1. [GlobalISel][TableGen] Fix ConstrainOperandRC bug (details)
Commit 3c1d015edc755e8f3fa9c2a92d0b9bc81ba4d5fd by mikael.holmen
[GlobalISel][TableGen] Fix ConstrainOperandRC bug

TableGen would pick the largest RC for constraining the operands, which
could potentially be an unallocatable RC. This patch removes selection
of unallocatable RCs.

Reviewed By: arsenm

Differential Revision:
The file was modifiedllvm/utils/TableGen/GlobalISelEmitter.cpp
The file was modifiedllvm/utils/TableGen/CodeGenTarget.h
The file was modifiedllvm/test/TableGen/
The file was modifiedllvm/utils/TableGen/CodeGenTarget.cpp