RFC: MI strlen()

[Julian Elischer]

> 
> I reran the test.  I had to change -O2 to -O to test builtin strlen,
> and made some other changes in a failed attempt to force __builtin_strlen
> with -O2).  builtin strlen is much slower than I remembered.  The
> NetBSD asm strlen (it uses the 0x8080 trick with 64-bit words) is
> about 4.5 faster for long strings but slower for short strings (ones
> shorter than the word size).  I expect your C version is similar.

any chance you could try this and make a suggestion as to whether we 
might adopt the new code?

>