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From: "jbeulich at suse dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/108941] Error: operand type mismatch for `shr' with binutils master
Date: Mon, 27 Feb 2023 10:17:40 +0000	[thread overview]
Message-ID: <bug-108941-4-heUwYsmPKl@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108941-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108941

--- Comment #4 from jbeulich at suse dot com ---
(In reply to Jakub Jelinek from comment #1)
> GCC inline asm has always worked like that, the operand is 8-bit and in GCC
> constants are always sign-extended.

But then ...

> If you try just
> static inline unsigned int
> foo (unsigned int a, signed char s)
> {
>   asm volatile ("# %1" : "+r" (a) : "ic" ((unsigned char) -s));

this should be sign-extension of the supplied value, i.e. the (potentially
negative) value cast to "unsigned char". And gas will be happy to accept that.

> In the assembly, if you have a spot which accepts 8-bit quantity, one
> shouldn't care if it is signed or unsigned.

I firmly disagree: I assume you did look at the description of the gas change.
A negative value for SHL may (by some) be viewed as reasonable (and as said in
the submission, I could have been convinced to further relax things, provided
fair arguments), but a negative value for RCL firmly is rubbish and hence
should have been rejected years ago.

  parent reply	other threads:[~2023-02-27 10:17 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-27  9:39 [Bug c/108941] New: " marxin at gcc dot gnu.org
2023-02-27  9:51 ` [Bug c/108941] " jakub at gcc dot gnu.org
2023-02-27 10:00 ` marxin at gcc dot gnu.org
2023-02-27 10:07 ` jakub at gcc dot gnu.org
2023-02-27 10:17 ` jbeulich at suse dot com [this message]
2023-02-27 10:33 ` jakub at gcc dot gnu.org
2023-02-27 10:57 ` jbeulich at suse dot com
2023-02-27 11:00 ` jbeulich at suse dot com
2023-02-27 11:02 ` jakub at gcc dot gnu.org
2023-02-27 11:11 ` jbeulich at suse dot com
2023-02-27 11:14 ` jakub at gcc dot gnu.org
2023-02-27 11:17 ` jakub at gcc dot gnu.org
2023-02-27 11:17 ` marxin at gcc dot gnu.org
2023-02-27 11:23 ` jakub at gcc dot gnu.org
2023-02-28  7:33 ` jbeulich at suse dot com
2023-02-28  7:47 ` jakub at gcc dot gnu.org
2023-02-28  7:59 ` jbeulich at suse dot com
2023-02-28  8:10 ` jakub at gcc dot gnu.org

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