Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site watcgl.UUCP Path: utzoo!watmath!watcgl!dmmartindale From: dmmartindale@watcgl.UUCP (Dave Martindale) Newsgroups: net.lang.c Subject: Re: Can ANSI Standard C be "Optimized" Message-ID: <2267@watcgl.UUCP> Date: Sun, 18-Mar-84 13:01:35 EST Article-I.D.: watcgl.2267 Posted: Sun Mar 18 13:01:35 1984 Date-Received: Mon, 19-Mar-84 07:22:54 EST References: <404@decvax.UUCP> Organization: U of Waterloo, Ontario Lines: 15 The "no optimization across statement boundaries" certainly wasn't part of the language spec before the ANSI committee. For as long as I can remember, the Ritchie C compiler for the PDP11 (actually c2, the optimizer) was happy to generate a SOB instruction if it could be done. You'll see some C code that contains loops of the form if (n > 0) do {} while (--n); By putting the loop termination condition in exactly that form, you got a SOB (Subtract One and Branch if non-zero) inserted. Writing the code using a while loop would have been clearer but slower.