String copy idiom.

[Daniel J. Salomon]

A recent article on language idioms gave the following C code
for a string copy:

     while (*s++ = *t++);

Serious C hackers should know that on VAX 4.2 BSD UNIX this
code produces a loop with 50% more assembler instructions
than the slightly clearer sequence:

     while ((*s = *t) != '\0')
     {   s++;
	 t++;
     }

This is true whether or not the object-code improver
is invoked, and may be true on other machines as well.