X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=include%2Fllvm%2FTarget%2FTargetInstrInfo.h;h=ec7aef3e5aa057cb7b96b24eaa9468e8d6afe371;hp=69fda8c47c227a86a3632a2e4e7110fa64d654a1;hb=41144b12f0a39e661048b7eb89fd9057802660fe;hpb=b86a0cdb674549d8493043331cecd9cbf53b80da diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h index 69fda8c47c2..ec7aef3e5aa 100644 --- a/include/llvm/Target/TargetInstrInfo.h +++ b/include/llvm/Target/TargetInstrInfo.h @@ -14,10 +14,12 @@ #ifndef LLVM_TARGET_TARGETINSTRINFO_H #define LLVM_TARGET_TARGETINSTRINFO_H +#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/SmallSet.h" -#include "llvm/CodeGen/DFAPacketizer.h" +#include "llvm/CodeGen/MachineCombinerPattern.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/MC/MCInstrInfo.h" +#include "llvm/Target/TargetRegisterInfo.h" namespace llvm { @@ -28,7 +30,8 @@ class MachineMemOperand; class MachineRegisterInfo; class MDNode; class MCInst; -class MCSchedModel; +struct MCSchedModel; +class MCSymbolRefExpr; class SDNode; class ScheduleHazardRecognizer; class SelectionDAG; @@ -36,6 +39,9 @@ class ScheduleDAG; class TargetRegisterClass; class TargetRegisterInfo; class BranchProbability; +class TargetSubtargetInfo; +class TargetSchedModel; +class DFAPacketizer; template class SmallVectorImpl; @@ -45,28 +51,30 @@ template class SmallVectorImpl; /// TargetInstrInfo - Interface to description of machine instruction set /// class TargetInstrInfo : public MCInstrInfo { - TargetInstrInfo(const TargetInstrInfo &) LLVM_DELETED_FUNCTION; - void operator=(const TargetInstrInfo &) LLVM_DELETED_FUNCTION; + TargetInstrInfo(const TargetInstrInfo &) = delete; + void operator=(const TargetInstrInfo &) = delete; public: - TargetInstrInfo(int CFSetupOpcode = -1, int CFDestroyOpcode = -1) + TargetInstrInfo(unsigned CFSetupOpcode = ~0u, unsigned CFDestroyOpcode = ~0u) : CallFrameSetupOpcode(CFSetupOpcode), CallFrameDestroyOpcode(CFDestroyOpcode) { } virtual ~TargetInstrInfo(); - /// getRegClass - Givem a machine instruction descriptor, returns the register + /// Given a machine instruction descriptor, returns the register /// class constraint for OpNum, or NULL. const TargetRegisterClass *getRegClass(const MCInstrDesc &TID, unsigned OpNum, const TargetRegisterInfo *TRI, const MachineFunction &MF) const; - /// isTriviallyReMaterializable - Return true if the instruction is trivially - /// rematerializable, meaning it has no side effects and requires no operands - /// that aren't always available. + /// Return true if the instruction is trivially rematerializable, meaning it + /// has no side effects and requires no operands that aren't always available. + /// This means the only allowed uses are constants and unallocatable physical + /// registers so that the instructions result is independent of the place + /// in the function. bool isTriviallyReMaterializable(const MachineInstr *MI, - AliasAnalysis *AA = 0) const { + AliasAnalysis *AA = nullptr) const { return MI->getOpcode() == TargetOpcode::IMPLICIT_DEF || (MI->getDesc().isRematerializable() && (isReallyTriviallyReMaterializable(MI, AA) || @@ -74,49 +82,53 @@ public: } protected: - /// isReallyTriviallyReMaterializable - For instructions with opcodes for - /// which the M_REMATERIALIZABLE flag is set, this hook lets the target - /// specify whether the instruction is actually trivially rematerializable, - /// taking into consideration its operands. This predicate must return false - /// if the instruction has any side effects other than producing a value, or - /// if it requres any address registers that are not always available. + /// For instructions with opcodes for which the M_REMATERIALIZABLE flag is + /// set, this hook lets the target specify whether the instruction is actually + /// trivially rematerializable, taking into consideration its operands. This + /// predicate must return false if the instruction has any side effects other + /// than producing a value, or if it requres any address registers that are + /// not always available. + /// Requirements must be check as stated in isTriviallyReMaterializable() . virtual bool isReallyTriviallyReMaterializable(const MachineInstr *MI, AliasAnalysis *AA) const { return false; } private: - /// isReallyTriviallyReMaterializableGeneric - For instructions with opcodes - /// for which the M_REMATERIALIZABLE flag is set and the target hook - /// isReallyTriviallyReMaterializable returns false, this function does - /// target-independent tests to determine if the instruction is really - /// trivially rematerializable. + /// For instructions with opcodes for which the M_REMATERIALIZABLE flag is + /// set and the target hook isReallyTriviallyReMaterializable returns false, + /// this function does target-independent tests to determine if the + /// instruction is really trivially rematerializable. bool isReallyTriviallyReMaterializableGeneric(const MachineInstr *MI, AliasAnalysis *AA) const; public: - /// getCallFrameSetup/DestroyOpcode - These methods return the opcode of the - /// frame setup/destroy instructions if they exist (-1 otherwise). Some - /// targets use pseudo instructions in order to abstract away the difference - /// between operating with a frame pointer and operating without, through the - /// use of these two instructions. - /// - int getCallFrameSetupOpcode() const { return CallFrameSetupOpcode; } - int getCallFrameDestroyOpcode() const { return CallFrameDestroyOpcode; } - - /// isCoalescableExtInstr - Return true if the instruction is a "coalescable" - /// extension instruction. That is, it's like a copy where it's legal for the - /// source to overlap the destination. e.g. X86::MOVSX64rr32. If this returns - /// true, then it's expected the pre-extension value is available as a subreg - /// of the result register. This also returns the sub-register index in - /// SubIdx. + /// These methods return the opcode of the frame setup/destroy instructions + /// if they exist (-1 otherwise). Some targets use pseudo instructions in + /// order to abstract away the difference between operating with a frame + /// pointer and operating without, through the use of these two instructions. + /// + unsigned getCallFrameSetupOpcode() const { return CallFrameSetupOpcode; } + unsigned getCallFrameDestroyOpcode() const { return CallFrameDestroyOpcode; } + + /// Returns the actual stack pointer adjustment made by an instruction + /// as part of a call sequence. By default, only call frame setup/destroy + /// instructions adjust the stack, but targets may want to override this + /// to enable more fine-grained adjustment, or adjust by a different value. + virtual int getSPAdjust(const MachineInstr *MI) const; + + /// Return true if the instruction is a "coalescable" extension instruction. + /// That is, it's like a copy where it's legal for the source to overlap the + /// destination. e.g. X86::MOVSX64rr32. If this returns true, then it's + /// expected the pre-extension value is available as a subreg of the result + /// register. This also returns the sub-register index in SubIdx. virtual bool isCoalescableExtInstr(const MachineInstr &MI, unsigned &SrcReg, unsigned &DstReg, unsigned &SubIdx) const { return false; } - /// isLoadFromStackSlot - If the specified machine instruction is a direct + /// If the specified machine instruction is a direct /// load from a stack slot, return the virtual or physical register number of /// the destination along with the FrameIndex of the loaded stack slot. If /// not, return 0. This predicate must return 0 if the instruction has @@ -126,26 +138,24 @@ public: return 0; } - /// isLoadFromStackSlotPostFE - Check for post-frame ptr elimination - /// stack locations as well. This uses a heuristic so it isn't - /// reliable for correctness. + /// Check for post-frame ptr elimination stack locations as well. + /// This uses a heuristic so it isn't reliable for correctness. virtual unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI, int &FrameIndex) const { return 0; } - /// hasLoadFromStackSlot - If the specified machine instruction has - /// a load from a stack slot, return true along with the FrameIndex - /// of the loaded stack slot and the machine mem operand containing - /// the reference. If not, return false. Unlike - /// isLoadFromStackSlot, this returns true for any instructions that - /// loads from the stack. This is just a hint, as some cases may be - /// missed. + /// If the specified machine instruction has a load from a stack slot, + /// return true along with the FrameIndex of the loaded stack slot and the + /// machine mem operand containing the reference. + /// If not, return false. Unlike isLoadFromStackSlot, this returns true for + /// any instructions that loads from the stack. This is just a hint, as some + /// cases may be missed. virtual bool hasLoadFromStackSlot(const MachineInstr *MI, const MachineMemOperand *&MMO, int &FrameIndex) const; - /// isStoreToStackSlot - If the specified machine instruction is a direct + /// If the specified machine instruction is a direct /// store to a stack slot, return the virtual or physical register number of /// the source reg along with the FrameIndex of the loaded stack slot. If /// not, return 0. This predicate must return 0 if the instruction has @@ -155,25 +165,57 @@ public: return 0; } - /// isStoreToStackSlotPostFE - Check for post-frame ptr elimination - /// stack locations as well. This uses a heuristic so it isn't - /// reliable for correctness. + /// Check for post-frame ptr elimination stack locations as well. + /// This uses a heuristic, so it isn't reliable for correctness. virtual unsigned isStoreToStackSlotPostFE(const MachineInstr *MI, int &FrameIndex) const { return 0; } - /// hasStoreToStackSlot - If the specified machine instruction has a - /// store to a stack slot, return true along with the FrameIndex of - /// the loaded stack slot and the machine