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From: "ubizjak at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/111698] Narrow memory access of compare to byte width
Date: Thu, 05 Oct 2023 11:29:36 +0000	[thread overview]
Message-ID: <bug-111698-4-i9WY1Fe6oP@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-111698-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111698

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Richard Biener from comment #1)
> I guess we could do this even on GIMPLE and in general to aligned sub-word
> accesses (where byte accesses are always aligned).
> 
> It might be also a good fit for RTL forwprop or that mem-offset pass in
> development.

I don't think this optimization should be universally enabled. According to
Agner Fog, older x86 cores suffer from store forwarding stall when smaller read
doesn't start at the same address. Intel Sandybridge and AMD Steamroller
families relaxed this constraint.

  parent reply	other threads:[~2023-10-05 11:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-04 20:52 [Bug target/111698] New: " ubizjak at gmail dot com
2023-10-05  7:51 ` [Bug target/111698] " rguenth at gcc dot gnu.org
2023-10-05 11:29 ` ubizjak at gmail dot com [this message]
2023-10-24 12:12 ` ubizjak at gmail dot com
2023-10-25 14:28 ` cvs-commit at gcc dot gnu.org
2023-10-25 14:30 ` ubizjak at gmail dot com

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