From: david laight <david.laight@runbox.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rasmus Villemoes <ravi@prevas.dk>,
"Yury Norov (NVIDIA)" <yury.norov@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
Nicolas Frattaroli <nicolas.frattaroli@collabora.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/21] lib: add alternatives for GENMASK()
Date: Thu, 27 Nov 2025 18:51:52 +0000 [thread overview]
Message-ID: <20251127185152.4f0c5288@pumpkin> (raw)
In-Reply-To: <20251126221718.6c595c57@pumpkin>
On Wed, 26 Nov 2025 22:17:18 +0000
david laight <david.laight@runbox.com> wrote:
...
> Both FIELD_PREP/GET(GENMASK(), v) are about 18k plus three copies of v.
> FIELD_GET(mask,v) has 18 expansions of 'mask'.
All the FIELD_XXX() are already statement expressions.
I think that means they should 'just work' if the parameters are
copied to locals - annoyingly there are a few bitfields...
Even after that a shed-load (or two) of bloat comes from __BF_FIELD_CHECK().
Not helped by expanding pointless checks because the same define is
used lots of times.
I'm not really sure the expensive test that uses __bf_cast_unsigned()
is actually worth doing - unless a trivial equivalent can be found.
Actually the 'mask' side can just be 'mask + 0u + 0ul + 0ull' which
zero-extends 'mask';
the other just '~0ull >> (64 - sizeof(_reg) * 8)'.
I see a patch lurking...
David
next prev parent reply other threads:[~2025-11-27 18:52 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-25 16:39 [PATCH 00/21] lib: add alternatives for GENMASK() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 01/21] arc: disasm: rename BITS() for FIELD() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 02/21] iwlwifi: drop unused BITS() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 03/21] select: rename BITS() to FDS_BITS() Yury Norov (NVIDIA)
2025-10-30 9:42 ` Jan Kara
2025-10-25 16:40 ` [PATCH 04/21] ALSA: rename BITS to R_BITS Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 05/21] zlib: rename BITS() to LOWBITS() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 06/21] mfd: prepare to generalize BITS() macro Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 07/21] bits: Add " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 08/21] mfd: drop local " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 09/21] bits: generalize BITMAP_{FIRST,LAST}_WORD_MASK Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 10/21] i2c: nomadik: don't use GENMASK() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 11/21] drivers: don't use GENMASK() in FIELD_PREP_WM16() Yury Norov (NVIDIA)
2025-10-27 8:49 ` Jani Nikula
2025-10-27 12:21 ` Nicolas Frattaroli
2025-10-27 13:10 ` Mark Brown
2025-10-25 16:40 ` [PATCH 12/21] bitmap: don't use GENMASK() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 13/21] trace: " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 14/21] lib: 842: don't use GENMASK_ULL() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 15/21] bpf: don't use GENMASK() Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 16/21] kcsan: " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 17/21] mm: " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 18/21] fprobe: " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 19/21] fs: " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 20/21] fortify-string: " Yury Norov (NVIDIA)
2025-10-25 16:40 ` [PATCH 21/21] Docs: add Functions parameters order section Yury Norov (NVIDIA)
2025-10-25 17:56 ` [PATCH 00/21] lib: add alternatives for GENMASK() Linus Torvalds
2025-11-26 9:07 ` Rasmus Villemoes
2025-11-26 10:38 ` david laight
2025-11-26 19:44 ` Linus Torvalds
2025-11-26 22:17 ` david laight
2025-11-26 23:47 ` Linus Torvalds
2025-11-27 9:37 ` david laight
2025-11-27 14:11 ` Nicolas Frattaroli
2025-11-27 17:29 ` Linus Torvalds
2025-11-27 18:51 ` david laight [this message]
2025-11-29 11:46 ` david laight
-- strict thread matches above, loose matches on Subject: below --
2025-10-25 18:01 Alexey Dobriyan
2025-10-25 16:28 Yury Norov (NVIDIA)
2025-10-25 16:37 ` Yury Norov
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