mem operand containing the - /// reference. If not, return false. Unlike isStoreToStackSlot, + /// If the specified machine instruction has a store to a stack slot, + /// return true along with the FrameIndex of the loaded stack slot and the + /// machine mem operand containing the reference. + /// If not, return false. Unlike isStoreToStackSlot, /// this returns true for any instructions that stores to the /// stack. This is just a hint, as some cases may be missed. virtual bool hasStoreToStackSlot(const MachineInstr *MI, const MachineMemOperand *&MMO, int &FrameIndex) const; - /// reMaterialize - Re-issue the specified 'original' instruction at the + /// Return true if the specified machine instruction + /// is a copy of one stack slot to another and has no other effect. + /// Provide the identity of the two frame indices. + virtual bool isStackSlotCopy(const MachineInstr *MI, int &DestFrameIndex, + int &SrcFrameIndex) const { + return false; + } + + /// Compute the size in bytes and offset within a stack slot of a spilled + /// register or subregister. + /// + /// \param [out] Size in bytes of the spilled value. + /// \param [out] Offset in bytes within the stack slot. + /// \returns true if both Size and Offset are successfully computed. + /// + /// Not all subregisters have computable spill slots. For example, + /// subregisters registers may not be byte-sized, and a pair of discontiguous + /// subregisters has no single offset. + /// + /// Targets with nontrivial bigendian implementations may need to override + /// this, particularly to support spilled vector registers. + virtual bool getStackSlotRange(const TargetRegisterClass *RC, unsigned SubIdx, + unsigned &Size, unsigned &Offset, + const MachineFunction &MF) const; + + /// Return true if the instruction is as cheap as a move instruction. + /// + /// Targets for different archs need to override this, and different + /// micro-architectures can also be finely tuned inside. + virtual bool isAsCheapAsAMove(const MachineInstr *MI) const { + return MI->isAsCheapAsAMove(); + } + + /// Re-issue the specified 'original' instruction at the /// specific location targeting a new destination register. /// The register in Orig->getOperand(0).getReg() will be substituted by /// DestReg:SubIdx. Any existing subreg index is preserved or composed with @@ -184,7 +226,7 @@ public: const MachineInstr *Orig, const TargetRegisterInfo &TRI) const; - /// duplicate - Create a duplicate of the Orig instruction in MF. This is like + /// Create a duplicate of the Orig instruction in MF. This is like /// MachineFunction::CloneMachineInstr(), but the target may update operands /// that are required to be unique. /// @@ -192,7 +234,7 @@ public: virtual MachineInstr *duplicate(MachineInstr *Orig, MachineFunction &MF) const; - /// convertToThreeAddress - This method must be implemented by targets that + /// This method must be implemented by targets that /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target /// may be able to convert a two-address instruction into one or more true /// three-address instructions on demand. This allows the X86 target (for @@ -205,13 +247,13 @@ public: virtual MachineInstr * convertToThreeAddress(MachineFunction::iterator &MFI, MachineBasicBlock::iterator &MBBI, LiveVariables *LV) const { - return 0; + return nullptr; } - /// commuteInstruction - If a target has any instructions that are - /// commutable but require converting to different instructions or making - /// non-trivial changes to commute them, this method can overloaded to do - /// that. The default implementation simply swaps the commutable operands. + /// If a target has any instructions that are commutable but require + /// converting to different instructions or making non-trivial changes to + /// commute them, this method can overloaded to do that. + /// The default implementation simply swaps the commutable operands. /// If NewMI is false, MI is modified in place and returned; otherwise, a /// new machine instruction is created and returned. Do not call this /// method for a non-commutable instruction, but there may be some cases @@ -219,22 +261,101 @@ public: virtual MachineInstr *commuteInstruction(MachineInstr *MI, bool NewMI = false) const; - /// findCommutedOpIndices - If specified MI is commutable, return the two - /// operand indices that would swap value. Return false if the instruction + /// If specified MI is commutable, return the two operand indices that would + /// swap value. Return false if the instruction /// is not in a form which this routine understands. virtual bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1, unsigned &SrcOpIdx2) const; - /// produceSameValue - Return true if two machine instructions would produce - /// identical values. By default, this is only true when the two instructions + /// A pair composed of a register and a sub-register index. + /// Used to give some type checking when modeling