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Removed incorrect logic in TEST optimisation

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This commit is contained in:
J. Gareth "Curious Kit" Moreton 2021-12-17 22:09:17 +00:00
parent 2b9ec05963
commit b4bd15a5c0
1 changed files with 1 additions and 52 deletions
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53
compiler/x86/aoptx86.pas
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@ -4489,58 +4489,7 @@ unit aoptx86;
Exit;
end;
if (taicpu(hp1).condition in [C_E, C_Z]) then
begin
{ Search for:
test $x,(reg/ref)
je @lbl1
test $y,(reg/ref)
je @lbl2
If (x or y) = x (i.e. all the bits of y appear in x), then je @lbl2 will never branch, so remove.
Also:
test $x,(reg/ref)
je @lbl1
test $y,(reg/ref)
jne @lbl2
If (x or y) = x (i.e. all the bits of y appear in x), then jne @lbl2 will always branch, so make unconditional
}
if ((FirstValue or SecondValue) = FirstValue) then
begin
if (taicpu(hp1_dist).condition in [C_E, C_Z]) then
begin
if IsJumpToLabel(taicpu(hp1_dist)) then
TAsmLabel(taicpu(hp1_dist).oper[0]^.ref^.symbol).DecRefs;
DebugMsg(SPeepholeOptimization + 'TEST/JE/TEST/JE merged', p);
RemoveInstruction(hp1_dist);
{ Only remove the second test if no jumps or other conditional instructions follow }
TransferUsedRegs(TmpUsedRegs);
UpdateUsedRegs(TmpUsedRegs, tai(p.Next));
UpdateUsedRegs(TmpUsedRegs, tai(hp1.Next));
if not RegUsedAfterInstruction(NR_DEFAULTFLAGS, p_dist, TmpUsedRegs) then
RemoveInstruction(p_dist);
Result := True;
Exit;
end
else if (taicpu(hp1_dist).condition in [C_NE, C_NZ]) then
begin
DebugMsg(SPeepholeOptimization + 'TEST/JE/TEST/JNE merged', p);
RemoveInstruction(p_dist);
MakeUnconditional(taicpu(hp1_dist));
RemoveDeadCodeAfterJump(hp1_dist);
Result := True;
Exit;
end;
end;
{ Drop out in any other situation }
end
else if (taicpu(hp1).condition in [C_NE, C_NZ]) and
if (taicpu(hp1).condition in [C_NE, C_NZ]) and
(taicpu(hp1_dist).condition in [C_NE, C_NZ]) and
{ If the first instruction is test %reg,%reg or test $-1,%reg,
then the second jump will never branch, so it can also be