{
Copyright (c) 1998-2002 by Florian Klaempfl and Jonas Maebe
This unit contains the peephole optimizer.
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 popt386;
{$i fpcdefs.inc}
interface
uses Aasmbase,aasmtai,aasmdata,aasmcpu,verbose;
procedure PrePeepHoleOpts(asml: TAsmList; BlockStart, BlockEnd: tai);
procedure PeepHoleOptPass1(asml: TAsmList; BlockStart, BlockEnd: tai);
procedure PeepHoleOptPass2(asml: TAsmList; BlockStart, BlockEnd: tai);
procedure PostPeepHoleOpts(asml: TAsmList; BlockStart, BlockEnd: tai);
implementation
uses
globtype,systems,
globals,cgbase,procinfo,
symsym,
{$ifdef finaldestdebug}
cobjects,
{$endif finaldestdebug}
cpuinfo,cpubase,cgutils,daopt386;
function RegUsedAfterInstruction(reg: Tregister; p: tai; var UsedRegs: TRegSet): Boolean;
var
supreg: tsuperregister;
begin
supreg := getsupreg(reg);
UpdateUsedRegs(UsedRegs, tai(p.Next));
RegUsedAfterInstruction :=
(supreg in UsedRegs) and
(not(getNextInstruction(p,p)) or
not(regLoadedWithNewValue(supreg,false,p)));
end;
function doFpuLoadStoreOpt(asmL: TAsmList; var p: tai): boolean;
{ returns true if a "continue" should be done after this optimization }
var hp1, hp2: tai;
begin
doFpuLoadStoreOpt := false;
if (taicpu(p).oper[0]^.typ = top_ref) and
getNextInstruction(p, hp1) and
(hp1.typ = ait_instruction) and
(((taicpu(hp1).opcode = A_FLD) and
(taicpu(p).opcode = A_FSTP)) or
((taicpu(p).opcode = A_FISTP) and
(taicpu(hp1).opcode = A_FILD))) and
(taicpu(hp1).oper[0]^.typ = top_ref) and
(taicpu(hp1).opsize = taicpu(p).opsize) and
refsEqual(taicpu(p).oper[0]^.ref^, taicpu(hp1).oper[0]^.ref^) then
begin
{ replacing fstp f;fld f by fst f is only valid for extended because of rounding }
if (taicpu(p).opsize=S_FX) and
getNextInstruction(hp1, hp2) and
(hp2.typ = ait_instruction) and
((taicpu(hp2).opcode = A_LEAVE) or
(taicpu(hp2).opcode = A_RET)) and
(taicpu(p).oper[0]^.ref^.base = current_procinfo.FramePointer) and
not(assigned(current_procinfo.procdef.funcretsym) and
(taicpu(p).oper[0]^.ref^.offset < tabstractnormalvarsym(current_procinfo.procdef.funcretsym).localloc.reference.offset)) and
(taicpu(p).oper[0]^.ref^.index = NR_NO) then
begin
asml.remove(p);
asml.remove(hp1);
p.free;
hp1.free;
p := hp2;
removeLastDeallocForFuncRes(asmL, p);
doFPULoadStoreOpt := true;
end
{ can't be done because the store operation rounds
else
{ fst can't store an extended value! }
if (taicpu(p).opsize <> S_FX) and
(taicpu(p).opsize <> S_IQ) then
begin
if (taicpu(p).opcode = A_FSTP) then
taicpu(p).opcode := A_FST
else taicpu(p).opcode := A_FIST;
asml.remove(hp1);
hp1.free;
end
}
end;
end;
procedure PrePeepHoleOpts(asml: TAsmList; BlockStart, BlockEnd: tai);
var
p,hp1: tai;
l: aint;
tmpRef: treference;
begin
p := BlockStart;
while (p <> BlockEnd) Do
begin
case p.Typ Of
Ait_Instruction:
begin
case taicpu(p).opcode Of
A_IMUL:
{changes certain "imul const, %reg"'s to lea sequences}
begin
if (taicpu(p).oper[0]^.typ = Top_Const) and
(taicpu(p).oper[1]^.typ = Top_Reg) and
(taicpu(p).opsize = S_L) then
if (taicpu(p).oper[0]^.val = 1) then
if (taicpu(p).ops = 2) then
{remove "imul $1, reg"}
begin
hp1 := tai(p.Next);
asml.remove(p);
p.free;
p := hp1;
continue;
end
else
{change "imul $1, reg1, reg2" to "mov reg1, reg2"}
begin
hp1 := taicpu.Op_Reg_Reg(A_MOV, S_L, taicpu(p).oper[1]^.reg,taicpu(p).oper[2]^.reg);
InsertLLItem(asml, p.previous, p.next, hp1);
p.free;
p := hp1;
end
else if
((taicpu(p).ops <= 2) or
(taicpu(p).oper[2]^.typ = Top_Reg)) and
(current_settings.optimizecputype < cpu_Pentium2) and
(taicpu(p).oper[0]^.val <= 12) and
not(cs_opt_size in current_settings.optimizerswitches) and
(not(GetNextInstruction(p, hp1)) or
{GetNextInstruction(p, hp1) and}
not((tai(hp1).typ = ait_instruction) and
((taicpu(hp1).opcode=A_Jcc) and
(taicpu(hp1).condition in [C_O,C_NO])))) then
begin
reference_reset(tmpref);
case taicpu(p).oper[0]^.val Of
3: begin
{imul 3, reg1, reg2 to
lea (reg1,reg1,2), reg2
imul 3, reg1 to
lea (reg1,reg1,2), reg1}
TmpRef.base := taicpu(p).oper[1]^.reg;
TmpRef.index := taicpu(p).oper[1]^.reg;
TmpRef.ScaleFactor := 2;
if (taicpu(p).ops = 2) then
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg)
else
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[2]^.reg);
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := hp1;
end;
5: begin
{imul 5, reg1, reg2 to
lea (reg1,reg1,4), reg2
imul 5, reg1 to
lea (reg1,reg1,4), reg1}
TmpRef.base := taicpu(p).oper[1]^.reg;
TmpRef.index := taicpu(p).oper[1]^.reg;
TmpRef.ScaleFactor := 4;
if (taicpu(p).ops = 2) then
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg)
else
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[2]^.reg);
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := hp1;
end;
6: begin
{imul 6, reg1, reg2 to
lea (,reg1,2), reg2
lea (reg2,reg1,4), reg2
imul 6, reg1 to
lea (reg1,reg1,2), reg1
add reg1, reg1}
if (current_settings.optimizecputype <= cpu_386) then
begin
TmpRef.index := taicpu(p).oper[1]^.reg;
if (taicpu(p).ops = 3) then
begin
TmpRef.base := taicpu(p).oper[2]^.reg;
TmpRef.ScaleFactor := 4;
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg);
end
else
begin
hp1 := taicpu.op_reg_reg(A_ADD, S_L,
taicpu(p).oper[1]^.reg,taicpu(p).oper[1]^.reg);
end;
InsertLLItem(asml,p, p.next, hp1);
reference_reset(tmpref);
TmpRef.index := taicpu(p).oper[1]^.reg;
TmpRef.ScaleFactor := 2;
if (taicpu(p).ops = 3) then
begin
TmpRef.base := NR_NO;
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef,
taicpu(p).oper[2]^.reg);
end
else
begin
TmpRef.base := taicpu(p).oper[1]^.reg;
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg);
end;
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := tai(hp1.next);
end
end;
9: begin
{imul 9, reg1, reg2 to
lea (reg1,reg1,8), reg2
imul 9, reg1 to
lea (reg1,reg1,8), reg1}
TmpRef.base := taicpu(p).oper[1]^.reg;
TmpRef.index := taicpu(p).oper[1]^.reg;
TmpRef.ScaleFactor := 8;
if (taicpu(p).ops = 2) then
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg)
else
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[2]^.reg);
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := hp1;
end;
10: begin
{imul 10, reg1, reg2 to
lea (reg1,reg1,4), reg2
add reg2, reg2
imul 10, reg1 to
lea (reg1,reg1,4), reg1
add reg1, reg1}
if (current_settings.optimizecputype <= cpu_386) then
begin
if (taicpu(p).ops = 3) then
hp1 := taicpu.op_reg_reg(A_ADD, S_L,
taicpu(p).oper[2]^.reg,taicpu(p).oper[2]^.reg)
else
hp1 := taicpu.op_reg_reg(A_ADD, S_L,
taicpu(p).oper[1]^.reg,taicpu(p).oper[1]^.reg);
