We are going to deprecate `WITH_RUNTIME` directive. The main reason
behind this change is that `WITH_STDLIB` directive better describes
its meaning, specifically it will add kotlin stdlib to test's classpath.
In general, we would rather prefer a range-based for loop to look like
a counter loop in Java ('for (i = start; i < end; ++i) { <BODY> }').
This corresponds to
i = start;
do {
if (i >= end) break;
<BODY>
} while ( { ++i; true } )
However, HotSpot doesn't recognize Kotlin unsigned integer comparison
in 'if (i >= end) break;' as a counter loop condition. Thus, the loop
doesn't get optimized as a counter loop, resulting in a performance
regression.
If we use exclusive range-based for loop instead, then we actually use
unsigned integer equality instead of unsigned integer comparison, which
is Ok for HotSpot.
KT-49444
Unlike signed integers, a larger unsigned type does not mean a lower
minimum value, so `x - 1` can overflow even if `x` is casted to a larger
type.
#KT-42186 Fixed
Ivan Kylchik