Path: utzoo!utgpu!water!watmath!clyde!rutgers!sri-spam!ames!nrl-cmf!cmcl2!brl-adm!adm!C90630JG%WUVMD.BITNET@CUNYVM.CUNY.EDU
From: C90630JG%WUVMD.BITNET@CUNYVM.CUNY.EDU
Newsgroups: comp.lang.c
Subject: Re: noalias
Message-ID: <11289@brl-adm.ARPA>
Date: 15 Jan 88 15:59:21 GMT
Sender: news@brl-adm.ARPA
Lines: 23

Doug Gywn writes:

>From:         Doug Gwyn <gwyn@brl-smoke.arpa>
>Subject:      Re: noalias and vectors
>
>In article <531@cresswell.quintus.UUCP> ok@quintus.UUCP (Richard A. O'Keefe)
> writes:
>>His statement that a "safe" vectorising compiler currently finds exactly
                                                                   -------
>>three safe places in "all the system software" is the kind of evidence I
>>was asking for that noalias would be useful.
>
>No, it's no such thing!  That's three places where "noalias" was NOT
>necessary in order to vectorize.  Because he didn't HAVE "noalias",

For once, Doug failed to carefully read the article to which he was
replying.  Clearly (at least to my mind) Richard, by using "exactly",
meant to make the same point Doug did; namely, that if noalias had
been available more vectorization would (presumably) have been possible,
with a resulting gain in speed, and that this was evidence that the
added keyword would have value.

Jonathan Goldberg