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7783df1bb4
PowerPC uses itineraries to describe processor pipelines (and dispatch-group restrictions for P7/P8 cores). Unfortunately, the target-independent implementation of TII.getInstrLatency calls ItinData->getStageLatency, and that looks for the largest cycle count in the pipeline for any given instruction. This, however, yields the wrong answer for the PPC itineraries, because we don't encode the full pipeline. Because the functional units are fully pipelined, we only model the initial stages (there are no relevant hazards in the later stages to model), and so the technique employed by getStageLatency does not really work. Instead, we should take the maximum output operand latency, and that's what PPCInstrInfo::getInstrLatency now does. This caused some test-case churn, including two unfortunate side effects. First, the new arrangement of copies we get from function parameters now sometimes blocks VSX FMA mutation (a FIXME has been added to the code and the test cases), and we have one significant test-suite regression: SingleSource/Benchmarks/BenchmarkGame/spectral-norm 56.4185% +/- 18.9398% In this benchmark we have a loop with a vectorized FP divide, and it with the new scheduling both divides end up in the same dispatch group (which in this case seems to cause a problem, although why is not exactly clear). The grouping structure is hard to predict from the bottom of the loop, and there may not be much we can do to fix this. Very few other test-suite performance effects were really significant, but almost all weakly favor this change. However, in light of the issues highlighted above, I've left the old behavior available via a command-line flag. llvm-svn: 242188
247 lines
10 KiB
C++
247 lines
10 KiB
C++
//===-- PPCInstrInfo.h - PowerPC Instruction Information --------*- 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 contains the PowerPC implementation of the TargetInstrInfo class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_POWERPC_PPCINSTRINFO_H
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#define LLVM_LIB_TARGET_POWERPC_PPCINSTRINFO_H
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#include "PPC.h"
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#include "PPCRegisterInfo.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#define GET_INSTRINFO_HEADER
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#include "PPCGenInstrInfo.inc"
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namespace llvm {
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/// PPCII - This namespace holds all of the PowerPC target-specific
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/// per-instruction flags. These must match the corresponding definitions in
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/// PPC.td and PPCInstrFormats.td.
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namespace PPCII {
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enum {
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// PPC970 Instruction Flags. These flags describe the characteristics of the
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// PowerPC 970 (aka G5) dispatch groups and how they are formed out of
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// raw machine instructions.
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/// PPC970_First - This instruction starts a new dispatch group, so it will
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/// always be the first one in the group.
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PPC970_First = 0x1,
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/// PPC970_Single - This instruction starts a new dispatch group and
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/// terminates it, so it will be the sole instruction in the group.
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PPC970_Single = 0x2,
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/// PPC970_Cracked - This instruction is cracked into two pieces, requiring
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/// two dispatch pipes to be available to issue.
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PPC970_Cracked = 0x4,
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/// PPC970_Mask/Shift - This is a bitmask that selects the pipeline type that
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/// an instruction is issued to.
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PPC970_Shift = 3,
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PPC970_Mask = 0x07 << PPC970_Shift
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};
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enum PPC970_Unit {
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/// These are the various PPC970 execution unit pipelines. Each instruction
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/// is one of these.
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PPC970_Pseudo = 0 << PPC970_Shift, // Pseudo instruction
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PPC970_FXU = 1 << PPC970_Shift, // Fixed Point (aka Integer/ALU) Unit
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PPC970_LSU = 2 << PPC970_Shift, // Load Store Unit
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PPC970_FPU = 3 << PPC970_Shift, // Floating Point Unit
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PPC970_CRU = 4 << PPC970_Shift, // Control Register Unit
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PPC970_VALU = 5 << PPC970_Shift, // Vector ALU
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PPC970_VPERM = 6 << PPC970_Shift, // Vector Permute Unit
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PPC970_BRU = 7 << PPC970_Shift // Branch Unit
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};
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} // end namespace PPCII
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class PPCSubtarget;
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class PPCInstrInfo : public PPCGenInstrInfo {
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PPCSubtarget &Subtarget;
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const PPCRegisterInfo RI;
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bool StoreRegToStackSlot(MachineFunction &MF,
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unsigned SrcReg, bool isKill, int FrameIdx,
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const TargetRegisterClass *RC,
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SmallVectorImpl<MachineInstr*> &NewMIs,
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bool &NonRI, bool &SpillsVRS) const;
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bool LoadRegFromStackSlot(MachineFunction &MF, DebugLoc DL,
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unsigned DestReg, int FrameIdx,
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const TargetRegisterClass *RC,
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SmallVectorImpl<MachineInstr*> &NewMIs,
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bool &NonRI, bool &SpillsVRS) const;
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virtual void anchor();
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public:
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explicit PPCInstrInfo(PPCSubtarget &STI);
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/// getRegisterInfo - TargetInstrInfo is a superset of MRegister info. As
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/// such, whenever a client has an instance of instruction info, it should
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/// always be able to get register info as well (through this method).
