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Re: A prototype loop reverser for the scalarizer
On 10/8/06, Steven Bosscher <stevenb.gcc@gmail.com> wrote:
On 10/8/06, Daniel Berlin <dberlin@dberlin.org> wrote:
> Really, you shouldn't be reimplementing these loop transforms at
> another level, you should improve the existing infrastructure so it
> has the heuristics to do what you want.
This is total bollocks unless you can optimize away the additional
temporary and the copy-in©-out operations. I don't see _that_
happening any time soon.
It will *never* happen unless people stop reimplementing things where
it may be temporarily easiest for them, and instead do it where it
will bring the most benefit, even if it's harder.
Plus, there is much more detailed information readily available in the
front end than what the middle-end will be able to derive.
And to avoid the situation we have in RTL, where we've lost all the
useful info, you should, you know, pass that information to the middle
end, so it can do this.
Going off and implementing a highly optimizing frontend may help you
in the short term, but it's an incredibly wrong headed strategy in the
long term.
But hey, why should we introduce long term thinking into GCC now, when
you can do something locally good with a design that won't work for
you in 5 years when the world changes.
So it's only right to add these transformations in the Fortran front end.
Again, I disagree.