llvm-6502/lib/Target/ARM/ARMBaseInstrInfo.h
Tim Northover 323ac85d6a ARM: fold prologue/epilogue sp updates into push/pop for code size
ARM prologues usually look like:
    push {r7, lr}
    sub sp, sp, #4

If code size is extremely important, this can be optimised to the single
instruction:
    push {r6, r7, lr}

where we don't actually care about the contents of r6, but pushing it subtracts
4 from sp as a side effect.

This should implement such a conversion, predicated on the "minsize" function
attribute (-Oz) since I've yet to find any code it actually makes faster.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194264 91177308-0d34-0410-b5e6-96231b3b80d8
2013-11-08 17:18:07 +00:00

438 lines
19 KiB
C++

//===-- ARMBaseInstrInfo.h - ARM Base Instruction Information ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the Base ARM implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef ARMBASEINSTRUCTIONINFO_H
#define ARMBASEINSTRUCTIONINFO_H
#include "ARM.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Target/TargetInstrInfo.h"
#define GET_INSTRINFO_HEADER
#include "ARMGenInstrInfo.inc"
namespace llvm {
class ARMSubtarget;
class ARMBaseRegisterInfo;
class ARMBaseInstrInfo : public ARMGenInstrInfo {
const ARMSubtarget &Subtarget;
protected:
// Can be only subclassed.
explicit ARMBaseInstrInfo(const ARMSubtarget &STI);
public:
// Return whether the target has an explicit NOP encoding.
bool hasNOP() const;
// Return the non-pre/post incrementing version of 'Opc'. Return 0
// if there is not such an opcode.
virtual unsigned getUnindexedOpcode(unsigned Opc) const =0;
virtual MachineInstr *convertToThreeAddress(MachineFunction::iterator &MFI,
MachineBasicBlock::iterator &MBBI,
LiveVariables *LV) const;
virtual const ARMBaseRegisterInfo &getRegisterInfo() const = 0;
const ARMSubtarget &getSubtarget() const { return Subtarget; }
ScheduleHazardRecognizer *
CreateTargetHazardRecognizer(const TargetMachine *TM,
const ScheduleDAG *DAG) const;
ScheduleHazardRecognizer *
CreateTargetPostRAHazardRecognizer(const InstrItineraryData *II,
const ScheduleDAG *DAG) const;
// Branch analysis.
virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify = false) const;
virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const;
virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond,
DebugLoc DL) const;
virtual
bool ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const;
// Predication support.
bool isPredicated(const MachineInstr *MI) const;
ARMCC::CondCodes getPredicate(const MachineInstr *MI) const {
int PIdx = MI->findFirstPredOperandIdx();
return PIdx != -1 ? (ARMCC::CondCodes)MI->getOperand(PIdx).getImm()
: ARMCC::AL;
}
virtual
bool PredicateInstruction(MachineInstr *MI,
const SmallVectorImpl<MachineOperand> &Pred) const;
virtual
bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1,
const SmallVectorImpl<MachineOperand> &Pred2) const;
virtual bool DefinesPredicate(MachineInstr *MI,
std::vector<MachineOperand> &Pred) const;
virtual bool isPredicable(MachineInstr *MI) const;
/// GetInstSize - Returns the size of the specified MachineInstr.
///
virtual unsigned GetInstSizeInBytes(const MachineInstr* MI) const;
virtual unsigned isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const;
virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const;
virtual unsigned isLoadFromStackSlotPostFE(const MachineInstr *MI,
int &FrameIndex) const;
virtual unsigned isStoreToStackSlotPostFE(const MachineInstr *MI,
int &FrameIndex) const;
virtual void copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const;
virtual void storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned SrcReg, bool isKill, int FrameIndex,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const;
virtual void loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned DestReg, int FrameIndex,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const;
virtual bool expandPostRAPseudo(MachineBasicBlock::iterator MI) const;
virtual void reMaterialize(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MI,
unsigned DestReg, unsigned SubIdx,
const MachineInstr *Orig,
const TargetRegisterInfo &TRI) const;
MachineInstr *duplicate(MachineInstr *Orig, MachineFunction &MF) const;
MachineInstr *commuteInstruction(MachineInstr*, bool=false) const;
const MachineInstrBuilder &AddDReg(MachineInstrBuilder &MIB, unsigned Reg,
unsigned SubIdx, unsigned State,
const TargetRegisterInfo *TRI) const;
virtual bool produceSameValue(const MachineInstr *MI0,
const MachineInstr *MI1,
const MachineRegisterInfo *MRI) const;
/// 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 is the offset. It also returns the
/// offsets by reference.