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///
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const PPCRegisterInfo &getRegisterInfo() const { return RI; }
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ScheduleHazardRecognizer *
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CreateTargetHazardRecognizer(const TargetSubtargetInfo *STI,
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const ScheduleDAG *DAG) const override;
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ScheduleHazardRecognizer *
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CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II,
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const ScheduleDAG *DAG) const override;
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unsigned getInstrLatency(const InstrItineraryData *ItinData,
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const MachineInstr *MI,
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unsigned *PredCost = nullptr) const override;
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int getOperandLatency(const InstrItineraryData *ItinData,
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const MachineInstr *DefMI, unsigned DefIdx,
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const MachineInstr *UseMI,
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unsigned UseIdx) const override;
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int getOperandLatency(const InstrItineraryData *ItinData,
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SDNode *DefNode, unsigned DefIdx,
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SDNode *UseNode, unsigned UseIdx) const override {
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return PPCGenInstrInfo::getOperandLatency(ItinData, DefNode, DefIdx,
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UseNode, UseIdx);
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}
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bool hasLowDefLatency(const TargetSchedModel &SchedModel,
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const MachineInstr *DefMI,
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unsigned DefIdx) const override {
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// Machine LICM should hoist all instructions in low-register-pressure
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// situations; none are sufficiently free to justify leaving in a loop
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// body.
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return false;
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}
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bool isCoalescableExtInstr(const MachineInstr &MI,
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unsigned &SrcReg, unsigned &DstReg,
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unsigned &SubIdx) const override;
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unsigned isLoadFromStackSlot(const MachineInstr *MI,
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int &FrameIndex) const override;
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unsigned isStoreToStackSlot(const MachineInstr *MI,
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int &FrameIndex) const override;
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// commuteInstruction - We can commute rlwimi instructions, but only if the
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// rotate amt is zero. We also have to munge the immediates a bit.
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MachineInstr *commuteInstruction(MachineInstr *MI, bool NewMI) const override;
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bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1,
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unsigned &SrcOpIdx2) const override;
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void insertNoop(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MI) const override;
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// Branch analysis.
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bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
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MachineBasicBlock *&FBB,
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SmallVectorImpl<MachineOperand> &Cond,
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bool AllowModify) const override;
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unsigned RemoveBranch(MachineBasicBlock &MBB) const override;
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unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
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MachineBasicBlock *FBB, ArrayRef<MachineOperand> Cond,
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DebugLoc DL) const override;
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// Select analysis.
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bool canInsertSelect(const MachineBasicBlock &, ArrayRef<MachineOperand> Cond,
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unsigned, unsigned, int &, int &, int &) const override;
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void insertSelect(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
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DebugLoc DL, unsigned DstReg, ArrayRef<MachineOperand> Cond,
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unsigned TrueReg, unsigned FalseReg) const override;
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void copyPhysReg(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator I, DebugLoc DL,
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unsigned DestReg, unsigned SrcReg,
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bool KillSrc) const override;
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void storeRegToStackSlot(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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unsigned SrcReg, bool isKill, int FrameIndex,
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const TargetRegisterClass *RC,
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const TargetRegisterInfo *TRI) const override;
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void loadRegFromStackSlot(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator MBBI,
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unsigned DestReg, int FrameIndex,
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const TargetRegisterClass *RC,
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const TargetRegisterInfo *TRI) const override;
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bool
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ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const override;
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bool FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI,
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unsigned Reg, MachineRegisterInfo *MRI) const override;
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// If conversion by predication (only supported by some branch instructions).
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// All of the profitability checks always return true; it is always
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// profitable to use the predicated branches.
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bool isProfitableToIfCvt(MachineBasicBlock &MBB,
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unsigned NumCycles, unsigned ExtraPredCycles,
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const BranchProbability &Probability) const override {
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return true;
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}
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bool isProfitableToIfCvt(MachineBasicBlock &TMBB,
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unsigned NumT, unsigned ExtraT,
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MachineBasicBlock &FMBB,
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unsigned NumF, unsigned ExtraF,
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const BranchProbability &Probability) const override;
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bool isProfitableToDupForIfCvt(MachineBasicBlock &MBB,
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unsigned NumCycles,
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const BranchProbability
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&Probability) const override {
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return true;
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}
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bool isProfitableToUnpredicate(MachineBasicBlock &TMBB,
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MachineBasicBlock &FMBB) const override {
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return false;
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}
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// Predication support.
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bool isPredicated(const MachineInstr *MI) const override;
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bool isUnpredicatedTerminator(const MachineInstr *MI) const override;
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bool PredicateInstruction(MachineInstr *MI,
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ArrayRef<MachineOperand> Pred) const override;
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bool SubsumesPredicate(ArrayRef<MachineOperand> Pred1,
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ArrayRef<MachineOperand> Pred2) const override;
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bool DefinesPredicate(MachineInstr *MI,
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std::vector<MachineOperand> &Pred) const override;
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bool isPredicable(MachineInstr *MI) const override;
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// Comparison optimization.
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bool analyzeCompare(const MachineInstr *MI,
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unsigned &SrcReg, unsigned &SrcReg2,
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int &Mask, int &Value) const override;
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bool optimizeCompareInstr(MachineInstr *CmpInstr,
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unsigned SrcReg, unsigned SrcReg2,
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int Mask, int Value,
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const MachineRegisterInfo *MRI) const override;
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/// GetInstSize - Return the number of bytes of code the specified
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/// instruction may be. This returns the maximum number of bytes.
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///
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unsigned GetInstSizeInBytes(const MachineInstr *MI) const;
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void getNoopForMachoTarget(MCInst &NopInst) const override;
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};
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}
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#endif
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