fpc/compiler/avr/aoptcpu.pas

{
    Copyright (c) 1998-2002 by Jonas Maebe, member of the Free Pascal
    Development Team

    This unit implements the ARM optimizer object

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ****************************************************************************
}


Unit aoptcpu;

{$i fpcdefs.inc}

{ $define DEBUG_AOPTCPU}

Interface

uses cpubase,cgbase,aasmtai,aopt,AoptObj, cclasses,aoptcpub;

Type
  TCpuAsmOptimizer = class(TAsmOptimizer)
    { outputs a debug message into the assembler file }
    procedure DebugMsg(const s: string; p: tai);

    Function GetNextInstructionUsingReg(Current: tai; Var Next: tai;reg : TRegister): Boolean;
    function RegInInstruction(Reg: TRegister; p1: tai): Boolean; override;
    function RegLoadedWithNewValue(reg : tregister; hp : tai) : boolean; override;
    function InstructionLoadsFromReg(const reg : TRegister; const hp : tai) : boolean; override;

    function InvertSkipInstruction(var p: tai): boolean;

    { uses the same constructor as TAopObj }
    function PeepHoleOptPass1Cpu(var p: tai): boolean; override;
    function PeepHoleOptPass2Cpu(var p: tai): boolean; override;
  private
    function OptPass1ADD(var p : tai) : boolean;
    function OptPass1ANDI(var p : tai) : boolean;
    function OptPass1CALL(var p : tai) : boolean;
    function OptPass1CLR(var p : tai) : boolean;
    function OptPass1IN(var p : tai) : boolean;
    function OptPass1LDI(var p : tai) : boolean;
    function OptPass1LDS(var p : tai) : boolean;
    function OptPass1MOV(var p : tai) : boolean;
    function OptPass1PUSH(var p : tai) : boolean;
    function OptPass1RCALL(var p : tai) : boolean;
    function OptPass1SBI(var p : tai) : boolean;
    function OptPass1SBR(var p : tai) : boolean;
    function OptPass1STS(var p : tai) : boolean;
    function OptPass1SUB(var p : tai) : boolean;

    function OptPass2MOV(var p : tai) : boolean;
  End;

Implementation

  uses
    cutils,
    verbose,
    cpuinfo,
    aasmbase,aasmcpu,aasmdata,
    aoptutils,
    globals,globtype,
    cgutils;

  type
    TAsmOpSet = set of TAsmOp;

  function CanBeCond(p : tai) : boolean;
    begin
      result:=(p.typ=ait_instruction) and (taicpu(p).condition=C_None);
    end;


  function RefsEqual(const r1, r2: treference): boolean;
    begin
      refsequal :=
        (r1.offset = r2.offset) and
        (r1.base = r2.base) and
        (r1.index = r2.index) and (r1.scalefactor = r2.scalefactor) and
        (r1.symbol=r2.symbol) and (r1.refaddr = r2.refaddr) and
        (r1.relsymbol = r2.relsymbol) and
        (r1.addressmode = r2.addressmode) and
        (r1.volatility=[]) and
        (r2.volatility=[]);
    end;


  function MatchOperand(const oper1: TOper; const oper2: TOper): boolean; inline;
    begin
      result:=oper1.typ=oper2.typ;

      if result then
        case oper1.typ of
          top_const:
            Result:=oper1.val = oper2.val;
          top_reg:
            Result:=oper1.reg = oper2.reg;
          top_ref:
            Result:=RefsEqual(oper1.ref^, oper2.ref^);
          else Result:=false;
        end
    end;


  function MatchOperand(const oper: TOper; const reg: TRegister): boolean; inline;
    begin
      result := (oper.typ = top_reg) and (oper.reg = reg);
    end;


  function MatchInstruction(const instr: tai; const op: TAsmOp): boolean;
    begin
      result :=
        (instr.typ = ait_instruction) and
        (taicpu(instr).opcode = op);
    end;


  function MatchInstruction(const instr: tai; const ops: TAsmOpSet): boolean;
    begin
      result :=
        (instr.typ = ait_instruction) and
        (taicpu(instr).opcode in ops);
    end;


  function MatchInstruction(const instr: tai; const ops: TAsmOpSet;opcount : byte): boolean;
    begin
      result :=
        (instr.typ = ait_instruction) and
        (taicpu(instr).opcode in ops) and
        (taicpu(instr).ops=opcount);
    end;


{$ifdef DEBUG_AOPTCPU}
  procedure TCpuAsmOptimizer.DebugMsg(const s: string;p : tai);
    begin
      asml.insertbefore(tai_comment.Create(strpnew(s)), p);
    end;
{$else DEBUG_AOPTCPU}
  procedure TCpuAsmOptimizer.DebugMsg(const s: string;p : tai);inline;
    begin
    end;
{$endif DEBUG_AOPTCPU}


  function TCpuAsmOptimizer.RegInInstruction(Reg: TRegister; p1: tai): Boolean;
    begin
      If (p1.typ = ait_instruction) and (taicpu(p1).opcode in [A_MUL,A_MULS,A_FMUL,A_FMULS,A_FMULSU]) and
              ((getsupreg(reg)=RS_R0) or (getsupreg(reg)=RS_R1)) then
        Result:=true
      else if (p1.typ = ait_instruction) and (taicpu(p1).opcode=A_MOVW) and
        ((TRegister(ord(taicpu(p1).oper[0]^.reg)+1)=reg) or (TRegister(ord(taicpu(p1).oper[1]^.reg)+1)=reg) or
         (taicpu(p1).oper[0]^.reg=reg) or (taicpu(p1).oper[1]^.reg=reg)) then
        Result:=true
      else if (p1.typ = ait_instruction) and (taicpu(p1).opcode=A_ADIW) and
        ((TRegister(ord(taicpu(p1).oper[0]^.reg)+1)=reg) or (taicpu(p1).oper[0]^.reg=reg)) then
        Result:=true
      else
        Result:=inherited RegInInstruction(Reg, p1);
    end;


  function TCpuAsmOptimizer.GetNextInstructionUsingReg(Current: tai;
    var Next: tai; reg: TRegister): Boolean;
    begin
      Next:=Current;
      repeat
        Result:=GetNextInstruction(Next,Next);
      until not(cs_opt_level3 in current_settings.optimizerswitches) or not(Result) or (Next.typ<>ait_instruction) or (RegInInstruction(reg,Next)) or
        (is_calljmp(taicpu(Next).opcode));
    end;


  function TCpuAsmOptimizer.RegLoadedWithNewValue(reg: tregister; hp: tai): boolean;
    var
      p: taicpu;
    begin
      if not assigned(hp) or
         (hp.typ <> ait_instruction) then
       begin
         Result := false;
         exit;
       end;
      p := taicpu(hp);
      Result := ((p.opcode in [A_LDI,A_MOV,A_LDS]) and (reg=p.oper[0]^.reg) and ((p.oper[1]^.typ<>top_reg) or (reg<>p.oper[1]^.reg))) or
        ((p.opcode in [A_LD,A_LDD,A_LPM]) and (reg=p.oper[0]^.reg) and not(RegInRef(reg,p.oper[1]^.ref^))) or
        ((p.opcode in [A_MOVW]) and ((reg=p.oper[0]^.reg) or (TRegister(ord(reg)+1)=p.oper[0]^.reg)) and not(reg=p.oper[1]^.reg) and not(TRegister(ord(reg)+1)=p.oper[1]^.reg)) or
        ((p.opcode in [A_POP]) and (reg=p.oper[0]^.reg));
    end;


  function TCpuAsmOptimizer.InstructionLoadsFromReg(const reg: TRegister; const hp: tai): boolean;
    var
      p: taicpu;
      i: longint;
    begin
      Result := false;

      if not (assigned(hp) and (hp.typ = ait_instruction)) then
        exit;
      p:=taicpu(hp);

      i:=0;

