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Message-ID: <CAFo99gaF5ax4uVn1UCxqh5S158bYsiAtV9T6h3Z=zT0ucQzSyw@mail.gmail.com> Date: Mon, 2 Jun 2014 19:59:39 +0200 From: Rickard Strandqvist <rickard_strandqvist@...ctrumdigital.se> To: Clemens Ladisch <clemens@...isch.de> Cc: Tony Luck <tony.luck@...el.com>, Fenghua Yu <fenghua.yu@...el.com>, Paul Gortmaker <paul.gortmaker@...driver.com>, "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>, "Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>, linux-ia64@...r.kernel.org, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH] arch: ia64: kernel: palinfo.c: Optimization of the Code Hi Thought I would be able to do that. But after testing, I could not measure any difference. Thought it would make a noticeable difference, but guess gcc resolve this in the best way. Best regards Rickard Strandqvist 2014-06-02 9:24 GMT+02:00 Clemens Ladisch <clemens@...isch.de>: > Rickard Strandqvist wrote: >> From what I know, AND is faster then modulo. > > Which is why the compiler does this optimization automatically, > if it can prove that it is correct. > >> - if (i != 0 && (i%64) == 0) >> + if (i != 0 && (i&63) == 0) > > Did you prove that i cannot be negative? > > > Regards, > Clemens -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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