Path: utzoo!utgpu!water!watmath!clyde!rutgers!cmcl2!brl-adm!adm!TLIMONCE%DREW.BITNET@CUNYVM.CUNY.EDU
From: TLIMONCE%DREW.BITNET@CUNYVM.CUNY.EDU
Newsgroups: comp.lang.c
Subject: Re: unofficial December notes
Message-ID: <10917@brl-adm.ARPA>
Date: 19 Dec 87 02:55:57 GMT
Sender: news@brl-adm.ARPA
Lines: 44

First of all, I'm all for noalias.  It helps generate faster
code for those who know how to use it.  It's like register;
if you don't know how to use it... DON'T USE IT.  Why
all the debate?  It simply is a warning to the compiler
that there are never going to be pointers to that object
that will change the value "behind the compilers back".
(actually, it says that there's no pointers that will
not change it either)

Second of all, I *HATE* the decision about parenthesis.  K&R says
that if the compiler can generate better code by re-writing
"(A+B)+C" to become "(A+C)+B" and now ANSI is saying no.  I guess
if functions a(), b() and c() have side effects ( a()+b() ) + c()
shouldn't be allowed to be re-grouped but why penilize the
programmers who don't use side effects.  This isn't encouraging
programmers to use side effects but it isn't helping either.

What happened to setting up a method of stateing "don't re-group me".
I know a #pragma was suggested but a lot of people don't like
pragmas.  What happened to the suggestion about a unary plus?
I see no problem with +( a()+b() ) + c() as a very clean method.
(I also think my macros may be nicer if I had a unary plus).

What really makes me not like this idea is the fact that I see
a lot of room for optimization when I realize that a[i] is *(a+i).
One of the reasons that "typical C" is faster than "typical
pascal"   (Ummm... note I say "typical"... I'm making a generalization
here.  No flames please) is that pascal people loop i from a to b
and process c[i].  That's a lot of (c+i)'s going on.  In C generally
you do i=&a and loop to &b.  When I do complex array processing
(a lot of my string work) I will now wonder what the optimizer
is NOT doing.

Someone stated (sorry, I forgot your name) that ANSI has given
us a new road to better code and removed anther.  I agree.
I think that removing this feature of C is the ONLY thing that
ANSI has done that I don't like so far.  This is certainly a
pretty good hit ratio.  Congradulations.

                Tom Limoncelli

BITNET: tlimonce@drew    LIFE: Drew U/Box 1060/Madison NJ/07940
Disclaimer:  Don't believe me.  It only encourages me to write more.
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