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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/40988] incorrect code when using ..._bit macros from asm/bitops.h in a loop in userspace program
Date: Wed, 03 Apr 2024 22:35:16 +0000	[thread overview]
Message-ID: <bug-40988-4-tpQrK6MSmm@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-40988-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40988

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So yes I was correct in saying the inline-asm was incorrect. it should have
been:
```

        __asm__ __volatile__(
                "btrl %2,%1\n\tsbbl %0,%0"
                :"=r" (oldbit), "+m" (ADDR)
                :"Ir" (nr) : "memory");
        return oldbit;
```

as this both reads and write the memory.

  parent reply	other threads:[~2024-04-03 22:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-40988-4@http.gcc.gnu.org/bugzilla/>
2021-08-09  5:19 ` pinskia at gcc dot gnu.org
2024-04-03 22:35 ` pinskia at gcc dot gnu.org [this message]
2024-04-03 22:46 ` pinskia at gcc dot gnu.org

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