InsertLLItem(asml,p, p.next, hp1);
TmpRef.base := taicpu(p).oper[1]^.reg;
TmpRef.index := taicpu(p).oper[1]^.reg;
TmpRef.ScaleFactor := 4;
if (taicpu(p).ops = 3) then
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[2]^.reg)
else
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg);
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := tai(hp1.next);
end
end;
12: begin
{imul 12, reg1, reg2 to
lea (,reg1,4), reg2
lea (,reg1,8) reg2
imul 12, reg1 to
lea (reg1,reg1,2), reg1
lea (,reg1,4), reg1}
if (current_settings.optimizecputype <= cpu_386)
then
begin
TmpRef.index := taicpu(p).oper[1]^.reg;
if (taicpu(p).ops = 3) then
begin
TmpRef.base := taicpu(p).oper[2]^.reg;
TmpRef.ScaleFactor := 8;
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[2]^.reg);
end
else
begin
TmpRef.base := NR_NO;
TmpRef.ScaleFactor := 4;
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg);
end;
InsertLLItem(asml,p, p.next, hp1);
reference_reset(tmpref);
TmpRef.index := taicpu(p).oper[1]^.reg;
if (taicpu(p).ops = 3) then
begin
TmpRef.base := NR_NO;
TmpRef.ScaleFactor := 4;
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[2]^.reg);
end
else
begin
TmpRef.base := taicpu(p).oper[1]^.reg;
TmpRef.ScaleFactor := 2;
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef, taicpu(p).oper[1]^.reg);
end;
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := tai(hp1.next);
end
end
end;
end;
end;
A_SAR, A_SHR:
{changes the code sequence
shr/sar const1, x
shl const2, x
to either "sar/and", "shl/and" or just "and" depending on const1 and const2}
begin
if GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_SHL) and
(taicpu(p).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).opsize = taicpu(p).opsize) and
(taicpu(hp1).oper[1]^.typ = taicpu(p).oper[1]^.typ) and
OpsEqual(taicpu(hp1).oper[1]^, taicpu(p).oper[1]^) then
if (taicpu(p).oper[0]^.val > taicpu(hp1).oper[0]^.val) and
not(cs_opt_size in current_settings.optimizerswitches) then
{ shr/sar const1, %reg
shl const2, %reg
with const1 > const2 }
begin
taicpu(p).loadConst(0,taicpu(p).oper[0]^.val-taicpu(hp1).oper[0]^.val);
taicpu(hp1).opcode := A_AND;
l := (1 shl (taicpu(hp1).oper[0]^.val)) - 1;
case taicpu(p).opsize Of
S_L: taicpu(hp1).loadConst(0,l Xor aint($ffffffff));
S_B: taicpu(hp1).loadConst(0,l Xor $ff);
S_W: taicpu(hp1).loadConst(0,l Xor $ffff);
end;
end
else if (taicpu(p).oper[0]^.val<taicpu(hp1).oper[0]^.val) and
not(cs_opt_size in current_settings.optimizerswitches) then
{ shr/sar const1, %reg
shl const2, %reg
with const1 < const2 }
begin
taicpu(hp1).loadConst(0,taicpu(hp1).oper[0]^.val-taicpu(p).oper[0]^.val);
taicpu(p).opcode := A_AND;
l := (1 shl (taicpu(p).oper[0]^.val))-1;
case taicpu(p).opsize Of
S_L: taicpu(p).loadConst(0,l Xor aint($ffffffff));
S_B: taicpu(p).loadConst(0,l Xor $ff);
S_W: taicpu(p).loadConst(0,l Xor $ffff);
end;
end
else
{ shr/sar const1, %reg
shl const2, %reg
with const1 = const2 }
if (taicpu(p).oper[0]^.val = taicpu(hp1).oper[0]^.val) then
begin
taicpu(p).opcode := A_AND;
l := (1 shl (taicpu(p).oper[0]^.val))-1;
case taicpu(p).opsize Of
S_B: taicpu(p).loadConst(0,l Xor $ff);
S_W: taicpu(p).loadConst(0,l Xor $ffff);
S_L: taicpu(p).loadConst(0,l Xor aint($ffffffff));
end;
asml.remove(hp1);
hp1.free;
end;
end;
A_XOR:
if (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
{ temporarily change this to 'mov reg,0' to make it easier }
{ for the CSE. Will be changed back in pass 2 }
begin
taicpu(p).opcode := A_MOV;
taicpu(p).loadConst(0,0);
end;
end;
end;
end;
p := tai(p.next)
end;
end;
procedure PeepHoleOptPass1(Asml: TAsmList; BlockStart, BlockEnd: tai);
{First pass of peepholeoptimizations}
var
l : longint;
p,hp1,hp2 : tai;
hp3,hp4: tai;
v:aint;
TmpRef: TReference;
UsedRegs, TmpUsedRegs: TRegSet;
TmpBool1, TmpBool2: Boolean;
function SkipLabels(hp: tai; var hp2: tai): boolean;
{skips all labels and returns the next "real" instruction}
begin
while assigned(hp.next) and
(tai(hp.next).typ in SkipInstr + [ait_label,ait_align]) Do
hp := tai(hp.next);
if assigned(hp.next) then
begin
SkipLabels := True;
hp2 := tai(hp.next)
end
else
begin
hp2 := hp;
SkipLabels := False
end;
end;
function GetFinalDestination(asml: TAsmList; hp: taicpu; level: longint): boolean;
{traces sucessive jumps to their final destination and sets it, e.g.
je l1 je l3
<code> <code>
l1: becomes l1:
je l2 je l3
<code> <code>
l2: l2:
jmp l3 jmp l3
the level parameter denotes how deeep we have already followed the jump,
to avoid endless loops with constructs such as "l5: ; jmp l5" }
var p1, p2: tai;
l: tasmlabel;
function FindAnyLabel(hp: tai; var l: tasmlabel): Boolean;
begin
FindAnyLabel := false;
while assigned(hp.next) and
(tai(hp.next).typ in (SkipInstr+[ait_align])) Do
hp := tai(hp.next);
if assigned(hp.next) and
(tai(hp.next).typ = ait_label) then
begin
FindAnyLabel := true;
l := tai_label(hp.next).labsym;
end
end;
begin
GetfinalDestination := false;
if level > 20 then
exit;
p1 := dfa.getlabelwithsym(tasmlabel(hp.oper[0]^.ref^.symbol));
if assigned(p1) then
begin
SkipLabels(p1,p1);
if (tai(p1).typ = ait_instruction) and
(taicpu(p1).is_jmp) then
if { the next instruction after the label where the jump hp arrives}
{ is unconditional or of the same type as hp, so continue }
(taicpu(p1).condition in [C_None,hp.condition]) or
{ the next instruction after the label where the jump hp arrives}
{ is the opposite of hp (so this one is never taken), but after }
{ that one there is a branch that will be taken, so perform a }
{ little hack: set p1 equal to this instruction (that's what the}
{ last SkipLabels is for, only works with short bool evaluation)}
((taicpu(p1).condition = inverse_cond(hp.condition)) and
SkipLabels(p1,p2) and
(p2.typ = ait_instruction) and
(taicpu(p2).is_jmp) and
(taicpu(p2).condition in [C_None,hp.condition]) and
SkipLabels(p1,p1)) then
begin
{ quick check for loops of the form "l5: ; jmp l5 }
if (tasmlabel(taicpu(p1).oper[0]^.ref^.symbol).labelnr =
tasmlabel(hp.oper[0]^.ref^.symbol).labelnr) then
exit;
if not GetFinalDestination(asml, taicpu(p1),succ(level)) then
exit;
tasmlabel(hp.oper[0]^.ref^.symbol).decrefs;
hp.oper[0]^.ref^.symbol:=taicpu(p1).oper[0]^.ref^.symbol;
tasmlabel(hp.oper[0]^.ref^.symbol).increfs;
end
else
if (taicpu(p1).condition = inverse_cond(hp.condition)) then
if not FindAnyLabel(p1,l) then
begin
{$ifdef finaldestdebug}
insertllitem(asml,p1,p1.next,tai_comment.Create(
strpnew('previous label inserted'))));
{$endif finaldestdebug}
current_asmdata.getjumplabel(l);
insertllitem(asml,p1,p1.next,tai_label.Create(l));
tasmlabel(taicpu(hp).oper[0]^.ref^.symbol).decrefs;
hp.oper[0]^.ref^.symbol := l;
l.increfs;
{ this won't work, since the new label isn't in the labeltable }
{ so it will fail the rangecheck. Labeltable should become a }
{ hashtable to support this: }
{ GetFinalDestination(asml, hp); }
end
else
begin
{$ifdef finaldestdebug}
insertllitem(asml,p1,p1.next,tai_comment.Create(
strpnew('next label reused'))));
{$endif finaldestdebug}
l.increfs;
hp.oper[0]^.ref^.symbol := l;
if not GetFinalDestination(asml, hp,succ(level)) then
exit;
end;
end;
GetFinalDestination := true;
end;
function DoSubAddOpt(var p: tai): Boolean;
begin
DoSubAddOpt := False;
if GetLastInstruction(p, hp1) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).opsize = taicpu(p).opsize) then
case taicpu(hp1).opcode Of
A_DEC:
if (taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg = taicpu(p).oper[1]^.reg) then
begin
taicpu(p).loadConst(0,taicpu(p).oper[0]^.val+1);
asml.remove(hp1);
hp1.free;
end;
A_SUB:
if (taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
begin
taicpu(p).loadConst(0,taicpu(p).oper[0]^.val+taicpu(hp1).oper[0]^.val);
asml.remove(hp1);
hp1.free;
end;
A_ADD:
if (taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
begin
taicpu(p).loadConst(0,taicpu(p).oper[0]^.val-taicpu(hp1).oper[0]^.val);
asml.remove(hp1);
hp1.free;
if (taicpu(p).oper[0]^.val = 0) then
begin
hp1 := tai(p.next);
asml.remove(p);
p.free;
if not GetLastInstruction(hp1, p) then
p := hp1;
DoSubAddOpt := True;
end
end;
end;
end;
begin
p := BlockStart;
UsedRegs := [];
while (p <> BlockEnd) Do
begin
UpDateUsedRegs(UsedRegs, tai(p.next));
case p.Typ Of
ait_instruction:
begin
{ Handle Jmp Optimizations }
if taicpu(p).is_jmp then
begin
{the following if-block removes all code between a jmp and the next label,
because it can never be executed}
if (taicpu(p).opcode = A_JMP) then
begin
while GetNextInstruction(p, hp1) and
(hp1.typ <> ait_label) do
if not(hp1.typ in ([ait_label,ait_align]+skipinstr)) then
begin
asml.remove(hp1);
hp1.free;
end
else break;
end;
{ remove jumps to a label coming right after them }
if GetNextInstruction(p, hp1) then
begin
if FindLabel(tasmlabel(taicpu(p).oper[0]^.ref^.symbol), hp1) and
{$warning FIXME removing the first instruction fails}
(p<>blockstart) then
begin
hp2:=tai(hp1.next);
asml.remove(p);
p.free;
p:=hp2;
continue;
end
else
begin
if hp1.typ = ait_label then
SkipLabels(hp1,hp1);
if (tai(hp1).typ=ait_instruction) and
(taicpu(hp1).opcode=A_JMP) and
GetNextInstruction(hp1, hp2) and
FindLabel(tasmlabel(taicpu(p).oper[0]^.ref^.symbol), hp2) then
begin
if taicpu(p).opcode=A_Jcc then
begin
taicpu(p).condition:=inverse_cond(taicpu(p).condition);
tai_label(hp2).labsym.decrefs;
taicpu(p).oper[0]^.ref^.symbol:=taicpu(hp1).oper[0]^.ref^.symbol;
{ when free'ing hp1, the ref. isn't decresed, so we don't
increase it (FK)
taicpu(p).oper[0]^.ref^.symbol.increfs;
}
asml.remove(hp1);
hp1.free;
GetFinalDestination(asml, taicpu(p),0);
end
else
begin
GetFinalDestination(asml, taicpu(p),0);
p:=tai(p.next);
continue;
end;
end
else
GetFinalDestination(asml, taicpu(p),0);
end;
end;
end
else
{ All other optimizes }
begin
for l := 0 to taicpu(p).ops-1 Do
if (taicpu(p).oper[l]^.typ = top_ref) then
With taicpu(p).oper[l]^.ref^ Do
begin
if (base = NR_NO) and
(index <> NR_NO) and
(scalefactor in [0,1]) then
begin
base := index;
index := NR_NO
end
end;
case taicpu(p).opcode Of
A_AND:
begin
if (taicpu(p).oper[0]^.typ = top_const) and
(taicpu(p).oper[1]^.typ = top_reg) and
GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_AND) and
(taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(p).oper[1]^.reg = taicpu(hp1).oper[1]^.reg) then
{change "and const1, reg; and const2, reg" to "and (const1 and const2), reg"}
begin
taicpu(p).loadConst(0,taicpu(p).oper[0]^.val and taicpu(hp1).oper[0]^.val);
asml.remove(hp1);
hp1.free;
end
else
{change "and x, reg; jxx" to "test x, reg", if reg is deallocated before the
jump, but only if it's a conditional jump (PFV) }
if (taicpu(p).oper[1]^.typ = top_reg) and
GetNextInstruction(p, hp1) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).is_jmp) and
(taicpu(hp1).opcode<>A_JMP) and
not(getsupreg(taicpu(p).oper[1]^.reg) in UsedRegs) then
taicpu(p).opcode := A_TEST;
end;
A_CMP:
begin
{ cmp register,$8000 neg register
je target --> jo target
.... only if register is deallocated before jump.}
case Taicpu(p).opsize of
S_B: v:=$80;
S_W: v:=$8000;
S_L: v:=aint($80000000);
end;
if (taicpu(p).oper[0]^.typ=Top_const) and
(taicpu(p).oper[0]^.val=v) and
(Taicpu(p).oper[1]^.typ=top_reg) and
GetNextInstruction(p, hp1) and
(hp1.typ=ait_instruction) and
(taicpu(hp1).opcode=A_Jcc) and
(Taicpu(hp1).condition in [C_E,C_NE]) and
not(getsupreg(Taicpu(p).oper[1]^.reg) in usedregs) then
begin
Taicpu(p).opcode:=A_NEG;
Taicpu(p).loadoper(0,Taicpu(p).oper[1]^);
Taicpu(p).clearop(1);
Taicpu(p).ops:=1;
if Taicpu(hp1).condition=C_E then
Taicpu(hp1).condition:=C_O
else
Taicpu(hp1).condition:=C_NO;
continue;
end;
{
@@2: @@2:
.... ....
cmp operand1,0
jle/jbe @@1
dec operand1 --> sub operand1,1
jmp @@2 jge/jae @@2
@@1: @@1:
... ....}
if (taicpu(p).oper[0]^.typ = top_const) and
(taicpu(p).oper[1]^.typ in [top_reg,top_ref]) and
(taicpu(p).oper[0]^.val = 0) and
GetNextInstruction(p, hp1) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).is_jmp) and
(taicpu(hp1).opcode=A_Jcc) and
(taicpu(hp1).condition in [C_LE,C_BE]) and
GetNextInstruction(hp1,hp2) and
(hp2.typ = ait_instruction) and
(taicpu(hp2).opcode = A_DEC) and
OpsEqual(taicpu(hp2).oper[0]^,taicpu(p).oper[1]^) and
GetNextInstruction(hp2, hp3) and
(hp3.typ = ait_instruction) and
(taicpu(hp3).is_jmp) and
(taicpu(hp3).opcode = A_JMP) and
GetNextInstruction(hp3, hp4) and
FindLabel(tasmlabel(taicpu(hp1).oper[0]^.ref^.symbol),hp4) then
begin
taicpu(hp2).Opcode := A_SUB;
taicpu(hp2).loadoper(1,taicpu(hp2).oper[0]^);
taicpu(hp2).loadConst(0,1);
taicpu(hp2).ops:=2;
taicpu(hp3).Opcode := A_Jcc;
case taicpu(hp1).condition of
C_LE: taicpu(hp3).condition := C_GE;
C_BE: taicpu(hp3).condition := C_AE;
end;
asml.remove(p);
asml.remove(hp1);
p.free;
hp1.free;
p := hp2;
continue;
end
end;
A_FLD:
begin
if (taicpu(p).oper[0]^.typ = top_reg) and
GetNextInstruction(p, hp1) and
(hp1.typ = Ait_Instruction) and
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg = NR_ST) and
(taicpu(hp1).oper[1]^.reg = NR_ST1) then
{ change to
fld reg fxxx reg,st
fxxxp st, st1 (hp1)
Remark: non commutative operations must be reversed!
