diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/BlockDecomposerLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/BlockDecomposerLowering.kt
index 29330e540bf..e720d09f2c4 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/BlockDecomposerLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/BlockDecomposerLowering.kt
@@ -346,7 +346,7 @@ class BlockDecomposerTransformer(
 
                 val newLoopCondition = newCondition.statements.last() as IrExpression
                 val newLoopBody = IrBlockImpl(
-                    newCondition.startOffset,
+                    newBody?.startOffset ?: newCondition.startOffset,
                     newBody?.endOffset ?: newCondition.endOffset,
                     newBody?.type ?: unitType
                 ).apply {