paweld/fpc
1
0
Fork 0
mirror of https://gitlab.com/freepascal.org/fpc/source.git synced 2025-09-01 23:10:24 +02:00
Code Issues Packages Projects Releases Wiki Activity

* x86: Fixed movzwl/movzbl bug in OptPass2Movx (resolves i40003)

Browse Source
This commit is contained in:
J. Gareth "Curious Kit" Moreton 2022-11-27 03:58:45 +00:00 committed by FPK
parent 348fbfde9d
commit cc27576339
1 changed files with 58 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

82
compiler/x86/aoptx86.pas
View File

@ -9652,20 +9652,26 @@ unit aoptx86;
{ Convert the output MOVZX to a MOV }
if SuperRegistersEqual(taicpu(hp1).oper[1]^.reg, ThisReg) then
begin
{ Or remove it completely! }
DebugMsg(SPeepholeOptimization + 'Movzx2Nop 2', hp1);
{ Be careful; if p = hp1 and p was also removed, p
will become a dangling pointer }
if p = hp1 then
{ Make sure the zero-expansion covers at least the minimum size (fixes i40003) }
if (MinSize = S_B) or
(not ShiftDownOverflow and (TryShiftDown = S_B)) or
((MinSize = S_W) and (taicpu(hp1).opsize = S_WL)) then
begin
RemoveCurrentp(p); { p = hp1 and will then become the next instruction }
p_removed := True;
end
else
RemoveInstruction(hp1);
{ Remove it completely! }
DebugMsg(SPeepholeOptimization + 'Movzx2Nop 2', hp1);
hp1_removed := True;
{ Be careful; if p = hp1 and p was also removed, p
will become a dangling pointer }
if p = hp1 then
begin
RemoveCurrentp(p); { p = hp1 and will then become the next instruction }
p_removed := True;
end
else
RemoveInstruction(hp1);
hp1_removed := True;
end;
end
else
begin
@ -10583,21 +10589,49 @@ unit aoptx86;
if UpperUnsignedOverflow or (taicpu(hp1).oper[0]^.typ <> top_reg) then
Break;
if not SuperRegistersEqual(taicpu(hp1).oper[0]^.reg, ThisReg) then
if (InstrMax = -1) then
begin
if (InstrMax = -1) and
{ Will return false if the second parameter isn't ThisReg
(can happen on -O2 and under) }
Reg1WriteOverwritesReg2Entirely(taicpu(hp1).oper[1]^.reg, ThisReg) then
if SuperRegistersEqual(taicpu(hp1).oper[0]^.reg, ThisReg) then
begin
{ The two MOVZX instructions are adjacent, so remove the first one }
DebugMsg(SPeepholeOptimization + 'Movzx2Nop 5', p);
RemoveCurrentP(p);
Result := True;
Exit;
end;
{ Optimise around i40003 }
if SuperRegistersEqual(taicpu(hp1).oper[1]^.reg, ThisReg) and
(taicpu(p).opsize = S_WL) and (taicpu(hp1).opsize = S_BL)
{$ifndef x86_64}
and (
(taicpu(p).oper[0]^.typ <> top_reg) or
{ Cannot encode byte-sized ESI, EDI, EBP or ESP under i386 }
(GetSupReg(taicpu(p).oper[0]^.reg) in [RS_EAX, RS_EBX, RS_ECX, RS_EDX])
)
{$endif not x86_64}
then
begin
if (taicpu(p).oper[0]^.typ = top_reg) then
setsubreg(taicpu(p).oper[0]^.reg, R_SUBL);
Break;
DebugMsg(SPeepholeOptimization + 'movzwl2movzbl 1', p);
taicpu(p).opsize := S_BL;
DebugMsg(SPeepholeOptimization + 'Movzx2Nop 2a', hp1);
RemoveInstruction(hp1);
Result := True;
Exit;
end;
end
else
begin
{ Will return false if the second parameter isn't ThisReg
(can happen on -O2 and under) }
if Reg1WriteOverwritesReg2Entirely(taicpu(hp1).oper[1]^.reg, ThisReg) then
begin
{ The two MOVZX instructions are adjacent, so remove the first one }
DebugMsg(SPeepholeOptimization + 'Movzx2Nop 5', p);
RemoveCurrentP(p);
Result := True;
Exit;
end;
Break;
end;
end;
Result := CompressInstructions;