{
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}
Interface
uses cpubase, aasmtai, aopt, aoptcpub;
Type
TCpuAsmOptimizer = class(TAsmOptimizer)
{ uses the same constructor as TAopObj }
function PeepHoleOptPass1Cpu(var p: tai): boolean; override;
procedure PeepHoleOptPass2;override;
End;
Implementation
uses
aasmbase,aasmcpu;
function CanBeCond(p : tai) : boolean;
begin
result:=(p.typ=ait_instruction) and (taicpu(p).condition=C_None);
end;
function TCpuAsmOptimizer.PeepHoleOptPass1Cpu(var p: tai): boolean;
var
next1: tai;
begin
result := false;
case p.typ of
ait_instruction:
begin
case taicpu(p).opcode of
A_MOV:
begin
{ fold
mov reg1,reg0, shift imm1
mov reg1,reg1, shift imm2
to
mov reg1,reg0, shift imm1+imm2
}
if (taicpu(p).ops=3) and
(taicpu(p).oper[0]^.typ = top_reg) and
(taicpu(p).oper[2]^.typ = top_shifterop) and
(taicpu(p).oper[2]^.shifterop^.rs = NR_NO) and
getnextinstruction(p,next1) and
(next1.typ = ait_instruction) and
(taicpu(next1).opcode = A_MOV) and
(taicpu(next1).ops=3) and
(taicpu(next1).oper[0]^.typ = top_reg) and
(taicpu(p).oper[0]^.reg=taicpu(next1).oper[0]^.reg) and
(taicpu(next1).oper[1]^.typ = top_reg) and
(taicpu(p).oper[0]^.reg=taicpu(next1).oper[1]^.reg) and
(taicpu(next1).oper[2]^.typ = top_shifterop) and
(taicpu(next1).oper[2]^.shifterop^.rs = NR_NO) and
(taicpu(p).oper[2]^.shifterop^.shiftmode=taicpu(next1).oper[2]^.shifterop^.shiftmode) then
begin
inc(taicpu(p).oper[2]^.shifterop^.shiftimm,taicpu(next1).oper[2]^.shifterop^.shiftimm);
asml.remove(next1);
next1.free;
result := true;
end;
end;
end;
end;
end;
end;
{ instructions modifying the CPSR can be only the last instruction }
function MustBeLast(p : tai) : boolean;
begin
Result:=(p.typ=ait_instruction) and
((taicpu(p).opcode in [A_BL,A_BLX,A_CMP,A_CMN,A_SWI,A_TEQ,A_TST,A_CMF,A_CMFE {,A_MSR}]) or
((taicpu(p).ops>=1) and (taicpu(p).oper[0]^.typ=top_reg) and (taicpu(p).oper[0]^.reg=NR_PC)) or
(taicpu(p).oppostfix=PF_S));
end;
procedure TCpuAsmOptimizer.PeepHoleOptPass2;
var
p,hp1,hp2: tai;
l : longint;
condition : tasmcond;
hp3: tai;
WasLast: boolean;
{ UsedRegs, TmpUsedRegs: TRegSet; }
begin
p := BlockStart;
{ UsedRegs := []; }
while (p <> BlockEnd) Do
begin
{ UpdateUsedRegs(UsedRegs, tai(p.next)); }
case p.Typ Of
Ait_Instruction:
begin
case taicpu(p).opcode Of
A_B:
if taicpu(p).condition<>C_None then
begin
{ check for
Bxx xxx
<several instructions>
xxx:
}
l:=0;
WasLast:=False;
GetNextInstruction(p, hp1);
while assigned(hp1) and
(l<=4) and
CanBeCond(hp1) and
{ stop on labels }
not(hp1.typ=ait_label) do
begin
inc(l);
if MustBeLast(hp1) then
begin
WasLast:=True;
GetNextInstruction(hp1,hp1);
break;
end
else
GetNextInstruction(hp1,hp1);
end;
if assigned(hp1) then
begin
if FindLabel(tasmlabel(taicpu(p).oper[0]^.ref^.symbol),hp1) then
begin
if (l<=4) and (l>0) then
begin
condition:=inverse_cond(taicpu(p).condition);
hp2:=p;
GetNextInstruction(p,hp1);
p:=hp1;
repeat
if hp1.typ=ait_instruction then
taicpu(hp1).condition:=condition;
if MustBeLast(hp1) then
begin
GetNextInstruction(hp1,hp1);
break;
end
else
GetNextInstruction(hp1,hp1);
until not(assigned(hp1)) or
not(CanBeCond(hp1)) or
(hp1.typ=ait_label);
{ wait with removing else GetNextInstruction could
ignore the label if it was the only usage in the
jump moved away }
tasmlabel(taicpu(hp2).oper[0]^.ref^.symbol).decrefs;
asml.remove(hp2);
hp2.free;
continue;
end;
end
else
{ do not perform further optimizations if there is inctructon
in block #1 which can not be optimized.
}
if not WasLast then
begin
{ check further for
Bcc xxx
<several instructions 1>
B yyy
xxx:
<several instructions 2>
yyy:
}
{ hp2 points to jmp yyy }
hp2:=hp1;
{ skip hp1 to xxx }
GetNextInstruction(hp1, hp1);
if assigned(hp2) and
assigned(hp1) and
(l<=3) and
(hp2.typ=ait_instruction) and
(taicpu(hp2).is_jmp) and
(taicpu(hp2).condition=C_None) and
{ real label and jump, no further references to the
label are allowed }
(tasmlabel(taicpu(p).oper[0]^.ref^.symbol).getrefs=2) and
FindLabel(tasmlabel(taicpu(p).oper[0]^.ref^.symbol),hp1) then
begin
l:=0;
{ skip hp1 to <several moves 2> }
GetNextInstruction(hp1, hp1);
while assigned(hp1) and
CanBeCond(hp1) do
begin
inc(l);
GetNextInstruction(hp1, hp1);
end;
{ hp1 points to yyy: }
if assigned(hp1) and
FindLabel(tasmlabel(taicpu(hp2).oper[0]^.ref^.symbol),hp1) then
begin
condition:=inverse_cond(taicpu(p).condition);
GetNextInstruction(p,hp1);
hp3:=p;
p:=hp1;
repeat
if hp1.typ=ait_instruction then
taicpu(hp1).condition:=condition;
GetNextInstruction(hp1,hp1);
until not(assigned(hp1)) or
not(CanBeCond(hp1));
{ hp2 is still at jmp yyy }
GetNextInstruction(hp2,hp1);
{ hp2 is now at xxx: }
condition:=inverse_cond(condition);
GetNextInstruction(hp1,hp1);
{ hp1 is now at <several movs 2> }
repeat
taicpu(hp1).condition:=condition;
GetNextInstruction(hp1,hp1);
until not(assigned(hp1)) or
not(CanBeCond(hp1)) or
(hp1.typ=ait_label);
{
asml.remove(hp1.next)
hp1.next.free;
asml.remove(hp1);
hp1.free;
}
{ remove Bcc }
tasmlabel(taicpu(hp3).oper[0]^.ref^.symbol).decrefs;
asml.remove(hp3);
hp3.free;
{ remove jmp }
tasmlabel(taicpu(hp2).oper[0]^.ref^.symbol).decrefs;
asml.remove(hp2);
hp2.free;
continue;
end;
end;
end;
end;
end;
end;
end;
end;
p := tai(p.next)
end;
end;
begin
casmoptimizer:=TCpuAsmOptimizer;
End.