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From: "rguenth at gcc dot gnu.org" <sourceware-bugzilla@sourceware.org>
To: glibc-bugs@sourceware.org
Subject: [Bug string/31055] Request: guarantee that memcpy(x, x, n) is well-defined
Date: Fri, 24 Nov 2023 09:37:05 +0000	[thread overview]
Message-ID: <bug-31055-131-DsgiE58WeL@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-31055-131@http.sourceware.org/bugzilla/>

https://sourceware.org/bugzilla/show_bug.cgi?id=31055

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Ralf Jung from comment #8)
> Is there a URL where that documentation can be found? That could be useful
> to reference in the future.

https://gcc.gnu.org/onlinedocs/gcc/Standards.html#C-Language

at its end it says

"Most of the compiler support routines used by GCC are present in libgcc, but
there are a few exceptions. GCC requires the freestanding environment provide
memcpy, memmove, memset and memcmp. Contrary to the standards covering memcpy
GCC expects the case of an exact overlap of source and destination to work and
not invoke undefined behavior. Finally, if __builtin_trap is used, and the
target does not implement the trap pattern, then GCC emits a call to abort."

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  parent reply	other threads:[~2023-11-24  9:37 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-11 17:37 [Bug string/31055] New: " post+sourceware.org at ralfj dot de
2023-11-11 18:41 ` [Bug string/31055] " sam at gentoo dot org
2023-11-13 18:47 ` adhemerval.zanella at linaro dot org
2023-11-18 17:56 ` post+sourceware.org at ralfj dot de
2023-11-21 15:30 ` adhemerval.zanella at linaro dot org
2023-11-23  7:36 ` post+sourceware.org at ralfj dot de
2023-11-23 11:53 ` adhemerval.zanella at linaro dot org
2023-11-23 14:48 ` sam at gentoo dot org
2023-11-23 15:18 ` post+sourceware.org at ralfj dot de
2023-11-24  7:46 ` rguenth at gcc dot gnu.org
2023-11-24  8:52 ` post+sourceware.org at ralfj dot de
2023-11-24  9:37 ` rguenth at gcc dot gnu.org [this message]
2023-11-28  7:18 ` sam at gentoo dot org

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