[Bug c/45831] 0 = 10 (with -O0, 0 = 0 with -O1, but 10 = 10 expected)

["MichieldeB at aim dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45831

--- Comment #16 from Michiel <MichieldeB at aim dot com> 2010-09-30 19:38:55 UTC ---
(In reply to comment #15)
> (In reply to comment #14)
> >
> > Is that really too hard?
>
> You are ignoring everything everybody is saying. If you think it is trivial,
> just take one single little case of the ones that bother you and fix it:
> 
> http://gcc.gnu.org/contribute.html
> 
> GCC needs more developers anyway, so you are welcome on board.

I am not ignoring everyone, since I formulated things far more concrete than
before. And I failed to formulate similar things to warnings for assigning
negative expressions to unsigned integers.

Another thing that is worth noting, is that recognizing expression as mentioned
above is also valuable for optimization, namely if you convert the result later
to a smaller integral type, and the larger integral type is larger than the
machines integral type, then you better do the computations with the smaller
integral type instead.

I have to apologize. There are already too many technically interesting things,
or just interesting things that are also technically, that I want to do.
Furthermore, I think that it will take very much time before I can make my
first contribution to the compiler, but I should browse the source to get a
better opinion on that. Some library routines would be more attainable, I will
think about that.