virtual bool areLoadsFromSameBasePtr(SDNode *Load1, SDNode *Load2,
int64_t &Offset1, int64_t &Offset2)const;
/// shouldScheduleLoadsNear - This is a used by the pre-regalloc scheduler to
/// determine (in conjunction with areLoadsFromSameBasePtr) if two loads
/// should be scheduled togther. On some targets if two loads are loading from
/// addresses in the same cache line, it's better if they are scheduled
/// together. This function takes two integers that represent the load offsets
/// from the common base address. It returns true if it decides it's desirable
/// to schedule the two loads together. "NumLoads" is the number of loads that
/// have already been scheduled after Load1.
virtual bool shouldScheduleLoadsNear(SDNode *Load1, SDNode *Load2,
int64_t Offset1, int64_t Offset2,
unsigned NumLoads) const;
virtual bool isSchedulingBoundary(const MachineInstr *MI,
const MachineBasicBlock *MBB,
const MachineFunction &MF) const;
virtual bool isProfitableToIfCvt(MachineBasicBlock &MBB,
unsigned NumCycles, unsigned ExtraPredCycles,
const BranchProbability &Probability) const;
virtual bool isProfitableToIfCvt(MachineBasicBlock &TMBB,
unsigned NumT, unsigned ExtraT,
MachineBasicBlock &FMBB,
unsigned NumF, unsigned ExtraF,
const BranchProbability &Probability) const;
virtual bool isProfitableToDupForIfCvt(MachineBasicBlock &MBB,
unsigned NumCycles,
const BranchProbability
&Probability) const {
return NumCycles == 1;
}
virtual bool isProfitableToUnpredicate(MachineBasicBlock &TMBB,
MachineBasicBlock &FMBB) const;
/// analyzeCompare - For a comparison instruction, return the source registers
/// in SrcReg and SrcReg2 if having two register operands, and the value it
/// compares against in CmpValue. Return true if the comparison instruction
/// can be analyzed.
virtual bool analyzeCompare(const MachineInstr *MI, unsigned &SrcReg,
unsigned &SrcReg2, int &CmpMask,
int &CmpValue) const;
/// optimizeCompareInstr - Convert the instruction to set the zero flag so
/// that we can remove a "comparison with zero"; Remove a redundant CMP
/// instruction if the flags can be updated in the same way by an earlier
/// instruction such as SUB.
virtual bool optimizeCompareInstr(MachineInstr *CmpInstr, unsigned SrcReg,
unsigned SrcReg2, int CmpMask, int CmpValue,
const MachineRegisterInfo *MRI) const;
virtual bool analyzeSelect(const MachineInstr *MI,
SmallVectorImpl<MachineOperand> &Cond,
unsigned &TrueOp, unsigned &FalseOp,
bool &Optimizable) const;
virtual MachineInstr *optimizeSelect(MachineInstr *MI, bool) const;
/// FoldImmediate - 'Reg' is known to be defined by a move immediate
/// instruction, try to fold the immediate into the use instruction.
virtual bool FoldImmediate(MachineInstr *UseMI, MachineInstr *DefMI,
unsigned Reg, MachineRegisterInfo *MRI) const;
virtual unsigned getNumMicroOps(const InstrItineraryData *ItinData,
const MachineInstr *MI) const;
virtual
int getOperandLatency(const InstrItineraryData *ItinData,
const MachineInstr *DefMI, unsigned DefIdx,
const MachineInstr *UseMI, unsigned UseIdx) const;
virtual
int getOperandLatency(const InstrItineraryData *ItinData,
SDNode *DefNode, unsigned DefIdx,
SDNode *UseNode, unsigned UseIdx) const;
/// VFP/NEON execution domains.
