On 6/18/2026 1:21 AM, Aldy Hernandez wrote:
Andrew MacLeod <[email protected]> writes:
This patch provides the initial implementation to track points-to
information in prange.
Very cool. This was one of two things I really wished I could've gotten
done before stepping aside. I'm glad it didn't fall through the cracks.
And the second one is... getting rid of DOM. With prange having
points-to info, ISTM that all that's standing in the way of getting rid
of DOM is doing the hard work of finding what the side tables are
getting that ranger doesn't. It theory it should be nothing; in
practice it's always complicated :).
Last time I did an audit of what the forward threader was getting I
think it was some pointer equivalency stuff, as I think we were even
getting all the floating point stuff with frange.
That is, if y'all still agree that removing the forward threader along
with DOM is the way to go. I don't know if anything has changed.
Maybe after summer is over, and the kids are back in school, I can take
a stab at auditing what remains to be done, to at least get an idea.
Again, thanks for your hard work on this. Sorry I haven't been able to
help much.
Dropping DOM's threading as well as DOM itself should still be the plan
of record. As you note, the actual mechanics of doing that without
regressing is complicated.
What I expected us to find in that effort was that things like
const/copy propagation and redundant expression elimination are better
handled by other passes and can largely be dropped. The path specific
optimizations are probably within reach of ranger now. What would be
left would be the backwards propagation bits. At least that's the way it
seems to me without actually instrumenting DOM to see what's left that's
triggering in practice.
jeff
