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* x86: Extended FuncMov2Func optimisation to handle 1, 3 and 4-operand functions

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J. Gareth "Curious Kit" Moreton 2022-10-21 19:58:16 +01:00 committed by FPK
parent 9fc2b9062d
commit d35be8a9ea
1 changed files with 35 additions and 8 deletions
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43
compiler/x86/aoptx86.pas
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@ -4817,6 +4817,9 @@ unit aoptx86;
Change to:
func. %reg1,%reg3 (see comment below for what a valid func. is)
Perform similar optimisations with 1, 3 and 4-operand instructions
that only have one output.
}
if MatchOpType(taicpu(p), top_reg, top_reg) then
begin
@ -4827,12 +4830,29 @@ unit aoptx86;
GetLastInstruction(p, hp2) and
(hp2.typ = ait_instruction) and
{ Have to make sure it's an instruction that only reads from
operand 1 and only writes (not reads or modifies) from operand 2;
in essence, a one-operand pure function such as BSR or POPCNT }
(taicpu(hp2).ops = 2) and
(insprop[taicpu(hp2).opcode].Ch * [Ch_Rop1, Ch_Wop2] = [Ch_Rop1, Ch_Wop2]) and
(taicpu(hp2).oper[1]^.typ = top_reg) and
(taicpu(hp2).oper[1]^.reg = p_SourceReg) then
the first operands and only writes (not reads or modifies) to
the last one; in essence, a pure function such as BSR, POPCNT
or ANDN }
(
(
(taicpu(hp2).ops = 1) and
(insprop[taicpu(hp2).opcode].Ch * [Ch_Wop1] = [Ch_Wop1])
) or
(
(taicpu(hp2).ops = 2) and
(insprop[taicpu(hp2).opcode].Ch * [Ch_Rop1, Ch_Wop2] = [Ch_Rop1, Ch_Wop2])
) or
(
(taicpu(hp2).ops = 3) and
(insprop[taicpu(hp2).opcode].Ch * [Ch_Rop1, Ch_Rop2, Ch_Wop3] = [Ch_Rop1, Ch_Rop2, Ch_Wop3])
) or
(
(taicpu(hp2).ops = 4) and
(insprop[taicpu(hp2).opcode].Ch * [Ch_Rop1, Ch_Rop2, Ch_Rop3, Ch_Wop4] = [Ch_Rop1, Ch_Rop2, Ch_Rop3, Ch_Wop4])
)
) and
(taicpu(hp2).oper[taicpu(hp2).ops-1]^.typ = top_reg) and
(taicpu(hp2).oper[taicpu(hp2).ops-1]^.reg = p_SourceReg) then
begin
case taicpu(hp2).opcode of
A_FSTSW, A_FNSTSW,
@ -4845,8 +4865,15 @@ unit aoptx86;
else
begin
DebugMsg(SPeepholeOptimization + 'Removed MOV and changed destination on previous instruction to optimise register usage (FuncMov2Func)', p);
taicpu(hp2).oper[1]^.reg := p_TargetReg;
AllocRegBetween(p_TargetReg, hp2, p, TmpUsedRegs);
taicpu(hp2).oper[taicpu(hp2).ops-1]^.reg := p_TargetReg;
if not RegInInstruction(p_TargetReg, hp2) then
begin
{ Since we're allocating from an earlier point, we
need to remove the register from the tracking }
ExcludeRegFromUsedRegs(p_TargetReg, TmpUsedRegs);
AllocRegBetween(p_TargetReg, hp2, p, TmpUsedRegs);
end;
RemoveCurrentp(p, hp1);
Result := True;
Exit;