From: Florian Weimer <fweimer@redhat.com>
To: Adam Sampson via Libc-alpha <libc-alpha@sourceware.org>
Subject: Re: [PATCH v1 2/2] x86_64: Add {u}int_fast defs ideal for x86_64
Date: Mon, 11 Apr 2022 08:34:31 +0200 [thread overview]
Message-ID: <87ee24nn60.fsf@oldenburg.str.redhat.com> (raw)
In-Reply-To: <y2a7d7w74ci.fsf@offog.org> (Adam Sampson via Libc-alpha's message of "Mon, 11 Apr 2022 03:15:25 +0100")
* Adam Sampson via Libc-alpha:
> Noah Goldstein via Libc-alpha <libc-alpha@sourceware.org> writes:
>
>> {u}int_fast{16|32} should never use 64-bit types. 64-bit instructions
>> often use more code size (REX prefix) and a variety of instructions
>> are slower on many implementations (div, bswap, etc...).
>
> Isn't that going to cause ABI breakage in other libraries, though?
> For example, the jasper JPEG2000 decoder library uses stdint.h's
> uint_fast32_t in its public API, and the HDF5 scientific data library
> includes constants for the sizes of various types including *int*fast*.
Agreed, it's too late for such changes.
Thanks,
Florian
next prev parent reply other threads:[~2022-04-11 6:34 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-11 1:09 [PATCH v1 1/2] stdlib: Refactor {u}int_fast defs in stdint Noah Goldstein
2022-04-11 1:09 ` [PATCH v1 2/2] x86_64: Add {u}int_fast defs ideal for x86_64 Noah Goldstein
2022-04-11 2:15 ` Adam Sampson
2022-04-11 6:34 ` Florian Weimer [this message]
2022-04-14 22:24 ` Joseph Myers
2022-04-14 22:44 ` Noah Goldstein
2022-04-14 22:21 ` [PATCH v1 1/2] stdlib: Refactor {u}int_fast defs in stdint Joseph Myers
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