diff --git a/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionGenerator.kt b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionGenerator.kt
index 1a09affd0be..d1cce279f01 100644
--- a/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionGenerator.kt
+++ b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/FunctionGenerator.kt
@@ -102,6 +102,30 @@ class FunctionGenerator(val function: IrFunction) {
             return expression
         }
 
+        override fun visitWhen(expression: IrWhen, data: Boolean): IrElement? {
+            if (data) {
+                builder.add(expression)
+            }
+            val whenExit = MergeCfgElement(expression, "When exit")
+            val branches = expression.branches
+            for (branch in branches) {
+                val condition = branch.condition
+                condition.process(includeSelf = false)
+                builder.jump(condition)
+            }
+            for (branch in branches) {
+                val result = branch.result
+                builder.move(branch.condition)
+                if (!result.process().isNothing()) {
+                    builder.jump(whenExit)
+                }
+                else {
+                    builder.move(branch.condition)
+                }
+            }
+            return whenExit
+        }
+
         override fun visitElement(element: IrElement, data: Boolean): IrElement? {
             TODO("not implemented")
         }
diff --git a/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/GeneralConnectorBuilder.kt b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/GeneralConnectorBuilder.kt
index 0b77c1d69e2..0586a5def9e 100644
--- a/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/GeneralConnectorBuilder.kt
+++ b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/GeneralConnectorBuilder.kt
@@ -36,9 +36,9 @@ class GeneralConnectorBuilder(private val element: IrElement) : BlockConnectorBu
     }
 
     override fun build() = when {
-        next.size == 1 -> JoinBlockConnector(previous.toReadOnlyList(), element, next.single())
+        next.size <= 1 -> JoinBlockConnector(previous.toReadOnlyList(), element, next.firstOrNull())
         previous.size == 1 -> SplitBlockConnector(previous.single(), element, next.toReadOnlyList())
-        else -> throw AssertionError("Connector should have either exactly one previous block or exactly one next block, " +
+        else -> throw AssertionError("Connector should have either exactly one previous block or no more than one next block, " +
                                      "actual previous = ${previous.size}, next = ${next.size}")
     }
 }
\ No newline at end of file
diff --git a/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/JoinBlockConnector.kt b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/JoinBlockConnector.kt
index 94cf86e4c4b..750f2b0e277 100644
--- a/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/JoinBlockConnector.kt
+++ b/compiler/ir/ir.ir2cfg/src/org/jetbrains/kotlin/ir2cfg/generators/JoinBlockConnector.kt
@@ -23,8 +23,8 @@ import org.jetbrains.kotlin.ir2cfg.graph.BlockConnector
 class JoinBlockConnector(
         override val previousBlocks: List<BasicBlock>,
         override val element: IrElement,
-        next: BasicBlock
+        next: BasicBlock?
 ) : BlockConnector {
 
