[PATCH] D29448: [RegAlloc] Don’t freeze reserved registers again if it is not necessary

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In https://reviews.llvm.org/D29448#672445, @qcolombet wrote:

> What happen if we just freeze in the regalloc code?
>  Basically, are there any other pass that needs to know about that?


This would be greatly preferable. I ran into this problem before. I think it's important to freeze this in regalloc because currently you can't make decisions in ExpandISelPseudos that change the set of reserved registers. Where it's called the first time is too early


https://reviews.llvm.org/D29448