From: Daniel Borkmann <daniel@iogearbox.net>
To: Andrii Nakryiko <andriin@fb.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com,
andrii.nakryiko@gmail.com, kernel-team@fb.com
Subject: Re: [PATCH bpf] selftests/bpf: adjust strobemeta loop to satisfy latest clang
Date: Wed, 25 Sep 2019 22:33:01 +0200 [thread overview]
Message-ID: <20190925203301.GE9500@pc-63.home> (raw)
In-Reply-To: <20190925185205.2857838-1-andriin@fb.com>
On Wed, Sep 25, 2019 at 11:52:05AM -0700, Andrii Nakryiko wrote:
> Some recent changes in latest Clang started causing the following
> warning when unrolling strobemeta test case main loop:
>
> progs/strobemeta.h:416:2: warning: loop not unrolled: the optimizer was
> unable to perform the requested transformation; the transformation might
> be disabled or specified as part of an unsupported transformation
> ordering [-Wpass-failed=transform-warning]
>
> This patch simplifies loop's exit condition to depend only on constant
> max iteration number (STROBE_MAX_MAP_ENTRIES), while moving early
> termination logic inside the loop body. The changes are equivalent from
> program logic standpoint, but fixes the warning. It also appears to
> improve generated BPF code, as it fixes previously failing non-unrolled
> strobemeta test cases.
>
> Cc: Alexei Starovoitov <ast@fb.com>
> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Sounds like a clang regression? Was that from an official release?
Applied.
next prev parent reply other threads:[~2019-09-25 20:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-25 18:52 [PATCH bpf] selftests/bpf: adjust strobemeta loop to satisfy latest clang Andrii Nakryiko
2019-09-25 20:33 ` Daniel Borkmann [this message]
2019-09-25 20:35 ` Andrii Nakryiko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190925203301.GE9500@pc-63.home \
--to=daniel@iogearbox.net \
--cc=andrii.nakryiko@gmail.com \
--cc=andriin@fb.com \
--cc=ast@fb.com \
--cc=bpf@vger.kernel.org \
--cc=kernel-team@fb.com \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox