fpc/compiler/arm/aoptcpu.pas
2012-04-26 20:31:13 +00:00

686 lines
30 KiB
ObjectPascal

{
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;
TCpuPreRegallocScheduler = class(TAsmOptimizer)
function PeepHoleOptPass1Cpu(var p: tai): boolean;override;
end;
TCpuThumb2AsmOptimizer = class(TCpuAsmOptimizer)
{ uses the same constructor as TAopObj }
procedure PeepHoleOptPass2;override;
End;
Implementation
uses
cutils,
verbose,
cgbase,cgutils,
aasmbase,aasmdata,aasmcpu;
function CanBeCond(p : tai) : boolean;
begin
result:=
(p.typ=ait_instruction) and
(taicpu(p).condition=C_None) and
((taicpu(p).opcode<>A_BLX) or
(taicpu(p).oper[0]^.typ=top_reg));
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.signindex = r2.signindex) and
(r1.shiftimm = r2.shiftimm) and
(r1.addressmode = r2.addressmode) and
(r1.shiftmode = r2.shiftmode);
end;
function MatchInstruction(const instr: tai; const op: TAsmOp; const cond: TAsmConds; const postfix: TOpPostfixes): boolean;
begin
result :=
(instr.typ = ait_instruction) and
(taicpu(instr).opcode = op) and
((cond = []) or (taicpu(instr).condition in cond)) and
((postfix = []) or (taicpu(instr).oppostfix in postfix));
end;
function MatchOperand(const oper1: TOper; const oper2: TOper): boolean; inline;
begin
result := (oper1.typ = oper2.typ) and
(
((oper1.typ = top_const) and (oper1.val = oper2.val)) or
((oper1.typ = top_reg) and (oper1.reg = oper2.reg)) or
((oper1.typ = top_conditioncode) and (oper1.cc = oper2.cc))
);
end;
function MatchOperand(const oper: TOper; const reg: TRegister): boolean; inline;
begin
result := (oper.typ = top_reg) and (oper.reg = reg);
end;
procedure RemoveRedundantMove(const cmpp: tai; movp: tai; asml: TAsmList) ;
begin
if (taicpu(movp).condition = C_EQ) and
(taicpu(cmpp).oper[0]^.reg = taicpu(movp).oper[0]^.reg) and
(taicpu(cmpp).oper[1]^.val = taicpu(movp).oper[1]^.val) then
begin
asml.insertafter(tai_comment.Create(strpnew('Peephole CmpMovMov - Removed redundant moveq')), movp);
asml.remove(movp);
movp.free;
end;
end;
function TCpuAsmOptimizer.PeepHoleOptPass1Cpu(var p: tai): boolean;
var
hp1,hp2: tai;
i: longint;
begin
result := false;
case p.typ of
ait_instruction:
begin
(* optimization proved not to be safe, see tw4768.pp
{
change
<op> reg,x,y
cmp reg,#0
into
<op>s reg,x,y
}
{ 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 (taicpu(p).opcode in [A_ADC,A_ADD,A_SUB {A_UDIV,A_SDIV,A_MUL,A_MVN,A_MOV,A_ORR,A_EOR,A_AND}]) and
(taicpu(p).oppostfix = PF_None) and
(taicpu(p).condition = C_None) and
GetNextInstruction(p, hp1) and
MatchInstruction(hp1, A_CMP, [C_None], [PF_None]) and
(taicpu(hp1).oper[1]^.typ = top_const) and
(taicpu(p).oper[0]^.reg = taicpu(hp1).oper[0]^.reg) and
(taicpu(hp1).oper[1]^.val = 0) { and
GetNextInstruction(hp1, hp2) and
(tai(hp2).typ = ait_instruction) and
// be careful here, following instructions could use other flags
// however after a jump fpc never depends on the value of flags
(taicpu(hp2).opcode = A_B) and
(taicpu(hp2).condition in [C_EQ,C_NE,C_MI,C_PL])} then
