From: Jakub Jelinek <jakub@redhat.com>
To: Uros Bizjak <ubizjak@gmail.com>, Hongtao Liu <crazylht@gmail.com>,
GCC Patches <gcc-patches@gcc.gnu.org>,
"H. J. Lu" <hjl.tools@gmail.com>,
richard.sandiford@arm.com
Subject: Re: [PATCH] [i386] Fix _mm256_zeroupper to notify LRA that vzeroupper will kill sse registers. [PR target/82735]
Date: Thu, 13 May 2021 13:37:04 +0200 [thread overview]
Message-ID: <20210513113704.GI1179226@tucnak> (raw)
In-Reply-To: <mptsg2qzx6d.fsf@arm.com>
On Thu, May 13, 2021 at 12:32:26PM +0100, Richard Sandiford wrote:
> Jakub Jelinek <jakub@redhat.com> writes:
> > On Thu, May 13, 2021 at 11:43:19AM +0200, Uros Bizjak wrote:
> >> > > Bootstrapped and regtested on X86_64-linux-gnu{-m32,}
> >> > > Ok for trunk?
> >> >
> >> > Some time ago a support for CLOBBER_HIGH RTX was added (and later
> >> > removed for some reason). Perhaps we could resurrect the patch for the
> >> > purpose of ferrying 128bit modes via vzeroupper RTX?
> >>
> >> https://gcc.gnu.org/legacy-ml/gcc-patches/2017-11/msg01325.html
> >
> > https://gcc.gnu.org/legacy-ml/gcc-patches/2019-09/msg01468.html
> > is where it got removed, CCing Richard.
>
> Yeah. Initially clobber_high seemed like the best appraoch for
> handling the tlsdesc thing, but in practice it was too difficult
> to shoe-horn the concept in after the fact, when so much rtl
> infrastructure wasn't prepared to deal with it. The old support
> didn't handle all cases and passes correctly, and handled others
> suboptimally.
>
> I think it would be worth using the same approach as
> https://gcc.gnu.org/legacy-ml/gcc-patches/2019-09/msg01466.html for
> vzeroupper: represent the instructions as call_insns in which the
> call has a special vzeroupper ABI. I think that's likely to lead
> to better code than clobber_high would (or at least, it did for tlsdesc).
Perhaps a magic call_insn that is split post-reload into a normal insn
with the sets then?
Jakub
next prev parent reply other threads:[~2021-05-13 11:37 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-13 9:23 Hongtao Liu
2021-05-13 9:40 ` Uros Bizjak
2021-05-13 9:43 ` Uros Bizjak
2021-05-13 9:54 ` Jakub Jelinek
2021-05-13 11:32 ` Richard Sandiford
2021-05-13 11:37 ` Jakub Jelinek [this message]
2021-05-13 11:52 ` Richard Sandiford
2021-05-14 2:27 ` Hongtao Liu
2021-05-17 8:44 ` Hongtao Liu
2021-05-17 9:56 ` Richard Sandiford
2021-05-18 13:12 ` Hongtao Liu
2021-05-18 15:18 ` Richard Sandiford
2021-05-25 6:04 ` Hongtao Liu
2021-05-25 6:30 ` Hongtao Liu
2021-05-27 5:07 ` Hongtao Liu
2021-05-27 7:05 ` Uros Bizjak
2021-06-01 2:24 ` Hongtao Liu
2021-06-03 6:54 ` [PATCH 1/2] CALL_INSN may not be a real function call liuhongt
2021-06-03 6:54 ` [PATCH 2/2] Fix _mm256_zeroupper by representing the instructions as call_insns in which the call has a special vzeroupper ABI liuhongt
2021-06-04 2:56 ` Hongtao Liu
2021-06-04 6:26 ` Uros Bizjak
2021-06-04 6:34 ` Hongtao Liu
2021-06-07 19:04 ` [PATCH] x86: Don't compile pr82735-[345].c for x32 H.J. Lu
2021-06-04 2:55 ` [PATCH 1/2] CALL_INSN may not be a real function call Hongtao Liu
2021-06-04 7:50 ` Jakub Jelinek
2021-07-05 23:30 ` Segher Boessenkool
2021-07-06 0:03 ` Jeff Law
2021-07-06 1:49 ` Hongtao Liu
2021-07-07 14:55 ` Segher Boessenkool
2021-07-07 17:56 ` Jeff Law
2021-07-06 1:37 ` Hongtao Liu
2021-07-07 2:44 ` Hongtao Liu
2021-07-07 8:15 ` Richard Biener
2021-07-07 14:52 ` Segher Boessenkool
2021-07-07 15:23 ` Hongtao Liu
2021-07-07 23:42 ` Segher Boessenkool
2021-07-08 4:14 ` Hongtao Liu
2021-07-07 15:32 ` Hongtao Liu
2021-07-07 23:54 ` Segher Boessenkool
2021-07-09 7:20 ` Hongtao Liu
2021-07-07 15:52 ` Hongtao Liu
2021-05-27 7:20 ` [PATCH] [i386] Fix _mm256_zeroupper to notify LRA that vzeroupper will kill sse registers. [PR target/82735] Jakub Jelinek
2021-05-27 10:50 ` Richard Sandiford
2021-06-01 2:22 ` Hongtao Liu
2021-06-01 2:25 ` Hongtao Liu
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