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Overflow bug fixes to MovZX/SX optimisations when CMP instructions are encountered.
This commit is contained in:
J. Gareth "Curious Kit" Moreton
parent
6dbe71cd30
commit
b4c8c1da12
@ -7968,7 +7968,7 @@ unit aoptx86;
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function CheckOverflowConditions: Boolean;
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begin
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Result := True;
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if (TestValSignedMax > SignedUpperLimit) or (TestValSignedMax < SignedUpperLimitBottom) then
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if (TestValSignedMax > SignedUpperLimit) then
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UpperSignedOverflow := True;
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if (TestValSignedMax > SignedLowerLimit) or (TestValSignedMax < SignedLowerLimitBottom) then
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@ -7978,7 +7978,7 @@ unit aoptx86;
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LowerUnsignedOverflow := True;
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if (TestValMin > UpperLimit) or (TestValMax > UpperLimit) or (TestValSignedMax > UpperLimit) or
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(TestValMin < SignedUpperLimitBottom) or (TestValMax < SignedUpperLimitBottom) or (TestValSignedMax > SignedUpperLimit) then
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(TestValMin < SignedUpperLimitBottom) or (TestValMax < SignedUpperLimitBottom) or (TestValSignedMax < SignedUpperLimitBottom) then
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begin
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{ Absolute overflow }
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Result := False;
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@ -8270,12 +8270,15 @@ unit aoptx86;
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smallest allowed signed value for the minimum size (e.g.
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-128 for 8-bit) }
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not (
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((taicpu(hp1).oper[0]^.val and UpperLimit) = taicpu(hp1).oper[0]^.val) or
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((taicpu(hp1).oper[0]^.val and LowerLimit) = taicpu(hp1).oper[0]^.val) or
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{ Is it in the negative range? }
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(taicpu(hp1).oper[0]^.val >= SignedLowerLimitBottom)
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(
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(taicpu(hp1).oper[0]^.val < 0) and
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(taicpu(hp1).oper[0]^.val >= SignedLowerLimitBottom)
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)
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) then
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Break;
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(*
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{ ANDing can't increase the value past the limit or decrease
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it below 0, so we can skip the checks, plus the test value
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won't change afterwards }
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@ -8285,17 +8288,6 @@ unit aoptx86;
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(taicpu(hp1).oper[0]^.val <> 0) then
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begin
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WorkingValue := taicpu(hp1).oper[0]^.val;
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case MinSize of
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S_B:
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if (WorkingValue and $ff)<>WorkingValue then
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break;
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S_W:
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if (WorkingValue and $ffff)<>WorkingValue then
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break;
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else
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;
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end;
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TestValMin := TestValMin - WorkingValue;
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TestValMax := TestValMax - WorkingValue;
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@ -8309,18 +8301,36 @@ unit aoptx86;
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TestValMin := TestValMin + WorkingValue;
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TestValMax := TestValMax + WorkingValue;
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TestValSignedMax := TestValSignedMax + WorkingValue;
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end;
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end; *)
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{ Check to see if the active register is used afterwards }
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TransferUsedRegs(TmpUsedRegs);
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IncludeRegInUsedRegs(ThisReg, TmpUsedRegs);
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if not RegUsedAfterInstruction(ThisReg, hp1, TmpUsedRegs) then
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begin
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case MinSize of
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{ Make sure the comparison or any previous instructions
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hasn't pushed the test values outside of the range of
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MinSize }
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if LowerUnsignedOverflow and not UpperUnsignedOverflow then
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begin
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{ Exceeded lower bound but not upper bound }
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TargetSize := MaxSize;
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end
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else if not LowerSignedOverflow or not LowerUnsignedOverflow then
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begin
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{ Size didn't exceed lower bound }
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TargetSize := MinSize;
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end
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else
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Break;
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case TargetSize of
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S_B:
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TargetSubReg := R_SUBL;
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S_W:
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TargetSubReg := R_SUBW;
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S_L:
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TargetSubReg := R_SUBD;
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else
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InternalError(2021051002);
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end;
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@ -8427,19 +8437,14 @@ unit aoptx86;
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end
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else
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begin
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TestValMin := TestValMin + taicpu(hp1).oper[0]^.val;
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TestValMax := TestValMax + taicpu(hp1).oper[0]^.val;
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TestValSignedMax := TestValSignedMax + taicpu(hp1).oper[0]^.val;
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WorkingValue := taicpu(hp1).oper[0]^.val;
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TestValMin := TestValMin + WorkingValue;
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TestValMax := TestValMax + WorkingValue;
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TestValSignedMax := TestValSignedMax + WorkingValue;
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end;
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end;
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A_SUB:
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begin
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if OrXorUsed then
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{ Too high a risk of non-linear behaviour that breaks DFA here }
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Break
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else
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BitwiseOnly := False;
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if (taicpu(hp1).oper[0]^.typ = top_reg) then
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begin
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TestValMin := 0;
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@ -8448,9 +8453,16 @@ unit aoptx86;
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end
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else
