Newly added tests are basically copies of the existing tests on `until`.
Note that this operator is optimized for all backends, but the fact that
it's optimized is only checked for the JVM backend in bytecode text
tests.
#KT-53330 Fixed
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
Alternatively, we could improve the lookup utilities and their usages to
always find the exact override of a symbol from
Collection/Iterable/CharSequence/etc, but since we need to load the
original symbol anyway in cases when the loop subject's type is a type
parameter, we might as well simplify everything and always reference the
original symbol.
Also improve exception message and removed unused declarations in
IrBackendUtils.kt.
Avoid using a separate origin for temporary variables introduced
for for loops. That doesn't add anything and gives one more case
for optimizations to deal with.
Extend the JVM specific optimizations to remove temporary
variables to deal with more cases encountered in for loops
lowering.
Use the class of the subtype of CharSequence when available. When
it is not (for type parameters bounded by CharSequence) call the
CharSequence getter and 'get' method. Using the most specific type
posible fixes the forInStringSpecialized test that expects the
use of INVOKEVIRTUAL and not INVOKEINTERFACE.
Add tests for the type parameter use.
Ilya Gorbunov