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
Dmitry Petrov
271368ac53