gcc3 vs 176.gcc

[dewar@gnat.com]

<<Having thought about it more, I now think gcc3's behavior in this
case is clearly wrong, at least as a quality-of-implementation issue.
The aliasing rules are there to permit compilers to make aggressive
assumptions when they can't tell whether two memrefs alias or not.
They are not there to permit compilers to do stupid things when they
can easily tell that two memrefs do alias.  The examples in the
Rationale make this clear.
>>

Sounds resaonable, but we can we have a bit more detail on the meaning
of "stupid things" and "easily tel that two memrefs do alias". These
things need to be defined by more than feel for what's right. For one
thing, compilers improve all the time in their ability to "easily tell"
things, and people's ideas of what constitute "stupid things" can easily
differe (as we see from this thread and others :-)

So there should be a clear statement of the language rule that you are
proposing here.