From: Richard Biener <richard.guenther@gmail.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] [AVX512] [PR87767] Optimize memory broadcast for constant vector under AVX512
Date: Fri, 28 Aug 2020 13:06:40 +0200 [thread overview]
Message-ID: <CAFiYyc3K4rJo1rtD3vkZXA5yvRNB-5odbsCnQRp1EMKQFTuCvw@mail.gmail.com> (raw)
In-Reply-To: <20200828104705.GR2961@tucnak>
On Fri, Aug 28, 2020 at 12:47 PM Jakub Jelinek <jakub@redhat.com> wrote:
>
> On Fri, Aug 28, 2020 at 12:36:00PM +0200, Richard Biener wrote:
> > Guess this would work indeed. It's probably quite common to have
> > both vector and non-vector constants because of vectorization
> > and scalar epilogues. But note that elsewhere we're using
> > the largest component mode to emit vector constant pool entries
> > to share { -1, -1, -1, -1 } and {-1l, -1l } for example so while the
> > below code works for FP modes it likely will break down for
> > integer modes?
>
> I don't see why it would break, it will not optimize { -1LL, -1LL }
> vs. -1 scalar, sure, but it uses the hash and equality function the
> rtl constant pool uses, which means it compares both the constants
> (rtx_equal_p) and mode we have recorded for it.
Oh, I thought my patch for PR54201 was installed but it was not
(I grepped my patch folder...). PR54201 complains about something
similar but then different ;) Guess post-processing that would also be
possible but also a bit awkward. Maybe we should hash the
full byte representation instead of the components.
Richard.
> Of course, on x86_64 integer scalar constants will pretty much never appear
> in the constant pool, so guess we'll need a different target for testing
> that.
>
> Jakub
>
next prev parent reply other threads:[~2020-08-28 11:06 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 8:33 Hongtao Liu
2020-07-10 9:24 ` Hongtao Liu
2020-07-17 7:24 ` Hongtao Liu
2020-07-23 8:39 ` Jan Hubicka
2020-07-23 13:53 ` Hongtao Liu
2020-07-24 2:37 ` Hongtao Liu
2020-08-04 6:05 ` Hongtao Liu
2020-08-26 21:23 ` Jeff Law
2020-08-27 11:09 ` Jan Hubicka
2020-08-27 12:24 ` Jakub Jelinek
2020-08-27 13:07 ` Richard Biener
2020-08-27 13:20 ` Jakub Jelinek
2020-08-28 6:47 ` Richard Biener
2020-08-28 8:52 ` Jakub Jelinek
2020-08-28 10:36 ` Richard Biener
2020-08-28 10:47 ` Jakub Jelinek
2020-08-28 11:06 ` Richard Biener [this message]
2020-08-28 11:26 ` Jakub Jelinek
2020-08-28 14:53 ` Jakub Jelinek
2020-08-28 16:07 ` Richard Sandiford
2020-08-28 16:25 ` Jakub Jelinek
2020-08-30 9:24 ` Jakub Jelinek
2020-08-31 8:18 ` Richard Biener
2020-08-28 17:18 ` Hongtao Liu
2020-09-01 9:55 ` Hongtao Liu
2020-09-01 10:11 ` Jakub Jelinek
2020-09-02 1:57 ` Hongtao Liu
2020-09-02 9:58 ` Jakub Jelinek
2020-09-03 2:11 ` Hongtao Liu
2020-09-03 7:27 ` Jakub Jelinek
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