      { we do not care about the stack pointer }
      if p.opcode in [A_POP] then
        exit;

      { first operand only written?
        then skip it }
      if p.opcode in [A_MOV,A_LD,A_LDD,A_LDS,A_LPM,A_LDI,A_MOVW] then
        i:=1;

      while i<p.ops do
        begin
          case p.oper[i]^.typ of
            top_reg:
              Result := (p.oper[i]^.reg = reg) or
                { MOVW }
                ((i=1) and (p.opcode=A_MOVW) and (getsupreg(p.oper[i]^.reg)+1=getsupreg(reg))) or
                { ADIW }
                ((i=0) and (p.opcode=A_ADIW) and (getsupreg(p.oper[i]^.reg)+1=getsupreg(reg)));
            top_ref:
              Result :=
                (p.oper[i]^.ref^.base = reg) or
                (p.oper[i]^.ref^.index = reg);
          end;
          { Bailout if we found something }
          if Result then
            exit;
          Inc(i);
        end;
    end;


  {
    Turns
      sbis ?
      jmp .Lx
      op
    .Lx:

    Into
      sbic ?
      op

    For all types of skip instructions
  }
  function TCpuAsmOptimizer.InvertSkipInstruction(var p: tai): boolean;

    function GetNextInstructionWithoutLabel(p: tai; var next: tai): boolean;
      begin
        repeat
          result:=GetNextInstruction(p,next);
          p:=next;
        until
          (not result) or
          (not assigned(next)) or
          (next.typ in [ait_instruction]);

        result:=assigned(next) and (next.typ in [ait_instruction]);
      end;

    var
      hp1, hp2, hp3: tai;
    begin
      result:=false;

      if GetNextInstruction(taicpu(p),hp1) and
        (hp1.typ=ait_instruction) and
        (taicpu(hp1).opcode in [A_RJMP,A_JMP]) and
        (taicpu(hp1).ops=1) and
        (taicpu(hp1).oper[0]^.typ=top_ref) and
        (taicpu(hp1).oper[0]^.ref^.offset=0) and
        (taicpu(hp1).oper[0]^.ref^.symbol is TAsmLabel) and
        GetNextInstructionWithoutLabel(hp1,hp2) and
        (hp2.typ=ait_instruction) and
        (not taicpu(hp2).is_jmp) and
        GetNextInstruction(hp2,hp3) and
        FindLabel(TAsmLabel(taicpu(hp1).oper[0]^.ref^.symbol),hp3) then
        begin
          DebugMsg('SkipJump2InvertedSkip', p);

          case taicpu(p).opcode of
            A_SBIS: taicpu(p).opcode:=A_SBIC;
            A_SBIC: taicpu(p).opcode:=A_SBIS;
            A_SBRS: taicpu(p).opcode:=A_SBRC;
            A_SBRC: taicpu(p).opcode:=A_SBRS;
          end;

          TAsmLabel(taicpu(hp1).oper[0]^.ref^.symbol).decrefs;

          asml.remove(hp1);
          hp1.free;
        end;
    end;


  function TCpuAsmOptimizer.OptPass1LDI(var p : tai) : boolean;
    var
      hp1 : tai;
      alloc ,dealloc: tai_regalloc;
    begin
      Result:=false;
      { turn
        ldi reg0, imm
        <op> reg1, reg0
        dealloc reg0
        into
        <op>i reg1, imm
      }
      if MatchOpType(taicpu(p),top_reg,top_const) and
         GetNextInstructionUsingReg(p, hp1, taicpu(p).oper[0]^.reg) and
         MatchInstruction(hp1,[A_CP,A_MOV,A_AND,A_SUB],2) and
         (not RegModifiedBetween(taicpu(p).oper[0]^.reg, p, hp1)) and
         MatchOpType(taicpu(hp1),top_reg,top_reg) and
         (getsupreg(taicpu(hp1).oper[0]^.reg) in [16..31]) and
         (taicpu(hp1).oper[1]^.reg=taicpu(p).oper[0]^.reg) and
         not(MatchOperand(taicpu(hp1).oper[0]^,taicpu(hp1).oper[1]^)) then
        begin
          TransferUsedRegs(TmpUsedRegs);
          UpdateUsedRegs(TmpUsedRegs,tai(p.next));
          UpdateUsedRegs(TmpUsedRegs,tai(hp1.next));
          if not(RegUsedAfterInstruction(taicpu(hp1).oper[1]^.reg, hp1, TmpUsedRegs)) then
            begin
              case taicpu(hp1).opcode of
                A_CP:
                  taicpu(hp1).opcode:=A_CPI;
                A_MOV:
                  taicpu(hp1).opcode:=A_LDI;
                A_AND:
                  taicpu(hp1).opcode:=A_ANDI;
                A_SUB:
                  taicpu(hp1).opcode:=A_SUBI;
                else
                  internalerror(2016111901);
              end;
              taicpu(hp1).loadconst(1, taicpu(p).oper[1]^.val);

              alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
              dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next));

              if assigned(alloc) and assigned(dealloc) then
                begin
                  asml.Remove(alloc);
                  alloc.Free;
                  asml.Remove(dealloc);
                  dealloc.Free;
                end;

