Clean up LDV, no functionality change.

Remove dead functions: renameRegister
Move private member variables from LDV to Impl
Remove ssp/uwtable from testing case


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175072 91177308-0d34-0410-b5e6-96231b3b80d8
For Mips 16, add the optimization where the 16 bit form of addiu sp can be used
if the offset fits in 11 bits. This makes use of the fact that the abi
requires sp to be 8 byte aligned so the actual offset can fit in 8
bits. It will be shifted left and sign extended before being actually used.
The assembler or direct object emitter will shift right the 11 bit
signed field by 3 bits. We don't need to deal with that here.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175073 91177308-0d34-0410-b5e6-96231b3b80d8