begin
taicpu(p).oppostfix:=PF_S;
asml.remove(hp1);
hp1.free;
end
else
*)
case taicpu(p).opcode of
A_STR:
begin
{ change
str reg1,ref
ldr reg2,ref
into
str reg1,ref
mov reg2,reg1
}
if (taicpu(p).oper[1]^.ref^.addressmode=AM_OFFSET) and
GetNextInstruction(p,hp1) and
MatchInstruction(hp1, A_LDR, [taicpu(p).condition, C_None], [PF_None]) and
RefsEqual(taicpu(p).oper[1]^.ref^,taicpu(hp1).oper[1]^.ref^) and
(taicpu(hp1).oper[1]^.ref^.addressmode=AM_OFFSET) then
begin
if taicpu(hp1).oper[0]^.reg=taicpu(p).oper[0]^.reg then
begin
asml.remove(hp1);
hp1.free;
end
else
begin
asml.insertbefore(tai_comment.Create(strpnew('Peephole StrLdr2StrMov done')), hp1);
taicpu(hp1).opcode:=A_MOV;
taicpu(hp1).oppostfix:=PF_None;
taicpu(hp1).loadreg(1,taicpu(p).oper[0]^.reg);
end;
result := true;
end;
end;
A_LDR:
begin
{ change
ldr reg1,ref
ldr reg2,ref
into
ldr reg1,ref
mov reg2,reg1
}
if (taicpu(p).oper[1]^.ref^.addressmode=AM_OFFSET) and
GetNextInstruction(p,hp1) and
MatchInstruction(hp1, A_LDR, [taicpu(p).condition, C_None], [PF_None]) and
RefsEqual(taicpu(p).oper[1]^.ref^,taicpu(hp1).oper[1]^.ref^) and
(taicpu(p).oper[0]^.reg<>taicpu(hp1).oper[1]^.ref^.index) and
(taicpu(p).oper[0]^.reg<>taicpu(hp1).oper[1]^.ref^.base) and
(taicpu(hp1).oper[1]^.ref^.addressmode=AM_OFFSET) then
begin
if taicpu(hp1).oper[0]^.reg=taicpu(p).oper[0]^.reg then
begin
asml.insertbefore(tai_comment.Create(strpnew('Peephole LdrLdr2Ldr done')), hp1);
asml.remove(hp1);
hp1.free;
end
else
begin
asml.insertbefore(tai_comment.Create(strpnew('Peephole LdrLdr2LdrMov done')), hp1);
taicpu(hp1).opcode:=A_MOV;
taicpu(hp1).oppostfix:=PF_None;
taicpu(hp1).loadreg(1,taicpu(p).oper[0]^.reg);
end;
result := true;
end;
end;
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[2]^.typ = top_shifterop) and
(taicpu(p).oper[2]^.shifterop^.rs = NR_NO) and
getnextinstruction(p,hp1) and
MatchInstruction(hp1, A_MOV, [taicpu(p).condition], [PF_None]) and
(taicpu(hp1).ops=3) and
MatchOperand(taicpu(hp1).oper[0]^, taicpu(p).oper[0]^.reg) and
MatchOperand(taicpu(hp1).oper[1]^, taicpu(p).oper[0]^.reg) and
(taicpu(hp1).oper[2]^.typ = top_shifterop) and
(taicpu(hp1).oper[2]^.shifterop^.rs = NR_NO) and
(taicpu(p).oper[2]^.shifterop^.shiftmode=taicpu(hp1).oper[2]^.shifterop^.shiftmode) then
begin
inc(taicpu(p).oper[2]^.shifterop^.shiftimm,taicpu(hp1).oper[2]^.shifterop^.shiftimm);
{ avoid overflows }
if taicpu(p).oper[2]^.shifterop^.shiftimm>31 then
case taicpu(p).oper[2]^.shifterop^.shiftmode of
SM_ROR:
taicpu(p).oper[2]^.shifterop^.shiftimm:=taicpu(p).oper[2]^.shifterop^.shiftimm and 31;
SM_ASR:
taicpu(p).oper[2]^.shifterop^.shiftimm:=31;
SM_LSR,
SM_LSL:
begin
hp1:=taicpu.op_reg_const(A_MOV,taicpu(p).oper[0]^.reg,0);
InsertLLItem(p.previous, p.next, hp1);
p.free;
p:=hp1;
end;
else
internalerror(2008072803);
end;
asml.insertbefore(tai_comment.Create(strpnew('Peephole ShiftShift2Shift done')), p);
asml.remove(hp1);
hp1.free;
result := true;
end;
{
This changes the very common
mov r0, #0
str r0, [...]
mov r0, #0
str r0, [...]
