* cFP class split into cFP32 and cFP64

* Fn args passed in registers are now recorded as used by the call instruction
`-> asm printer updated to not print out those registers with the call instr
* Stack frame layout in prolog/epilog fixed, spills and vararg fns now work
* float/double to signed int codegen now correct
* various single precision float codegen bugs fixed
* const integer multiply codegen fixed
* select and setcc blocks inserted into the correct place in machine CFG
* load of integer constant code optimized

All of Shootout tests now work.  Great thanks to Nate Begeman for the patch!

llvm-svn: 15014