Files
kotlin/compiler/testData/codegen/bytecodeText/forLoop/unsigned/emptyUntilProgressionToMinValue.kt
Mark Punzalan 177967258b ForLoopsLowering: Eliminate construction/boxing/unboxing of UInt/ULong.
This needs further cleanup to encapsulate more logic into ProgressionType.
2020-05-13 13:54:35 +02:00

41 lines
1.3 KiB
Kotlin
Vendored

// TARGET_BACKEND: JVM_IR
// WITH_RUNTIME
fun box(): String {
for (i in 2u until UInt.MIN_VALUE step 2) {
}
return "OK"
}
// For "until" progressions in JVM IR, there is a check that the range is not empty: upper bound != MIN_VALUE.
// When the upper bound == const MIN_VALUE, the backend can eliminate the entire loop as dead code.
// Calls to getProgressionLastElement() are still present because these happen before the eliminated loop.
//
// Expected lowered form of loop (before bytecode optimizations):
//
// // Standard form of loop over progression
// var inductionVar = 2u
// val last = getProgressionLastElement(2u, UInt.MIN_VALUE - 1, 2) // `(UInt.MIN_VALUE - 1)` underflows to UInt.MAX_VALUE
// val step = 2
// if (false && inductionVar <= last) { // `false` comes from constant folding of `Int.MIN_VALUE != Int.MIN_VALUE`
// // Loop is not empty
// do {
// val i = inductionVar
// inductionVar += step
// // Loop body
// } while (i != last)
// }
// 0 iterator
// 0 getStart
// 0 getEnd
// 0 getFirst
// 0 getLast
// 0 getStep
// 1 INVOKESTATIC kotlin/internal/UProgressionUtilKt.getProgressionLastElement
// 0 NEW java/lang/IllegalArgumentException
// 0 ATHROW
// 0 IF
// 0 INVOKESTATIC kotlin/UInt.constructor-impl
// 0 INVOKE\w+ kotlin/UInt.(un)?box-impl