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From: Jakub Jelinek <jakub@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Richard Biener <rguenther@suse.de>,
	linux-toolchains@vger.kernel.org, Michael Matz <matz@suse.de>,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: older gccs and case labels producing integer constants
Date: Wed, 6 Apr 2022 11:53:15 +0200	[thread overview]
Message-ID: <Yk1jC4oLnIklOTHI@tucnak> (raw)
In-Reply-To: <YkwbygWj/C3XooMV@zn.tnic>

On Tue, Apr 05, 2022 at 12:36:58PM +0200, Borislav Petkov wrote:
> On Tue, Apr 05, 2022 at 12:06:45PM +0200, Richard Biener wrote:
> > Wird auch mit gcc 11 rejected.  Kanns sein dass mit gcc 7 andere
> > compiler flags genommen werden?
> 
> Found it:
> 
> $ gcc -fsanitize=shift -c switch.c
> switch.c: In function ‘foo’:
> switch.c:10:7: error: case label does not reduce to an integer constant
>        case (((0xfc08) << 16) | (0x0101)):;
> 
> $ gcc --version
> gcc (SUSE Linux) 7.4.1 20190905 [gcc-7-branch revision 275407]
> Copyright (C) 2017 Free Software Foundation, Inc.
> 
> Something not fully backported?

That is rejected with -fsanitize=shift even on current trunk (in C, C++ is
fine).
C++ constexpr code has cases for ubsan builtins and internal functions,
but C just doesn't handle those apparently.

	Jakub


  parent reply	other threads:[~2022-04-06 13:17 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-05  9:50 older gccs and case labels producing integer constants Borislav Petkov
2022-04-05  9:58 ` Richard Biener
2022-04-05 10:04   ` Borislav Petkov
2022-04-05 10:06   ` Richard Biener
2022-04-05 10:36     ` Borislav Petkov
2022-04-05 10:45       ` Borislav Petkov
2022-04-05 11:41         ` Richard Biener
2022-04-07 15:16           ` Borislav Petkov
2022-04-05 11:37       ` Richard Biener
2022-04-06  9:53       ` Jakub Jelinek [this message]
2022-04-06 10:04         ` Jakub Jelinek
2022-04-05 12:23 ` Peter Zijlstra
2022-04-05 12:39   ` Michael Matz
2022-04-05 12:53     ` Richard Biener
2022-04-05 13:04       ` Borislav Petkov
2022-04-06 10:13   ` Jakub Jelinek

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