On Thu, Apr 21, 2016 at 6:48 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
> 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.
I tried and it doesn't work since the correct mode may not be always
available in predicates. Yes, they pass mode. But they just do
mode = GET_MODE (op);
which returns VOIDmode for -1.
--
H.J.
