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From: "linkw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/107412] Miss to fold LEN_{LOAD,STORE} when the specified length equal to vector length
Date: Mon, 31 Oct 2022 06:39:47 +0000	[thread overview]
Message-ID: <bug-107412-4-cXMhOKfJ2o@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107412-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107412

--- Comment #3 from Kewen Lin <linkw at gcc dot gnu.org> ---
(In reply to Segher Boessenkool from comment #2)
> Make sure we only use "plain" accesses on machines that allow all unaligned
> accesses?  p8 and later I think.  The load-with-length insns are even later,
> but a builtin does not necessarily translate to those newer insns, so some
> care is required :-)

Thanks for raising this, for now these LEN_{LOAD,STORE} can ONLY be generated
when the target defines the relevant optab len_{load,store}, on power it's
power9 and later, while on s390 it should be some latest cpu I guess. Those are
internal function and invisible for users, the support and the documentation
assume it can work for unaligned access, if some target wants to emulate it
later, it needs some more updates (not only this folding). So we don't need to
bother it for now IHMO. :)

  parent reply	other threads:[~2022-10-31  6:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-26  9:13 [Bug tree-optimization/107412] New: " linkw at gcc dot gnu.org
2022-10-26  9:15 ` [Bug tree-optimization/107412] " linkw at gcc dot gnu.org
2022-10-27 22:03 ` segher at gcc dot gnu.org
2022-10-31  6:39 ` linkw at gcc dot gnu.org [this message]
2022-11-07  8:17 ` cvs-commit at gcc dot gnu.org
2022-11-07  8:25 ` linkw at gcc dot gnu.org
2022-11-07  8:25 ` linkw at gcc dot gnu.org
2022-12-05  5:28 ` cvs-commit at gcc dot gnu.org

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