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* x86: Improvements to JccMov2CMov to catch Jcc @Lbl; <movs>; JMP @Lbl

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This commit is contained in:
J. Gareth "Curious Kit" Moreton 2022-02-16 10:09:39 +00:00 committed by FPK
parent 82df643b74
commit 696b7b6f68
1 changed files with 36 additions and 8 deletions
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44
compiler/x86/aoptx86.pas
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@ -10335,6 +10335,15 @@ unit aoptx86;
jCC xxx
<several movs>
xxx:
Also spot:
Jcc xxx
<several movs>
jmp xxx
Change to:
<several cmovs with inverted condition>
jmp xxx
}
l:=0;
while assigned(hp1) and
@ -10349,7 +10358,12 @@ unit aoptx86;
if assigned(hp1) then
begin
TransferUsedRegs(TmpUsedRegs);
if FindLabel(tasmlabel(symbol),hp1) then
if (
MatchInstruction(hp1, A_JMP, []) and
(JumpTargetOp(taicpu(hp1))^.typ=top_ref) and
(JumpTargetOp(taicpu(hp1))^.ref^.symbol=symbol)
) or
FindLabel(tasmlabel(symbol),hp1) then
begin
if (l<=4) and (l>0) then
begin
@ -10385,6 +10399,14 @@ unit aoptx86;
hp2 := tai(hp2.Next);
Continue;
end;
ait_instruction:
begin
if taicpu(hp2).opcode<>A_JMP then
InternalError(2018062912);
{ This is the Jcc @Lbl; <several movs>; JMP @Lbl variant }
Break;
end
else
begin
{ Might be a comment or temporary allocation entry }
@ -10406,15 +10428,21 @@ unit aoptx86;
{ Remove the original jump }
RemoveInstruction(p); { Note, the choice to not use RemoveCurrentp is deliberate }
UpdateUsedRegs(tai(hp2.next));
GetNextInstruction(hp2, p); { Instruction after the label }
if hp2.typ=ait_instruction then
begin
p:=hp2;
Result:=True;
end
else
begin
UpdateUsedRegs(tai(hp2.next));
Result:=GetNextInstruction(hp2, p); { Instruction after the label }
{ Remove the label if this is its final reference }
if (tasmlabel(symbol).getrefs=0) then
StripLabelFast(hp1);
{ Remove the label if this is its final reference }
if (tasmlabel(symbol).getrefs=0) then
StripLabelFast(hp1);
end;
if Assigned(p) then
result:=true;
exit;
end;
end