From: peterz@infradead.org (Peter Zijlstra)
To: linux-arm-kernel@lists.infradead.org
Subject: Build failure with v4.9-rc1 and GCC trunk -- compiler weirdness
Date: Thu, 2 Feb 2017 10:02:16 +0100 [thread overview]
Message-ID: <20170202090216.GV6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1485975894.2560.13.camel@perches.com>
On Wed, Feb 01, 2017 at 11:04:54AM -0800, Joe Perches wrote:
> > +#define order_base_2(n) \
> > +( \
> > + __builtin_constant_p(n) ? ( \
> > + ((n) < 2) ? (n) : \
> > + ilog2((n) - 1) + 1) : \
> > + __order_base_2(n) \
> > + )
>
> Does this work properly when n is a signed negative value?
Do you see it returning a complex number?
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Joe Perches <joe@perches.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Laura Abbott <labbott@redhat.com>,
Will Deacon <will.deacon@arm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Markus Trippelsdorf <markus@trippelsdorf.de>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
james.greenhalgh@arm.com,
Gregory Clement <gregory.clement@free-electrons.com>,
Stephen Boyd <sboyd@codeaurora.org>
Subject: Re: Build failure with v4.9-rc1 and GCC trunk -- compiler weirdness
Date: Thu, 2 Feb 2017 10:02:16 +0100 [thread overview]
Message-ID: <20170202090216.GV6515@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1485975894.2560.13.camel@perches.com>
On Wed, Feb 01, 2017 at 11:04:54AM -0800, Joe Perches wrote:
> > +#define order_base_2(n) \
> > +( \
> > + __builtin_constant_p(n) ? ( \
> > + ((n) < 2) ? (n) : \
> > + ilog2((n) - 1) + 1) : \
> > + __order_base_2(n) \
> > + )
>
> Does this work properly when n is a signed negative value?
Do you see it returning a complex number?
next prev parent reply other threads:[~2017-02-02 9:02 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-17 18:38 Build failure with v4.9-rc1 and GCC trunk -- compiler weirdness Will Deacon
2016-10-17 18:38 ` Will Deacon
2016-10-17 19:43 ` Ard Biesheuvel
2016-10-17 19:43 ` Ard Biesheuvel
2016-10-19 13:35 ` Will Deacon
2016-10-19 13:35 ` Will Deacon
2016-10-19 14:59 ` Ard Biesheuvel
2016-10-19 14:59 ` Ard Biesheuvel
2016-10-19 15:01 ` Ard Biesheuvel
2016-10-19 15:01 ` Ard Biesheuvel
2016-10-19 15:11 ` Arnd Bergmann
2016-10-19 15:11 ` Arnd Bergmann
2016-10-19 15:27 ` Ard Biesheuvel
2016-10-19 15:27 ` Ard Biesheuvel
2016-10-19 15:44 ` Arnd Bergmann
2016-10-19 15:44 ` Arnd Bergmann
2016-10-19 15:32 ` Gregory CLEMENT
2016-10-19 15:32 ` Gregory CLEMENT
2016-10-19 15:58 ` Russell King - ARM Linux
2016-10-19 15:58 ` Russell King - ARM Linux
2016-10-19 15:37 ` Markus Trippelsdorf
2016-10-19 15:37 ` Markus Trippelsdorf
2016-10-19 15:55 ` Linus Torvalds
2016-10-19 15:55 ` Linus Torvalds
2016-10-19 15:56 ` Markus Trippelsdorf
2016-10-19 15:56 ` Markus Trippelsdorf
2016-10-19 16:00 ` Ard Biesheuvel
2016-10-19 16:00 ` Ard Biesheuvel
2016-10-19 16:01 ` Linus Torvalds
2016-10-19 16:01 ` Linus Torvalds
2016-10-19 16:22 ` Will Deacon
2016-10-19 16:22 ` Will Deacon
2017-02-01 16:58 ` Laura Abbott
2017-02-01 16:58 ` Laura Abbott
2017-02-01 17:36 ` Ard Biesheuvel
2017-02-01 17:36 ` Ard Biesheuvel
2017-02-01 18:19 ` Ard Biesheuvel
2017-02-01 18:19 ` Ard Biesheuvel
2017-02-01 19:04 ` Joe Perches
2017-02-01 19:04 ` Joe Perches
2017-02-01 19:31 ` Ard Biesheuvel
2017-02-01 19:31 ` Ard Biesheuvel
2017-02-01 19:49 ` Joe Perches
2017-02-01 19:49 ` Joe Perches
2017-02-01 19:53 ` Ard Biesheuvel
2017-02-01 19:53 ` Ard Biesheuvel
2017-02-01 20:34 ` Joe Perches
2017-02-01 20:34 ` Joe Perches
2017-02-01 21:11 ` Ard Biesheuvel
2017-02-01 21:11 ` Ard Biesheuvel
2017-02-02 9:02 ` Peter Zijlstra [this message]
2017-02-02 9:02 ` Peter Zijlstra
2017-02-01 21:50 ` Laura Abbott
2017-02-01 21:50 ` Laura Abbott
2017-02-02 9:17 ` Ard Biesheuvel
2017-02-02 9:17 ` Ard Biesheuvel
2017-02-02 15:43 ` Laura Abbott
2017-02-02 15:43 ` Laura Abbott
2017-02-02 15:45 ` Ard Biesheuvel
2017-02-02 15:45 ` Ard Biesheuvel
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