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From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.lang.c
Subject: Re: low level optimization
Message-ID: <26956:Apr2217:39:1291@kramden.acf.nyu.edu>
Date: 22 Apr 91 17:39:12 GMT
References: <21815@lanl.gov> <25371:Apr1907:22:5091@kramden.acf.nyu.edu> <22004@lanl.gov>
Organization: IR
Lines: 25

In article <22004@lanl.gov> jlg@cochiti.lanl.gov (Jim Giles) writes:
> It has been suggested that a program of the following type constitutes
> a counterexample to my previous statements about pointers and aliasing:
> func(i,j)
> char *i;
> float *j;

Well, no, that's not what I said, and you should learn the difference
between char/void pointers and non-char/void pointers.

> However, my original statement about pointers and aliasing was that
> pointer arguments to the _same_ underlying type must be assumed to be
> aliased to each other and to all globals of that type

Jim, I despise the way that you are trying to escape your mistake by
failing to quote what you claim to be responding to. You were arguing
with Doug Gwyn; you said ``I have never seen any of these hypothetical
contexts in which anonymous pointer arguments passed in as parameters
can be safely assumed not to be aliased.'' I showed you how a very
common type of sorting routine provided exactly such a context.

Now are you saying you've never seen such sorting routines? Or do you
admit that you simply haven't thought through the issues here?

---Dan