              DebugMsg('Peephole LdiOp2Opi performed', p);

              result:=RemoveCurrentP(p);
            end;
        end;
    end;


  function TCpuAsmOptimizer.OptPass1STS(var p : tai) : boolean;
    begin
      Result:=false;
      if (taicpu(p).oper[0]^.ref^.symbol=nil) and
        (taicpu(p).oper[0]^.ref^.relsymbol=nil) and
        (getsupreg(taicpu(p).oper[0]^.ref^.base)=RS_NO) and
        (getsupreg(taicpu(p).oper[0]^.ref^.index)=RS_NO) and
        (taicpu(p).oper[0]^.ref^.addressmode=AM_UNCHANGED) and
        (((CPUAVR_NOMEMMAPPED_REGS in cpu_capabilities[current_settings.cputype]) and
          (taicpu(p).oper[0]^.ref^.offset>=0) and
          (taicpu(p).oper[0]^.ref^.offset<=63)) or
         (not(CPUAVR_NOMEMMAPPED_REGS in cpu_capabilities[current_settings.cputype]) and
          (taicpu(p).oper[0]^.ref^.offset>=32) and
          (taicpu(p).oper[0]^.ref^.offset<=95))) then
        begin
          DebugMsg('Peephole Sts2Out performed', p);

          taicpu(p).opcode:=A_OUT;
          if CPUAVR_NOMEMMAPPED_REGS in cpu_capabilities[current_settings.cputype] then
            taicpu(p).loadconst(0,taicpu(p).oper[0]^.ref^.offset)
          else
            taicpu(p).loadconst(0,taicpu(p).oper[0]^.ref^.offset-32);
          result:=true;
        end;
    end;


  function TCpuAsmOptimizer.OptPass1LDS(var p : tai) : boolean;
    var
      hp1, hp2, hp3, alloc, dealloc: tai;
    begin
      Result:=false;
      if (taicpu(p).oper[1]^.ref^.symbol=nil) and
      (taicpu(p).oper[1]^.ref^.relsymbol=nil) and
      (getsupreg(taicpu(p).oper[1]^.ref^.base)=RS_NO) and
      (getsupreg(taicpu(p).oper[1]^.ref^.index)=RS_NO) and
      (taicpu(p).oper[1]^.ref^.addressmode=AM_UNCHANGED) and
      (((CPUAVR_NOMEMMAPPED_REGS in cpu_capabilities[current_settings.cputype]) and
        (taicpu(p).oper[1]^.ref^.offset>=0) and
        (taicpu(p).oper[1]^.ref^.offset<=63)) or
       (not(CPUAVR_NOMEMMAPPED_REGS in cpu_capabilities[current_settings.cputype]) and
        (taicpu(p).oper[1]^.ref^.offset>=32) and
        (taicpu(p).oper[1]^.ref^.offset<=95))) then
      begin
        DebugMsg('Peephole Lds2In performed', p);

        taicpu(p).opcode:=A_IN;
        if CPUAVR_NOMEMMAPPED_REGS in cpu_capabilities[current_settings.cputype] then
          taicpu(p).loadconst(1,taicpu(p).oper[1]^.ref^.offset)
        else
          taicpu(p).loadconst(1,taicpu(p).oper[1]^.ref^.offset-32);

        result:=true;
      end

      { turn
          alloc reg0
          alloc reg1
          lds reg0, label
          lds reg1, label
          mov reg2, reg0
          mov reg3, reg1
          dealloc reg0
          dealloc reg1

        into
          lds reg2, label
          lds reg3, label
      }
      else if not(cs_opt_level3 in current_settings.optimizerswitches) and
      (taicpu(p).oper[0]^.typ=top_reg) and
      assigned(FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous))) and
      (GetNextInstruction(p,hp1)) and MatchInstruction(hp1,A_LDS) and
      (taicpu(hp1).oper[0]^.typ=top_reg) and
      assigned(FindRegAllocBackward(taicpu(hp1).oper[0]^.reg,tai(hp1.Previous))) and
      (GetNextInstruction(hp1, hp2)) and MatchInstruction(hp2,A_MOV) and
      (taicpu(hp2).oper[1]^.reg=taicpu(p).oper[0]^.reg) and
      assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp2.Next))) and
      (GetNextInstruction(hp2, hp3)) and MatchInstruction(hp3,A_MOV) and
      (taicpu(hp3).oper[1]^.reg=taicpu(hp1).oper[0]^.reg) and
      assigned(FindRegDeAlloc(taicpu(hp1).oper[0]^.reg,tai(hp3.Next))) then
      begin
        DebugMsg('Peephole LdsLdsMovMov2LdsLds performed', p);

        alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
        dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp2.Next));
        if assigned(alloc) and assigned(dealloc) then
          begin
            asml.Remove(alloc);
            alloc.Free;
            asml.Remove(dealloc);
            dealloc.Free;
          end;
        taicpu(p).oper[0]^.reg:=taicpu(hp2).oper[0]^.reg;
        RemoveInstruction(hp2);

        alloc:=FindRegAllocBackward(taicpu(hp1).oper[0]^.reg,tai(hp1.Previous));
        dealloc:=FindRegDeAlloc(taicpu(hp1).oper[0]^.reg,tai(hp3.Next));
        if assigned(alloc) and assigned(dealloc) then
          begin
            asml.Remove(alloc);
            alloc.Free;
            asml.Remove(dealloc);
            dealloc.Free;
          end;

        taicpu(hp1).oper[0]^.reg:=taicpu(hp3).oper[0]^.reg;
        RemoveInstruction(hp3);
        Result:=true;
      end

      { turn
          alloc reg0
          lds reg0, label
          ...
          mov reg1, reg0
          dealloc reg0

        into
          lds reg1, label
      }
      else if (cs_opt_level3 in current_settings.optimizerswitches) and
      (taicpu(p).oper[0]^.typ=top_reg) and
      (GetNextInstructionUsingReg(p,hp1,taicpu(p).oper[0]^.reg)) and
      MatchInstruction(hp1,A_MOV) and
      (taicpu(hp1).oper[1]^.reg=taicpu(p).oper[0]^.reg) and
      (not RegModifiedBetween(taicpu(p).oper[0]^.reg, p, hp1)) and
      (not RegUsedBetween(taicpu(hp1).oper[0]^.reg, p, hp1)) then
      begin
        alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
        dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next));
        if assigned(alloc) and assigned(dealloc) then
          begin
            DebugMsg('Peephole LdsMov2Lds performed', p);
            asml.Remove(alloc);
            alloc.Free;
            asml.Remove(dealloc);
            dealloc.Free;
            taicpu(p).oper[0]^.reg:=taicpu(hp1).oper[0]^.reg;
            RemoveInstruction(hp1);
            result:=true;
          end;
      end;
    end;


  function TCpuAsmOptimizer.OptPass1IN(var p : tai) : boolean;
    var
      hp1, hp2: tai;
      l : TAsmLabel;
    begin
      Result:=false;
      if GetNextInstruction(p,hp1) then
        begin
          {
            in rX,Y
            ori rX,n
            out Y,rX

            into
            sbi rX,lg(n)
          }
          if (taicpu(p).oper[1]^.val<=31) and
            MatchInstruction(hp1,A_ORI) and
            (taicpu(hp1).oper[0]^.reg=taicpu(p).oper[0]^.reg) and
            (PopCnt(byte(taicpu(hp1).oper[1]^.val))=1) and
            GetNextInstruction(hp1,hp2) and
            MatchInstruction(hp2,A_OUT) and
            MatchOperand(taicpu(hp2).oper[1]^,taicpu(p).oper[0]^) and
            MatchOperand(taicpu(hp2).oper[0]^,taicpu(p).oper[1]^) then
            begin
              DebugMsg('Peephole InOriOut2Sbi performed', p);