Reg:SubReg. + struct RegSubRegPair { + unsigned Reg; + unsigned SubReg; + RegSubRegPair(unsigned Reg = 0, unsigned SubReg = 0) + : Reg(Reg), SubReg(SubReg) {} + }; + /// A pair composed of a pair of a register and a sub-register index, + /// and another sub-register index. + /// Used to give some type checking when modeling Reg:SubReg1, SubReg2. + struct RegSubRegPairAndIdx : RegSubRegPair { + unsigned SubIdx; + RegSubRegPairAndIdx(unsigned Reg = 0, unsigned SubReg = 0, + unsigned SubIdx = 0) + : RegSubRegPair(Reg, SubReg), SubIdx(SubIdx) {} + }; + + /// Build the equivalent inputs of a REG_SEQUENCE for the given \p MI + /// and \p DefIdx. + /// \p [out] InputRegs of the equivalent REG_SEQUENCE. Each element of + /// the list is modeled as . + /// E.g., REG_SEQUENCE vreg1:sub1, sub0, vreg2, sub1 would produce + /// two elements: + /// - vreg1:sub1, sub0 + /// - vreg2<:0>, sub1 + /// + /// \returns true if it is possible to build such an input sequence + /// with the pair \p MI, \p DefIdx. False otherwise. + /// + /// \pre MI.isRegSequence() or MI.isRegSequenceLike(). + /// + /// \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 + getRegSequenceInputs(const MachineInstr &MI, unsigned DefIdx, + SmallVectorImpl &InputRegs) const; + + /// Build the equivalent inputs of a EXTRACT_SUBREG for the given \p MI + /// and \p DefIdx. + /// \p [out] InputReg of the equivalent EXTRACT_SUBREG. + /// E.g., EXTRACT_SUBREG vreg1:sub1, sub0, sub1 would produce: + /// - vreg1:sub1, sub0 + /// + /// \returns true if it is possible to build such an input sequence + /// with the pair \p MI, \p DefIdx. False otherwise. + /// + /// \pre MI.isExtractSubreg() or MI.isExtractSubregLike(). + /// + /// \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; + + + /// 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 = 0) const; + const MachineRegisterInfo *MRI = nullptr) const; - /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning + /// 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: @@ -266,15 +387,60 @@ public: return true; } - /// RemoveBranch - Remove the branching code at the end of the specific MBB. + /// Represents a predicate at the MachineFunction level. The control flow a + /// MachineBranchPredicate represents is: + /// + /// Reg = LHS `Predicate` RHS == ConditionDef + /// if Reg then goto TrueDest else goto FalseDest + /// + struct MachineBranchPredicate { + enum ComparePredicate { + PRED_EQ, // True if two values are equal + PRED_NE, // True if two values are not equal + PRED_INVALID // Sentinel value + }; + + ComparePredicate Predicate; + MachineOperand LHS; + MachineOperand RHS; + MachineBasicBlock *TrueDest; + MachineBasicBlock *FalseDest; + MachineInstr *ConditionDef; + + /// SingleUseCondition is true if ConditionDef is dead except for the + /// branch(es) at the end of the basic block. + /// + bool SingleUseCondition; + + explicit MachineBranchPredicate() + : Predicate(PRED_INVALID), LHS(MachineOperand::CreateImm(0)), + RHS(MachineOperand::CreateImm(0)), TrueDest(nullptr), + FalseDest(nullptr), ConditionDef(nullptr), SingleUseCondition(false) { + } + }; + + /// Analyze the branching code at the end of MBB and parse it into the + /// MachineBranchPredicate structure if possible. Returns false on success + /// and true on failure. + /// + /// If AllowModify is true, then this routine is allowed to modify the basic + /// block (e.g. delete instructions after the unconditional branch). + /// + virtual bool AnalyzeBranchPredicate(MachineBasicBlock &MBB, + MachineBranchPredicate &MBP, + bool AllowModify = false) const { + return true; + } + + /// 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 + /// 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. @@ -285,18 +451,51 @@ public: /// merging needs to be disabled. virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB, - const SmallVectorImpl &Cond, + ArrayRef 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. + /// 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; - /// isLegalToSplitMBBAt - Return true if it's legal to split the given basic + /// 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!"); + } + + /// Get a machine trap instruction. + virtual void getTrap(MCInst &MI) const { + llvm_unreachable("Target didn't implement TargetInstrInfo::getTrap!"); + } + + /// Get a number of bytes that suffices to hold + /// either the instruction returned by getUnconditionalBranch or the + /// instruction returned by getTrap. This only makes sense because + /// getUnconditionalBranch returns a single, specific instruction. This + /// information is needed by the jumptable construction code, since it must + /// decide how many bytes to use for a jumptable entry so it can generate the + /// right mask. + /// + /// Note that if the jumptable instruction requires alignment, then that + /// alignment should be factored into this required bound so that the + /// resulting bound gives the right