Supporting FP cmp lib routines

[Joern Rennecke]

Quoting Mohamed Shafi <shafitvm@gmail.com>:
> I have implemented the above solution and it works. I have to support
> the same for DF also. But with DF i have a problem with the
> constraints. My target generates code for both big and little endian.
> The ABI specifies that when a 64bit value is passed as an argument
> they are passed in R6 and R7, R6 containing the most significant  long
> word and R7 containing the least significant long word, regardless of
> the  endianess mode. How can i do this in the DF compare pattern?

If 64 bit values are generally held in registers this way - or if it's OK
for the compiler to make it so - just change the nominal register numbers
in GCC so that endianness works as expected - register names and the nominal
numbers in gcc do not need to match.