              taicpu(p).opcode:=A_SBI;
              taicpu(p).loadconst(0,taicpu(p).oper[1]^.val);
              taicpu(p).loadconst(1,BsrByte(taicpu(hp1).oper[1]^.val));
              asml.Remove(hp1);
              hp1.Free;
              asml.Remove(hp2);
              hp2.Free;
              result:=true;
            end
           {
            in rX,Y
            andi rX,not(n)
            out Y,rX

            into
            cbi rX,lg(n)
          }
          else if (taicpu(p).oper[1]^.val<=31) and
             MatchInstruction(hp1,A_ANDI) and
             (taicpu(hp1).oper[0]^.reg=taicpu(p).oper[0]^.reg) and
             (PopCnt(byte(not(taicpu(hp1).oper[1]^.val)))=1) and
             GetNextInstruction(hp1,hp2) and
             MatchInstruction(hp2,A_OUT) and
             MatchOperand(taicpu(hp2).oper[1]^,taicpu(p).oper[0]^) and
             MatchOperand(taicpu(hp2).oper[0]^,taicpu(p).oper[1]^) then
            begin
              DebugMsg('Peephole InAndiOut2Cbi performed', p);

              taicpu(p).opcode:=A_CBI;
              taicpu(p).loadconst(0,taicpu(p).oper[1]^.val);
              taicpu(p).loadconst(1,BsrByte(not(taicpu(hp1).oper[1]^.val)));
              asml.Remove(hp1);
              hp1.Free;
              asml.Remove(hp2);
              hp2.Free;
              result:=true;
            end
           {
                in rX,Y
                andi rX,n
                breq/brne L1

            into
                sbis/sbic Y,lg(n)
                jmp L1
              .Ltemp:
          }
          else if (taicpu(p).oper[1]^.val<=31) and
             MatchInstruction(hp1,A_ANDI) and
             (taicpu(hp1).oper[0]^.reg=taicpu(p).oper[0]^.reg) and
             (PopCnt(byte(taicpu(hp1).oper[1]^.val))=1) and
             GetNextInstruction(hp1,hp2) and
             MatchInstruction(hp2,A_BRxx) and
             (taicpu(hp2).condition in [C_EQ,C_NE]) then
            begin
              if taicpu(hp2).condition=C_EQ then
                taicpu(p).opcode:=A_SBIS
              else
                taicpu(p).opcode:=A_SBIC;

              DebugMsg('Peephole InAndiBrx2SbixJmp performed', p);

              taicpu(p).loadconst(0,taicpu(p).oper[1]^.val);
              taicpu(p).loadconst(1,BsrByte(taicpu(hp1).oper[1]^.val));
              asml.Remove(hp1);
              hp1.Free;

              taicpu(hp2).condition:=C_None;
              if CPUAVR_HAS_JMP_CALL in cpu_capabilities[current_settings.cputype] then
                taicpu(hp2).opcode:=A_JMP
              else
                taicpu(hp2).opcode:=A_RJMP;

              current_asmdata.getjumplabel(l);
              l.increfs;
              asml.InsertAfter(tai_label.create(l), hp2);

              result:=true;
            end;
        end;
    end;


  function TCpuAsmOptimizer.OptPass1SBR(var p : tai) : boolean;
    var
      hp1 : tai;
    begin
      Result:=false;
      {
        Turn
          in rx, y
          sbr* rx, z
        Into
          sbi* y, z
      }
      if (taicpu(p).ops=2) and
         (taicpu(p).oper[0]^.typ=top_reg) and
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(p.next))) and
         GetLastInstruction(p,hp1) and
         (hp1.typ=ait_instruction) and
         (taicpu(hp1).opcode=A_IN) and
         (taicpu(hp1).ops=2) and
         (taicpu(hp1).oper[1]^.typ=top_const) and
         (taicpu(hp1).oper[1]^.val in [0..31]) and
         MatchOperand(taicpu(hp1).oper[0]^,taicpu(p).oper[0]^.reg) and
         (not RegModifiedBetween(taicpu(p).oper[0]^.reg, hp1, p)) then
        begin
          if taicpu(p).opcode=A_SBRS then
            taicpu(p).opcode:=A_SBIS
          else
            taicpu(p).opcode:=A_SBIC;

          taicpu(p).loadconst(0, taicpu(hp1).oper[1]^.val);

          DebugMsg('Peephole InSbrx2Sbix performed', p);

          asml.Remove(hp1);
          hp1.free;

          result:=true;
        end;

      if InvertSkipInstruction(p) then
        result:=true;
    end;


  function TCpuAsmOptimizer.OptPass1SBI(var p : tai) : boolean;
    var
      hp1, hp2, hp3, hp4, hp5: tai;
    begin
      Result:=false;
      {
        Turn
            sbic/sbis X, y
            jmp .L1
            op
          .L1:

        into
            sbis/sbic X,y
            op
          .L1:
      }
      if InvertSkipInstruction(p) then
        result:=true
      {
        Turn
            sbiX X, y
            jmp .L1
            jmp .L2
          .L1:
            op
          .L2:

        into
            sbiX X,y
          .L1:
            op
          .L2:
      }
      else if GetNextInstruction(p, hp1) and
         (hp1.typ=ait_instruction) and
         (taicpu(hp1).opcode in [A_JMP,A_RJMP]) and
         (taicpu(hp1).ops>0) and
         (taicpu(hp1).oper[0]^.typ = top_ref) and
         (taicpu(hp1).oper[0]^.ref^.symbol is TAsmLabel) and

         GetNextInstruction(hp1, hp2) and
         (hp2.typ=ait_instruction) and
         (taicpu(hp2).opcode in [A_JMP,A_RJMP]) and
         (taicpu(hp2).ops>0) and
         (taicpu(hp2).oper[0]^.typ = top_ref) and
         (taicpu(hp2).oper[0]^.ref^.symbol is TAsmLabel) and

         GetNextInstruction(hp2, hp3) and
         (hp3.typ=ait_label) and
         (taicpu(hp1).oper[0]^.ref^.symbol=tai_label(hp3).labsym) and

         GetNextInstruction(hp3, hp4) and
         (hp4.typ=ait_instruction) and

         GetNextInstruction(hp4, hp5) and
         (hp3.typ=ait_label) and
         (taicpu(hp2).oper[0]^.ref^.symbol=tai_label(hp5).labsym) then
        begin
          DebugMsg('Peephole SbiJmpJmp2Sbi performed',p);

          tai_label(hp3).labsym.decrefs;
          tai_label(hp5).labsym.decrefs;

          AsmL.remove(hp1);
          taicpu(hp1).Free;