and removes all superfluous mov instructions
}
if (taicpu(p).ops = 2) and
(taicpu(p).oper[1]^.typ = top_const) and
GetNextInstruction(p,hp1) then
begin
while MatchInstruction(hp1, A_STR, [], []) and
MatchOperand(taicpu(hp1).oper[0]^, taicpu(p).oper[0]^) and
GetNextInstruction(hp1, hp2) and
MatchInstruction(hp2, A_MOV, [taicpu(p).condition], [taicpu(p).oppostfix]) and
(taicpu(hp2).ops = 2) and
MatchOperand(taicpu(hp2).oper[0]^, taicpu(p).oper[0]^) and
MatchOperand(taicpu(hp2).oper[1]^, taicpu(p).oper[1]^) do
begin
asml.insertbefore(tai_comment.Create(strpnew('Peephole MovStrMov done')), hp2);
GetNextInstruction(hp2,hp1);
asml.remove(hp2);
hp2.free;
if not assigned(hp1) then break;
end;
end;
{
change
mov r1, r0
add r1, r1, #1
to
add r1, r0, #1
}
if (taicpu(p).ops = 2) and
(taicpu(p).oper[1]^.typ = top_reg) and
(taicpu(p).oppostfix = PF_NONE) and
GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode in [A_ADD, A_ADC, A_RSB, A_RSC, A_SUB, A_SBC,
A_AND, A_BIC, A_EOR, A_ORR]) and
(taicpu(hp1).condition in [C_NONE, taicpu(hp1).condition]) and
MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[0]^.reg) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[2]^.typ in [top_reg, top_const]) then
begin
{ When we get here we still don't know if the registers match}
for I:=1 to 2 do
{
If the first loop was successful p will be replaced with hp1.
The checks will still be ok, because all required information
will also be in hp1 then.
}
if MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[I]^.reg) then
begin
asml.insertbefore(tai_comment.Create(strpnew('Peephole RedundantMovProcess done ')), hp1);
taicpu(hp1).oper[I]^.reg := taicpu(p).oper[1]^.reg;
if p<>hp1 then
begin
asml.remove(p);
p.free;
p:=hp1;
end;
end;
end;
end;
A_AND:
begin
{
change
and reg2,reg1,const1
and reg2,reg2,const2
to
and reg2,reg1,(const1 and const2)
}
if (taicpu(p).oper[1]^.typ = top_reg) and
(taicpu(p).oper[2]^.typ = top_const) and
GetNextInstruction(p, hp1) and
MatchInstruction(hp1, A_AND, [taicpu(p).condition], [PF_None]) and
MatchOperand(taicpu(hp1).oper[0]^, taicpu(p).oper[0]^.reg) and
MatchOperand(taicpu(hp1).oper[1]^, taicpu(p).oper[0]^.reg) and
(taicpu(hp1).oper[2]^.typ = top_const) then
begin
asml.insertbefore(tai_comment.Create(strpnew('Peephole AndAnd2And done')), p);
taicpu(p).loadConst(2,taicpu(p).oper[2]^.val and taicpu(hp1).oper[2]^.val);
taicpu(p).oppostfix:=taicpu(hp1).oppostfix;
asml.remove(hp1);
hp1.free;
end;
end;
A_CMP:
begin
{
change
cmp reg,const1
moveq reg,const1
movne reg,const2
to
cmp reg,const1
movne reg,const2
}
if (taicpu(p).oper[1]^.typ = top_const) and
GetNextInstruction(p, hp1) and
MatchInstruction(hp1, A_MOV, [C_EQ, C_NE], [PF_NONE]) and
(taicpu(hp1).oper[1]^.typ = top_const) and
GetNextInstruction(hp1, hp2) and
MatchInstruction(hp2, A_MOV, [C_EQ, C_NE], [PF_NONE]) and
(taicpu(hp1).oper[1]^.typ = top_const) then
begin
RemoveRedundantMove(p, hp1, asml);
RemoveRedundantMove(p, hp2, asml);
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;
const
{ set of opcode which might or do write to memory }
{ TODO : extend armins.dat to contain r/w info }
opcode_could_mem_write = [A_B,A_BL,A_BLX,A_BKPT,A_BX,A_STR,A_STRB,A_STRBT,
A_STRH,A_STRT,A_STF,A_SFM,A_STM,A_FSTS,A_FSTD];
function TCpuPreRegallocScheduler.PeepHoleOptPass1Cpu(var p: tai): boolean;
{ TODO : schedule also forward }
{ TODO : schedule distance > 1 }
var
