llvm-6502/lib/Target/SystemZ/SystemZInstrInfo.h
Richard Sandiford ea14085be5 [SystemZ] Rework compare and branch support
Before the patch we took advantage of the fact that the compare and
branch are glued together in the selection DAG and fused them together
(where possible) while emitting them.  This seemed to work well in practice.
However, fusing the compare so early makes it harder to remove redundant
compares in cases where CC already has a suitable value.  This patch
therefore uses the peephole analyzeCompare/optimizeCompareInstr pair of
functions instead.

No behavioral change intended, but it paves the way for a later patch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187116 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-25 09:34:38 +00:00

205 lines
8.3 KiB
C++

//===-- SystemZInstrInfo.h - SystemZ 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 SystemZ implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_SYSTEMZINSTRINFO_H
#define LLVM_TARGET_SYSTEMZINSTRINFO_H
#include "SystemZ.h"
#include "SystemZRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#define GET_INSTRINFO_HEADER
#include "SystemZGenInstrInfo.inc"
namespace llvm {
class SystemZTargetMachine;
namespace SystemZII {
enum {
// See comments in SystemZInstrFormats.td.
SimpleBDXLoad = (1 << 0),
SimpleBDXStore = (1 << 1),
Has20BitOffset = (1 << 2),
HasIndex = (1 << 3),
Is128Bit = (1 << 4),
AccessSizeMask = (31 << 5),
AccessSizeShift = 5
};
static inline unsigned getAccessSize(unsigned int Flags) {
return (Flags & AccessSizeMask) >> AccessSizeShift;
}
// SystemZ MachineOperand target flags.
enum {
// Masks out the bits for the access model.
MO_SYMBOL_MODIFIER = (1 << 0),
// @GOT (aka @GOTENT)
MO_GOT = (1 << 0)
};
// Classifies a branch.
enum BranchType {
// An instruction that branches on the current value of CC.
BranchNormal,
// An instruction that peforms a 32-bit signed comparison and branches
// on the result.
BranchC,
// An instruction that peforms a 64-bit signed comparison and branches
// on the result.
BranchCG
};
// Information about a branch instruction.
struct Branch {
// The type of the branch.
BranchType Type;
// CCMASK_<N> is set if the branch should be taken when CC == N.
unsigned CCMask;
// The target of the branch.
const MachineOperand *Target;
Branch(BranchType type, unsigned ccMask, const MachineOperand *target)
: Type(type), CCMask(ccMask), Target(target) {}
};
}
class SystemZInstrInfo : public SystemZGenInstrInfo {
const SystemZRegisterInfo RI;
SystemZTargetMachine &TM;
void splitMove(MachineBasicBlock::iterator MI, unsigned NewOpcode) const;
void splitAdjDynAlloc(MachineBasicBlock::iterator MI) const;
public:
explicit SystemZInstrInfo(SystemZTargetMachine &TM);
// Override TargetInstrInfo.
virtual unsigned isLoadFromStackSlot(const MachineInstr *MI,
int &FrameIndex) const LLVM_OVERRIDE;
virtual unsigned isStoreToStackSlot(const MachineInstr *MI,
int &FrameIndex) const LLVM_OVERRIDE;
virtual bool isStackSlotCopy(const MachineInstr *MI, int &DestFrameIndex,
int &SrcFrameIndex) const LLVM_OVERRIDE;
virtual bool AnalyzeBranch(MachineBasicBlock &MBB,
MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const LLVM_OVERRIDE;
virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const LLVM_OVERRIDE;
virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond,
DebugLoc DL) const LLVM_OVERRIDE;
virtual bool analyzeCompare(const MachineInstr *MI,
unsigned &SrcReg, unsigned &SrcReg2,
int &Mask, int &Value) const LLVM_OVERRIDE;
virtual bool optimizeCompareInstr(MachineInstr *CmpInstr,
unsigned SrcReg, unsigned SrcReg2,
int Mask, int Value,
const MachineRegisterInfo *MRI) const
LLVM_OVERRIDE;
virtual bool isPredicable(MachineInstr *MI) const LLVM_OVERRIDE;
virtual bool isProfitableToIfCvt(MachineBasicBlock &MBB, unsigned NumCycles,
unsigned ExtraPredCycles,
const BranchProbability &Probability) const
LLVM_OVERRIDE;
virtual bool isProfitableToIfCvt(MachineBasicBlock &TMBB,
unsigned NumCyclesT,
unsigned ExtraPredCyclesT,
MachineBasicBlock &FMBB,
unsigned NumCyclesF,
unsigned ExtraPredCyclesF,
const BranchProbability &Probability) const
LLVM_OVERRIDE;
virtual bool
PredicateInstruction(MachineInstr *MI,
const SmallVectorImpl<MachineOperand> &Pred) const
LLVM_OVERRIDE;
virtual void copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const LLVM_OVERRIDE;
virtual void
storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned SrcReg, bool isKill, int FrameIndex,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const LLVM_OVERRIDE;
virtual void
loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned DestReg, int FrameIdx,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const LLVM_OVERRIDE;
virtual MachineInstr *
convertToThreeAddress(MachineFunction::iterator &MFI,
MachineBasicBlock::iterator &MBBI,
LiveVariables *LV) const;
virtual MachineInstr *
foldMemoryOperandImpl(MachineFunction &MF, MachineInstr *MI,
const SmallVectorImpl<unsigned> &Ops,
int FrameIndex) const;
virtual MachineInstr *
foldMemoryOperandImpl(MachineFunction &MF, MachineInstr* MI,
const SmallVectorImpl<unsigned> &Ops,
MachineInstr* LoadMI) const;
virtual bool
expandPostRAPseudo(MachineBasicBlock::iterator MBBI) const LLVM_OVERRIDE;
virtual bool
ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const
LLVM_OVERRIDE;
// Return the SystemZRegisterInfo, which this class owns.
const SystemZRegisterInfo &getRegisterInfo() const { return RI; }
// Return the size in bytes of MI.
uint64_t getInstSizeInBytes(const MachineInstr *MI) const;
// Return true if MI is a conditional or unconditional branch.
// When returning true, set Cond to the mask of condition-code
// values on which the instruction will branch, and set Target
// to the operand that contains the branch target. This target
// can be a register or a basic block.
SystemZII::Branch getBranchInfo(const MachineInstr *MI) const;
// Get the load and store opcodes for a given register class.
void getLoadStoreOpcodes(const TargetRegisterClass *RC,
unsigned &LoadOpcode, unsigned &StoreOpcode) const;
// Opcode is the opcode of an instruction that has an address operand,
// and the caller wants to perform that instruction's operation on an
// address that has displacement Offset. Return the opcode of a suitable
// instruction (which might be Opcode itself) or 0 if no such instruction
// exists.
unsigned getOpcodeForOffset(unsigned Opcode, int64_t Offset) const;
// If Opcode is a COMPARE opcode for which an associated COMPARE AND
// BRANCH exists, return the opcode for the latter, otherwise return 0.
// MI, if nonnull, is the compare instruction.
unsigned getCompareAndBranch(unsigned Opcode,
const MachineInstr *MI = 0) const;
// Emit code before MBBI in MI to move immediate value Value into
// physical register Reg.
void loadImmediate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned Reg, uint64_t Value) const;
};
} // end namespace llvm
#endif