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Re: Bug in loop optimize (invalid postinc to preinc transformation)
- To: Dave Korn <davek-ml at ntlworld dot com>
- Subject: Re: Bug in loop optimize (invalid postinc to preinc transformation)
- From: Richard Henderson <rth at redhat dot com>
- Date: Fri, 29 Dec 2000 00:52:48 -0800
- Cc: Tim Hollebeek <tim at hollebeek dot com>, Geoff Keating <geoffk at geoffk dot org>, Alexandre Oliva <aoliva at redhat dot com>, kenner at vlsi1 dot ultra dot nyu dot edu, gcc <gcc at gcc dot gnu dot org>, Robert Dewar <dewar at gnat dot com>
- References: <200012282342.SAA29717@cj44686-b.reston1.va.home.com> <028901c0715f$36a61620$1998fd3e@ubik>
On Fri, Dec 29, 2000 at 06:18:26AM -0000, Dave Korn wrote:
> >int main(void) {
> > do {
> > i++;
> > } while(p++<(unsigned char *)0xffffffff);
[...]
> Now, what follows is from the n869 draft of the C9X standard....
All this is well and good, except that I don't believe
that it was ever claimed that this program was supposed
to be strictly conforming.
What is being lost sight of is that GCC is also used to
develop programs in non-hosted situations. In these
situations it is Known how the address space is shaped,
and we often do Very Nonconforming Things with addresses.
I don't see any particular reason why GCC should fail
this test. It just makes things less useful.
r~