on 2022/12/1 20:16, guojiufu wrote:
> On 2022-12-01 15:10, Jiufu Guo via Gcc-patches wrote:
>> Hi Kewen,
>>
>> 在 12/1/22 2:11 PM, Kewen.Lin 写道:
>>> on 2022/12/1 13:35, Jiufu Guo wrote:
>>>> Hi Kewen,
>>>>
>>>> Thanks for your quick and insight review!
>>>>
>>>> 在 12/1/22 1:17 PM, Kewen.Lin 写道:
>>>>> Hi Jeff,
>>>>>
>>>>> on 2022/12/1 09:36, Jiufu Guo wrote:
>>>>>> Hi,
>>>>>>
>>>>>> This patch just uses sext_hwi to replace the expression like:
>>>>>> ((value & 0xf..f) ^ 0x80..0) - 0x80..0 for rs6000.cc and rs6000.md.
>>>>>>
>>>>>> Bootstrap & regtest pass on ppc64{,le}.
>>>>>> Is this ok for trunk?
>>>>>
>>>>> You didn't say it clearly but I guessed you have grepped in the whole
>>>>> config/rs6000 directory, right? I noticed there are still two places
>>>>> using this kind of expression in function constant_generates_xxspltiw,
>>>>> but I assumed it's intentional as their types are not HOST_WIDE_INT.
>>>>>
>>>>> gcc/config/rs6000/rs6000.cc: short sign_h_word = ((h_word & 0xffff)
>>>>> ^ 0x8000) - 0x8000;
>>>>> gcc/config/rs6000/rs6000.cc: int sign_word = ((word & 0xffffffff) ^
>>>>> 0x80000000) - 0x80000000;
>>>>>
>>>>> If so, could you state it clearly in commit log like "with type
>>>>> signed/unsigned HOST_WIDE_INT" or similar?
>>>>>
>>>> Good question!
>>>>
>>>> And as you said sext_hwi is more for "signed/unsigned HOST_WIDE_INT".
>>>> For these two places, it seems sext_hwi is not needed actually!
>>>> And I did see why these expressions are used, may be just an assignment
>>>> is ok.
>>>
>>> ah, I see. I agree using the assignment is quite enough. Could you
>>> please also simplify them together? Since they are with the form
>>> "((value & 0xf..f) ^ 0x80..0) - 0x80..0" too, and can be refactored
>>> in a better way. Thanks!
>>
>> Sure, I believe just "short sign_h_word = vsx_const->half_words[0];"
>> should be correct :-), and included in the updated patch.
>>
>> Updated patch is attached, bootstrap®test is on going.
>
on 2022/12/1 15:10, Jiufu Guo wrote:
> From 8aa8e1234b6ec34473434951a3a6177253aac770 Mon Sep 17 00:00:00 2001
> From: Jiufu Guo <guoji...@linux.ibm.com>
> Date: Wed, 30 Nov 2022 13:13:37 +0800
> Subject: [PATCH 2/2]rs6000: update ((v&0xf..f)^0x80..0) - 0x80..0 with code:
> like sext_hwi
>
May be shorter with "rs6000: Update sign extension computation with sext_hwi"?
> This patch just replaces the expression like:
> ((value & 0xf..f) ^ 0x80..0) - 0x80..0 to better code(e.g. sext_hwi) for
> rs6000.cc, rs6000.md and predicates.md (files under rs6000/).
> Bootstrap and regtest pass on ppc64{,le}.
>
Thanks for updating and testing, this patch is OK.
BR,
Kewen