alignment for the instruction. + virtual unsigned getJumpInstrTableEntryBound() const { + // This method gets called by LLVMTargetMachine always, so it can't fail + // just because there happens to be no implementation for this target. + // Any code that tries to use a jumptable annotation without defining + // getUnconditionalBranch on the appropriate Target will fail anyway, and + // the value returned here won't matter in that case. + return 0; + } + + /// 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, @@ -304,7 +503,7 @@ public: return true; } - /// isProfitableToIfCvt - Return true if it's profitable to predicate + /// 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 @@ -316,7 +515,7 @@ public: return false; } - /// isProfitableToIfCvt - Second variant of isProfitableToIfCvt, this one + /// 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 @@ -331,9 +530,9 @@ public: 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. + /// 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. @@ -343,7 +542,7 @@ public: return false; } - /// isProfitableToUnpredicate - Return true if it's profitable to unpredicate + /// 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. @@ -359,7 +558,7 @@ public: return false; } - /// canInsertSelect - Return true if it is possible to insert a select + /// Return true if it is possible to insert a select /// instruction that chooses between TrueReg and FalseReg based on the /// condition code in Cond. /// @@ -377,16 +576,15 @@ public: /// @param TrueCycles Latency from TrueReg to select output. /// @param FalseCycles Latency from FalseReg to select output. virtual bool canInsertSelect(const MachineBasicBlock &MBB, - const SmallVectorImpl &Cond, + ArrayRef 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. + /// 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 @@ -402,13 +600,12 @@ public: /// @param FalseReg Virtual register to copy when Cons is false. virtual void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator I, DebugLoc DL, - unsigned DstReg, - const SmallVectorImpl &Cond, + unsigned DstReg, ArrayRef Cond, unsigned TrueReg, unsigned FalseReg) const { llvm_unreachable("Target didn't implement TargetInstrInfo::insertSelect!"); } - /// analyzeSelect - Analyze the given select instruction, returning true if + /// 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 @@ -434,7 +631,7 @@ public: return true; } - /// optimizeSelect - Given a select instruction that was understood by + /// 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. /// @@ -445,15 +642,18 @@ public: /// a side. /// /// @param MI Optimizable select instruction. + /// @param NewMIs Set that record all MIs in the basic block up to \p + /// MI. Has to be updated with any newly created MI or deleted ones. /// @param PreferFalse Try to optimize FalseOp instead of TrueOp. /// @returns Optimized instruction or NULL. virtual MachineInstr *optimizeSelect(MachineInstr *MI, + SmallPtrSetImpl &NewMIs, 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. + /// 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. @@ -468,11 +668,10 @@ public: 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. + /// 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, @@ -482,10 +681,9 @@ public: "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. + /// 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, @@ -495,7 +693,7 @@ public: "TargetInstrInfo::loadRegFromStackSlot!"); } - /// expandPostRAPseudo - This function is called for all pseudo instructions + /// 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 @@ -505,66 +703,125 @@ public: return false; } - /// emitFrameIndexDebugValue - Emit a target-dependent form of - /// DBG_VALUE encoding the address of a frame index. Addresses would - /// normally be lowered the same way as other addresses on the target, - /// e.g. in load instructions. For targets that do not support this - /// the debug info is simply lost. - /// If you add this for a target you should handle this DBG_VALUE in the - /// target-specific AsmPrinter code as well; you will probably get invalid - /// assembly output if you don't. - virtual MachineInstr *emitFrameIndexDebugValue(MachineFunction &MF, - int FrameIx, - uint64_t Offset, - const MDNode *MDPtr, - DebugLoc dl) const { - return 0; - } - - /// foldMemoryOperand - Attempt to fold a load or store of the specified stack + /// 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 &Ops, - int FrameIndex) const; + MachineInstr *foldMemoryOperand(MachineBasicBlock::iterator MI, + ArrayRef Ops, int FrameIndex) const; + + /// 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, + ArrayRef Ops, + MachineInstr *LoadMI) const; + + /// Return true when there is potentially a faster code sequence + /// for an instruction chain ending in \p Root. All potential patterns 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 patterns + virtual bool getMachineCombinerPatterns( + MachineInstr &Root, + SmallVectorImpl &Pattern) const { + return false; + } + + /// When getMachineCombinerPatterns() finds patterns, this function generates + /// the instructions that could replace the original code sequence. The client + /// has to decide whether the actual replacement is beneficial or not. + /// \param Root - Instruction that could be combined with one of its operands + /// \param Pattern - 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 Pattern, + SmallVectorImpl &InsInstrs, + SmallVectorImpl &DelInstrs, + DenseMap &InstrIdxForVirtReg) const { + return; + } - /// 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 &Ops, - MachineInstr* LoadMI) const; + /// 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 + /// 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 &Ops, - int FrameIndex) const { - return 0; + /// The instruction and any auxiliary instructions necessary will be inserted + /// at InsertPt. + virtual MachineInstr *foldMemoryOperandImpl( + MachineFunction &MF, MachineInstr *MI, ArrayRef Ops, + MachineBasicBlock::iterator InsertPt, int FrameIndex) const { + return nullptr; } - /// foldMemoryOperandImpl - Target-dependent implementation for - /// foldMemoryOperand. Target-independent code in foldMemoryOperand will + /// 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 &Ops, - MachineInstr* LoadMI) const { - return 0; + /// The instruction and any auxiliary instructions necessary will be inserted + /// at InsertPt. + virtual MachineInstr *foldMemoryOperandImpl( + MachineFunction &MF, MachineInstr *MI, ArrayRef Ops, + MachineBasicBlock::iterator InsertPt, 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 &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 &Ops) const; + /// Returns true for the specified load / store if folding is possible. + virtual bool canFoldMemoryOperand(const MachineInstr *MI, + ArrayRef 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 @@ -580,7 +837,7 @@ public: return false; } - /// getOpcodeAfterMemoryUnfold - Returns the opcode of the would be new + /// 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 @@ -588,23 +845,22 @@ public: /// value. virtual unsigned getOpcodeAfterMemoryUnfold(unsigned Opc, bool UnfoldLoad, bool UnfoldStore, - unsigned *LoadRegIndex = 0) const { + 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. + /// 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 + /// This is a used by the pre-regalloc scheduler to determine (in conjunction + /// with areLoadsFromSameBasePtr) if two loads should be scheduled together. + /// 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 @@ -616,71 +872,69 @@ public: 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 { + /// Get the base register and byte offset of an instruction that reads/writes + /// memory. + virtual bool getMemOpBaseRegImmOfs(MachineInstr *MemOp, 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 + /// 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. + /// Reverses the branch condition of the specified condition list, + /// returning false on success and true if it cannot be reversed. virtual bool ReverseBranchCondition(SmallVectorImpl &Cond) const { return true; } - /// insertNoop - Insert a noop into the instruction stream at the specified - /// point. + /// Insert a noop into the instruction stream at the specified point. virtual void insertNoop(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const; - /// getNoopForMachoTarget - Return the noop instruction to use for a noop. - virtual void getNoopForMachoTarget(MCInst &NopInst) const { - // Default to just using 'nop' string. - } + /// Return the noop instruction to use for a noop. + virtual void getNoopForMachoTarget(MCInst &NopInst) const; - /// isPredicated - Returns true if the instruction is already predicated. - /// + /// 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 + /// 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. + /// Convert the instruction into a predicated instruction. + /// It returns true if the operation was successful. virtual bool PredicateInstruction(MachineInstr *MI, - const SmallVectorImpl &Pred) const; + ArrayRef Pred) const; - /// SubsumesPredicate - Returns true if the first specified predicate + /// Returns true if the first specified predicate /// subsumes the second, e.g. GE subsumes GT. virtual - bool SubsumesPredicate(const SmallVectorImpl &Pred1, - const SmallVectorImpl &Pred2) const { + bool SubsumesPredicate(ArrayRef Pred1, + ArrayRef Pred2) const { return false; } - /// DefinesPredicate - If the specified instruction defines any predicate + /// 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, @@ -688,22 +942,21 @@ public: return false; } - /// isPredicable - Return true if the specified instruction can be predicated. + /// 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 + /// 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. + /// 