Re: test13-pre5

From: Andi Kleen (
Date: Thu Dec 28 2000 - 18:43:47 EST

On Thu, Dec 28, 2000 at 03:37:51PM -0800, Linus Torvalds wrote:
> On Fri, 29 Dec 2000, Andi Kleen wrote:
> >
> > Hopefully all the "goto out" micro optimizations can be taken out then too,
> "goto out" often generates much more readable code, so the optimization is
> secondary.

I was more thinking of cases like the scheduler's gotos, which has gotten
rather spagetti recently. Admittedly classic goto out is often more readable
than many nested if()s with error handling.

> > I recently found out that gcc 2.97's block moving pass has the tendency
> > to move the outlined blocks inline again ;)
> Too bad. Maybe somebody should tell gcc maintainers about programmers that
> know more than the compiler again.

In x86-64 which relies on 2.97 I'm using __builtin_expect, defined to
likely() and unlikely(), which seems to generate good code.

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