This patch adds the register class for MIPS16 as well as the ability for
llc to recognize MIPS16 as a MIPS ASE extension. -mips16 will mean the
mips16 ASE for mips32 by default.
As part of fixing of adding this we discovered some small changes that
need to be made to MipsInstrInfo::storeRegToStackSLot and
MipsInstrInfo::loadRegFromStackSlot. We were using some "==" equality tests
where in fact we should have been using Mips::<regclas>.hasSubClassEQ instead,
per suggestion of Jakob Stoklund Olesen.
Patch by Reed Kotler.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156958
91177308-0d34-0410-b5e6-
96231b3b80d8