String copy idiom.

[G A Moffett]

As long as we're comparing compilers, the UTS C compiler produces
basically the same code with either construction (with slightly
different register usage), except that the instruction ordering
is different.  The code is the same size in either case.

This seems like a reasonable thing to expect, since the code IS
doing the same thing, only in slightly different ways.  (370
architectures do not have auto-increment like DEC and other
machines).
-- 
Gordon A. Moffett		...!{ihnp4,hplabs,sun}!amdahl!gam