}
begin
case taicpu(hp1).opcode Of
A_FMULP,A_FADDP,
A_FSUBP,A_FDIVP,A_FSUBRP,A_FDIVRP:
begin
case taicpu(hp1).opcode Of
A_FADDP: taicpu(hp1).opcode := A_FADD;
A_FMULP: taicpu(hp1).opcode := A_FMUL;
A_FSUBP: taicpu(hp1).opcode := A_FSUBR;
A_FSUBRP: taicpu(hp1).opcode := A_FSUB;
A_FDIVP: taicpu(hp1).opcode := A_FDIVR;
A_FDIVRP: taicpu(hp1).opcode := A_FDIV;
end;
taicpu(hp1).oper[0]^.reg := taicpu(p).oper[0]^.reg;
taicpu(hp1).oper[1]^.reg := NR_ST;
asml.remove(p);
p.free;
p := hp1;
continue;
end;
end;
end
else
if (taicpu(p).oper[0]^.typ = top_ref) and
GetNextInstruction(p, hp2) and
(hp2.typ = Ait_Instruction) and
(taicpu(hp2).ops = 2) and
(taicpu(hp2).oper[0]^.typ = top_reg) and
(taicpu(hp2).oper[1]^.typ = top_reg) and
(taicpu(p).opsize in [S_FS, S_FL]) and
(taicpu(hp2).oper[0]^.reg = NR_ST) and
(taicpu(hp2).oper[1]^.reg = NR_ST1) then
if GetLastInstruction(p, hp1) and
(hp1.typ = Ait_Instruction) and
((taicpu(hp1).opcode = A_FLD) or
(taicpu(hp1).opcode = A_FST)) and
(taicpu(hp1).opsize = taicpu(p).opsize) and
(taicpu(hp1).oper[0]^.typ = top_ref) and
RefsEqual(taicpu(p).oper[0]^.ref^, taicpu(hp1).oper[0]^.ref^) then
if ((taicpu(hp2).opcode = A_FMULP) or
(taicpu(hp2).opcode = A_FADDP)) then
{ change to
fld/fst mem1 (hp1) fld/fst mem1
fld mem1 (p) fadd/
faddp/ fmul st, st
fmulp st, st1 (hp2) }
begin
asml.remove(p);
p.free;
p := hp1;
if (taicpu(hp2).opcode = A_FADDP) then
taicpu(hp2).opcode := A_FADD
else
taicpu(hp2).opcode := A_FMUL;
taicpu(hp2).oper[1]^.reg := NR_ST;
end
else
{ change to
fld/fst mem1 (hp1) fld/fst mem1
fld mem1 (p) fld st}
begin
taicpu(p).changeopsize(S_FL);
taicpu(p).loadreg(0,NR_ST);
end
else
begin
case taicpu(hp2).opcode Of
A_FMULP,A_FADDP,A_FSUBP,A_FDIVP,A_FSUBRP,A_FDIVRP:
{ change to
fld/fst mem1 (hp1) fld/fst mem1
fld mem2 (p) fxxx mem2
fxxxp st, st1 (hp2) }
begin
case taicpu(hp2).opcode Of
A_FADDP: taicpu(p).opcode := A_FADD;
A_FMULP: taicpu(p).opcode := A_FMUL;
A_FSUBP: taicpu(p).opcode := A_FSUBR;
A_FSUBRP: taicpu(p).opcode := A_FSUB;
A_FDIVP: taicpu(p).opcode := A_FDIVR;
A_FDIVRP: taicpu(p).opcode := A_FDIV;
end;
asml.remove(hp2);
hp2.free;
end
end
end
end;
A_FSTP,A_FISTP:
if doFpuLoadStoreOpt(asmL,p) then
continue;
A_LEA:
begin
{removes seg register prefixes from LEA operations, as they
don't do anything}
taicpu(p).oper[0]^.ref^.Segment := NR_NO;
{changes "lea (%reg1), %reg2" into "mov %reg1, %reg2"}
if (taicpu(p).oper[0]^.ref^.base <> NR_NO) and
(getsupreg(taicpu(p).oper[0]^.ref^.base) in [RS_EAX..RS_ESP]) and
(taicpu(p).oper[0]^.ref^.index = NR_NO) and
(not(Assigned(taicpu(p).oper[0]^.ref^.Symbol))) then
if (taicpu(p).oper[0]^.ref^.base <> taicpu(p).oper[1]^.reg) and
(taicpu(p).oper[0]^.ref^.offset = 0) then
begin
hp1 := taicpu.op_reg_reg(A_MOV, S_L,taicpu(p).oper[0]^.ref^.base,
taicpu(p).oper[1]^.reg);
InsertLLItem(asml,p.previous,p.next, hp1);
p.free;
p := hp1;
continue;
end
else if (taicpu(p).oper[0]^.ref^.offset = 0) then
begin
hp1 := tai(p.Next);
asml.remove(p);
p.free;
p := hp1;
continue;
end
else
with taicpu(p).oper[0]^.ref^ do
if (base = taicpu(p).oper[1]^.reg) then
begin
l := offset;
if (l=1) then
begin
taicpu(p).opcode := A_INC;
taicpu(p).loadreg(0,taicpu(p).oper[1]^.reg);
taicpu(p).ops := 1
end
else if (l=-1) then
begin
taicpu(p).opcode := A_DEC;
taicpu(p).loadreg(0,taicpu(p).oper[1]^.reg);
taicpu(p).ops := 1;
end
else
begin
taicpu(p).opcode := A_ADD;
taicpu(p).loadConst(0,l);
end;
end;
end;
A_MOV:
begin
TmpUsedRegs := UsedRegs;
if (taicpu(p).oper[1]^.typ = top_reg) and
(getsupreg(taicpu(p).oper[1]^.reg) in [RS_EAX, RS_EBX, RS_ECX, RS_EDX, RS_ESI, RS_EDI]) and
GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_MOV) and
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg = taicpu(p).oper[1]^.reg) then
begin
{we have "mov x, %treg; mov %treg, y}
if not(RegUsedAfterInstruction(taicpu(p).oper[1]^.reg, hp1, TmpUsedRegs)) then
{we've got "mov x, %treg; mov %treg, y; with %treg is not used after }
case taicpu(p).oper[0]^.typ Of
top_reg:
begin
{ change "mov %reg, %treg; mov %treg, y"
to "mov %reg, y" }
taicpu(p).loadOper(1,taicpu(hp1).oper[1]^);
asml.remove(hp1);
hp1.free;
continue;
end;
top_ref:
if (taicpu(hp1).oper[1]^.typ = top_reg) then
begin
{ change "mov mem, %treg; mov %treg, %reg"
to "mov mem, %reg" }
taicpu(p).loadoper(1,taicpu(hp1).oper[1]^);
asml.remove(hp1);
hp1.free;
continue;
end;
end
end
else
{Change "mov %reg1, %reg2; xxx %reg2, ???" to
"mov %reg1, %reg2; xxx %reg1, ???" to avoid a write/read
penalty}
if (taicpu(p).oper[0]^.typ = top_reg) and
(taicpu(p).oper[1]^.typ = top_reg) and
GetNextInstruction(p,hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).ops >= 1) and
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg = taicpu(p).oper[1]^.reg) then
{we have "mov %reg1, %reg2; XXX %reg2, ???"}
begin
if ((taicpu(hp1).opcode = A_OR) or
(taicpu(hp1).opcode = A_TEST)) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg = taicpu(hp1).oper[1]^.reg) then
{we have "mov %reg1, %reg2; test/or %reg2, %reg2"}
begin
TmpUsedRegs := UsedRegs;
{ reg1 will be used after the first instruction, }
{ so update the allocation info }
allocRegBetween(asmL,taicpu(p).oper[0]^.reg,p,hp1,usedregs);
if GetNextInstruction(hp1, hp2) and
(hp2.typ = ait_instruction) and
taicpu(hp2).is_jmp and
not(RegUsedAfterInstruction(taicpu(hp1).oper[0]^.reg, hp1, TmpUsedRegs)) then
{ change "mov %reg1, %reg2; test/or %reg2, %reg2; jxx" to
"test %reg1, %reg1; jxx" }
begin
taicpu(hp1).loadoper(0,taicpu(p).oper[0]^);
taicpu(hp1).loadoper(1,taicpu(p).oper[0]^);
asml.remove(p);
p.free;
p := hp1;
continue
end
else
{change "mov %reg1, %reg2; test/or %reg2, %reg2" to
"mov %reg1, %reg2; test/or %reg1, %reg1"}
begin
taicpu(hp1).loadoper(0,taicpu(p).oper[0]^);
taicpu(hp1).loadoper(1,taicpu(p).oper[0]^);
end;
end
{ else
if (taicpu(p.next)^.opcode
in [A_PUSH, A_OR, A_XOR, A_AND, A_TEST])}
{change "mov %reg1, %reg2; push/or/xor/... %reg2, ???" to
"mov %reg1, %reg2; push/or/xor/... %reg1, ???"}
end
else
{leave out the mov from "mov reg, x(%frame_pointer); leave/ret" (with
x >= RetOffset) as it doesn't do anything (it writes either to a
parameter or to the temporary storage room for the function
result)}
if GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) then
if ((taicpu(hp1).opcode = A_LEAVE) or
(taicpu(hp1).opcode = A_RET)) and
(taicpu(p).oper[1]^.typ = top_ref) and
(taicpu(p).oper[1]^.ref^.base = current_procinfo.FramePointer) and
not(assigned(current_procinfo.procdef.funcretsym) and
(taicpu(p).oper[1]^.ref^.offset < tabstractnormalvarsym(current_procinfo.procdef.funcretsym).localloc.reference.offset)) and
(taicpu(p).oper[1]^.ref^.index = NR_NO) and
(taicpu(p).oper[0]^.typ = top_reg) then
begin
asml.remove(p);
p.free;
p := hp1;
RemoveLastDeallocForFuncRes(asmL,p);