std::pair<uint16_t, uint16_t>
getExecutionDomain(const MachineInstr *MI) const;
void setExecutionDomain(MachineInstr *MI, unsigned Domain) const;
unsigned getPartialRegUpdateClearance(const MachineInstr*, unsigned,
const TargetRegisterInfo*) const;
void breakPartialRegDependency(MachineBasicBlock::iterator, unsigned,
const TargetRegisterInfo *TRI) const;
/// Get the number of addresses by LDM or VLDM or zero for unknown.
unsigned getNumLDMAddresses(const MachineInstr *MI) const;
private:
unsigned getInstBundleLength(const MachineInstr *MI) const;
int getVLDMDefCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &DefMCID,
unsigned DefClass,
unsigned DefIdx, unsigned DefAlign) const;
int getLDMDefCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &DefMCID,
unsigned DefClass,
unsigned DefIdx, unsigned DefAlign) const;
int getVSTMUseCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &UseMCID,
unsigned UseClass,
unsigned UseIdx, unsigned UseAlign) const;
int getSTMUseCycle(const InstrItineraryData *ItinData,
const MCInstrDesc &UseMCID,
unsigned UseClass,
unsigned UseIdx, unsigned UseAlign) const;
int getOperandLatency(const InstrItineraryData *ItinData,
const MCInstrDesc &DefMCID,
unsigned DefIdx, unsigned DefAlign,
const MCInstrDesc &UseMCID,
unsigned UseIdx, unsigned UseAlign) const;
unsigned getPredicationCost(const MachineInstr *MI) const;
unsigned getInstrLatency(const InstrItineraryData *ItinData,
const MachineInstr *MI,
unsigned *PredCost = 0) const;
int getInstrLatency(const InstrItineraryData *ItinData,
SDNode *Node) const;
bool hasHighOperandLatency(const InstrItineraryData *ItinData,
const MachineRegisterInfo *MRI,
const MachineInstr *DefMI, unsigned DefIdx,
const MachineInstr *UseMI, unsigned UseIdx) const;
bool hasLowDefLatency(const InstrItineraryData *ItinData,
const MachineInstr *DefMI, unsigned DefIdx) const;
/// verifyInstruction - Perform target specific instruction verification.
bool verifyInstruction(const MachineInstr *MI, StringRef &ErrInfo) const;
private:
/// Modeling special VFP / NEON fp MLA / MLS hazards.
/// MLxEntryMap - Map fp MLA / MLS to the corresponding entry in the internal
/// MLx table.
DenseMap<unsigned, unsigned> MLxEntryMap;
/// MLxHazardOpcodes - Set of add / sub and multiply opcodes that would cause
/// stalls when scheduled together with fp MLA / MLS opcodes.
SmallSet<unsigned, 16> MLxHazardOpcodes;
public:
/// isFpMLxInstruction - Return true if the specified opcode is a fp MLA / MLS
/// instruction.
bool isFpMLxInstruction(unsigned Opcode) const {
return MLxEntryMap.count(Opcode);
}
/// isFpMLxInstruction - This version also returns the multiply opcode and the
/// addition / subtraction opcode to expand to. Return true for 'HasLane' for
/// the MLX instructions with an extra lane operand.
bool isFpMLxInstruction(unsigned Opcode, unsigned &MulOpc,
unsigned &AddSubOpc, bool &NegAcc,
bool &HasLane) const;
/// canCauseFpMLxStall - Return true if an instruction of the specified opcode
/// will cause stalls when scheduled after (within 4-cycle window) a fp
/// MLA / MLS instruction.
bool canCauseFpMLxStall(unsigned Opcode) const {
return MLxHazardOpcodes.count(Opcode);
}
/// Returns true if the instruction has a shift by immediate that can be
/// executed in one cycle less.
