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.
last-exclusive progressions (i.e., "until" progressions and loop over
array indices).
This change makes it possible to correctly implement the handling of
"step" progressions. Computing the last element of a stepped progression
requires that the last is inclusive.
Also invert the while loop (into if + do-while) that is used when
lowering for-loops over progressions that cannot overflow. This keeps
the performance characteristics closer to the ForLoopsLowering in
kotlin-native, since the goal is to converge to this shared version.
Also used IrType instead of KotlinType, where possible.
https://github.com/JetBrains/kotlin/pull/2390https://github.com/JetBrains/kotlin/pull/2305
We get the info for the underlying progression and invert it. For
progressions whose last bound was open (e.g., `until` loop), the
reversed version will have an open first bound and so the induction
variable must be incremented first.
Also unified the way of extracting HeaderInfo out of changed calls
(e.g., `indices.reversed()`), and fixed declaration parents in
ForLoopsLowering.
HeaderInfo object, and modifying the operator in the loop condition.
The "additional emptiness condition" is no longer necessary with this.
The open/closed property was removed from HeaderInfo in an earlier
commit, but bringing it back in to simplify the loop building makes
more sense.
Also expanded tests for evaluation order of range bounds.
do-while with enclosing "not empty" check).
Also do not add additional "not empty" condition for `until` loops when
the given bound is a constant != MIN_VALUE.
non-specialized progressions, including "step" progressions.
DefaultProgressionHandler uses the "first/last/step" properties of
the progression when building the loop header.
Ivan Kochurkin