* Use LI(S) to copy constants into registers intead of ADDI(S) as the latter is

* Use LI(S) to copy constants into registers intead of ADDI(S) as the latter is
  a funky way to "use" R0 for a 0-valued operand
* Add IMPLICIT_DEFs for incoming function arguments via registers to help the
  register allocator not clobber those registers
* Implement comparisons with longs
* Teach emitSelectOperation() to fold the SetCC operation

Patch contributed by Nate Begeman

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14901 91177308-0d34-0410-b5e6-96231b3b80d8