From: David Laight <david.laight.linux@gmail.com>
To: I Hsin Cheng <richard120310@gmail.com>
Cc: yury.norov@gmail.com, anshuman.khandual@arm.com, arnd@arndb.de,
linux-kernel@vger.kernel.org, jserv@ccns.ncku.edu.tw,
skhan@linuxfoundation.org, mka@chromium.org,
akpm@linux-foundation.org
Subject: Re: [PATCH v2] uapi: Revert "bitops: avoid integer overflow in GENMASK(_ULL)"
Date: Sat, 22 Feb 2025 09:11:28 +0000 [thread overview]
Message-ID: <20250222091128.5429f1c2@pumpkin> (raw)
In-Reply-To: <20250221074208.832153-1-richard120310@gmail.com>
On Fri, 21 Feb 2025 15:41:49 +0800
I Hsin Cheng <richard120310@gmail.com> wrote:
> This patch reverts 'commit c32ee3d9abd2("bitops: avoid integer overflow in
> GENMASK(_ULL)")'.
>
> The code generation can be shrink by over 1k by reverting the commit.
While you are setup for testing this (and me being lazy) does changing
the definition to be:
(2u << hi) - (1u << lo)
make it any smaller.
(A summary of the size summary would do, no point listing lots of '-1')
That can also be written:
((one + one) << hi) - (one << lo)
so an appropriately typed 'one' (1, 1u, 1ul, 1ull, (__uint128)1 etc) can
be passed.
David
next prev parent reply other threads:[~2025-02-22 9:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-21 7:41 [PATCH v2] uapi: Revert "bitops: avoid integer overflow in GENMASK(_ULL)" I Hsin Cheng
2025-02-21 17:00 ` I Hsin Cheng
2025-02-21 17:48 ` I Hsin Cheng
2025-02-21 19:03 ` Yury Norov
2025-02-23 18:59 ` I Hsin Cheng
2025-02-21 18:58 ` Yury Norov
2025-02-22 9:11 ` David Laight [this message]
2025-02-23 19:02 ` I Hsin Cheng
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