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; @@ -713,23 +966,20 @@ public: 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. + /// Allocate and return a hazard recognizer to use for this target when + /// scheduling the machine instructions before register allocation. virtual ScheduleHazardRecognizer* - CreateTargetHazardRecognizer(const TargetMachine *TM, + 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. + /// 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. + /// 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; @@ -738,7 +988,7 @@ public: /// targets may choose to honor. bool usePreRAHazardRecognizer() const; - /// analyzeCompare - For a comparison instruction, return the source registers + /// 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. @@ -748,7 +998,7 @@ public: return false; } - /// optimizeCompareInstr - See if the comparison instruction can be converted + /// 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, @@ -757,9 +1007,10 @@ public: 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 + /// 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 @@ -769,11 +1020,11 @@ public: const MachineRegisterInfo *MRI, unsigned &FoldAsLoadDefReg, MachineInstr *&DefMI) const { - return 0; + return nullptr; } - /// FoldImmediate - 'Reg' is known to be defined by a move immediate - /// instruction, try to fold the immediate into the use instruction. + /// '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 @@ -783,14 +1034,14 @@ public: return false; } - /// getNumMicroOps - Return the number of u-operations the given machine + /// 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 + /// 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. @@ -802,73 +1053,74 @@ public: 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. + /// 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. + /// This is a raw interface to the itinerary that may be directly overridden + /// 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 + /// 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. + /// 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 = 0) const; + 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, + 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. + /// 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 + /// Compute operand latency between a def of 'Reg' + /// and a 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 + /// determine whether it makes sense to hoist an instruction out even in a /// high register pressure situation. virtual - bool hasHighOperandLatency(const InstrItineraryData *ItinData, + bool hasHighOperandLatency(const TargetSchedModel &SchedModel, 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 + /// Compute operand latency of a def of 'Reg'. Return true /// if the target considered it 'low'. virtual - bool hasLowDefLatency(const InstrItineraryData *ItinData, + bool hasLowDefLatency(const TargetSchedModel &SchedModel, const MachineInstr *DefMI, unsigned DefIdx) const; - /// verifyInstruction - Perform target specific instruction verification. + /// 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 + /// Return the current execution domain and bit mask of /// possible domains for instruction. /// /// Some micro-architectures have multiple execution domains, and multiple @@ -892,15 +1144,14 @@ public: return std::make_pair(0, 0); } - /// setExecutionDomain - Change the opcode of MI to execute in Domain. + /// 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 + /// 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 @@ -946,7 +1197,27 @@ public: return 0; } - /// breakPartialRegDependency - Insert a dependency-breaking instruction + /// \brief Return the minimum clearance before an instruction that reads an + /// unused register. + /// + /// For example, AVX instructions may copy part of a register operand into + /// the unused high bits of the destination register. + /// + /// vcvtsi2sdq %rax, %xmm0, %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; + } + + /// 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 @@ -968,15 +1239,37 @@ public: const TargetRegisterInfo *TRI) const {} /// Create machine specific model for scheduling. - virtual DFAPacketizer* - CreateTargetScheduleState(const TargetMachine*, const ScheduleDAG*) const { - return NULL; + virtual DFAPacketizer * + CreateTargetScheduleState(const TargetSubtargetInfo &) const { + return nullptr; + } + + // 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; + } + + /// \brief Return the value to use for the MachineCSE's LookAheadLimit, + /// which is a heuristic used for CSE'ing phys reg defs. + virtual unsigned getMachineCSELookAheadLimit () const { + // The default lookahead is small to prevent unprofitable quadratic + // behavior. + return 5; } private: - int CallFrameSetupOpcode, CallFrameDestroyOpcode; + unsigned CallFrameSetupOpcode, CallFrameDestroyOpcode; }; -} // End llvm namespace +} // namespace llvm #endif