mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-21 00:32:23 +00:00
66ac53165e
Before:
adr r12, #LJTI3_0_0
ldr pc, [r12, +r0, lsl #2]
LJTI3_0_0:
.long LBB3_24
.long LBB3_30
.long LBB3_31
.long LBB3_32
After:
adr r12, #LJTI3_0_0
add pc, r12, +r0, lsl #2
LJTI3_0_0:
b.w LBB3_24
b.w LBB3_30
b.w LBB3_31
b.w LBB3_32
This has several advantages.
1. This will make it easier to optimize this to a TBB / TBH instruction +
(smaller) table.
2. This eliminate the need for ugly asm printer hack to force the address
into thumb addresses (bit 0 is one).
3. Same codegen for pic and non-pic.
4. This eliminate the need to align the table so constantpool island pass
won't have to over-estimate the size.
Based on my calculation, the later is probably slightly faster as well since
ldr pc with shifter address is very slow. That is, it should be a win as long
as the HW implementation can do a reasonable job of branch predict the second
branch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77024 91177308-0d34-0410-b5e6-96231b3b80d8
300 lines
10 KiB
C++
300 lines
10 KiB
C++
//===- ARMBaseInstrInfo.h - ARM Base 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 Base ARM implementation of the TargetInstrInfo class.
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//
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//===----------------------------------------------------------------------===//
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#ifndef ARMBASEINSTRUCTIONINFO_H
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#define ARMBASEINSTRUCTIONINFO_H
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#include "ARM.h"
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#include "ARMRegisterInfo.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/Target/TargetInstrInfo.h"
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namespace llvm {
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class ARMSubtarget;
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/// ARMII - This namespace holds all of the target specific flags that
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/// instruction info tracks.
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///
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namespace ARMII {
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enum {
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//===------------------------------------------------------------------===//
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// Instruction Flags.
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//===------------------------------------------------------------------===//
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// This four-bit field describes the addressing mode used.
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AddrModeMask = 0xf,
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AddrModeNone = 0,
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AddrMode1 = 1,
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AddrMode2 = 2,
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AddrMode3 = 3,
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AddrMode4 = 4,
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AddrMode5 = 5,
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AddrMode6 = 6,
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AddrModeT1_1 = 7,
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AddrModeT1_2 = 8,
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AddrModeT1_4 = 9,
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AddrModeT1_s = 10, // i8 * 4 for pc and sp relative data
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AddrModeT2_i12 = 11,
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AddrModeT2_i8 = 12,
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AddrModeT2_so = 13,
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AddrModeT2_pc = 14, // +/- i12 for pc relative data
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AddrModeT2_i8s4 = 15, // i8 * 4
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// Size* - Flags to keep track of the size of an instruction.
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SizeShift = 4,
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SizeMask = 7 << SizeShift,
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SizeSpecial = 1, // 0 byte pseudo or special case.
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Size8Bytes = 2,
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Size4Bytes = 3,
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Size2Bytes = 4,
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// IndexMode - Unindex, pre-indexed, or post-indexed. Only valid for load
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// and store ops
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IndexModeShift = 7,
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IndexModeMask = 3 << IndexModeShift,
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IndexModePre = 1,
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IndexModePost = 2,
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//===------------------------------------------------------------------===//
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// Instruction encoding formats.
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//
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FormShift = 9,
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FormMask = 0x3f << FormShift,
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// Pseudo instructions
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Pseudo = 0 << FormShift,
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// Multiply instructions
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MulFrm = 1 << FormShift,
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// Branch instructions
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BrFrm = 2 << FormShift,
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BrMiscFrm = 3 << FormShift,
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// Data Processing instructions
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DPFrm = 4 << FormShift,
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DPSoRegFrm = 5 << FormShift,
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// Load and Store
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LdFrm = 6 << FormShift,
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StFrm = 7 << FormShift,
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LdMiscFrm = 8 << FormShift,
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StMiscFrm = 9 << FormShift,
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LdStMulFrm = 10 << FormShift,
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// Miscellaneous arithmetic instructions
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ArithMiscFrm = 11 << FormShift,
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// Extend instructions
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ExtFrm = 12 << FormShift,
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// VFP formats
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VFPUnaryFrm = 13 << FormShift,
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VFPBinaryFrm = 14 << FormShift,
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VFPConv1Frm = 15 << FormShift,
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VFPConv2Frm = 16 << FormShift,
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VFPConv3Frm = 17 << FormShift,
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VFPConv4Frm = 18 << FormShift,
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VFPConv5Frm = 19 << FormShift,
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VFPLdStFrm = 20 << FormShift,
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VFPLdStMulFrm = 21 << FormShift,
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VFPMiscFrm = 22 << FormShift,
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// Thumb format
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ThumbFrm = 23 << FormShift,
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// NEON format
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NEONFrm = 24 << FormShift,
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NEONGetLnFrm = 25 << FormShift,
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NEONSetLnFrm = 26 << FormShift,
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NEONDupFrm = 27 << FormShift,
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//===------------------------------------------------------------------===//
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// Misc flags.
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// UnaryDP - Indicates this is a unary data processing instruction, i.e.
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// it doesn't have a Rn operand.
