[vyodaiken]

There was no size_t in K&R1. Size_t was introduced in the standards process as was the definition of index variables in the for loop. You may have a complain with the standard there.

As for the optimization, it is based on misunderstanding of C semantics. The only place where the sign extend makes a difference is where pointers are longer than "ints" AND where the the iterator can overflow, and in that case, sign extend only makes a difference if the loop is incorrectly coded so that the end condition is never true. The code should just provoke a warning and then omit the sign extend (and it almost certainly doesn't make much of a difference since sign extend is highly optimized and has zero cost in a pipelined processor).

[astrange]

> There was no size_t in K&R1. Size_t was introduced in the standards process as was the definition of index variables in the for loop. You may have a complain with the standard there.

I certainly do. C and descendants makes you over-specify variables by declaring them all int/size_t/etc individually. It should've had C++11-style "auto" from the start and there should be a statement like "for i=0..n" that declares "i" the same type as "n".