HomePhabricator

[X86] Fix a bug in handling GRXX subclasses in Domain Reassignment pass

Description

[X86] Fix a bug in handling GRXX subclasses in Domain Reassignment pass

When trying to determine the correct Mask register class corresponding
to a GPR register class, not all register classes were handled.
This caused an assertion to be raised on some scenarios.

Differential Revision:
https://reviews.llvm.org/D40290