On Thu, Apr 21, 2016 at 3:43 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
> On Thu, Apr 21, 2016 at 6:33 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
>> On Thu, Apr 21, 2016 at 2:59 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>>
>>>> We know, that const_int (-1) is allowed with TARGET_SSE2 and that
>>>> const_wide_int (-1) is allowed with TARGET_AVX2. Probably we don't
>>>> have to check AVX512F in standard_sse_constant_p, as it implies
>>>> TARGET_AVX2.
>>>>
>>>> As said, it is the job of insn mode attributes to emit correct instruction.
>>>>
>>>> Based on the above observations, mode checks for -1 are not needed in
>>>> standard_sse_constant_p.
>>>
>>> void
>>> ix86_expand_vector_move (machine_mode mode, rtx operands[])
>>> {
>>> rtx op0 = operands[0], op1 = operands[1];
>>> /* Use GET_MODE_BITSIZE instead of GET_MODE_ALIGNMENT for IA MCU
>>> psABI since the biggest alignment is 4 byte for IA MCU psABI. */
>>> unsigned int align = (TARGET_IAMCU
>>> ? GET_MODE_BITSIZE (mode)
>>> : GET_MODE_ALIGNMENT (mode));
>>>
>>> if (push_operand (op0, VOIDmode))
>>> op0 = emit_move_resolve_push (mode, op0);
>>>
>>> /* Force constants other than zero into memory. We do not know how
>>> the instructions used to build constants modify the upper 64 bits
>>> of the register, once we have that information we may be able
>>> to handle some of them more efficiently. */
>>> if (can_create_pseudo_p ()
>>> && register_operand (op0, mode)
>>> && (CONSTANT_P (op1)
>>> || (SUBREG_P (op1)
>>> && CONSTANT_P (SUBREG_REG (op1))))
>>> && !standard_sse_constant_p (op1))
>>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>
>>> What should it return for op1 == (VOIDmode) -1 when
>>> TARGET_AVX is true and TARGET_AVX2 is false for
>>> mode == TImode and mode == OImode?
>>>
>>> op1 = validize_mem (force_const_mem (mode, op1));
>>
>> Let me rethink and redesign this whole mess, so we will have
>> consistent predicates.
>
> The problem is because -1 has no mode. We can't tell
> if -1 is a valid SSE constant without mode. That is my
> change to standard_sse_constant_p and
> ix86_expand_vector_move is for. It is sufficient for
> all my tests, including benchmark runs.
I'm not against mode checks, but IMO, we have to do these checks in
predicates, where we know operand mode.
Uros.
