From: Robert Jarzmik <robert.jarzmik@free.fr>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 2/4] introduce region_overlap() function
Date: Sat, 06 Oct 2012 21:44:54 +0200 [thread overview]
Message-ID: <87obkfxu4p.fsf@free.fr> (raw)
In-Reply-To: <20121005213302.GZ1322@pengutronix.de> (Sascha Hauer's message of "Fri, 5 Oct 2012 23:33:02 +0200")
Sascha Hauer <s.hauer@pengutronix.de> writes:
> You made me curious. I tried to compile both and here is the result on
> ARM (I swapped the arguments left and right of the &&):
>
...zip...
>
> Maybe gcc isn't so clever on other architectures, I don't know ;)
You're right.
Same conclusion on x86 with gcc 4.7. I had tried that a long time ago (maybe 10
years or so) on x86, benchmarking both pure C and Java on this very function (it
was for aircrafts timeslots conflicts discovery).
At that time, the "startA <= endB && endA >= startB" was fastest. So compilation
technique have improved enough to write maintainable code after all :)
Cheers.
--
Robert
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next prev parent reply other threads:[~2012-10-06 19:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-05 16:45 [PATCH] cleanup arm startup a bit Sascha Hauer
2012-10-05 16:45 ` [PATCH 1/4] ARM: add assembly function for setting up C environment Sascha Hauer
2012-10-05 16:45 ` [PATCH 2/4] introduce region_overlap() function Sascha Hauer
2012-10-05 19:55 ` Robert Jarzmik
2012-10-05 21:33 ` Sascha Hauer
2012-10-06 19:44 ` Robert Jarzmik [this message]
2012-10-07 6:59 ` Antony Pavlov
2012-10-05 16:45 ` [PATCH 3/4] ARM: cleanup piggydata copy check Sascha Hauer
2012-10-05 16:45 ` [PATCH 4/4] ARM: simplify start.c Sascha Hauer
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