From: Dale Johannesen <dalej@apple.com>
To: Joe Buck <Joe.Buck@synopsys.COM>
Cc: gcc@gcc.gnu.org, Hiroshi Fujishima <hiroshi.fujishima@gmail.com>,
Dale Johannesen <dalej@apple.com>,
Eric Botcazou <ebotcazou@libertysurf.fr>
Subject: Re: isinf
Date: Wed, 13 Jul 2005 23:39:00 -0000 [thread overview]
Message-ID: <73cf76e2f096ced076770648b329776d@apple.com> (raw)
In-Reply-To: <20050713232903.GA14174@synopsys.com>
On Jul 13, 2005, at 4:29 PM, Joe Buck wrote:
> On Thu, Jul 14, 2005 at 08:16:07AM +0900, Hiroshi Fujishima wrote:
>> Eric Botcazou <ebotcazou@libertysurf.fr> writes:
>>
>>>> The configure script which is included in rrdtool[1] checks whether
>>>> the system has isinf() as below.
>>>>
>>>> #include <math.h>
>>>> int
>>>> main ()
>>>> {
>>>> float f = 0.0; isinf(f)
>>>> ;
>>>> return 0;
>>>> }
>>>
>>> The test is clearly fragile. Assigning the return value of isinf to
>>> a
>>> variable should be sufficient for 4.0.x at -O0.
>>
>> Yes, I contact rrdtool maintainer. Thank you.
>
> Best to make it a global variable, to guard against dead code
> elimination.
Volatile would be even better. It's valid to eliminate stores into
globals
if you can determine the value isn't used thereafter, which we can here,
at least theoretically.
next prev parent reply other threads:[~2005-07-13 23:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-07-13 17:07 isinf Hiroshi Fujishima
2005-07-13 19:08 ` isinf Eric Botcazou
2005-07-13 22:32 ` isinf Hiroshi Fujishima
2005-07-13 22:59 ` isinf Eric Botcazou
2005-07-13 23:17 ` isinf Hiroshi Fujishima
2005-07-13 23:29 ` isinf Joe Buck
2005-07-13 23:39 ` Dale Johannesen [this message]
2005-07-13 23:48 ` isinf Hiroshi Fujishima
2005-07-14 6:27 ` isinf Eric Botcazou
2005-07-14 6:52 ` isinf Michael Veksler
2005-07-14 7:33 ` isinf Eric Botcazou
2005-07-14 7:56 ` isinf Michael Veksler
2005-07-14 8:59 ` isinf Andreas Schwab
2005-07-14 9:10 ` isinf Eric Botcazou
2005-07-14 9:27 ` isinf Hiroshi Fujishima
2005-07-14 9:35 ` isinf Jakub Jelinek
2005-07-14 9:47 ` isinf Andreas Schwab
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