paweld/fpc
1
0
Fork 0
mirror of https://gitlab.com/freepascal.org/fpc/source.git synced 2025-08-13 10:39:39 +02:00
Code Issues Packages Projects Releases Wiki Activity

* x86: Fixed "Cmp1Jl2Cmp0Jle" and "CmpJe2NegJo" optimisations

Browse Source 
being applied incorrectly if another jump follows
This commit is contained in:
J. Gareth "Curious Kit" Moreton 2024-02-17 07:14:24 +00:00 committed by FPK
parent e406cbd9c8
commit ae927b0689
1 changed files with 78 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

144
compiler/x86/aoptx86.pas
View File

@ -7873,7 +7873,7 @@ unit aoptx86;
function TX86AsmOptimizer.OptPass1Cmp(var p: tai): boolean; function TX86AsmOptimizer.OptPass1Cmp(var p: tai): boolean;
var var
v: TCGInt; v: TCGInt;
hp1, hp2, p_dist, p_jump, hp1_dist, p_label, hp1_label: tai; true_hp1, hp1, hp2, p_dist, p_jump, hp1_dist, p_label, hp1_label: tai;
FirstMatch, TempBool: Boolean; FirstMatch, TempBool: Boolean;
NewReg: TRegister; NewReg: TRegister;
JumpLabel, JumpLabel_dist, JumpLabel_far: TAsmLabel; JumpLabel, JumpLabel_dist, JumpLabel_far: TAsmLabel;
@ -7884,6 +7884,8 @@ unit aoptx86;
if not GetNextInstruction(p, hp1) then if not GetNextInstruction(p, hp1) then
Exit; Exit;
true_hp1 := hp1;
{ Search for: { Search for:
cmp ###,### cmp ###,###
j(c1) @lbl1 j(c1) @lbl1
@ -8058,6 +8060,8 @@ unit aoptx86;
) then ) then
begin begin
DebugMsg(SPeepholeOptimization + 'CMP/Jcc/CMP; removed superfluous CMP', hp2); DebugMsg(SPeepholeOptimization + 'CMP/Jcc/CMP; removed superfluous CMP', hp2);
TransferUsedRegs(TmpUsedRegs);
AllocRegBetween(NR_DEFAULTFLAGS, p, hp2, TmpUsedRegs);
RemoveInstruction(hp2); RemoveInstruction(hp2);
Result := True; Result := True;
{ Continue the while loop in case "Jcc/CMP" follows the second CMP that was just removed } { Continue the while loop in case "Jcc/CMP" follows the second CMP that was just removed }
@ -8075,7 +8079,7 @@ unit aoptx86;
if ( if (
{ Don't call GetNextInstruction again if we already have it } { Don't call GetNextInstruction again if we already have it }
(hp1 = p_jump) or (true_hp1 = p_jump) or
GetNextInstruction(p, hp1) GetNextInstruction(p, hp1)
) and ) and
MatchInstruction(hp1, A_Jcc, []) and MatchInstruction(hp1, A_Jcc, []) and
@ -8210,12 +8214,12 @@ unit aoptx86;
end; end;
end; end;
if taicpu(p).oper[0]^.typ = top_const then if (taicpu(p).oper[0]^.typ = top_const) and
MatchInstruction(hp1,A_Jcc,A_SETcc,[]) then
begin begin
if (taicpu(p).oper[0]^.val = 0) and if (taicpu(p).oper[0]^.val = 0) and
(taicpu(p).oper[1]^.typ = top_reg) and (taicpu(p).oper[1]^.typ = top_reg) then
MatchInstruction(hp1,A_Jcc,A_SETcc,[]) then
begin begin
hp2 := p; hp2 := p;
FirstMatch := True; FirstMatch := True;
@ -8232,6 +8236,7 @@ unit aoptx86;
MatchInstruction(hp1,A_Jcc,A_SETcc,[]) MatchInstruction(hp1,A_Jcc,A_SETcc,[])
) do ) do
begin begin
Prefetch(hp1.Next);
FirstMatch := False; FirstMatch := False;
case taicpu(hp1).condition of case taicpu(hp1).condition of
C_B, C_C, C_NAE, C_O: C_B, C_C, C_NAE, C_O:
@ -8316,72 +8321,79 @@ unit aoptx86;
Result := True; Result := True;
Exit; Exit;
end end
else if (taicpu(p).oper[0]^.val = 1) and else
MatchInstruction(hp1,A_Jcc,A_SETcc,[]) and
(taicpu(hp1).condition in [C_L, C_NL, C_NGE, C_GE]) then
begin begin
{ Convert; To: TransferUsedRegs(TmpUsedRegs);
