[llvm] [TailDuplicator] Add a limit on the number of indirect branch successors (PR #78582)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

The PHI node issue is interesting... I would have thought that if you have a bunch of identical PHIs, the register allocator would do the right thing, but maybe not.

> I'll continue to work on this issue. Even if I submit a workaround, I'll try to explain the various issues I've found. :)

Okay, sounds good.

https://github.com/llvm/llvm-project/pull/78582