On Sun, Sep 28, 2025 at 11:18 AM H.J. Lu <[email protected]> wrote:
>
> On Sun, Sep 28, 2025, 10:26 AM Hongtao Liu <[email protected]> wrote:
>>
>> On Sun, Sep 28, 2025 at 9:49 AM H.J. Lu <[email protected]> wrote:
>> >
>> > On Sun, Sep 28, 2025 at 9:29 AM Liu, Hongtao <[email protected]> wrote:
>> > >
>> > >
>> > >
>> > > > -----Original Message-----
>> > > > From: H.J. Lu <[email protected]>
>> > > > Sent: Sunday, September 28, 2025 9:11 AM
>> > > > To: Hongtao Liu <[email protected]>
>> > > > Cc: Liu, Hongtao <[email protected]>; [email protected]
>> > > > Subject: Re: [PATCH] Deprecate -mmove-max= and related tuning.
>> > > >
>> > > > On Sun, Sep 28, 2025 at 9:08 AM Hongtao Liu <[email protected]> wrote:
>> > > > >
>> > > > > On Sun, Sep 28, 2025 at 8:32 AM H.J. Lu <[email protected]> wrote:
>> > > > > >
>> > > > > > On Sun, Sep 28, 2025 at 8:18 AM Liu, Hongtao 
>> > > > > > <[email protected]>
>> > > > wrote:
>> > > > > > >
>> > > > > > >
>> > > > > > >
>> > > > > > > > -----Original Message-----
>> > > > > > > > From: H.J. Lu <[email protected]>
>> > > > > > > > Sent: Sunday, September 28, 2025 6:33 AM
>> > > > > > > > To: Liu, Hongtao <[email protected]>
>> > > > > > > > Cc: [email protected]
>> > > > > > > > Subject: Re: [PATCH] Deprecate -mmove-max= and related tuning.
>> > > > > > > >
>> > > > > > > > On Fri, Sep 26, 2025 at 9:40 AM liuhongt 
>> > > > > > > > <[email protected]>
>> > > > wrote:
>> > > > > > > > >
>> > > > > > > > > For memset, the size of used vector is decided by
>> > > > > > > > > MIN(MOVE_MAX_PIECES, STORE_MAX_PIECES).
>> > > > > > > > > Unless there's u-arch prefer big size vector for memcpy and
>> > > > > > > > > small size vector for memset, there's no need to have a
>> > > > > > > > > separate option or tune for it.
>> > > > > > > > > In general, x86 backend always prefer big size vector for
>> > > > > > > > > memset due to STLF issue.
>> > > > > > > > > So for maintaince convenience, the patch remove store_max
>> > > > > > > > > related tune and marked the mstore-max as deprecated.
>> > > > > > > > >
>> > > > > > > > > Bootstrapped and regtested on x86_64-pc-linux{-m32,}.
>> > > > > > > > > H.J Any comments?
>> > > > > > > >
>> > > > > > > > Does it change -mstore-max or -mmove-max?  The subject says
>> > > > > > > > -mmove-max, but the commit message says -mstore-max.
>> > > > > > >
>> > > > > > > Typo, The patch only changes -mstore-max 1. It removes tune of
>> > > > > > > {AVX256,AVX512}_STORE_BY_PIECES.
>> > > > > > > 2. Deprecate mstore-max by aliasing it to -mmove-max and issues a
>> > > > warning.
>> > > > > >
>> > > > > > Does the patch include tests for -mmove-max aliasing and the 
>> > > > > > warning
>> > > > message?
>> > > > > No, do we need it? It seems simple enough.
>> > > >
>> > > > Any change should have tests to verify that it is done correctly.
>> > > The change is also ready verified by adjusting testcase, those memset 
>> > > related testcases will fail due to new warning message.
>> >
>> > I didn't see the -mstore-max tests.  The new warning message should be
>> > part of the tests.
>> Ok, Will add a testcase like
>>
>> /* { dg-do compile } */
>> /* { dg-options "-O2 -march=x86-64-v4  -mstore-max=256" } */
>> // { dg-warning ".-mstore-max=. is deprecated; use .-mmove-max=.
>> instead" "" { target *-*-* } 0 }
>
>
> Can you add a warning message to the existing -mstore-max test?
Changed in V3.
>
>>
>>
>> >
>> > > >
>> > > > --
>> > > > H.J.
>> >
>> >
>> >
>> > --
>> > H.J.
>>
>>
>>
>> --
>> BR,
>> Hongtao
>>


-- 
BR,
Hongtao

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