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begin
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TestValMin := TestValMin - taicpu(hp1).oper[0]^.val;
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TestValMax := TestValMax - taicpu(hp1).oper[0]^.val;
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TestValSignedMax := TestValSignedMax - taicpu(hp1).oper[0]^.val;
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if OrXorUsed then
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{ Too high a risk of non-linear behaviour that breaks DFA here }
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Break
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else
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BitwiseOnly := False;
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WorkingValue := taicpu(hp1).oper[0]^.val;
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TestValMin := TestValMin - WorkingValue;
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TestValMax := TestValMax - WorkingValue;
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TestValSignedMax := TestValSignedMax - WorkingValue;
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end;
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end;
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A_AND:
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@ -8485,9 +8497,10 @@ unit aoptx86;
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InternalError(2020112320);
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end;
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TestValMin := TestValMin and taicpu(hp1).oper[0]^.val;
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TestValMax := TestValMax and taicpu(hp1).oper[0]^.val;
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TestValSignedMax := TestValSignedMax and taicpu(hp1).oper[0]^.val;
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WorkingValue := taicpu(hp1).oper[0]^.val;
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TestValMin := TestValMin and WorkingValue;
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TestValMax := TestValMax and WorkingValue;
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TestValSignedMax := TestValSignedMax and WorkingValue;
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end;
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A_OR:
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begin
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@ -8496,33 +8509,49 @@ unit aoptx86;
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OrXorUsed := True;
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TestValMin := TestValMin or taicpu(hp1).oper[0]^.val;
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TestValMax := TestValMax or taicpu(hp1).oper[0]^.val;
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TestValSignedMax := TestValSignedMax or taicpu(hp1).oper[0]^.val;
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WorkingValue := taicpu(hp1).oper[0]^.val;
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TestValMin := TestValMin or WorkingValue;
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TestValMax := TestValMax or WorkingValue;
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TestValSignedMax := TestValSignedMax or WorkingValue;
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end;
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A_XOR:
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begin
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if not BitwiseOnly then
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Break;
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if (taicpu(hp1).oper[0]^.typ = top_reg) then
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begin
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TestValMin := 0;
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TestValMax := 0;
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TestValSignedMax := 0;
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end
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else
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begin
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if not BitwiseOnly then
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Break;
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OrXorUsed := True;
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OrXorUsed := True;
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TestValMin := TestValMin xor taicpu(hp1).oper[0]^.val;
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TestValMax := TestValMax xor taicpu(hp1).oper[0]^.val;
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TestValSignedMax := TestValSignedMax xor taicpu(hp1).oper[0]^.val;
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WorkingValue := taicpu(hp1).oper[0]^.val;
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TestValMin := TestValMin xor WorkingValue;
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TestValMax := TestValMax xor WorkingValue;
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TestValSignedMax := TestValSignedMax xor WorkingValue;
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end;
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end;
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A_SHL:
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begin
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TestValMin := TestValMin shl taicpu(hp1).oper[0]^.val;
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TestValMax := TestValMax shl taicpu(hp1).oper[0]^.val;
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TestValSignedMax := TestValSignedMax shl taicpu(hp1).oper[0]^.val;
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BitwiseOnly := False;
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WorkingValue := taicpu(hp1).oper[0]^.val;
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TestValMin := TestValMin shl WorkingValue;
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TestValMax := TestValMax shl WorkingValue;
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TestValSignedMax := TestValSignedMax shl WorkingValue;
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end;
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A_SHR,
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{ The first instruction was MOVZX, so the value won't be negative }
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A_SAR:
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begin
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{ we might be able to go smaller if SHR appears first }
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if InstrMax = -1 then
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if InstrMax <> -1 then
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BitwiseOnly := False
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else
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{ we might be able to go smaller if SHR appears first }
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case MinSize of
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S_B:
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;
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@ -8553,17 +8582,18 @@ unit aoptx86;
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InternalError(2020112321);
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end;
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WorkingValue := taicpu(hp1).oper[0]^.val;
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if taicpu(hp1).opcode = A_SAR then
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begin
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TestValMin := SarInt64(TestValMin, taicpu(hp1).oper[0]^.val);
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TestValMax := SarInt64(TestValMax, taicpu(hp1).oper[0]^.val);
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TestValSignedMax := SarInt64(TestValSignedMax, taicpu(hp1).oper[0]^.val);
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TestValMin := SarInt64(TestValMin, WorkingValue);
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TestValMax := SarInt64(TestValMax, WorkingValue);
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TestValSignedMax := SarInt64(TestValSignedMax, WorkingValue);
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end
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else
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begin
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TestValMin := TestValMin shr taicpu(hp1).oper[0]^.val;
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TestValMax := TestValMax shr taicpu(hp1).oper[0]^.val;
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TestValSignedMax := TestValSignedMax shr taicpu(hp1).oper[0]^.val;
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TestValMin := TestValMin shr WorkingValue;
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TestValMax := TestValMax shr WorkingValue;
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TestValSignedMax := TestValSignedMax shr WorkingValue;
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end;
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end;
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else
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