Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 11/2/84; site seismo.UUCP Path: utzoo!watmath!clyde!bonnie!akgua!gatech!seismo!mo From: mo@seismo.UUCP (Mike O'Dell) Newsgroups: net.unix Subject: Re: Anybody have any experience with (Vax) Tartan C compiler? Message-ID: <5805@seismo.UUCP> Date: Tue, 4-Dec-84 10:04:05 EST Article-I.D.: seismo.5805 Posted: Tue Dec 4 10:04:05 1984 Date-Received: Thu, 6-Dec-84 03:03:15 EST References: <505@astrovax.UUCP> Organization: Center for Seismic Studies, Arlington, VA Lines: 18 Super-optimizing C compilers may be wonderful, but don't expect to compile your Kernel with such a beast. Also, be careful of code which calls time functions. It is very easy to break the kernel by moving code around!!!! The proposed ANSI C standard includes a new declaration keyword "volitile" to tell the compiler "don't optimize accesses to this variable", but until this is implemented, among other things, super-optimizing C compilers should be used with considerable care. Compilers which do a good job of code generation are another matter, but keep in mind that one person's good code generation may be another person's block optimizations. These comments are based on conversations with an author of a merely well-optimizing C compiler who had to work hard to make his kernel work again. -Mike O'Dell