Messages in this thread | | | Date | Fri, 26 Aug 2005 19:49:05 -0700 (PDT) | Subject | Re: [patch] IBM HDAPS accelerometer driver, with probing. | From | "David S. Miller" <> |
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From: Andi Kleen <ak@suse.de> Date: 27 Aug 2005 04:34:07 +0200
> "David S. Miller" <davem@davemloft.net> writes: > > > From: Alexey Dobriyan <adobriyan@gmail.com> > > Date: Sat, 27 Aug 2005 02:58:48 +0400 > > > > > What's the point of having unlikely() attached to every possible if ()? > > > > If can result in smaller code, for one thing, even if it > > isn't a performance critical path. > > Really? At least on x86 it tends to generate bigger code when > block reordering is enabled because a jump forward and a jump > backward and a possible label alignment are bigger than just > a single jump forward.
In the cases I've studied on sparc64 it keeps gcc from doing basic block replication in the unlikely paths.
I've only checked gcc-3.4 and earlier, gcc-4.x is just big bloated useless garbage and should be avoided for a couple of years. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.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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