[PATCH] D30661: [x86] Split MXCSR into two pseudo-registers

[Reid Kleckner via Phabricator via llvm-commits]

rnk added a comment.

In https://reviews.llvm.org/D30661#693773, @efriedma wrote:

> This isn't backward-compatible with existing IR which clobbers mxcsr.  You could auto-upgrade, I guess.  Alternatively, you could make the status bits a subregister of MXCSR instead of modeling it as two completely separate registers.


I didn't think these were supported for modelling inline asm constraints. Besides, the "mxcsr" constraint is less than two months old. Certainly we aren't required to be backwards compatible with it yet.


Repository:
  rL LLVM

https://reviews.llvm.org/D30661