Path: utzoo!utgpu!water!watmath!clyde!rutgers!mit-eddie!uw-beaver!tektronix!zeus!tekla!dant
From: dant@tekla.TEK.COM (Dan Tilque;1893;92-789;LP=A;60aC)
Newsgroups: comp.lang.c
Subject: noalias; parens honored
Keywords: ANSI C standard
Message-ID: <2845@zeus.TEK.COM>
Date: 17 Dec 87 07:20:43 GMT
References: <6829@brl-smoke.ARPA>
Sender: news@zeus.TEK.COM
Reply-To: dant@tekla.UUCP (Dan Tilque)
Organization: Church of Christ, Secular Humanist
Lines: 31

Doug Gwyn writes:
>
>The good news is, it appears that the second formal public review of
>the draft proposed standard for C may start as early as February.
>This time it will last for two months, and we hope that nothing will
>turn up that requires more than minor editorial changes for the final
>official standard.
>
>A new keyword, "noalias", was added; it's a type-qualifier like const
>and volatile.  Its only function is to permit tighter optimization,
>
>Parenthesis grouping is now honored.  

The Committee giveth and the Committee taketh away.  On the one hand they
take away optimization by requiring the parenthesis be honored but then
they add a whole new keyword, "noalias", to allow better optimization by
compilers.  Will they please make up their collective mind.

It also seems pretty late in the process to be making major changes like
adding keywords.  Is there any current compiler (i.e. prior art) which
uses 'noalias'?  If so, how much better is the code generated by it?

Also, how much worse will the code be when paren grouping must be honored?

I'm still trying to figure out exactly how to use 'const' and 'volatile'.
Of course, I don't have a compiler which will accept them, so the question
is moot for now.

---
Dan Tilque
dant@tekla.tek.com  or dant@tekla.UUCP