From: "Rémi Denis-Courmont" <remi@remlab.net>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH 4/5] lavu/intmath.h: Fix UB in ff_ctz_c() and ff_ctzll_c()
Date: Thu, 30 May 2024 17:32:42 +0300
Message-ID: <F66CDAE7-A3A6-4F2E-A7CA-FD8A2FB7E4DB@remlab.net> (raw)
In-Reply-To: <7572dd13e369feb7b373330a65270f8f4f842598.camel@haerdin.se>
Le 30 mai 2024 17:03:09 GMT+03:00, "Tomas Härdin" <git@haerdin.se> a écrit :
>> I don't get how that prevents using the GCC and Clang builtins (on
>> GCC and Clang).
>
>Does MSVC have builtins for these?
I don't know, but insofar as MSVC is used for x86, it should use x86 instructions rather than the complex fallback algo anyway, be it via built-ins, or assembler.
Either way, I don't see how that detracts from using the built-ins on compilers that do have them.
> Do all compilers we support?
No, unless all other compilers are C23 (CTZ and CLZ are in stdbit.h). Again, that's hardly a reason not to use built-ins where available.
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next prev parent reply other threads:[~2024-05-30 14:32 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-29 22:13 [FFmpeg-devel] [PATCH 1/5] lavu/common.h: Fix UB in av_clipl_int32_c() Tomas Härdin
2024-05-29 22:13 ` [FFmpeg-devel] [PATCH 2/5] lavu/common.h: Fix UB in av_clip_intp2_c() Tomas Härdin
2024-05-29 22:24 ` Andreas Rheinhardt
2024-05-29 23:08 ` Tomas Härdin
2024-05-29 22:14 ` [FFmpeg-devel] [PATCH 3/5] lavu/common.h: Fix UB in av_clip_uintp2_c() Tomas Härdin
2024-05-31 0:27 ` Michael Niedermayer
2024-05-29 22:14 ` [FFmpeg-devel] [PATCH 4/5] lavu/intmath.h: Fix UB in ff_ctz_c() and ff_ctzll_c() Tomas Härdin
2024-05-30 7:54 ` Rémi Denis-Courmont
2024-05-30 9:50 ` Tomas Härdin
2024-05-30 12:29 ` Hendrik Leppkes
2024-05-30 13:06 ` Rémi Denis-Courmont
2024-05-30 14:03 ` Tomas Härdin
2024-05-30 14:32 ` Rémi Denis-Courmont [this message]
2024-05-31 0:43 ` Ronald S. Bultje
2024-05-31 0:41 ` Michael Niedermayer
2024-05-31 5:48 ` Rémi Denis-Courmont
2024-05-31 0:31 ` Michael Niedermayer
2024-05-29 22:15 ` [FFmpeg-devel] [PATCH 5/5] lavu/mathematics: Return early if either a or b is zero Tomas Härdin
2024-05-31 0:22 ` Michael Niedermayer
2024-05-31 15:21 ` Tomas Härdin
2024-05-29 22:31 ` [FFmpeg-devel] [PATCH 1/5] lavu/common.h: Fix UB in av_clipl_int32_c() Andreas Rheinhardt
2024-05-30 9:48 ` Tomas Härdin
2024-05-30 6:41 ` Rémi Denis-Courmont
2024-05-30 9:40 ` Tomas Härdin
2024-05-30 11:50 ` Rémi Denis-Courmont
2024-05-30 14:07 ` Tomas Härdin
2024-05-30 14:28 ` Rémi Denis-Courmont
2024-05-30 15:32 ` Tomas Härdin
2024-05-30 15:38 ` Rémi Denis-Courmont
2024-05-31 1:03 ` Michael Niedermayer
2024-06-03 7:32 ` Rémi Denis-Courmont
2024-06-03 21:21 ` Michael Niedermayer
2024-05-30 15:42 ` James Almer
2024-05-30 16:48 ` Tomas Härdin
2024-05-30 17:49 ` Rémi Denis-Courmont
2024-05-30 19:07 ` Michael Niedermayer
2024-05-30 19:20 ` Rémi Denis-Courmont
2024-05-31 15:23 ` Tomas Härdin
2024-06-14 12:31 ` Tomas Härdin
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