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* patch by J. Gareth Moreton, issue #36271, part 2: x86 specific rework of the jump optimizer
git-svn-id: trunk@43440 -
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florian
parent
47dcc5b05b
commit
2d295a3816
@ -3318,49 +3318,44 @@ unit aoptx86;
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end;
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end;
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if ((hp1.typ = ait_label) and (symbol = tai_label(hp1).labsym))
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or ((hp1.typ = ait_align) and GetNextInstruction(hp1, hp2) and (hp2.typ = ait_label) and (symbol = tai_label(hp2).labsym)) then
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{ Detect the following:
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jmp<cond> @Lbl1
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jmp @Lbl2
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...
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@Lbl1:
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ret
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Change to:
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jmp<inv_cond> @Lbl2
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ret
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}
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if MatchInstruction(hp1, A_JMP, []) then
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begin
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{ If Jcc is immediately followed by the label that it's supposed to jump to, remove it }
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DebugMsg(SPeepholeOptimization + 'Removed conditional jump whose destination was immediately after it', p);
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UpdateUsedRegs(hp1);
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TAsmLabel(symbol).decrefs;
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{ if the label refs. reach zero, remove any alignment before the label }
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if (hp1.typ = ait_align) then
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hp2 := getlabelwithsym(TAsmLabel(symbol));
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if Assigned(hp2) and SkipLabels(hp2,hp2) and
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MatchInstruction(hp2,A_RET,[S_NO]) then
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begin
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UpdateUsedRegs(hp2);
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if (TAsmLabel(symbol).getrefs = 0) then
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begin
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asml.Remove(hp1);
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hp1.Free;
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taicpu(p).condition := inverse_cond(taicpu(p).condition);
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{ Change label address to that of the unconditional jump }
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taicpu(p).loadoper(0, taicpu(hp1).oper[0]^);
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TAsmLabel(symbol).DecRefs;
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taicpu(hp1).opcode := A_RET;
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taicpu(hp1).is_jmp := false;
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taicpu(hp1).ops := taicpu(hp2).ops;
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case taicpu(hp2).ops of
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0:
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taicpu(hp1).clearop(0);
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1:
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taicpu(hp1).loadconst(0,taicpu(hp2).oper[0]^.val);
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else
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internalerror(2016041302);
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end;
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hp1 := hp2; { Set hp1 to the label }
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end;
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asml.remove(p);
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p.free;
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if (TAsmLabel(symbol).getrefs = 0) then
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begin
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GetNextInstruction(hp1, p); { Instruction following the label }
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asml.remove(hp1);
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hp1.free;
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UpdateUsedRegs(p);
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Result := True;
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end
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else
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begin
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{ We don't need to set the result to True because we know hp1
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is a label and won't trigger any optimisation routines. [Kit] }
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p := hp1;
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end;
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Exit;
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end;
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end;
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{$ifndef i8086}
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if CPUX86_HAS_CMOV in cpu_capabilities[current_settings.cputype] then
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begin
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@ -3415,24 +3410,29 @@ unit aoptx86;
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else
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hp2 := hp1;
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if not Assigned(hp2) then
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InternalError(2018062910);
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{ Remember what the first hp2 is in case there's multiple aligns and labels to get rid of }
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hp3 := hp2;
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repeat
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if not Assigned(hp2) then
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InternalError(2018062910);
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if (hp2.typ <> ait_label) then
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begin
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{ There's something other than CMOVs here. Move the original jump
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to right before this point, then break out.
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Originally this was part of the above internal error, but it got
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triggered on the bootstrapping process sometimes. Investigate. [Kit] }
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asml.remove(p);
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asml.insertbefore(p, hp2);
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DebugMsg('Jcc/CMOVcc drop-out', p);
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UpdateUsedRegs(p);
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Result := True;
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Exit;
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case hp2.typ of
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ait_label:
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{ What we expected - break out of the loop (it won't be a dead label at the top of
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a cluster because that was optimised at an earlier stage) }
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Break;
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ait_align:
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{ Go to the next entry until a label is found (may be multiple aligns before it) }
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begin
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hp2 := tai(hp2.Next);
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Continue;
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end;
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else
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InternalError(2018062911);
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end;
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until False;
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{ Now we can safely decrement the reference count }
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tasmlabel(symbol).decrefs;
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@ -3444,10 +3444,7 @@ unit aoptx86;
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{ Remove the label if this is its final reference }
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if (tasmlabel(symbol).getrefs=0) then
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begin
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asml.remove(hp2);
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hp2.free;
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end;
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StripLabelFast(hp3);
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if Assigned(p) then
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begin
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@ -3541,16 +3538,7 @@ unit aoptx86;
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hp1.free;
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{ Remove label xxx (it will have a ref of zero due to the initial check }
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if (hp4.typ = ait_align) then
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begin
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{ Account for alignment as well }
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GetNextInstruction(hp4, hp1);
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asml.remove(hp1);
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hp1.free;
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end;
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asml.remove(hp4);
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hp4.free;
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StripLabelFast(hp4);
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{ Now we can safely decrement it }
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tasmlabel(symbol).decrefs;
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@ -3561,23 +3549,12 @@ unit aoptx86;
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asml.remove(hp2);
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hp2.free;
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{ Remove label yyy (and the optional alignment) if its reference will fall to zero }
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if tasmlabel(symbol).getrefs = 1 then
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begin
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if (hp3.typ = ait_align) then
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begin
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{ Account for alignment as well }
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GetNextInstruction(hp3, hp1);
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asml.remove(hp1);
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hp1.free;
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end;
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{ As before, now we can safely decrement it }
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tasmlabel(symbol).decrefs;
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asml.remove(hp3);
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hp3.free;
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{ As before, now we can safely decrement it }
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tasmlabel(symbol).decrefs;
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end;
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{ Remove label yyy (and the optional alignment) if its reference falls to zero }
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if tasmlabel(symbol).getrefs = 0 then
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StripLabelFast(hp3);
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if Assigned(p) then
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begin
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