          AsmL.remove(hp2);
          taicpu(hp2).Free;

          result:=true;
        end;
    end;


  function TCpuAsmOptimizer.OptPass1ANDI(var p : tai) : boolean;
    var
      hp1, hp2, hp3: tai;
      i : longint;
    begin
      Result:=false;
      {
        Turn
            andi rx, #pow2
            brne l
            <op>
          l:
        Into
            sbrs rx, #(1 shl imm)
            <op>
          l:
      }
      if (taicpu(p).ops=2) and
         (taicpu(p).oper[1]^.typ=top_const) and
         ispowerof2(taicpu(p).oper[1]^.val,i) and
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(p.next))) and
         GetNextInstruction(p,hp1) and
         (hp1.typ=ait_instruction) and
         (taicpu(hp1).opcode=A_BRxx) and
         (taicpu(hp1).condition in [C_EQ,C_NE]) and
         (taicpu(hp1).ops>0) and
         (taicpu(hp1).oper[0]^.typ = top_ref) and
         (taicpu(hp1).oper[0]^.ref^.symbol is TAsmLabel) and
         GetNextInstruction(hp1,hp2) and
         (hp2.typ=ait_instruction) and
         GetNextInstruction(hp2,hp3) and
         (hp3.typ=ait_label) and
         (taicpu(hp1).oper[0]^.ref^.symbol=tai_label(hp3).labsym) then
        begin
          DebugMsg('Peephole AndiBr2Sbr performed', p);

          taicpu(p).oper[1]^.val:=i;

          if taicpu(hp1).condition=C_NE then
            taicpu(p).opcode:=A_SBRS
          else
            taicpu(p).opcode:=A_SBRC;

          asml.Remove(hp1);
          hp1.free;

          result:=true;
        end
      {
        Remove
          andi rx, #y
          dealloc rx
      }
      else if (taicpu(p).ops=2) and
         (taicpu(p).oper[0]^.typ=top_reg) and
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(p.next))) and
         (assigned(FindRegDeAlloc(NR_DEFAULTFLAGS,tai(p.Next))) or
          (not RegInUsedRegs(NR_DEFAULTFLAGS,UsedRegs))) then
        begin
          DebugMsg('Redundant Andi removed', p);

          result:=RemoveCurrentP(p);
        end;
    end;


  function TCpuAsmOptimizer.OptPass1ADD(var p : tai) : boolean;
    var
      hp1: tai;
    begin
      Result:=false;
      if (taicpu(p).oper[1]^.reg=GetDefaultZeroReg) and
      GetNextInstruction(p, hp1) and
      MatchInstruction(hp1,A_ADC) then
      begin
        DebugMsg('Peephole AddAdc2Add performed', p);

        RemoveCurrentP(p, hp1);
        Result := True;
      end;
    end;


  function TCpuAsmOptimizer.OptPass1SUB(var p : tai) : boolean;
    var
      hp1: tai;
    begin
      Result:=false;
      if (taicpu(p).oper[1]^.reg=GetDefaultZeroReg) and
      GetNextInstruction(p, hp1) and
      MatchInstruction(hp1,A_SBC) then
      begin
        DebugMsg('Peephole SubSbc2Sub performed', p);

        taicpu(hp1).opcode:=A_SUB;

        RemoveCurrentP(p, hp1);
        Result := True;
      end;
    end;


  function TCpuAsmOptimizer.OptPass2MOV(var p: tai): boolean;
    var
      hp1: tai;
    begin
      result:=false;
      { fold
        mov reg2,reg0
        mov reg3,reg1
        to
        movw reg2,reg0
      }
      if (CPUAVR_HAS_MOVW in cpu_capabilities[current_settings.cputype]) and
         (taicpu(p).ops=2) and
         (taicpu(p).oper[0]^.typ = top_reg) and
         (taicpu(p).oper[1]^.typ = top_reg) and
         getnextinstruction(p,hp1) and
         (hp1.typ = ait_instruction) and
         (taicpu(hp1).opcode = A_MOV) and
         (taicpu(hp1).ops=2) and
         (taicpu(hp1).oper[0]^.typ = top_reg) and
         (taicpu(hp1).oper[1]^.typ = top_reg) and
         (getsupreg(taicpu(hp1).oper[0]^.reg)=getsupreg(taicpu(p).oper[0]^.reg)+1) and
         ((getsupreg(taicpu(p).oper[0]^.reg) mod 2)=0) and
         ((getsupreg(taicpu(p).oper[1]^.reg) mod 2)=0) and
         (getsupreg(taicpu(hp1).oper[1]^.reg)=getsupreg(taicpu(p).oper[1]^.reg)+1) then
        begin
          DebugMsg('Peephole MovMov2Movw performed', p);

          AllocRegBetween(taicpu(hp1).oper[0]^.reg,p,hp1,UsedRegs);
          AllocRegBetween(taicpu(hp1).oper[1]^.reg,p,hp1,UsedRegs);

          taicpu(p).opcode:=A_MOVW;
          asml.remove(hp1);
          hp1.free;
          result:=true;
        end
    end;


  function TCpuAsmOptimizer.OptPass1CLR(var p : tai) : boolean;
    var
      hp1: tai;
      alloc, dealloc: tai_regalloc;
    begin
      Result:=false;
      { turn the common
        clr rX
        mov/ld rX, rY
        into
        mov/ld rX, rY
      }
      if (taicpu(p).ops=1) and
         (taicpu(p).oper[0]^.typ=top_reg) and
         GetNextInstructionUsingReg(p, hp1, taicpu(p).oper[0]^.reg) and
         (not RegModifiedBetween(taicpu(p).oper[0]^.reg, p, hp1)) and
         (hp1.typ=ait_instruction) and
         (taicpu(hp1).opcode in [A_MOV,A_LD]) and
         (taicpu(hp1).ops>0) and
         (taicpu(hp1).oper[0]^.typ=top_reg) and
         (taicpu(hp1).oper[0]^.reg=taicpu(p).oper[0]^.reg) then
        begin
          DebugMsg('Peephole ClrMov2Mov performed', p);

          result:=RemoveCurrentP(p);
        end
      { turn
        clr rX
        ...
        adc rY, rX
        into
        ...
        adc rY, r1
      }
      else if (taicpu(p).ops=1) and
         (taicpu(p).oper[0]^.typ=top_reg) and
         GetNextInstructionUsingReg(p, hp1, taicpu(p).oper[0]^.reg) and
         (not RegModifiedBetween(taicpu(p).oper[0]^.reg, p, hp1)) and
         (hp1.typ=ait_instruction) and
         (taicpu(hp1).opcode in [A_ADC,A_SBC]) and
         (taicpu(hp1).ops=2) and
         (taicpu(hp1).oper[1]^.typ=top_reg) and
         (taicpu(hp1).oper[1]^.reg=taicpu(p).oper[0]^.reg) and
         (taicpu(hp1).oper[0]^.reg<>taicpu(p).oper[0]^.reg) and
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next))) then
        begin
          DebugMsg('Peephole ClrAdc2Adc performed', p);

          taicpu(hp1).oper[1]^.reg:=GetDefaultZeroReg;

          alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
          dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next));

          if assigned(alloc) and assigned(dealloc) then
            begin
              asml.Remove(alloc);
              alloc.Free;
              asml.Remove(dealloc);
              dealloc.Free;
            end;

          result:=RemoveCurrentP(p);
        end;
    end;


  function TCpuAsmOptimizer.OptPass1PUSH(var p : tai) : boolean;
    var
      hp1, hp2, hp3: tai;
    begin
      Result:=false;
      { turn
        push reg0
        push reg1
        pop reg3
        pop reg2

        into

        movw reg2,reg0

        or

        mov  reg3,reg1
        mov  reg2,reg0

      }
      if GetNextInstruction(p,hp1) and
         MatchInstruction(hp1,A_PUSH) and

