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* Fixed general peephole optimization of conditional jumps after r30446. It has been broken, since r30446 had added some IsJumpToLabel() checks, which tests for unconditional jump, but the optimization code expects also conditional jumps.

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- Renamed IsJumpToLabel() to IsJumpToLabelUncond() to avoid confusions.
  - Added IsJumpToLabel() to check for any jump to a label.
  - Added comments.

git-svn-id: trunk@32114 -
This commit is contained in:
yury 2015-10-21 15:35:54 +00:00
parent 3d2919acae
commit 5771073e0b
1 changed files with 26 additions and 7 deletions
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33
compiler/aoptobj.pas
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@ -1174,7 +1174,9 @@ Unit AoptObj;
end;
{$pop}
function IsJumpToLabel(hp: taicpu): boolean;
{ Returns True if hp is an unconditional jump to a label }
function IsJumpToLabelUncond(hp: taicpu): boolean;
begin
{$if defined(avr)}
result:=(hp.opcode in aopt_uncondjmp) and
@ -1190,6 +1192,16 @@ Unit AoptObj;
end;
{ Returns True if hp is any jump to a label }
function IsJumpToLabel(hp: taicpu): boolean;
begin
result:=hp.is_jmp and
(hp.ops>0) and
(JumpTargetOp(hp)^.typ = top_ref) and
(JumpTargetOp(hp)^.ref^.symbol is TAsmLabel);
end;
procedure TAOptObj.RemoveDelaySlot(hp1:tai);
var
hp2: tai;
@ -1239,7 +1251,7 @@ Unit AoptObj;
(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 }
IsJumpToLabel(taicpu(p1))
IsJumpToLabelUncond(taicpu(p1))
{$if not defined(MIPS) and not defined(JVM)}
{ for MIPS, it isn't enough to check the condition; first operands must be same, too. }
or
@ -1254,7 +1266,7 @@ Unit AoptObj;
SkipLabels(p1,p2) and
(p2.typ = ait_instruction) and
(taicpu(p2).is_jmp) and
(IsJumpToLabel(taicpu(p2)) or
(IsJumpToLabelUncond(taicpu(p2)) or
(conditions_equal(taicpu(p2).condition,hp.condition))) and
SkipLabels(p1,p1))
{$endif not MIPS and not JVM}
@ -1354,7 +1366,7 @@ Unit AoptObj;
{ the following if-block removes all code between a jmp and the next label,
because it can never be executed
}
if IsJumpToLabel(taicpu(p)) then
if IsJumpToLabelUncond(taicpu(p)) then
begin
hp2:=p;
while GetNextInstruction(hp2, hp1) and
@ -1387,11 +1399,11 @@ Unit AoptObj;
end
else break;
end;
{ remove jumps to a label coming right after them }
if GetNextInstruction(p, hp1) then
begin
SkipEntryExitMarker(hp1,hp1);
if IsJumpToLabel(taicpu(p)) and
{ remove unconditional jumps to a label coming right after them }
if IsJumpToLabelUncond(taicpu(p)) and
FindLabel(tasmlabel(JumpTargetOp(taicpu(p))^.ref^.symbol), hp1) and
{ TODO: FIXME removing the first instruction fails}
(p<>blockstart) then
@ -1409,10 +1421,17 @@ Unit AoptObj;
end
else if assigned(hp1) then
begin
{ change the following jumps:
jmp<cond> lab_1 jmp<cond_inverted> lab_2
jmp lab_2 >>> <code>
lab_1: lab_2:
<code>
lab_2:
}
if hp1.typ = ait_label then
SkipLabels(hp1,hp1);
if (tai(hp1).typ=ait_instruction) and
IsJumpToLabel(taicpu(hp1)) and
IsJumpToLabelUncond(taicpu(hp1)) and
GetNextInstruction(hp1, hp2) and
IsJumpToLabel(taicpu(p)) and
FindLabel(tasmlabel(JumpTargetOp(taicpu(p))^.ref^.symbol), hp2) then