end
else
if (taicpu(p).oper[0]^.typ = top_reg) and
(taicpu(p).oper[1]^.typ = top_ref) and
(taicpu(p).opsize = taicpu(hp1).opsize) and
(taicpu(hp1).opcode = A_CMP) and
(taicpu(hp1).oper[1]^.typ = top_ref) and
RefsEqual(taicpu(p).oper[1]^.ref^, taicpu(hp1).oper[1]^.ref^) then
{change "mov reg1, mem1; cmp x, mem1" to "mov reg, mem1; cmp x, reg1"}
begin
taicpu(hp1).loadreg(1,taicpu(p).oper[0]^.reg);
allocRegBetween(asmL,taicpu(p).oper[0]^.reg,p,hp1,usedregs);
end;
{ Next instruction is also a MOV ? }
if GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_MOV) and
(taicpu(hp1).opsize = taicpu(p).opsize) then
begin
if (taicpu(hp1).oper[0]^.typ = taicpu(p).oper[1]^.typ) and
(taicpu(hp1).oper[1]^.typ = taicpu(p).oper[0]^.typ) then
{mov reg1, mem1 or mov mem1, reg1
mov mem2, reg2 mov reg2, mem2}
begin
if OpsEqual(taicpu(hp1).oper[1]^,taicpu(p).oper[0]^) then
{mov reg1, mem1 or mov mem1, reg1
mov mem2, reg1 mov reg2, mem1}
begin
if OpsEqual(taicpu(hp1).oper[0]^,taicpu(p).oper[1]^) then
{ Removes the second statement from
mov reg1, mem1/reg2
mov mem1/reg2, reg1 }
begin
if (taicpu(p).oper[0]^.typ = top_reg) then
AllocRegBetween(asmL,taicpu(p).oper[0]^.reg,p,hp1,usedregs);
asml.remove(hp1);
hp1.free;
end
else
begin
TmpUsedRegs := UsedRegs;
UpdateUsedRegs(TmpUsedRegs, tai(hp1.next));
if (taicpu(p).oper[1]^.typ = top_ref) and
{ mov reg1, mem1
mov mem2, reg1 }
(taicpu(hp1).oper[0]^.ref^.refaddr = addr_no) and
GetNextInstruction(hp1, hp2) and
(hp2.typ = ait_instruction) and
(taicpu(hp2).opcode = A_CMP) and
(taicpu(hp2).opsize = taicpu(p).opsize) and
(taicpu(hp2).oper[0]^.typ = TOp_Ref) and
(taicpu(hp2).oper[1]^.typ = TOp_Reg) and
RefsEqual(taicpu(hp2).oper[0]^.ref^, taicpu(p).oper[1]^.ref^) and
(taicpu(hp2).oper[1]^.reg= taicpu(p).oper[0]^.reg) and
not(RegUsedAfterInstruction(taicpu(p).oper[0]^.reg, hp2, TmpUsedRegs)) then
{ change to
mov reg1, mem1 mov reg1, mem1
mov mem2, reg1 cmp reg1, mem2
cmp mem1, reg1 }
begin
asml.remove(hp2);
hp2.free;
taicpu(hp1).opcode := A_CMP;
taicpu(hp1).loadref(1,taicpu(hp1).oper[0]^.ref^);
taicpu(hp1).loadreg(0,taicpu(p).oper[0]^.reg);
end;
end;
end
else
begin
tmpUsedRegs := UsedRegs;
if GetNextInstruction(hp1, hp2) and
(taicpu(p).oper[0]^.typ = top_ref) and
(taicpu(p).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg = taicpu(p).oper[1]^.reg) and
(taicpu(hp1).oper[1]^.typ = top_ref) and
(tai(hp2).typ = ait_instruction) and
(taicpu(hp2).opcode = A_MOV) and
(taicpu(hp2).opsize = taicpu(p).opsize) and
(taicpu(hp2).oper[1]^.typ = top_reg) and
(taicpu(hp2).oper[0]^.typ = top_ref) and
RefsEqual(taicpu(hp2).oper[0]^.ref^, taicpu(hp1).oper[1]^.ref^) then
if not regInRef(getsupreg(taicpu(hp2).oper[1]^.reg),taicpu(hp2).oper[0]^.ref^) and
not(RegUsedAfterInstruction(taicpu(p).oper[1]^.reg,hp1,tmpUsedRegs)) then
{ mov mem1, %reg1
mov %reg1, mem2
mov mem2, reg2
to:
mov mem1, reg2
mov reg2, mem2}
begin
AllocRegBetween(asmL,taicpu(hp2).oper[1]^.reg,p,hp2,usedregs);
taicpu(p).loadoper(1,taicpu(hp2).oper[1]^);
taicpu(hp1).loadoper(0,taicpu(hp2).oper[1]^);
asml.remove(hp2);
hp2.free;
end
else
if (taicpu(p).oper[1]^.reg <> taicpu(hp2).oper[1]^.reg) and
not(RegInRef(getsupreg(taicpu(p).oper[1]^.reg),taicpu(p).oper[0]^.ref^)) and
not(RegInRef(getsupreg(taicpu(hp2).oper[1]^.reg),taicpu(hp2).oper[0]^.ref^)) then
{ mov mem1, reg1 mov mem1, reg1
mov reg1, mem2 mov reg1, mem2
mov mem2, reg2 mov mem2, reg1
to: to:
mov mem1, reg1 mov mem1, reg1
mov mem1, reg2 mov reg1, mem2
mov reg1, mem2
or (if mem1 depends on reg1
and/or if mem2 depends on reg2)
to:
mov mem1, reg1
mov reg1, mem2
mov reg1, reg2
}
begin
taicpu(hp1).loadRef(0,taicpu(p).oper[0]^.ref^);
taicpu(hp1).loadReg(1,taicpu(hp2).oper[1]^.reg);
taicpu(hp2).loadRef(1,taicpu(hp2).oper[0]^.ref^);
taicpu(hp2).loadReg(0,taicpu(p).oper[1]^.reg);
allocRegBetween(asmL,taicpu(p).oper[1]^.reg,p,hp2,usedregs);
if (taicpu(p).oper[0]^.ref^.base <> NR_NO) and
(getsupreg(taicpu(p).oper[0]^.ref^.base) in [RS_EAX,RS_EBX,RS_ECX,RS_EDX,RS_ESI,RS_EDI]) then
allocRegBetween(asmL,taicpu(p).oper[0]^.ref^.base,p,hp2,usedregs);
if (taicpu(p).oper[0]^.ref^.index <> NR_NO) and
(getsupreg(taicpu(p).oper[0]^.ref^.index) in [RS_EAX,RS_EBX,RS_ECX,RS_EDX,RS_ESI,RS_EDI]) then
allocRegBetween(asmL,taicpu(p).oper[0]^.ref^.index,p,hp2,usedregs);
end
else
if (taicpu(hp1).Oper[0]^.reg <> taicpu(hp2).Oper[1]^.reg) then
begin
taicpu(hp2).loadReg(0,taicpu(hp1).Oper[0]^.reg);
allocRegBetween(asmL,taicpu(p).oper[1]^.reg,p,hp2,usedregs);
end
else
begin
asml.remove(hp2);
hp2.free;
end
end
end
else
(* {movl [mem1],reg1
movl [mem1],reg2
to:
movl [mem1],reg1
movl reg1,reg2 }
if (taicpu(p).oper[0]^.typ = top_ref) and
(taicpu(p).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.typ = top_ref) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(p).opsize = taicpu(hp1).opsize) and
RefsEqual(TReference(taicpu(p).oper[0]^^),taicpu(hp1).oper[0]^^.ref^) and
(taicpu(p).oper[1]^.reg<>taicpu(hp1).oper[0]^^.ref^.base) and
(taicpu(p).oper[1]^.reg<>taicpu(hp1).oper[0]^^.ref^.index) then
taicpu(hp1).loadReg(0,taicpu(p).oper[1]^.reg)
else*)
{ movl const1,[mem1]
movl [mem1],reg1
to:
movl const1,reg1
movl reg1,[mem1] }
if (taicpu(p).oper[0]^.typ = top_const) and
(taicpu(p).oper[1]^.typ = top_ref) and
(taicpu(hp1).oper[0]^.typ = top_ref) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(p).opsize = taicpu(hp1).opsize) and
RefsEqual(taicpu(hp1).oper[0]^.ref^,taicpu(p).oper[1]^.ref^) and
not(reginref(getsupreg(taicpu(hp1).oper[1]^.reg),taicpu(hp1).oper[0]^.ref^)) then
begin
allocregbetween(asml,taicpu(hp1).oper[1]^.reg,p,hp1,usedregs);
taicpu(hp1).loadReg(0,taicpu(hp1).oper[1]^.reg);
taicpu(hp1).loadRef(1,taicpu(p).oper[1]^.ref^);
taicpu(p).loadReg(1,taicpu(hp1).oper[0]^.reg);
end
end;
end;
A_MOVZX:
begin
{removes superfluous And's after movzx's}
if (taicpu(p).oper[1]^.typ = top_reg) and
GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_AND) and
(taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
case taicpu(p).opsize Of
S_BL, S_BW:
if (taicpu(hp1).oper[0]^.val = $ff) then
begin
asml.remove(hp1);
hp1.free;
end;
S_WL:
if (taicpu(hp1).oper[0]^.val = $ffff) then
begin
asml.remove(hp1);
hp1.free;
end;
end;
{changes some movzx constructs to faster synonims (all examples
are given with eax/ax, but are also valid for other registers)}
if (taicpu(p).oper[1]^.typ = top_reg) then
if (taicpu(p).oper[0]^.typ = top_reg) then
case taicpu(p).opsize of
S_BW:
begin
if (getsupreg(taicpu(p).oper[0]^.reg)=getsupreg(taicpu(p).oper[1]^.reg)) and
not(cs_opt_size in current_settings.optimizerswitches) then
{Change "movzbw %al, %ax" to "andw $0x0ffh, %ax"}
begin
taicpu(p).opcode := A_AND;
taicpu(p).changeopsize(S_W);
taicpu(p).loadConst(0,$ff);
end
else if GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_AND) and
(taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
{Change "movzbw %reg1, %reg2; andw $const, %reg2"
to "movw %reg1, reg2; andw $(const1 and $ff), %reg2"}
begin
taicpu(p).opcode := A_MOV;
taicpu(p).changeopsize(S_W);
setsubreg(taicpu(p).oper[0]^.reg,R_SUBW);
taicpu(hp1).loadConst(0,taicpu(hp1).oper[0]^.val and $ff);
end;
end;
S_BL:
begin
if (getsupreg(taicpu(p).oper[0]^.reg)=getsupreg(taicpu(p).oper[1]^.reg)) and
not(cs_opt_size in current_settings.optimizerswitches) then
{Change "movzbl %al, %eax" to "andl $0x0ffh, %eax"}
begin
taicpu(p).opcode := A_AND;
taicpu(p).changeopsize(S_L);
taicpu(p).loadConst(0,$ff)
end
else if GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_AND) and
(taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
{Change "movzbl %reg1, %reg2; andl $const, %reg2"
to "movl %reg1, reg2; andl $(const1 and $ff), %reg2"}
begin
taicpu(p).opcode := A_MOV;
taicpu(p).changeopsize(S_L);
setsubreg(taicpu(p).oper[0]^.reg,R_SUBWHOLE);
taicpu(hp1).loadConst(0,taicpu(hp1).oper[0]^.val and $ff);
end
end;
S_WL:
begin
if (getsupreg(taicpu(p).oper[0]^.reg)=getsupreg(taicpu(p).oper[1]^.reg)) and
not(cs_opt_size in current_settings.optimizerswitches) then
{Change "movzwl %ax, %eax" to "andl $0x0ffffh, %eax"}
begin
taicpu(p).opcode := A_AND;
taicpu(p).changeopsize(S_L);
taicpu(p).loadConst(0,$ffff);
end
else if GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_AND) and
(taicpu(hp1).oper[0]^.typ = top_const) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
{Change "movzwl %reg1, %reg2; andl $const, %reg2"
to "movl %reg1, reg2; andl $(const1 and $ffff), %reg2"}
begin
taicpu(p).opcode := A_MOV;
taicpu(p).changeopsize(S_L);
setsubreg(taicpu(p).oper[0]^.reg,R_SUBWHOLE);
taicpu(hp1).loadConst(0,taicpu(hp1).oper[0]^.val and $ffff);
end;
end;
end
else if (taicpu(p).oper[0]^.typ = top_ref) then
begin
if GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_AND) and
(taicpu(hp1).oper[0]^.typ = Top_Const) and
(taicpu(hp1).oper[1]^.typ = Top_Reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
begin
taicpu(p).opcode := A_MOV;
case taicpu(p).opsize Of
S_BL:
begin
taicpu(p).changeopsize(S_L);
taicpu(hp1).loadConst(0,taicpu(hp1).oper[0]^.val and $ff);
end;
S_WL:
begin
taicpu(p).changeopsize(S_L);
taicpu(hp1).loadConst(0,taicpu(hp1).oper[0]^.val and $ffff);
end;
S_BW:
begin
taicpu(p).changeopsize(S_W);
taicpu(hp1).loadConst(0,taicpu(hp1).oper[0]^.val and $ff);
end;
end;
end;
end;
end;
(* should not be generated anymore by the current code generator
A_POP:
begin
if target_info.system=system_i386_go32v2 then
begin
{ Transform a series of pop/pop/pop/push/push/push to }
{ 'movl x(%esp),%reg' for go32v2 (not for the rest, }
{ because I'm not sure whether they can cope with }
{ 'movl x(%esp),%reg' with x > 0, I believe we had }
{ such a problem when using esp as frame pointer (JM) }
if (taicpu(p).oper[0]^.typ = top_reg) then
begin
hp1 := p;
hp2 := p;
l := 0;
while getNextInstruction(hp1,hp1) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).opcode = A_POP) and
(taicpu(hp1).oper[0]^.typ = top_reg) do
begin
hp2 := hp1;
inc(l,4);
end;
getLastInstruction(p,hp3);
l1 := 0;
while (hp2 <> hp3) and
assigned(hp1) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).opcode = A_PUSH) and
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg.enum = taicpu(hp2).oper[0]^.reg.enum) do
begin
{ change it to a two op operation }
taicpu(hp2).oper[1]^.typ:=top_none;
taicpu(hp2).ops:=2;
taicpu(hp2).opcode := A_MOV;
taicpu(hp2).loadoper(1,taicpu(hp1).oper[0]^);
reference_reset(tmpref);
tmpRef.base.enum:=R_INTREGISTER;
tmpRef.base.number:=NR_STACK_POINTER_REG;
convert_register_to_enum(tmpref.base);
tmpRef.offset := l;
taicpu(hp2).loadRef(0,tmpRef);
hp4 := hp1;
getNextInstruction(hp1,hp1);
asml.remove(hp4);
hp4.free;
getLastInstruction(hp2,hp2);
dec(l,4);
inc(l1);
end;
if l <> -4 then
begin
inc(l,4);
for l1 := l1 downto 1 do
begin
getNextInstruction(hp2,hp2);
dec(taicpu(hp2).oper[0]^.ref^.offset,l);
end
end
end
end
else
begin
if (taicpu(p).oper[0]^.typ = top_reg) and
GetNextInstruction(p, hp1) and
(tai(hp1).typ=ait_instruction) and
(taicpu(hp1).opcode=A_PUSH) and
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg.enum=taicpu(p).oper[0]^.reg.enum) then
begin
{ change it to a two op operation }
taicpu(p).oper[1]^.typ:=top_none;
taicpu(p).ops:=2;
taicpu(p).opcode := A_MOV;
taicpu(p).loadoper(1,taicpu(p).oper[0]^);
reference_reset(tmpref);
TmpRef.base.enum := R_ESP;
taicpu(p).loadRef(0,TmpRef);
asml.remove(hp1);
hp1.free;
end;
end;
end;
*)
A_PUSH:
begin
if (taicpu(p).opsize = S_W) and
(taicpu(p).oper[0]^.typ = Top_Const) and
GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_PUSH) and
(taicpu(hp1).oper[0]^.typ = Top_Const) and
(taicpu(hp1).opsize = S_W) then
begin
taicpu(p).changeopsize(S_L);
taicpu(p).loadConst(0,taicpu(p).oper[0]^.val shl 16 + word(taicpu(hp1).oper[0]^.val));
asml.remove(hp1);
hp1.free;
end;
end;
A_SHL, A_SAL:
begin
if (taicpu(p).oper[0]^.typ = Top_Const) and
(taicpu(p).oper[1]^.typ = Top_Reg) and
(taicpu(p).opsize = S_L) and
(taicpu(p).oper[0]^.val <= 3) then
{Changes "shl const, %reg32; add const/reg, %reg32" to one lea statement}
begin
TmpBool1 := True; {should we check the next instruction?}
TmpBool2 := False; {have we found an add/sub which could be
integrated in the lea?}
reference_reset(tmpref);
TmpRef.index := taicpu(p).oper[1]^.reg;
TmpRef.scalefactor := 1 shl taicpu(p).oper[0]^.val;
while TmpBool1 and
GetNextInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
((((taicpu(hp1).opcode = A_ADD) or
(taicpu(hp1).opcode = A_SUB)) and
(taicpu(hp1).oper[1]^.typ = Top_Reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg)) or
(((taicpu(hp1).opcode = A_INC) or
(taicpu(hp1).opcode = A_DEC)) and
(taicpu(hp1).oper[0]^.typ = Top_Reg) and
(taicpu(hp1).oper[0]^.reg = taicpu(p).oper[1]^.reg))) and
(not GetNextInstruction(hp1,hp2) or
not instrReadsFlags(hp2)) Do
begin
TmpBool1 := False;
if (taicpu(hp1).oper[0]^.typ = Top_Const) then
begin
TmpBool1 := True;
TmpBool2 := True;
case taicpu(hp1).opcode of
A_ADD:
inc(TmpRef.offset, longint(taicpu(hp1).oper[0]^.val));
A_SUB:
dec(TmpRef.offset, longint(taicpu(hp1).oper[0]^.val));
end;
asml.remove(hp1);
hp1.free;
end
else
if (taicpu(hp1).oper[0]^.typ = Top_Reg) and
(((taicpu(hp1).opcode = A_ADD) and
(TmpRef.base = NR_NO)) or
(taicpu(hp1).opcode = A_INC) or
(taicpu(hp1).opcode = A_DEC)) then
begin
TmpBool1 := True;
TmpBool2 := True;
case taicpu(hp1).opcode of
A_ADD:
TmpRef.base := taicpu(hp1).oper[0]^.reg;
A_INC:
inc(TmpRef.offset);
A_DEC:
dec(TmpRef.offset);
end;
asml.remove(hp1);
hp1.free;
end;
end;
if TmpBool2 or
((current_settings.optimizecputype < cpu_Pentium2) and
(taicpu(p).oper[0]^.val <= 3) and
