[PATCH] D22122: [SCCP] Teach the pass about bitcasts

[Davide Italiano via llvm-commits]

davide added a comment.

In http://reviews.llvm.org/D22122#477670, @eli.friedman wrote:

> I guess it's a good idea to try to fold constants as we build them... it's slightly more efficient, and it could avoid spurious "overdefined" markings in some cases.  Might as well make a pass over the whole file while you're at it to find other places where we do something similar.
>
> That said, I doubt it makes much of a difference in practice.


Thanks! I'll land this and go over the file to find other cases where we can fold as we build.
As a meta-goal, and something I'm trying to work on in the near future:

1. SCCP doesn't  handle vectors. There's some code for it but it's `#if 0`'d . I re-enabled that code and tried to build and it passes test suite and it's able to self-host LLVM, so, I'm not entirely sure why that code is disabled and the comments in the code don't help :| Do you happen to know what's the reason?
2. SCCP doesn't process multiple value ret instructions at the moment. I plan to add support for that soon.


http://reviews.llvm.org/D22122