When Mips16 frames grow large, the immediate field may exceed the maximum
allowed size for the instruction. This code uses RegScavenger to fix this.
We sometimes need 2 registers for Mips16 so we must handle things
differently than how register scavenger is normally used.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174696 91177308-0d34-0410-b5e6-96231b3b80d8