not(cs_opt_size in current_settings.optimizerswitches)) then
begin
if not(TmpBool2) and
(taicpu(p).oper[0]^.val = 1) then
begin
hp1 := taicpu.Op_reg_reg(A_ADD,taicpu(p).opsize,
taicpu(p).oper[1]^.reg, taicpu(p).oper[1]^.reg)
end
else
hp1 := taicpu.op_ref_reg(A_LEA, S_L, TmpRef,
taicpu(p).oper[1]^.reg);
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := hp1;
end;
end
else
if (current_settings.optimizecputype < cpu_Pentium2) and
(taicpu(p).oper[0]^.typ = top_const) and
(taicpu(p).oper[1]^.typ = top_reg) then
if (taicpu(p).oper[0]^.val = 1) then
{changes "shl $1, %reg" to "add %reg, %reg", which is the same on a 386,
but faster on a 486, and Tairable in both U and V pipes on the Pentium
(unlike shl, which is only Tairable in the U pipe)}
begin
hp1 := taicpu.Op_reg_reg(A_ADD,taicpu(p).opsize,
taicpu(p).oper[1]^.reg, taicpu(p).oper[1]^.reg);
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := hp1;
end
else if (taicpu(p).opsize = S_L) and
(taicpu(p).oper[0]^.val<= 3) then
{changes "shl $2, %reg" to "lea (,%reg,4), %reg"
"shl $3, %reg" to "lea (,%reg,8), %reg}
begin
reference_reset(tmpref);
TmpRef.index := taicpu(p).oper[1]^.reg;
TmpRef.scalefactor := 1 shl taicpu(p).oper[0]^.val;
hp1 := taicpu.Op_ref_reg(A_LEA,S_L,TmpRef, taicpu(p).oper[1]^.reg);
InsertLLItem(asml,p.previous, p.next, hp1);
p.free;
p := hp1;
end
end;
A_SETcc :
{ changes
setcc (funcres) setcc reg
movb (funcres), reg to leave/ret
leave/ret }
begin
if (taicpu(p).oper[0]^.typ = top_ref) and
GetNextInstruction(p, hp1) and
GetNextInstruction(hp1, hp2) and
(hp2.typ = ait_instruction) and
((taicpu(hp2).opcode = A_LEAVE) or
(taicpu(hp2).opcode = A_RET)) and
(taicpu(p).oper[0]^.ref^.base = current_procinfo.FramePointer) and
(taicpu(p).oper[0]^.ref^.index = NR_NO) and
not(assigned(current_procinfo.procdef.funcretsym) and
(taicpu(p).oper[0]^.ref^.offset < tabstractnormalvarsym(current_procinfo.procdef.funcretsym).localloc.reference.offset)) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).opcode = A_MOV) and
(taicpu(hp1).opsize = S_B) and
(taicpu(hp1).oper[0]^.typ = top_ref) and
RefsEqual(taicpu(hp1).oper[0]^.ref^, taicpu(p).oper[0]^.ref^) then
begin
taicpu(p).loadReg(0,taicpu(hp1).oper[1]^.reg);
asml.remove(hp1);
hp1.free;
end
end;
A_SUB:
{ * change "subl $2, %esp; pushw x" to "pushl x"}
{ * change "sub/add const1, reg" or "dec reg" followed by
"sub const2, reg" to one "sub ..., reg" }
begin
if (taicpu(p).oper[0]^.typ = top_const) and
(taicpu(p).oper[1]^.typ = top_reg) then
if (taicpu(p).oper[0]^.val = 2) and
(taicpu(p).oper[1]^.reg = NR_ESP) and
{ Don't do the sub/push optimization if the sub }
{ comes from setting up the stack frame (JM) }
(not getLastInstruction(p,hp1) or
(hp1.typ <> ait_instruction) or
(taicpu(hp1).opcode <> A_MOV) or
(taicpu(hp1).oper[0]^.typ <> top_reg) or
(taicpu(hp1).oper[0]^.reg <> NR_ESP) or
(taicpu(hp1).oper[1]^.typ <> top_reg) or
(taicpu(hp1).oper[1]^.reg <> NR_EBP)) then
begin
hp1 := tai(p.next);
while Assigned(hp1) and
(tai(hp1).typ in [ait_instruction]+SkipInstr) and
not regReadByInstruction(RS_ESP,hp1) and
not regModifiedByInstruction(RS_ESP,hp1) do
hp1 := tai(hp1.next);
if Assigned(hp1) and
(tai(hp1).typ = ait_instruction) and
(taicpu(hp1).opcode = A_PUSH) and
(taicpu(hp1).opsize = S_W) then
begin
taicpu(hp1).changeopsize(S_L);
if taicpu(hp1).oper[0]^.typ=top_reg then
setsubreg(taicpu(hp1).oper[0]^.reg,R_SUBWHOLE);
hp1 := tai(p.next);
asml.remove(p);
p.free;
p := hp1;
continue
end;
if DoSubAddOpt(p) then
continue;
end
else if DoSubAddOpt(p) then
continue
end;
end;
end; { if is_jmp }
end;
end;
updateUsedRegs(UsedRegs,p);
p:=tai(p.next);
end;
end;
function isFoldableArithOp(hp1: taicpu; reg: tregister): boolean;
begin
isFoldableArithOp := False;
case hp1.opcode of
A_ADD,A_SUB,A_OR,A_XOR,A_AND,A_SHL,A_SHR,A_SAR:
isFoldableArithOp :=
((taicpu(hp1).oper[0]^.typ = top_const) or
((taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg <> reg))) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = reg);
A_INC,A_DEC:
isFoldableArithOp :=
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[0]^.reg = reg);
end;
end;
procedure PeepHoleOptPass2(asml: TAsmList; BlockStart, BlockEnd: tai);
{$ifdef USECMOV}
function CanBeCMOV(p : tai) : boolean;
begin
CanBeCMOV:=assigned(p) and (p.typ=ait_instruction) and
(taicpu(p).opcode=A_MOV) and
(taicpu(p).opsize in [S_L,S_W]) and
((taicpu(p).oper[0]^.typ = top_reg)
{ we can't use cmov ref,reg because
ref could be nil and cmov still throws an exception
if ref=nil but the mov isn't done (FK)
or ((taicpu(p).oper[0]^.typ = top_ref) and
(taicpu(p).oper[0]^.ref^.refaddr = addr_no))
}
) and
(taicpu(p).oper[1]^.typ in [top_reg]);
end;
{$endif USECMOV}
var
p,hp1,hp2: tai;
{$ifdef USECMOV}
l : longint;
condition : tasmcond;
hp3: tai;
{$endif USECMOV}
UsedRegs, TmpUsedRegs: TRegSet;
begin
p := BlockStart;
UsedRegs := [];
while (p <> BlockEnd) Do
begin
UpdateUsedRegs(UsedRegs, tai(p.next));
case p.Typ Of
Ait_Instruction:
begin
case taicpu(p).opcode Of
{$ifdef USECMOV}
A_Jcc:
if (current_settings.cputype>=cpu_Pentium2) then
begin
{ check for
jCC xxx
<several movs>
xxx:
}
l:=0;
GetNextInstruction(p, hp1);
while assigned(hp1) and
CanBeCMOV(hp1) and
{ stop on labels }
not(hp1.typ=ait_label) do
begin
inc(l);
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
taicpu(hp1).opcode:=A_CMOVcc;
taicpu(hp1).condition:=condition;
GetNextInstruction(hp1,hp1);
until not(assigned(hp1)) or
not(CanBeCMOV(hp1));
{ 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
begin
{ check further for
jCC xxx
<several movs 1>
jmp yyy
xxx:
<several movs 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
CanBeCMOV(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
taicpu(hp1).opcode:=A_CMOVcc;
taicpu(hp1).condition:=condition;
GetNextInstruction(hp1,hp1);
until not(assigned(hp1)) or
not(CanBeCMOV(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).opcode:=A_CMOVcc;
taicpu(hp1).condition:=condition;
GetNextInstruction(hp1,hp1);
until not(assigned(hp1)) or
not(CanBeCMOV(hp1));
{
asml.remove(hp1.next)
hp1.next.free;
asml.remove(hp1);
hp1.free;
}
{ remove jCC }
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;
{$endif USECMOV}
A_FSTP,A_FISTP:
if doFpuLoadStoreOpt(asmL,p) then
continue;
A_IMUL:
begin
if (taicpu(p).ops >= 2) and
((taicpu(p).oper[0]^.typ = top_const) or
((taicpu(p).oper[0]^.typ = top_ref) and (taicpu(p).oper[0]^.ref^.refaddr=addr_full))) and
(taicpu(p).oper[1]^.typ = top_reg) and
((taicpu(p).ops = 2) or
((taicpu(p).oper[2]^.typ = top_reg) and
(taicpu(p).oper[2]^.reg = taicpu(p).oper[1]^.reg))) and
getLastInstruction(p,hp1) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).opcode = A_MOV) and
(taicpu(hp1).oper[0]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