         GetNextInstruction(hp1,hp2) and
         MatchInstruction(hp2,A_POP) and

         GetNextInstruction(hp2,hp3) and
         MatchInstruction(hp3,A_POP) then
        begin
         if (CPUAVR_HAS_MOVW in cpu_capabilities[current_settings.cputype]) and
           (getsupreg(taicpu(hp1).oper[0]^.reg)=getsupreg(taicpu(p).oper[0]^.reg)+1) and
           ((getsupreg(taicpu(p).oper[0]^.reg) mod 2)=0) and
           (getsupreg(taicpu(hp2).oper[0]^.reg)=getsupreg(taicpu(hp3).oper[0]^.reg)+1) and
           ((getsupreg(taicpu(hp3).oper[0]^.reg) mod 2)=0) then
           begin
             DebugMsg('Peephole PushPushPopPop2Movw performed', p);

             taicpu(hp3).ops:=2;
             taicpu(hp3).opcode:=A_MOVW;

             taicpu(hp3).loadreg(1, taicpu(p).oper[0]^.reg);

             { We're removing 3 concurrent instructions.  Remove hp1
               and hp2 manually instead of calling RemoveCurrentP
               as this means we won't be calling UpdateUsedRegs 3 times }
             asml.Remove(hp1);
             hp1.Free;

             asml.Remove(hp2);
             hp2.Free;

             { By removing p last, we've guaranteed that p.Next is
               valid (storing it prior to removing the instructions
               may result in a dangling pointer if hp1 immediately
               follows p), and because hp1, hp2 and hp3 came from
               sequential calls to GetNextInstruction, it is
               guaranteed that UpdateUsedRegs will stop at hp3. [Kit] }
             RemoveCurrentP(p, hp3);
             Result := True;
           end
         else
           begin
             DebugMsg('Peephole PushPushPopPop2MovMov performed', p);

             taicpu(p).ops:=2;
             taicpu(p).opcode:=A_MOV;

             taicpu(hp1).ops:=2;
             taicpu(hp1).opcode:=A_MOV;

             taicpu(p).loadreg(1, taicpu(p).oper[0]^.reg);
             taicpu(p).loadreg(0, taicpu(hp3).oper[0]^.reg);

             taicpu(hp1).loadreg(1, taicpu(hp1).oper[0]^.reg);
             taicpu(hp1).loadreg(0, taicpu(hp2).oper[0]^.reg);

             { life range of reg2 and reg3 is increased, fix register allocation entries }
             TransferUsedRegs(TmpUsedRegs);
             UpdateUsedRegs(TmpUsedRegs,tai(p.Next));
             AllocRegBetween(taicpu(hp2).oper[0]^.reg,hp1,hp2,TmpUsedRegs);

             TransferUsedRegs(TmpUsedRegs);
             AllocRegBetween(taicpu(hp3).oper[0]^.reg,p,hp3,TmpUsedRegs);

             IncludeRegInUsedRegs(taicpu(hp3).oper[0]^.reg,UsedRegs);
             UpdateUsedRegs(tai(p.Next));

             asml.Remove(hp2);
             hp2.Free;
             asml.Remove(hp3);
             hp3.Free;

             result:=true;
           end

        end;
    end;


  function TCpuAsmOptimizer.OptPass1CALL(var p : tai) : boolean;
    var
      hp1: tai;
    begin
      Result:=false;
      if (cs_opt_level4 in current_settings.optimizerswitches) and
        GetNextInstruction(p,hp1) and
        MatchInstruction(hp1,A_RET) then
        begin
           DebugMsg('Peephole CallReg2Jmp performed', p);

           taicpu(p).opcode:=A_JMP;

           asml.Remove(hp1);
           hp1.Free;

           result:=true;
        end;
    end;


  function TCpuAsmOptimizer.OptPass1RCALL(var p : tai) : boolean;
    var
      hp1: tai;
    begin
      Result:=false;
      if (cs_opt_level4 in current_settings.optimizerswitches) and
        GetNextInstruction(p,hp1) and
        MatchInstruction(hp1,A_RET) then
        begin
           DebugMsg('Peephole RCallReg2RJmp performed', p);

           taicpu(p).opcode:=A_RJMP;

           asml.Remove(hp1);
           hp1.Free;

           result:=true;
        end;
    end;


  function TCpuAsmOptimizer.OptPass1MOV(var p : tai) : boolean;
    var
      hp1, hp2: tai;
      i : Integer;
      alloc, dealloc: tai_regalloc;
    begin
      Result:=false;
      { change
        mov reg0, reg1
        dealloc reg0
        into
        dealloc reg0
      }
      if MatchOpType(taicpu(p),top_reg,top_reg) then
        begin
          TransferUsedRegs(TmpUsedRegs);
          UpdateUsedRegs(TmpUsedRegs,tai(p.Next));
          if not(RegInUsedRegs(taicpu(p).oper[0]^.reg,TmpUsedRegs)) and
            { reg. allocation information before calls is not perfect, so don't do this before
              calls/icalls }
            GetNextInstruction(p,hp1) and
            not(MatchInstruction(hp1,[A_CALL,A_RCALL])) then
            begin
              DebugMsg('Peephole Mov2Nop performed', p);
              RemoveCurrentP(p, hp1);
              Result := True;
              exit;
            end;
        end;

      { turn
        mov reg0, reg1
        <op> reg2,reg0
        dealloc reg0
        into
        <op> reg2,reg1
      }
      if MatchOpType(taicpu(p),top_reg,top_reg) and
         GetNextInstructionUsingReg(p,hp1,taicpu(p).oper[0]^.reg) and
         (not RegModifiedBetween(taicpu(p).oper[1]^.reg, p, hp1)) and
         (MatchInstruction(hp1,[A_PUSH,A_MOV,A_CP,A_CPC,A_ADD,A_SUB,A_ADC,A_SBC,A_EOR,A_AND,A_OR,
                                 A_OUT,A_IN]) or
         { the reference register of ST/STD cannot be replaced }
         (MatchInstruction(hp1,[A_STD,A_ST,A_STS]) and (MatchOperand(taicpu(p).oper[0]^,taicpu(hp1).oper[1]^)))) and
         (not RegModifiedByInstruction(taicpu(p).oper[0]^.reg, hp1)) and
         {(taicpu(hp1).ops=1) and
         (taicpu(hp1).oper[0]^.typ = top_reg) and
         (taicpu(hp1).oper[0]^.reg=taicpu(p).oper[0]^.reg) and  }
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next))) then
        begin
          DebugMsg('Peephole MovOp2Op 1 performed', p);

          for i := 0 to taicpu(hp1).ops-1 do
            if taicpu(hp1).oper[i]^.typ=top_reg then
              if taicpu(hp1).oper[i]^.reg=taicpu(p).oper[0]^.reg then
                taicpu(hp1).oper[i]^.reg:=taicpu(p).oper[1]^.reg;

          alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
          dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next));

          if assigned(alloc) and assigned(dealloc) then
            begin
              asml.Remove(alloc);
              alloc.Free;
              asml.Remove(dealloc);
              dealloc.Free;
            end;

