From mboxrd@z Thu Jan  1 00:00:00 1970
From: fche@redhat.com (Frank Ch. Eigler)
To: Joe Buck <jbuck@synopsys.COM>
Cc: max@e-soft.ru (Maxim Dementiev), gcc@gcc.gnu.org
Subject: Re: Using throw(): to use or not to use?
Date: Thu, 29 Nov 2001 12:59:00 -0000
Message-ID: <o5k7w9s3b4.fsf@toenail.toronto.redhat.com>
References: <200111291735.JAA05491@atrus.synopsys.com>
X-SW-Source: 2001-11/msg01581.html
Message-ID: <20011129125900.avPSCYuFW1iahNSdAtQK62Yte5QSjnDw5Ghpiyp0ZEs@z>

Joe Buck <jbuck@synopsys.COM> writes:

: [...]  Specififying throw() should, if anything, make it possible to
: generate slightly faster code.  If the code is instead slower, I'd
: call it a bug, [...]

Not really.  Within the body of a function declared with throw(), the
compiler must normally emit *extra* code that asserts that there are
no exceptions thrown from it, sort of like this:

   try { BODY } catch (...) { abort(); }

The *caller* of such a function may in turn assume that no exceptions
can come back out, so the compiler may (eventually?) optimize based on
that.  So, specifying throw() allows new optimization opportunities
only at the caller.


- FChE