cmp $1,r/m cmp $0,r/m UpdateUsedRegs(TmpUsedRegs, tai(p.Next));
jl @lbl jle @lbl
(Also do inverted conditions)
}
DebugMsg(SPeepholeOptimization + 'Cmp1Jl2Cmp0Jle', p);
taicpu(p).oper[0]^.val := 0;
if taicpu(hp1).condition in [C_L, C_NGE] then
taicpu(hp1).condition := C_LE
else
taicpu(hp1).condition := C_NLE;
{ If the instruction is now "cmp $0,%reg", convert it to a if not RegUsedAfterInstruction(NR_DEFAULTFLAGS, hp1, TmpUsedRegs) then
TEST (and effectively do the work of the "cmp $0,%reg" in
the block above)
}
if (taicpu(p).oper[1]^.typ = top_reg) then
begin begin
taicpu(p).opcode := A_TEST; if (taicpu(p).oper[0]^.val = 1) and
taicpu(p).loadreg(0,taicpu(p).oper[1]^.reg); (taicpu(hp1).condition in [C_L, C_NL, C_NGE, C_GE]) then
end;
Result := True;
Exit;
end
else if (taicpu(p).oper[1]^.typ = top_reg)
{$ifdef x86_64}
and (taicpu(p).opsize <> S_Q) { S_Q will never happen: cmp with 64 bit constants is not possible }
{$endif x86_64}
then
begin
{ cmp register,$8000 neg register
je target --> jo target
.... only if register is deallocated before jump.}
case Taicpu(p).opsize of
S_B: v:=$80;
S_W: v:=$8000;
S_L: v:=qword($80000000);
else
internalerror(2013112905);
end;
if (taicpu(p).oper[0]^.val=v) and
MatchInstruction(hp1,A_Jcc,A_SETcc,[]) and
(Taicpu(hp1).condition in [C_E,C_NE]) then
begin
TransferUsedRegs(TmpUsedRegs);
UpdateUsedRegs(TmpUsedRegs,tai(p.next));
if not(RegInUsedRegs(Taicpu(p).oper[1]^.reg, TmpUsedRegs)) then
begin begin
DebugMsg(SPeepholeOptimization + 'CmpJe2NegJo done',p); { Convert; To:
Taicpu(p).opcode:=A_NEG; cmp $1,r/m cmp $0,r/m
Taicpu(p).loadoper(0,Taicpu(p).oper[1]^); jl @lbl jle @lbl
Taicpu(p).clearop(1); (Also do inverted conditions)
Taicpu(p).ops:=1; }
if Taicpu(hp1).condition=C_E then DebugMsg(SPeepholeOptimization + 'Cmp1Jl2Cmp0Jle', p);
Taicpu(hp1).condition:=C_O taicpu(p).oper[0]^.val := 0;
if taicpu(hp1).condition in [C_L, C_NGE] then
taicpu(hp1).condition := C_LE
else else
Taicpu(hp1).condition:=C_NO; taicpu(hp1).condition := C_NLE;
Result:=true;
exit; { If the instruction is now "cmp $0,%reg", convert it to a
TEST (and effectively do the work of the "cmp $0,%reg" in
the block above)
}
if (taicpu(p).oper[1]^.typ = top_reg) then
begin
taicpu(p).opcode := A_TEST;
taicpu(p).loadreg(0,taicpu(p).oper[1]^.reg);
end;
Result := True;
Exit;
end
else if (taicpu(p).oper[1]^.typ = top_reg)
{$ifdef x86_64}
and (taicpu(p).opsize <> S_Q) { S_Q will never happen: cmp with 64 bit constants is not possible }
{$endif x86_64}
then
begin
{ cmp register,$8000 neg register
je target --> jo target
.... only if register is deallocated before jump.}
case Taicpu(p).opsize of
S_B: v:=$80;
S_W: v:=$8000;
S_L: v:=qword($80000000);
else
internalerror(2013112905);
end;
if (taicpu(p).oper[0]^.val=v) and
(Taicpu(hp1).condition in [C_E,C_NE]) then
begin
TransferUsedRegs(TmpUsedRegs);
UpdateUsedRegs(TmpUsedRegs,tai(p.next));
if not(RegInUsedRegs(Taicpu(p).oper[1]^.reg, TmpUsedRegs)) then
begin
DebugMsg(SPeepholeOptimization + 'CmpJe2NegJo done',p);
Taicpu(p).opcode:=A_NEG;
Taicpu(p).loadoper(0,Taicpu(p).oper[1]^);
Taicpu(p).clearop(1);
Taicpu(p).ops:=1;
if Taicpu(hp1).condition=C_E then
Taicpu(hp1).condition:=C_O
else
Taicpu(hp1).condition:=C_NO;
Result:=true;
exit;
end;
end;
end; end;
end; end;
end; end;