Give Sparc instruction patterns direct types instead of register classes.

Also update the documentation since Sparc is the nicest backend, and
used as an example in WritingAnLLVMBackend.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177835 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed