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Postings from August 2010
* Eric Brine <ikegami@adaelis.com> [2010-07-12 06:55]:
> On Sun, Jul 11, 2010 at 10:22 PM, David Golden <xdaveg@gmail.com> wrote:
> > I'm suggesting that we disclaim any implicit guarantee that the
> > compiler won't optimize away expressions that have side effects when
> > evaluated.
> >
>
> Without that guarantee,
>
> my $x = f()
> or DEBUG && warn(...);
> return $x;
>
> would be buggy. Dunno if that matters
Why?
As far as I can tell, the compiler would statically determine
that it can optimise the `DEBUG && warn` part down to `!1` when
`DEBUG` is false. This seems correct to me.
It would also statically determine that an `or !1` clause in that
statement does nothing, and so fold it away altogether.
That would leave the code looking like
my $x = f();
return $x;
when `DEBUG` is false.
Which seems 100% on the mark to me.
Am I missing something in your objection?
Regards,
--
Aristotle Pagaltzis // <http://plasmasturm.org/>
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