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From: "rearnsha at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/109166] Built-in  __atomic_test_and_set does not seem to be atomic on ARMv4T
Date: Mon, 25 Sep 2023 11:48:55 +0000	[thread overview]
Message-ID: <bug-109166-4-sH7VYOQrXl@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109166-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109166

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |WONTFIX
             Status|NEW                         |RESOLVED

--- Comment #8 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
I'm going to close this as WONTFIX.

There are several reasons for this.

There's no SWPH operation, so it's impossible to generalize atomic operations
for all basic data types.  It's not possible to synthesize a 16-bit atomic type
with either SWP or SWPB.

There's no support in Thumb state for SWP[B].

The instruction was removed in later versions of the architecture, which makes
code non-portable.

Finally, Armv4, which dates to around 1995, is essentially in maintenance only
mode and this is really a new feature request.  In fact, I don't think we'd
really want to add new features for anything before Armv7 these days (even that
is more than 10 years old).

  parent reply	other threads:[~2023-09-25 11:48 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-17  1:33 [Bug target/109166] New: " jdx at o2 dot pl
2023-03-17  2:26 ` [Bug target/109166] " pinskia at gcc dot gnu.org
2023-03-17  2:27 ` pinskia at gcc dot gnu.org
2023-03-19  7:37 ` jdx at o2 dot pl
2023-03-19 10:26 ` pinskia at gcc dot gnu.org
2023-03-19 13:57 ` jdx at o2 dot pl
2023-09-22 16:56 ` hp at gcc dot gnu.org
2023-09-22 17:30 ` hp at gcc dot gnu.org
2023-09-25 11:48 ` rearnsha at gcc dot gnu.org [this message]
2023-09-25 16:20 ` hp at gcc dot gnu.org
2023-09-26 21:40 ` cvs-commit at gcc dot gnu.org

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