I think the Adopt OpenJDK j9 jvm jit messes with Kotlin somehow

fjeremic · October 28, 2020, 7:02pm

This is an occurrence of a bug in the OpenJ9 JIT compiler. I’ve opened up a bug report here and I’ll have a fix shortly:

github.com/eclipse-openj9/openj9

OpenJ9 produces incorrect results when java/lang/Math.abs is used successively

opened 06:45PM - 28 Oct 20 UTC

closed 11:03PM - 29 Oct 20 UTC

fjeremic

comp:jit userRaised

Opening up an issue on behalf of @travisfw from an original bug report [[1]](htt…ps://discuss.kotlinlang.org/t/i-think-the-adopt-openjdk-j9-jvm-jit-messes-with-kotlin-somehow/19596/10) on the Kotlin Discussion boards. Running the following program intermittently results in the exception being thrown: ``` package com.travisfw.voxelsphere.lwjgl3 import kotlin.math.abs data class Vector3(val x: Float, val y: Float, val z: Float) { operator fun minus(v2: Vector3): Vector3 =Vector3(x-v2.x, y-v2.y, z-v2.z) fun taxiDistance(): Float = abs(x) + abs(y) + abs(z) } fun main(args: Array<String>) { val gridCenter = Vector3(32.0f, 32.0f, 32.0f) for (x in 0..320) for (y in 0..320) for (z in 0..320) { val cornerPosition = Vector3(x.toFloat(), y.toFloat(), z.toFloat()) val centeredPos = cornerPosition - gridCenter val taxiFromCenter = centeredPos.taxiDistance() val centeredPos2 = Vector3(centeredPos.x, centeredPos.y, centeredPos.z) val taxiFromCenter2 = centeredPos2.taxiDistance() if (taxiFromCenter != taxiFromCenter2) { val recomputed = centeredPos2.taxiDistance() throw Exception("taxiFromcenter are not equal $taxiFromCenter ($centeredPos) $taxiFromCenter2 ($centeredPos2) - recomputed = $recomputed") } } println("If you reached here, it worked (and you are likely using a non-J9 openjdk)") } ``` Save as `test.kt` and compile with `kotlinc test.kt -include-runtime -d test.jar`. [1] https://discuss.kotlinlang.org/t/i-think-the-adopt-openjdk-j9-jvm-jit-messes-with-kotlin-somehow/19596/10

Apologies for the churn here, and thanks for reporting this to the Adopt community!

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I think the Adopt OpenJDK j9 jvm jit messes with Kotlin somehow

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