          { life range of reg1 is increased }
          AllocRegBetween(taicpu(p).oper[1]^.reg,p,hp1,usedregs);
          { p will be removed, update used register as we continue
            with the next instruction after p }

          result:=RemoveCurrentP(p);
        end
      { turn
        mov reg1, reg0
        <op> reg1,xxxx
        dealloc reg1
        into
        <op> reg1,xxx
      }
      else if MatchOpType(taicpu(p),top_reg,top_reg) and
         GetNextInstructionUsingReg(p,hp1,taicpu(p).oper[0]^.reg) and
         not(RegModifiedBetween(taicpu(p).oper[1]^.reg, p, hp1)) and
         MatchInstruction(hp1,[A_CP,A_CPC,A_CPI,A_SBRS,A_SBRC]) and
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next))) then
        begin
          DebugMsg('Peephole MovOp2Op 2 performed', p);

          for i := 0 to taicpu(hp1).ops-1 do
            if taicpu(hp1).oper[i]^.typ=top_reg then
              if taicpu(hp1).oper[i]^.reg=taicpu(p).oper[0]^.reg then
                taicpu(hp1).oper[i]^.reg:=taicpu(p).oper[1]^.reg;

          alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
          dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp1.Next));

          if assigned(alloc) and assigned(dealloc) then
            begin
              asml.Remove(alloc);
              alloc.Free;
              asml.Remove(dealloc);
              dealloc.Free;
            end;

          { life range of reg1 is increased }
          AllocRegBetween(taicpu(p).oper[1]^.reg,p,hp1,usedregs);
          { p will be removed, update used register as we continue
            with the next instruction after p }

          result:=RemoveCurrentP(p);
        end
      { remove
        mov reg0,reg0
      }
      else if (taicpu(p).ops=2) and
         (taicpu(p).oper[0]^.typ = top_reg) and
         (taicpu(p).oper[1]^.typ = top_reg) and
         (taicpu(p).oper[0]^.reg = taicpu(p).oper[1]^.reg) then
        begin
          DebugMsg('Peephole RedundantMov performed', p);

          result:=RemoveCurrentP(p);
        end
      {
        Turn
          mov rx,ry
          op rx,rz
          mov ry, rx
        Into
          op ry,rz
      }
      else if (taicpu(p).ops=2) and
         MatchOpType(taicpu(p),top_reg,top_reg) and
         GetNextInstructionUsingReg(p,hp1,taicpu(p).oper[0]^.reg) and
         (hp1.typ=ait_instruction) and
         (taicpu(hp1).ops >= 1) and
         (taicpu(hp1).oper[0]^.typ = top_reg) and
         GetNextInstructionUsingReg(hp1,hp2,taicpu(hp1).oper[0]^.reg) and
         MatchInstruction(hp2,A_MOV) and
         MatchOpType(taicpu(hp2),top_reg,top_reg) and
         (taicpu(hp2).oper[0]^.reg = taicpu(p).oper[1]^.reg) and
         (taicpu(hp2).oper[1]^.reg = taicpu(hp1).oper[0]^.reg) and
         (taicpu(hp2).oper[1]^.reg = taicpu(p).oper[0]^.reg) and
         (not RegModifiedBetween(taicpu(p).oper[1]^.reg,p,hp2)) and
         (taicpu(hp1).opcode in [A_ADD,A_ADC,A_SUB,A_SBC,A_AND,A_OR,A_EOR,
                                 A_INC,A_DEC,
                                 A_LSL,A_LSR,A_ASR,A_ROR,A_ROL]) and
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg, tai(hp2.Next))) then
        begin
          DebugMsg('Peephole MovOpMov2Op performed', p);

          if (taicpu(hp1).ops=2) and
             (taicpu(hp1).oper[1]^.typ=top_reg) and
             (taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
            taicpu(hp1).oper[1]^.reg:=taicpu(p).oper[1]^.reg;

          taicpu(hp1).oper[0]^.reg:=taicpu(p).oper[1]^.reg;

          alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
          dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp2.Next));

          if assigned(alloc) and assigned(dealloc) then
            begin
              asml.Remove(alloc);
              alloc.Free;
              asml.Remove(dealloc);
              dealloc.Free;
            end;

          asml.remove(hp2);
          hp2.free;

          result:=RemoveCurrentP(p);
        end
      {
        Turn
          mov rx,ry
          op  rx,rw
          mov rw,rx
        Into
          op rw,ry
      }
      else if (taicpu(p).ops=2) and
         MatchOpType(taicpu(p),top_reg,top_reg) and
         GetNextInstructionUsingReg(p,hp1,taicpu(p).oper[0]^.reg) and
         (hp1.typ=ait_instruction) and
         (taicpu(hp1).ops = 2) and
         MatchOpType(taicpu(hp1),top_reg,top_reg) and
         GetNextInstructionUsingReg(hp1,hp2,taicpu(hp1).oper[0]^.reg) and
         (hp2.typ=ait_instruction) and
         (taicpu(hp2).opcode=A_MOV) and
         MatchOpType(taicpu(hp2),top_reg,top_reg) and
         (taicpu(hp2).oper[0]^.reg = taicpu(hp1).oper[1]^.reg) and
         (taicpu(hp2).oper[1]^.reg = taicpu(hp1).oper[0]^.reg) and
         (taicpu(hp2).oper[1]^.reg = taicpu(p).oper[0]^.reg) and
         (not RegModifiedBetween(taicpu(p).oper[1]^.reg,p,hp1)) and
         (taicpu(hp1).opcode in [A_ADD,A_ADC,A_AND,A_OR,A_EOR]) and
         assigned(FindRegDeAlloc(taicpu(p).oper[0]^.reg, tai(hp2.Next))) then
        begin
          DebugMsg('Peephole MovOpMov2Op2 performed', p);

          taicpu(hp1).oper[0]^.reg:=taicpu(hp2).oper[0]^.reg;
          taicpu(hp1).oper[1]^.reg:=taicpu(p).oper[1]^.reg;

          alloc:=FindRegAllocBackward(taicpu(p).oper[0]^.reg,tai(p.Previous));
          dealloc:=FindRegDeAlloc(taicpu(p).oper[0]^.reg,tai(hp2.Next));

          if assigned(alloc) and assigned(dealloc) then
            begin
              asml.Remove(alloc);
              alloc.Free;
              asml.Remove(dealloc);
              dealloc.Free;
            end;

          result:=RemoveCurrentP(p);

          asml.remove(hp2);
          hp2.free;
        end
      {
        This removes the first mov from
        mov rX,...
        mov rX,...
      }
      else if GetNextInstruction(p,hp1) and MatchInstruction(hp1,A_MOV) and
        { test condition here already instead in the while loop only, else MovMov2Mov 2 might be oversight }
        MatchInstruction(hp1,A_MOV) and
        MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[0]^) then
        while MatchInstruction(hp1,A_MOV) and
              MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[0]^) and
              { don't remove the first mov if the second is a mov rX,rX }
              not(MatchOperand(taicpu(hp1).oper[0]^,taicpu(hp1).oper[1]^)) do
          begin
            DebugMsg('Peephole MovMov2Mov 1 performed', p);

