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From: "Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com>
To: Richard Biener <rguenther@suse.de>
Cc: Jakub Jelinek <jakub@redhat.com>,
	Richard Sandiford <richard.sandiford@arm.com>,
	"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] Teach vectorizer to deal with bitfield accesses (was: [RFC] Teach vectorizer to deal with bitfield reads)
Date: Wed, 28 Sep 2022 10:43:04 +0100	[thread overview]
Message-ID: <42e266bd-7224-76b7-c782-c00063531917@arm.com> (raw)
In-Reply-To: <nycvar.YFH.7.77.849.2209271229280.6652@jbgna.fhfr.qr>


On 27/09/2022 13:34, Richard Biener wrote:
> On Mon, 26 Sep 2022, Andre Vieira (lists) wrote:
>
>> On 08/09/2022 12:51, Richard Biener wrote:
>>> I'm curious, why the push to redundant_ssa_names?  That could use
>>> a comment ...
>> So I purposefully left a #if 0 #else #endif in there so you can see the two
>> options. But the reason I used redundant_ssa_names is because ifcvt seems to
>> use that as a container for all pairs of (old, new) ssa names to replace
>> later. So I just piggy backed on that. I don't know if there's a specific
>> reason they do the replacement at the end? Maybe some ordering issue? Either
>> way both adding it to redundant_ssa_names or doing the replacement inline work
>> for the bitfield lowering (or work in my testing at least).
> Possibly because we (in the past?) inserted/copied stuff based on
> predicates generated at analysis time after we decide to elide something
> so we need to watch for later appearing uses.  But who knows ... my mind
> fails me here.
>
> If it works to replace uses immediately please do so.  But now
> I wonder why we need this - the value shouldn't change so you
> should get away with re-using the existing SSA name for the final value?

Yeah... good point. A quick change and minor testing seems to agree. I'm sure I had a good reason to do it initially ;)

I'll run a full-regression on this change to make sure I didn't miss anything.


  reply	other threads:[~2022-09-28  9:43 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-26 10:00 [RFC] Teach vectorizer to deal with bitfield reads Andre Vieira (lists)
2022-07-27 11:37 ` Richard Biener
2022-07-29  8:57   ` Andre Vieira (lists)
2022-07-29  9:11     ` Richard Biener
2022-07-29 10:31     ` Jakub Jelinek
2022-07-29 10:52       ` Richard Biener
2022-08-01 10:21         ` Andre Vieira (lists)
2022-08-01 13:16           ` Richard Biener
2022-08-08 14:06             ` [PATCH] Teach vectorizer to deal with bitfield accesses (was: [RFC] Teach vectorizer to deal with bitfield reads) Andre Vieira (lists)
2022-08-09 14:34               ` Richard Biener
2022-08-16 10:24                 ` Andre Vieira (lists)
2022-08-17 12:49                   ` Richard Biener
2022-08-25  9:09                     ` Andre Vieira (lists)
2022-09-08  9:07                       ` Andre Vieira (lists)
2022-09-08 11:51                       ` Richard Biener
2022-09-26 15:23                         ` Andre Vieira (lists)
2022-09-27 12:34                           ` Richard Biener
2022-09-28  9:43                             ` Andre Vieira (lists) [this message]
2022-09-28 17:31                               ` Andre Vieira (lists)
2022-09-29  7:54                                 ` Richard Biener
2022-10-07 14:20                                   ` Andre Vieira (lists)
2022-10-12  1:55                                     ` Hongtao Liu
2022-10-12  2:11                                       ` Hongtao Liu
2022-08-01 10:13       ` [RFC] Teach vectorizer to deal with bitfield reads Andre Vieira (lists)
2022-10-12  9:02 ` Eric Botcazou

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