo &) const {
 | |
|     return nullptr;
 | |
|   }
 | |
| 
 | |
|   // areMemAccessesTriviallyDisjoint - Sometimes, it is possible for the target
 | |
|   // to tell, even without aliasing information, that two MIs access different
 | |
|   // memory addresses. This function returns true if two MIs access different
 | |
|   // memory addresses, and false otherwise.
 | |
|   virtual bool
 | |
|   areMemAccessesTriviallyDisjoint(MachineInstr *MIa, MachineInstr *MIb,
 | |
|                                   AliasAnalysis *AA = nullptr) const {
 | |
|     assert(MIa && (MIa->mayLoad() || MIa->mayStore()) &&
 | |
|            "MIa must load from or modify a memory location");
 | |
|     assert(MIb && (MIb->mayLoad() || MIb->mayStore()) &&
 | |
|            "MIb must load from or modify a memory location");
 | |
|     return false;
 | |
|   }
 | |
| 
 | |
| private:
 | |
|   int CallFrameSetupOpcode, CallFrameDestroyOpcode;
 | |
| };
 | |
| 
 | |
| } // End llvm namespace
 | |
| 
 | |
| #endif
 |