            RemoveCurrentP(p,hp1);
            Result := True;

            GetNextInstruction(hp1,hp1);
            if not assigned(hp1) then
              break;
          end
      {
        This removes the second mov from
        mov rX,rY

        ...

        mov rX,rY

        if rX and rY are not modified in-between
      }
      else if GetNextInstructionUsingReg(p,hp1,taicpu(p).oper[1]^.reg) and
        MatchInstruction(hp1,A_MOV) and
        MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[0]^) and
        MatchOperand(taicpu(p).oper[1]^, taicpu(hp1).oper[1]^) and
        not(RegModifiedBetween(taicpu(p).oper[0]^.reg,p,hp1)) then
        begin
          DebugMsg('Peephole MovMov2Mov 2 performed', p);
          AllocRegBetween(taicpu(p).oper[0]^.reg,p,hp1,UsedRegs);
          RemoveInstruction(hp1);
          Result := True;
        end;
    end;

  function TCpuAsmOptimizer.PeepHoleOptPass1Cpu(var p: tai): boolean;
    var
      hp1,hp2: tai;
    begin
      result := false;
      case p.typ of
        ait_instruction:
          begin
            {
              change
              <op> reg,x
              cp reg,r1
              into
              <op>s reg,x
            }
            { this optimization can applied only to the currently enabled operations because
              the other operations do not update all flags and FPC does not track flag usage }
            if MatchInstruction(p, [A_ADC,A_ADD,A_AND,A_ANDI,A_ASR,A_COM,A_DEC,A_EOR,
                                    A_INC,A_LSL,A_LSR,
                                    A_OR,A_ORI,A_ROL,A_ROR,A_SBC,A_SBCI,A_SUB,A_SUBI]) and
              GetNextInstruction(p, hp1) and
              ((MatchInstruction(hp1, A_CP) and
                (((taicpu(p).oper[0]^.reg = taicpu(hp1).oper[0]^.reg) and
                  (taicpu(hp1).oper[1]^.reg = GetDefaultZeroReg)) or
                 ((taicpu(p).oper[0]^.reg = taicpu(hp1).oper[1]^.reg) and
                  (taicpu(hp1).oper[0]^.reg = GetDefaultZeroReg) and
                  (taicpu(p).opcode in [A_ADC,A_ADD,A_AND,A_ANDI,A_ASR,A_COM,A_EOR,
                                        A_LSL,A_LSR,
                                        A_OR,A_ORI,A_ROL,A_ROR,A_SUB,A_SBI])))) or
               (MatchInstruction(hp1, A_CPI) and
                (taicpu(p).opcode = A_ANDI) and
                (taicpu(p).oper[1]^.typ=top_const) and
                (taicpu(hp1).oper[1]^.typ=top_const) and
                (taicpu(hp1).oper[1]^.val=0))) and
              GetNextInstruction(hp1, hp2) and
              { be careful here, following instructions could use other flags
                however after a jump fpc never depends on the value of flags }
              { All above instructions set Z and N according to the following
                Z := result = 0;
                N := result[7];
                EQ = Z=1; NE = Z=0;
                MI = N=1; PL = N=0; }
              MatchInstruction(hp2, A_BRxx) and
              ((taicpu(hp2).condition in [C_EQ,C_NE,C_MI,C_PL]) or
              { sub/sbc set all flags }
               (taicpu(p).opcode in [A_SUB,A_SBI])){ and
              no flag allocation tracking implemented yet on avr
              assigned(FindRegDealloc(NR_DEFAULTFLAGS,tai(hp2.Next)))} then
              begin
                { move flag allocation if possible }
                { no flag allocation tracking implemented yet on avr
                GetLastInstruction(hp1, hp2);
                hp2:=FindRegAlloc(NR_DEFAULTFLAGS,tai(hp2.Next));
                if assigned(hp2) then
                  begin
                    asml.Remove(hp2);
                    asml.insertbefore(hp2, p);
                  end;
                }

                // If we compare to the same value we are masking then invert the comparison
                if (taicpu(hp1).opcode=A_CPI) or
                  { sub/sbc with reverted? }
                  ((taicpu(hp1).oper[0]^.reg = GetDefaultZeroReg) and (taicpu(p).opcode in [A_SUB,A_SBI])) then
                  taicpu(hp2).condition:=inverse_cond(taicpu(hp2).condition);

                asml.InsertBefore(tai_regalloc.alloc(NR_DEFAULTFLAGS,p), p);
                asml.InsertAfter(tai_regalloc.dealloc(NR_DEFAULTFLAGS,hp2), hp2);
                IncludeRegInUsedRegs(NR_DEFAULTFLAGS,UsedRegs);

                DebugMsg('Peephole OpCp2Op performed', p);

                asml.remove(hp1);
                hp1.free;
                Result:=true;
              end
            else
              case taicpu(p).opcode of
                A_LDI:
                 Result:=OptPass1LDI(p);
                A_STS:
                  Result:=OptPass1STS(p);
                A_LDS:
                  Result:=OptPass1LDS(p);
                A_IN:
                  Result:=OptPass1IN(p);
                A_SBRS,
                A_SBRC:
                  Result:=OptPass1SBR(p);
                A_ANDI:
                  Result:=OptPass1ANDI(p);
                A_ADD:
                  Result:=OptPass1ADD(p);
                A_SUB:
                  Result:=OptPass1SUB(p);
                A_CLR:
                  Result:=OptPass1CLR(p);
                A_PUSH:
                  Result:=OptPass1PUSH(p);
                A_CALL:
                  Result:=OptPass1CALL(p);
                A_RCALL:
                  Result:=OptPass1RCALL(p);
                A_MOV:
                  Result:=OptPass1MOV(p);
                A_SBIC,
                A_SBIS:
                  Result:=OptPass1SBI(p);
              end;
          end;
      end;
    end;


  function TCpuAsmOptimizer.PeepHoleOptPass2Cpu(var p: tai): boolean;
    begin
      result := false;
      case p.typ of
        ait_instruction:
          begin
            case taicpu(p).opcode of
              A_MOV:
                Result:=OptPass2MOV(p);
            end;
          end;
      end;
    end;


begin
  casmoptimizer:=TCpuAsmOptimizer;
End.