(taicpu(hp1).oper[1]^.reg = taicpu(p).oper[1]^.reg) then
{ change "mov reg1,reg2; imul y,reg2" to "imul y,reg1,reg2" }
begin
taicpu(p).ops := 3;
taicpu(p).loadreg(1,taicpu(hp1).oper[0]^.reg);
taicpu(p).loadreg(2,taicpu(hp1).oper[1]^.reg);
asml.remove(hp1);
hp1.free;
end;
end;
A_MOV:
begin
if (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) or
(taicpu(hp1).opcode = A_MOVZX) or
(taicpu(hp1).opcode = A_MOVSX)) and
(taicpu(hp1).oper[0]^.typ = top_ref) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
((taicpu(hp1).oper[0]^.ref^.base = taicpu(p).oper[1]^.reg) or
(taicpu(hp1).oper[0]^.ref^.index = taicpu(p).oper[1]^.reg)) and
(getsupreg(taicpu(hp1).oper[1]^.reg) = getsupreg(taicpu(p).oper[1]^.reg)) then
{mov reg1, reg2
mov/zx/sx (reg2, ..), reg2 to mov/zx/sx (reg1, ..), reg2}
begin
if (taicpu(hp1).oper[0]^.ref^.base = taicpu(p).oper[1]^.reg) then
taicpu(hp1).oper[0]^.ref^.base := taicpu(p).oper[0]^.reg;
if (taicpu(hp1).oper[0]^.ref^.index = taicpu(p).oper[1]^.reg) then
taicpu(hp1).oper[0]^.ref^.index := taicpu(p).oper[0]^.reg;
asml.remove(p);
p.free;
p := hp1;
continue;
end
else if (taicpu(p).oper[0]^.typ = top_ref) and
GetNextInstruction(p,hp1) and
(hp1.typ = ait_instruction) and
IsFoldableArithOp(taicpu(hp1),taicpu(p).oper[1]^.reg) and
GetNextInstruction(hp1,hp2) and
(hp2.typ = ait_instruction) and
(taicpu(hp2).opcode = A_MOV) and
(taicpu(hp2).oper[0]^.typ = top_reg) and
(taicpu(hp2).oper[0]^.reg = taicpu(p).oper[1]^.reg) and
(taicpu(hp2).oper[1]^.typ = top_ref) then
begin
TmpUsedRegs := UsedRegs;
UpdateUsedRegs(TmpUsedRegs,tai(hp1.next));
if (RefsEqual(taicpu(hp2).oper[1]^.ref^, taicpu(p).oper[0]^.ref^) and
not(RegUsedAfterInstruction(taicpu(p).oper[1]^.reg,
hp2, TmpUsedRegs))) then
{ change mov (ref), reg }
{ add/sub/or/... reg2/$const, reg }
{ mov reg, (ref) }
{ # release reg }
{ to add/sub/or/... reg2/$const, (ref) }
begin
case taicpu(hp1).opcode of
A_INC,A_DEC:
taicpu(hp1).loadRef(0,taicpu(p).oper[0]^.ref^)
else
taicpu(hp1).loadRef(1,taicpu(p).oper[0]^.ref^);
end;
asml.remove(p);
asml.remove(hp2);
p.free;
hp2.free;
p := hp1
end;
end
end;
end;
end;
end;
p := tai(p.next)
end;
end;
procedure PostPeepHoleOpts(asml: TAsmList; BlockStart, BlockEnd: tai);
var
p,hp1,hp2: tai;
begin
p := BlockStart;
while (p <> BlockEnd) Do
begin
case p.Typ Of
Ait_Instruction:
begin
case taicpu(p).opcode Of
A_CALL:
if (current_settings.optimizecputype < cpu_Pentium2) and
GetNextInstruction(p, hp1) and
(hp1.typ = ait_instruction) and
(taicpu(hp1).opcode = A_JMP) and
((taicpu(hp1).oper[0]^.typ=top_ref) and (taicpu(hp1).oper[0]^.ref^.refaddr=addr_full)) then
begin
hp2 := taicpu.Op_sym(A_PUSH,S_L,taicpu(hp1).oper[0]^.ref^.symbol);
InsertLLItem(asml, p.previous, p, hp2);
taicpu(p).opcode := A_JMP;
taicpu(p).is_jmp := true;
asml.remove(hp1);
hp1.free;
end;
A_CMP:
begin
if (taicpu(p).oper[0]^.typ = top_const) and
(taicpu(p).oper[0]^.val = 0) and
(taicpu(p).oper[1]^.typ = top_reg) then
{change "cmp $0, %reg" to "test %reg, %reg"}
begin
taicpu(p).opcode := A_TEST;
taicpu(p).loadreg(0,taicpu(p).oper[1]^.reg);
continue;
end;
end;
(*
Optimization is not safe; xor clears the carry flag.
See test/tgadint64 in the test suite.
A_MOV:
if (taicpu(p).oper[0]^.typ = Top_Const) and
(taicpu(p).oper[0]^.val = 0) and
(taicpu(p).oper[1]^.typ = Top_Reg) then
{ change "mov $0, %reg" into "xor %reg, %reg" }
begin
taicpu(p).opcode := A_XOR;
taicpu(p).loadReg(0,taicpu(p).oper[1]^.reg);
end;
*)
A_MOVZX:
{ if register vars are on, it's possible there is code like }
{ "cmpl $3,%eax; movzbl 8(%ebp),%ebx; je .Lxxx" }
{ so we can't safely replace the movzx then with xor/mov, }
{ since that would change the flags (JM) }
if not(cs_opt_regvar in current_settings.optimizerswitches) then
begin
if (taicpu(p).oper[1]^.typ = top_reg) then
if (taicpu(p).oper[0]^.typ = top_reg)
then
case taicpu(p).opsize of
S_BL:
begin
if IsGP32Reg(getsupreg(taicpu(p).oper[1]^.reg)) and
not(cs_opt_size in current_settings.optimizerswitches) and
(current_settings.optimizecputype = cpu_Pentium) then
{Change "movzbl %reg1, %reg2" to
"xorl %reg2, %reg2; movb %reg1, %reg2" for Pentium and
PentiumMMX}
begin
hp1 := taicpu.op_reg_reg(A_XOR, S_L,
taicpu(p).oper[1]^.reg, taicpu(p).oper[1]^.reg);
InsertLLItem(asml,p.previous, p, hp1);
taicpu(p).opcode := A_MOV;
taicpu(p).changeopsize(S_B);
setsubreg(taicpu(p).oper[1]^.reg,R_SUBL);
end;
end;
end
else if (taicpu(p).oper[0]^.typ = top_ref) and
(taicpu(p).oper[0]^.ref^.base <> taicpu(p).oper[1]^.reg) and
(taicpu(p).oper[0]^.ref^.index <> taicpu(p).oper[1]^.reg) and
not(cs_opt_size in current_settings.optimizerswitches) and
IsGP32Reg(getsupreg(taicpu(p).oper[1]^.reg)) and
(current_settings.optimizecputype = cpu_Pentium) and
(taicpu(p).opsize = S_BL) then
{changes "movzbl mem, %reg" to "xorl %reg, %reg; movb mem, %reg8" for
Pentium and PentiumMMX}
begin
hp1 := taicpu.Op_reg_reg(A_XOR, S_L, taicpu(p).oper[1]^.reg,
taicpu(p).oper[1]^.reg);
taicpu(p).opcode := A_MOV;
taicpu(p).changeopsize(S_B);
setsubreg(taicpu(p).oper[1]^.reg,R_SUBL);
InsertLLItem(asml,p.previous, p, hp1);
end;
end;
A_TEST, A_OR:
{removes the line marked with (x) from the sequence
and/or/xor/add/sub/... $x, %y
test/or %y, %y (x)
j(n)z _Label
as the first instruction already adjusts the ZF}
begin
if OpsEqual(taicpu(p).oper[0]^,taicpu(p).oper[1]^) then
if GetLastInstruction(p, hp1) and
(tai(hp1).typ = ait_instruction) and
GetNextInstruction(hp1,hp2) and
(hp2.typ = ait_instruction) and
((taicpu(hp2).opcode = A_SETcc) or
(taicpu(hp2).opcode = A_Jcc)) then
case taicpu(hp1).opcode Of
A_ADD, A_SUB, A_OR, A_XOR, A_AND{, A_SHL, A_SHR}:
begin
if OpsEqual(taicpu(hp1).oper[1]^,taicpu(p).oper[0]^) and
{ does not work in case of overflow for G(E)/L(E)/C_O/C_NO }
{ and in case of carry for A(E)/B(E)/C/NC }
((taicpu(hp2).condition in [C_Z,C_NZ,C_E,C_NE]) or
((taicpu(hp1).opcode <> A_ADD) and
(taicpu(hp1).opcode <> A_SUB))) then
begin
hp1 := tai(p.next);
asml.remove(p);
p.free;
p := tai(hp1);
continue
end;
end;
A_DEC, A_INC, A_NEG:
begin
if OpsEqual(taicpu(hp1).oper[0]^,taicpu(p).oper[0]^) and
{ does not work in case of overflow for G(E)/L(E)/C_O/C_NO }
{ and in case of carry for A(E)/B(E)/C/NC }
(taicpu(hp2).condition in [C_Z,C_NZ,C_E,C_NE]) then
begin
case taicpu(hp1).opcode Of
A_DEC, A_INC:
{replace inc/dec with add/sub 1, because inc/dec doesn't set the carry flag}
begin
case taicpu(hp1).opcode Of
A_DEC: taicpu(hp1).opcode := A_SUB;
A_INC: taicpu(hp1).opcode := A_ADD;
end;
taicpu(hp1).loadoper(1,taicpu(hp1).oper[0]^);
taicpu(hp1).loadConst(0,1);
taicpu(hp1).ops:=2;
end
end;
hp1 := tai(p.next);
asml.remove(p);
p.free;
p := tai(hp1);
continue
end;
end
end
end;
end;
end;
end;
p := tai(p.next)
end;
end;
end.
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