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UnaryDP = 1 << 15,
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// Xform16Bit - Indicates this Thumb2 instruction may be transformed into
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// a 16-bit Thumb instruction if certain conditions are met.
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Xform16Bit = 1 << 16,
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//===------------------------------------------------------------------===//
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// Field shifts - such shifts are used to set field while generating
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// machine instructions.
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M_BitShift = 5,
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ShiftImmShift = 5,
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ShiftShift = 7,
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N_BitShift = 7,
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ImmHiShift = 8,
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SoRotImmShift = 8,
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RegRsShift = 8,
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ExtRotImmShift = 10,
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RegRdLoShift = 12,
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RegRdShift = 12,
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RegRdHiShift = 16,
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RegRnShift = 16,
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S_BitShift = 20,
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W_BitShift = 21,
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AM3_I_BitShift = 22,
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D_BitShift = 22,
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U_BitShift = 23,
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P_BitShift = 24,
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I_BitShift = 25,
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CondShift = 28
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};
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/// ARMII::Op - Holds all of the instruction types required by
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/// target specific instruction and register code. ARMBaseInstrInfo
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/// and subclasses should return a specific opcode that implements
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/// the instruction type.
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///
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enum Op {
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ADDri,
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ADDrs,
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ADDrr,
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B,
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Bcc,
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BX_RET,
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LDRrr,
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LDRri,
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MOVr,
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STRrr,
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STRri,
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SUBri,
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SUBrs,
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SUBrr
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};
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}
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static inline
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const MachineInstrBuilder &AddDefaultPred(const MachineInstrBuilder &MIB) {
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return MIB.addImm((int64_t)ARMCC::AL).addReg(0);
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}
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static inline
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const MachineInstrBuilder &AddDefaultCC(const MachineInstrBuilder &MIB) {
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return MIB.addReg(0);
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}
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static inline
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const MachineInstrBuilder &AddDefaultT1CC(const MachineInstrBuilder &MIB) {
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return MIB.addReg(ARM::CPSR);
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}
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class ARMBaseInstrInfo : public TargetInstrInfoImpl {
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protected:
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// Can be only subclassed.
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explicit ARMBaseInstrInfo(const ARMSubtarget &STI);
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public:
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// Return the non-pre/post incrementing version of 'Opc'. Return 0
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// if there is not such an opcode.
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virtual unsigned getUnindexedOpcode(unsigned Opc) const =0;
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// Return the opcode that implements 'Op', or 0 if no opcode
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virtual unsigned getOpcode(ARMII::Op Op) const =0;
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// Return true if the block does not fall through.
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virtual bool BlockHasNoFallThrough(const MachineBasicBlock &MBB) const =0;
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virtual MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
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MachineBasicBlock::iterator &MBBI,
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LiveVariables *LV) const;
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virtual const ARMBaseRegisterInfo &getRegisterInfo() const =0;
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// Branch analysis.
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virtual 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;
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virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const;
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virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
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MachineBasicBlock *FBB,
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const SmallVectorImpl<MachineOperand> &Cond) const;
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virtual
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bool ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const;
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// Predication support.
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bool isPredicated(const MachineInstr *MI) const {
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int PIdx = MI->findFirstPredOperandIdx();
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return PIdx != -1 && MI->getOperand(PIdx).getImm() != ARMCC::AL;
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}
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ARMCC::CondCodes getPredicate(const MachineInstr *MI) const {
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int PIdx = MI->findFirstPredOperandIdx();
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return PIdx != -1 ? (ARMCC::CondCodes)MI->getOperand(PIdx).getImm()
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: ARMCC::AL;
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}
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virtual
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bool PredicateInstruction(MachineInstr *MI,
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const SmallVectorImpl<MachineOperand> &Pred) const;
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virtual
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bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
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const SmallVectorImpl<MachineOperand> &Pred2) const;
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virtual bool DefinesPredicate(MachineInstr *MI,
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std::vector<MachineOperand> &Pred) const;
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/// GetInstSize - Returns the size of the specified MachineInstr.
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///
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virtual unsigned GetInstSizeInBytes(const MachineInstr* MI) const;
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/// Return true if the instruction is a register to register move and return
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/// the source and dest operands and their sub-register indices by reference.
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virtual bool isMoveInstr(const MachineInstr &MI,
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unsigned &SrcReg, unsigned &DstReg,
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unsigned &SrcSubIdx, unsigned &DstSubIdx) const;
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virtual unsigned isLoadFromStackSlot(const MachineInstr *MI,
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int &FrameIndex) const;
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virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
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int &FrameIndex) const;
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virtual bool copyRegToReg(MachineBasicBlock &MBB,
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MachineBasicBlock::iterator I,
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unsigned DestReg, unsigned SrcReg,
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const TargetRegisterClass *DestRC,
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const TargetRegisterClass *SrcRC) const;
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virtual 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) const;
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virtual 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) const;
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virtual bool canFoldMemoryOperand(const MachineInstr *MI,
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const SmallVectorImpl<unsigned> &Ops) const;
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virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF,
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MachineInstr* MI,
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const SmallVectorImpl<unsigned> &Ops,
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int FrameIndex) const;
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virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF,
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MachineInstr* MI,
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const SmallVectorImpl<unsigned> &Ops,
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MachineInstr* LoadMI) const;
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};
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}
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#endif
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