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On Tue, 10 Feb 2004 22:28:11 -0800 Alex Pankratov <ap@swapped.cc> wrote: > > Second patch removes if's from hlist_xxx() functions. The idea > is to terminate the list not with 0, but with a pointer at a > special 'null' item. Luckily a single 'null' can be shared > between all hlists _without_ any synchronization, because its > 'next' and 'pprev' fields are never read. In fact, 'next' is > not accessed at all, and 'pprev' is used only for writing. I disagree with this change. The problem is that in a loop you need a register now to store the terminating element and compare to it instead of just testing for zero. This can generate much worse code on register starved i386 than having the conditional. If you really want to avoid the conditional you could restructure it so that i386 gcc can use a CMOV* (by using a pointer that either points to a dummy or the target). But that would make the code somewhat uglier and may not be worth it. -Andi - 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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