From: Timothy Miller <miller@techsource.com>
To: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] only use 48-bit lba when necessary
Date: Fri, 18 Apr 2003 10:34:44 -0400 [thread overview]
Message-ID: <3EA00D04.6090705@techsource.com> (raw)
In-Reply-To: 200304172137_MC3-1-34EB-2D39@compuserve.com
Chuck Ebbert wrote:
>Matt Mackall wrote:
>
>
>
>
>>FYI, GCC as of 3.2.3 doesn't yet reduce the if(...) form to branchless
>>code but the & and && versions come out the same with -O2.
>>
>>
>
>
> The operands of & can be evaluated in any order, while && requires
>left-to-right and does not evaluate the right operand if the left one
>is false. Only the simplest cases could possibly generate the same
>code.
>
>
>
I have a vague memory of reading a kerneltrap.org article or comment
thread which discussed this. The determination was that a compiler
could choose to fully evaluate the logical expression if there were no
side-effects.
next prev parent reply other threads:[~2003-04-18 14:07 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-18 1:34 [PATCH] only use 48-bit lba when necessary Chuck Ebbert
2003-04-18 4:18 ` Matt Mackall
2003-04-18 14:34 ` Timothy Miller [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-04-18 9:50 Chuck Ebbert
2003-04-18 3:32 linux-kernel
2003-04-04 17:02 Chuck Ebbert
2003-04-17 14:20 ` Matt Mackall
2003-04-17 15:24 ` Timothy Miller
2003-04-17 16:05 ` Matt Mackall
2003-04-17 18:49 ` Timothy Miller
2003-04-04 12:29 Jens Axboe
2003-04-04 13:19 ` Juan Quintela
2003-04-04 13:22 ` Jens Axboe
2003-04-04 15:48 ` Juan Quintela
2003-04-04 15:54 ` Jens Axboe
2003-04-04 17:06 ` John Bradford
2003-04-04 14:40 ` Andries Brouwer
2003-04-04 15:13 ` Jens Axboe
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