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Re: [PATCH] Allow all 1s of integer as standard SSE constants
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 21 Apr 2016 15:33:56 +0200
- Subject: Re: [PATCH] Allow all 1s of integer as standard SSE constants
- Authentication-results: sourceware.org; auth=none
- References: <20160420195359 dot GA3113 at intel dot com> <CAFULd4ZJrw9hWtkxCZmRHinz+aACOvnkRU4FUXVYcFD4_qjeVA at mail dot gmail dot com> <CAFULd4Y8HGC=+iFtp9PmqW2XcVwnhNygH6si0J1OCNWipGjBLg at mail dot gmail dot com> <CAFULd4b3WPYGr=uL=1D7RmnrYBeviVt0=-ckgT-8zJJcae+m3A at mail dot gmail dot com> <CAMe9rOr9B+X-H0PmBt=fsO3BmQR_MrF3nAg2pdsOoa3NpNV3PA at mail dot gmail dot com> <CAFULd4auhHb54j3GwZRCUiuAxdPcbKk+oA4+paWU=tWsQ+7Whw at mail dot gmail dot com> <CAMe9rOovKPRPNZyaq+-uWz3kwFXJRrTuh4-cFrxYMaWaUZJoYg at mail dot gmail dot com>
On Thu, Apr 21, 2016 at 2:59 PM, H.J. Lu <hjl.tools@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.
Uros.