(1) Avoid hard-coding some register numbers.
(2) Fix some incorrect branch opcodes.
(3) Don't try to move int register to float register!
(4) If an operand being forwarded is a constant and it doesn't fit
into the immed field of the copy machine instruction, then
generate a load-constant instead of a copy.
(5) Use (unsigned long) 0 for copying a pointer via "add 0, ptr -> ptr2".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@683 91177308-0d34-0410-b5e6-96231b3b80d8