bool isSwiftFastImmShift(const MachineInstr *MI) const;
};
static inline
const MachineInstrBuilder &AddDefaultPred(const MachineInstrBuilder &MIB) {
return MIB.addImm((int64_t)ARMCC::AL).addReg(0);
}
static inline
const MachineInstrBuilder &AddDefaultCC(const MachineInstrBuilder &MIB) {
return MIB.addReg(0);
}
static inline
const MachineInstrBuilder &AddDefaultT1CC(const MachineInstrBuilder &MIB,
bool isDead = false) {
return MIB.addReg(ARM::CPSR, getDefRegState(true) | getDeadRegState(isDead));
}
static inline
const MachineInstrBuilder &AddNoT1CC(const MachineInstrBuilder &MIB) {
return MIB.addReg(0);
}
static inline
bool isUncondBranchOpcode(int Opc) {
return Opc == ARM::B || Opc == ARM::tB || Opc == ARM::t2B;
}
static inline
bool isCondBranchOpcode(int Opc) {
return Opc == ARM::Bcc || Opc == ARM::tBcc || Opc == ARM::t2Bcc;
}
static inline
bool isJumpTableBranchOpcode(int Opc) {
return Opc == ARM::BR_JTr || Opc == ARM::BR_JTm || Opc == ARM::BR_JTadd ||
Opc == ARM::tBR_JTr || Opc == ARM::t2BR_JT;
}
static inline
bool isIndirectBranchOpcode(int Opc) {
return Opc == ARM::BX || Opc == ARM::MOVPCRX || Opc == ARM::tBRIND;
}
static inline bool isPopOpcode(int Opc) {
return Opc == ARM::tPOP_RET || Opc == ARM::LDMIA_RET ||
Opc == ARM::t2LDMIA_RET || Opc == ARM::tPOP || Opc == ARM::LDMIA_UPD ||
Opc == ARM::t2LDMIA_UPD || Opc == ARM::VLDMDIA_UPD;
}
static inline bool isPushOpcode(int Opc) {
return Opc == ARM::tPUSH || Opc == ARM::t2STMDB_UPD ||
Opc == ARM::STMDB_UPD || Opc == ARM::VSTMDDB_UPD;
}
/// getInstrPredicate - If instruction is predicated, returns its predicate
/// condition, otherwise returns AL. It also returns the condition code
/// register by reference.
ARMCC::CondCodes getInstrPredicate(const MachineInstr *MI, unsigned &PredReg);
int getMatchingCondBranchOpcode(int Opc);
/// Determine if MI can be folded into an ARM MOVCC instruction, and return the
/// opcode of the SSA instruction representing the conditional MI.
unsigned canFoldARMInstrIntoMOVCC(unsigned Reg,
MachineInstr *&MI,
const MachineRegisterInfo &MRI);
/// Map pseudo instructions that imply an 'S' bit onto real opcodes. Whether
/// the instruction is encoded with an 'S' bit is determined by the optional
/// CPSR def operand.
unsigned convertAddSubFlagsOpcode(unsigned OldOpc);
/// emitARMRegPlusImmediate / emitT2RegPlusImmediate - Emits a series of
/// instructions to materializea destreg = basereg + immediate in ARM / Thumb2
/// code.
void emitARMRegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, DebugLoc dl,
unsigned DestReg, unsigned BaseReg, int NumBytes,
ARMCC::CondCodes Pred, unsigned PredReg,
const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
void emitT2RegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, DebugLoc dl,
unsigned DestReg, unsigned BaseReg, int NumBytes,
ARMCC::CondCodes Pred, unsigned PredReg,
const ARMBaseInstrInfo &TII, unsigned MIFlags = 0);
void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator &MBBI, DebugLoc dl,
unsigned DestReg, unsigned BaseReg,
int NumBytes, const TargetInstrInfo &TII,
const ARMBaseRegisterInfo& MRI,
unsigned MIFlags = 0);
/// Tries to add registers to the reglist of a given base-updating
/// push/pop instruction to adjust the stack by an additional
/// NumBytes. This can save a few bytes per function in code-size, but
/// obviously generates more memory traffic. As such, it only takes
/// effect in functions being optimised for size.
bool tryFoldSPUpdateIntoPushPop(MachineFunction &MF, MachineInstr *MI,
unsigned NumBytes);
/// rewriteARMFrameIndex / rewriteT2FrameIndex -
/// Rewrite MI to access 'Offset' bytes from the FP. Return false if the
/// offset could not be handled directly in MI, and return the left-over
/// portion by reference.
bool rewriteARMFrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const ARMBaseInstrInfo &TII);
bool rewriteT2FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const ARMBaseInstrInfo &TII);
} // End llvm namespace
#endif