From VMS to UNIX

[dbj.rice%rand-relay at sri-unix.UUCP]

From:  Dave Johnson <dbj.rice at rand-relay>

        "If the VMS C compiler is as good (code wise) as BLISS ..."

Sadly, the VMS C compiler's code isn't as good as the Bliss compiler's.
While it does an excellent job of optimizing register usage over the whole
procedure and emiminating all kinds of "dead" code, etc., it fails fairly
badly on some very simple local optimizations.  For example, it generates
three instructions to check if one of the "wonderful" VMS return codes
(currently being discussed on this list (sigh)) is a success or failure
code.  The Unix C compiler (pcc) generates only one instruction for the same
thing...

                                        Dave Johnson
                                        Dept. of Math Science
                                        Rice University
                                        dbj.rice at Rand-Relay