RE: Kernel bugs found using inspect tool

From: Ben Kosse (
Date: Tue Feb 29 2000 - 03:19:15 EST

> wrote:
> > > if((a == b) | (c == d) | (e < f))
> >
> > I'm right when I say "The rules have changed. Consider bit-logicals. Time
> > your critical inner loops". It all depends on the exact details of the code
> > & the processor. When c, d, e, and f are simple variables and the first two
> > branches are hard to predict, bit-ors should be faster on all the latest
> > superscalar systems.
> If c, d, e and f are simple variables, then the compiler should be able to
> tell that it makes no difference whatsoever whether | or || is used, and
> should generate the same (fastest) code for both.

Not necessarily true. || has the side effect of allowing you to jump out after
the first comparison. | *REQUIRES* you do all comparisons.

Ben Kosse <>

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