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+ patch by J. Gareth Moreton: AddMov2LeaAdd and AddMov2Lea optimizations, resolves #38579

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git-svn-id: trunk@48989 -
This commit is contained in:
florian 2021-03-15 21:12:02 +00:00
parent 6a92798603
commit 612f063795
1 changed files with 95 additions and 37 deletions
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132
compiler/x86/aoptx86.pas
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@ -7025,7 +7025,7 @@ unit aoptx86;
function TX86AsmOptimizer.OptPass2ADD(var p : tai) : boolean;
var
hp1: tai;
hp1: tai; NewRef: TReference;
{ This entire nested function is used in an if-statement below, but we
want to avoid all the used reg transfers and GetNextInstruction calls
@ -7045,45 +7045,103 @@ unit aoptx86;
begin
Result := False;
if not GetNextInstruction(p, hp1) or (hp1.typ <> ait_instruction) then
Exit;
{ Change:
add %reg2,%reg1
mov/s/z #(%reg1),%reg1 (%reg1 superregisters must be the same)
To:
mov/s/z #(%reg1,%reg2),%reg1
}
if (taicpu(p).opsize in [S_L{$ifdef x86_64}, S_Q{$endif}]) and
MatchOpType(taicpu(p), top_reg, top_reg) and
GetNextInstruction(p, hp1) and
MatchInstruction(hp1, [A_MOV, A_MOVZX, A_MOVSX{$ifdef x86_64}, A_MOVSXD{$endif}], []) and
MatchOpType(taicpu(hp1), top_ref, top_reg) and
(taicpu(hp1).oper[0]^.ref^.scalefactor <= 1) and
(
(
(taicpu(hp1).oper[0]^.ref^.base = taicpu(p).oper[1]^.reg) and
(taicpu(hp1).oper[0]^.ref^.index = NR_NO)
) or (
(taicpu(hp1).oper[0]^.ref^.index = taicpu(p).oper[1]^.reg) and
(taicpu(hp1).oper[0]^.ref^.base = NR_NO)
)
) and (
Reg1WriteOverwritesReg2Entirely(taicpu(p).oper[1]^.reg, taicpu(hp1).oper[1]^.reg) or
(
{ If the super registers ARE equal, then this MOV/S/Z does a partial write }
not SuperRegistersEqual(taicpu(p).oper[1]^.reg, taicpu(hp1).oper[1]^.reg) and
MemRegisterNotUsedLater
)
) then
if (taicpu(p).opsize in [S_L{$ifdef x86_64}, S_Q{$endif}]) then
begin
taicpu(hp1).oper[0]^.ref^.base := taicpu(p).oper[1]^.reg;
taicpu(hp1).oper[0]^.ref^.index := taicpu(p).oper[0]^.reg;
{ Change:
add %reg2,%reg1
mov/s/z #(%reg1),%reg1 (%reg1 superregisters must be the same)
DebugMsg(SPeepholeOptimization + 'AddMov2Mov done', p);
RemoveCurrentp(p, hp1);
Result := True;
Exit;
To:
mov/s/z #(%reg1,%reg2),%reg1
}
if MatchOpType(taicpu(p), top_reg, top_reg) and
MatchInstruction(hp1, [A_MOV, A_MOVZX, A_MOVSX{$ifdef x86_64}, A_MOVSXD{$endif}], []) and
MatchOpType(taicpu(hp1), top_ref, top_reg) and
(taicpu(hp1).oper[0]^.ref^.scalefactor <= 1) and
(
(
(taicpu(hp1).oper[0]^.ref^.base = taicpu(p).oper[1]^.reg) and
(taicpu(hp1).oper[0]^.ref^.index = NR_NO)
) or (
(taicpu(hp1).oper[0]^.ref^.index = taicpu(p).oper[1]^.reg) and
(taicpu(hp1).oper[0]^.ref^.base = NR_NO)
)
) and (
Reg1WriteOverwritesReg2Entirely(taicpu(p).oper[1]^.reg, taicpu(hp1).oper[1]^.reg) or
(
{ If the super registers ARE equal, then this MOV/S/Z does a partial write }
not SuperRegistersEqual(taicpu(p).oper[1]^.reg, taicpu(hp1).oper[1]^.reg) and
MemRegisterNotUsedLater
)
) then
begin
taicpu(hp1).oper[0]^.ref^.base := taicpu(p).oper[1]^.reg;
taicpu(hp1).oper[0]^.ref^.index := taicpu(p).oper[0]^.reg;
DebugMsg(SPeepholeOptimization + 'AddMov2Mov done', p);
RemoveCurrentp(p, hp1);
Result := True;
Exit;
end;
{ Change:
addl/q $x,%reg1
movl/q %reg1,%reg2
To:
leal/q $x(%reg1),%reg2
addl/q $x,%reg1 (can be removed if %reg1 or the flags are not used afterwards)
Breaks the dependency chain.
}
if MatchOpType(taicpu(p),top_const,top_reg) and
MatchInstruction(hp1, A_MOV, [taicpu(p).opsize]) and
(taicpu(hp1).oper[1]^.typ = top_reg) and
MatchOperand(taicpu(hp1).oper[0]^, taicpu(p).oper[1]^.reg) and
(
{ Don't do AddMov2LeaAdd under -Os, but do allow AddMov2Lea }
not (cs_opt_size in current_settings.optimizerswitches) or
(
not RegUsedAfterInstruction(taicpu(p).oper[1]^.reg, hp1, TmpUsedRegs) and
RegUsedAfterInstruction(NR_DEFAULTFLAGS, hp1, TmpUsedRegs)
)
) then
begin
{ Change the MOV instruction to a LEA instruction, and update the
first operand }
reference_reset(NewRef, 1, []);
NewRef.base := taicpu(p).oper[1]^.reg;
NewRef.scalefactor := 1;
NewRef.offset := taicpu(p).oper[0]^.val;
taicpu(hp1).opcode := A_LEA;
taicpu(hp1).loadref(0, NewRef);
TransferUsedRegs(TmpUsedRegs);
UpdateUsedRegs(TmpUsedRegs, tai(p.Next));
if RegUsedAfterInstruction(NewRef.base, hp1, TmpUsedRegs) or
RegUsedAfterInstruction(NR_DEFAULTFLAGS, hp1, TmpUsedRegs) then
begin
{ Move what is now the LEA instruction to before the SUB instruction }
Asml.Remove(hp1);
Asml.InsertBefore(hp1, p);
AllocRegBetween(taicpu(hp1).oper[1]^.reg, hp1, p, UsedRegs);
DebugMsg(SPeepholeOptimization + 'AddMov2LeaAdd', p);
p := hp1;
end
else
begin
{ Since %reg1 or the flags aren't used afterwards, we can delete p completely }
RemoveCurrentP(p, hp1);
DebugMsg(SPeepholeOptimization + 'AddMov2Lea', p);
end;
Result := True;
end;
end;
end;