hp1,hp2,hp3,hp4,hp5 : tai;
list : TAsmList;
begin
result:=true;
list:=TAsmList.Create;
p := BlockStart;
{ UsedRegs := []; }
while (p <> BlockEnd) Do
begin
if (p.typ=ait_instruction) and
GetNextInstruction(p,hp1) and
(hp1.typ=ait_instruction) and
{ for now we don't reschedule if the previous instruction changes potentially a memory location }
( (not(taicpu(p).opcode in opcode_could_mem_write) and
not(RegModifiedByInstruction(NR_PC,p)) and
(taicpu(hp1).opcode in [A_LDR,A_LDRB,A_LDRH,A_LDRSB,A_LDRSH])
) or
((taicpu(p).opcode in [A_STM,A_STRB,A_STRH,A_STR]) and
(taicpu(hp1).opcode in [A_LDR,A_LDRB,A_LDRH,A_LDRSB,A_LDRSH]) and
((taicpu(hp1).oper[1]^.ref^.base=NR_PC) or
(assigned(taicpu(hp1).oper[1]^.ref^.symboldata) and
(taicpu(hp1).oper[1]^.ref^.offset=0)
)
) or
{ try to prove that the memory accesses don't overlapp }
((taicpu(p).opcode in [A_STRB,A_STRH,A_STR]) and
(taicpu(hp1).opcode in [A_LDR,A_LDRB,A_LDRH,A_LDRSB,A_LDRSH]) and
(taicpu(p).oper[1]^.ref^.base=taicpu(hp1).oper[1]^.ref^.base) and
(taicpu(p).oppostfix=PF_None) and
(taicpu(hp1).oppostfix=PF_None) and
(taicpu(p).oper[1]^.ref^.index=NR_NO) and
(taicpu(hp1).oper[1]^.ref^.index=NR_NO) and
{ get operand sizes and check if the offset distance is large enough to ensure no overlapp }
(abs(taicpu(p).oper[1]^.ref^.offset-taicpu(hp1).oper[1]^.ref^.offset)>=max(tcgsize2size[reg_cgsize(taicpu(p).oper[0]^.reg)],tcgsize2size[reg_cgsize(taicpu(hp1).oper[0]^.reg)]))
)
)
) and
GetNextInstruction(hp1,hp2) and
(hp2.typ=ait_instruction) and
{ loaded register used by next instruction? }
(RegInInstruction(taicpu(hp1).oper[0]^.reg,hp2)) and
{ loaded register not used by previous instruction? }
not(RegInInstruction(taicpu(hp1).oper[0]^.reg,p)) and
{ same condition? }
(taicpu(p).condition=taicpu(hp1).condition) and
{ first instruction might not change the register used as base }
((taicpu(hp1).oper[1]^.ref^.base=NR_NO) or
not(RegModifiedByInstruction(taicpu(hp1).oper[1]^.ref^.base,p))
) and
{ first instruction might not change the register used as index }
((taicpu(hp1).oper[1]^.ref^.index=NR_NO) or
not(RegModifiedByInstruction(taicpu(hp1).oper[1]^.ref^.index,p))
) then
begin
hp3:=tai(p.Previous);
hp5:=tai(p.next);
asml.Remove(p);
{ if there is a reg. dealloc instruction associated with p, move it together with p }
{ before the instruction? }
while assigned(hp3) and (hp3.typ<>ait_instruction) do
begin
if (hp3.typ=ait_regalloc) and (tai_regalloc(hp3).ratype in [ra_dealloc]) and
RegInInstruction(tai_regalloc(hp3).reg,p) then
begin
hp4:=hp3;
hp3:=tai(hp3.Previous);
asml.Remove(hp4);
list.Concat(hp4);
end
else
hp3:=tai(hp3.Previous);
end;
list.Concat(p);
{ after the instruction? }
while assigned(hp5) and (hp5.typ<>ait_instruction) do
begin
if (hp5.typ=ait_regalloc) and (tai_regalloc(hp5).ratype in [ra_dealloc]) and
RegInInstruction(tai_regalloc(hp5).reg,p) then
begin
hp4:=hp5;
hp5:=tai(hp5.next);
asml.Remove(hp4);
list.Concat(hp4);
end
else
hp5:=tai(hp5.Next);
end;
asml.Remove(hp1);
{$ifdef DEBUG_PREREGSCHEDULER}
asml.InsertBefore(tai_comment.Create(strpnew('Rescheduled')),hp2);
{$endif DEBUG_PREREGSCHEDULER}
asml.InsertBefore(hp1,hp2);
asml.InsertListBefore(hp2,list);
end;
p := tai(p.next)
end;
list.Free;
end;
procedure TCpuThumb2AsmOptimizer.PeepHoleOptPass2;
begin
{ TODO: Add optimizer code }
end;
begin
casmoptimizer:=TCpuAsmOptimizer;
cpreregallocscheduler:=TCpuPreRegallocScheduler;
End.