Add floating-point branches and compares. Compares don't complete

Add floating-point branches and compares.  Compares don't complete
until the next cycle, and there's no interlock, so they effectively
have a delay slot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14686 91177308-0d34-0410-b5e6-96231b3b80d8