reduction of GP registers in MIPS backend

[Jim Wilson]

kernel coder wrote:
> Would you please give a bit more explaination of "GPRs come in pairs"
> and  where this assumption is being checked in function
> override_options.

These two lines
           else if (GP_REG_P (regno))
             temp = ((regno & 1) == 0 || size <= UNITS_PER_WORD);
which say that any register can hold a value smaller or equal to the 
word size, and any even numbered register can hold a value larger than 
the word size.  The latter implicitly assumes that the largest possible 
value is twice the word size, which is not quite correct, but good 
enough for now.
-- 
Jim Wilson, GNU Tools Support, http://www.specifix.com