-    override val nextBlocks = listOf(next)
+    override val nextBlocks = listOfNotNull(next)
 }
\ No newline at end of file
diff --git a/compiler/testData/ir/irCfg/when/cascadeIf.kt b/compiler/testData/ir/irCfg/when/cascadeIf.kt
new file mode 100644
index 00000000000..736e63eb7c0
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/cascadeIf.kt
@@ -0,0 +1 @@
+fun compare(x: Int, y: Int) = if (x > y) 1 else if (x < y) -1 else 0
\ No newline at end of file
diff --git a/compiler/testData/ir/irCfg/when/cascadeIf.txt b/compiler/testData/ir/irCfg/when/cascadeIf.txt
new file mode 100644
index 00000000000..f18fdeeacce
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/cascadeIf.txt
@@ -0,0 +1,53 @@
+// FILE: /cascadeIf.kt
+// FUN: compare
+BB 0
+CONTENT
+      1 FUN public fun compare(x: kotlin.Int, y: kotlin.Int): kotlin.Int
+      2 WHEN type=kotlin.Int origin=WHEN
+OUTGOING -> BB 1, 3
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+BB 1
+INCOMING <- BB 0
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+CONTENT
+OUTGOING -> BB 2, 4
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+BB 2
+INCOMING <- BB 1
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+OUTGOING -> BB 5
+    CONST Boolean type=kotlin.Boolean value='true'
+BB 3
+INCOMING <- BB 0
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+CONTENT
+      1 CONST Int type=kotlin.Int value='1'
+OUTGOING -> BB 6
+    When exit: WHEN type=kotlin.Int origin=WHEN
+BB 4
+INCOMING <- BB 1
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+      1 CONST Int type=kotlin.Int value='-1'
+OUTGOING -> BB 6
+    When exit: WHEN type=kotlin.Int origin=WHEN
+BB 5
+INCOMING <- BB 2
+    CONST Boolean type=kotlin.Boolean value='true'
+CONTENT
+      1 CONST Int type=kotlin.Int value='0'
+OUTGOING -> BB 6
+    When exit: WHEN type=kotlin.Int origin=WHEN
+BB 6
+INCOMING <- BB 3, 4, 5
+    When exit: WHEN type=kotlin.Int origin=WHEN
+CONTENT
+      1 RETURN type=kotlin.Nothing from='compare(Int, Int): Int'
+OUTGOING -> NONE
+    Function exit: FUN public fun compare(x: kotlin.Int, y: kotlin.Int): kotlin.Int
+
+// END FUN: compare
+
+// END FILE: /cascadeIf.kt
+
diff --git a/compiler/testData/ir/irCfg/when/emptyWhen.kt b/compiler/testData/ir/irCfg/when/emptyWhen.kt
new file mode 100644
index 00000000000..98c25237275
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/emptyWhen.kt
@@ -0,0 +1,3 @@
+fun empty() = when {
+    else -> 42
+}
\ No newline at end of file
diff --git a/compiler/testData/ir/irCfg/when/emptyWhen.txt b/compiler/testData/ir/irCfg/when/emptyWhen.txt
new file mode 100644
index 00000000000..4ac02015210
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/emptyWhen.txt
@@ -0,0 +1,27 @@
+// FILE: /emptyWhen.kt
+// FUN: empty
+BB 0
+CONTENT
+      1 FUN public fun empty(): kotlin.Int
+      2 WHEN type=kotlin.Int origin=WHEN
+OUTGOING -> BB 1
+    CONST Boolean type=kotlin.Boolean value='true'
+BB 1
+INCOMING <- BB 0
+    CONST Boolean type=kotlin.Boolean value='true'
+CONTENT
+      1 CONST Int type=kotlin.Int value='42'
+OUTGOING -> BB 2
+    When exit: WHEN type=kotlin.Int origin=WHEN
+BB 2
+INCOMING <- BB 1
+    When exit: WHEN type=kotlin.Int origin=WHEN
+CONTENT
+      1 RETURN type=kotlin.Nothing from='empty(): Int'
+OUTGOING -> NONE
+    Function exit: FUN public fun empty(): kotlin.Int
+
+// END FUN: empty
+
+// END FILE: /emptyWhen.kt
+
diff --git a/compiler/testData/ir/irCfg/when/expressionIf.kt b/compiler/testData/ir/irCfg/when/expressionIf.kt
new file mode 100644
index 00000000000..575dc2f31fd
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/expressionIf.kt
@@ -0,0 +1 @@
+fun max(x: Int, y: Int) = if (x > y) x else y
\ No newline at end of file
diff --git a/compiler/testData/ir/irCfg/when/expressionIf.txt b/compiler/testData/ir/irCfg/when/expressionIf.txt
new file mode 100644
index 00000000000..e9a440ddcc3
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/expressionIf.txt
@@ -0,0 +1,40 @@
+// FILE: /expressionIf.kt
+// FUN: max
+BB 0
+CONTENT
+      1 FUN public fun max(x: kotlin.Int, y: kotlin.Int): kotlin.Int
+      2 WHEN type=kotlin.Int origin=null
+OUTGOING -> BB 1, 2
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+BB 1
+INCOMING <- BB 0
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+CONTENT
+OUTGOING -> BB 3
+    CONST Boolean type=kotlin.Boolean value='true'
+BB 2
+INCOMING <- BB 0
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+CONTENT
+      1 GET_VAR 'value-parameter x: Int' type=kotlin.Int origin=null
+OUTGOING -> BB 4
+    When exit: WHEN type=kotlin.Int origin=null
+BB 3
+INCOMING <- BB 1
+    CONST Boolean type=kotlin.Boolean value='true'
+CONTENT
+      1 GET_VAR 'value-parameter y: Int' type=kotlin.Int origin=null
+OUTGOING -> BB 4
+    When exit: WHEN type=kotlin.Int origin=null
+BB 4
+INCOMING <- BB 2, 3
+    When exit: WHEN type=kotlin.Int origin=null
+CONTENT
+      1 RETURN type=kotlin.Nothing from='max(Int, Int): Int'
+OUTGOING -> NONE
+    Function exit: FUN public fun max(x: kotlin.Int, y: kotlin.Int): kotlin.Int
+
+// END FUN: max
+
+// END FILE: /expressionIf.kt
+
diff --git a/compiler/testData/ir/irCfg/when/ifChain.kt b/compiler/testData/ir/irCfg/when/ifChain.kt
new file mode 100644
index 00000000000..6ea0fc912ef
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/ifChain.kt
@@ -0,0 +1,14 @@
+fun minBiRoot(a: Double, b: Double, c: Double): Double {
+    if (a == 0.0) {
+        if (b == 0.0) return 1.0
+        val bc = -c / b
+        if (bc < 0.0) return 2.0
+        return -bc
+    }
+    val d = b * b - 4 * a * c
+    if (d < 0.0) return 3.0
+    val y1 = (-b + d) / (2 * a)
+    val y2 = (-b - d) / (2 * a)
+    val y3 = if (y1 > y2) y1 else y2
+    return if (y3 < 0.0) 4.0 else -y3
+}
\ No newline at end of file
diff --git a/compiler/testData/ir/irCfg/when/ifChain.txt b/compiler/testData/ir/irCfg/when/ifChain.txt
new file mode 100644
index 00000000000..fb6bb644a70
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/ifChain.txt
@@ -0,0 +1,136 @@
+// FILE: /ifChain.kt
+// FUN: minBiRoot
+BB 0
+CONTENT
+      1 FUN public fun minBiRoot(a: kotlin.Double, b: kotlin.Double, c: kotlin.Double): kotlin.Double
+      2 WHEN type=kotlin.Unit origin=null
+OUTGOING -> BB 1, 6
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+BB 1
+INCOMING <- BB 0
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 WHEN type=kotlin.Unit origin=null
+OUTGOING -> BB 2, 3
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+BB 2
+INCOMING <- BB 1
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 CONST Double type=kotlin.Double value='1.0'
+      2 RETURN type=kotlin.Nothing from='minBiRoot(Double, Double, Double): Double'
+OUTGOING -> NONE
+    Function exit: FUN public fun minBiRoot(a: kotlin.Double, b: kotlin.Double, c: kotlin.Double): kotlin.Double
+BB 3
+INCOMING <- BB 1
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 CALL 'div(Double): Double' type=kotlin.Double origin=DIV
+      2 VAR val bc: kotlin.Double
+      3 WHEN type=kotlin.Unit origin=null
+OUTGOING -> BB 4, 5
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+BB 4
+INCOMING <- BB 3
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+      1 CONST Double type=kotlin.Double value='2.0'
+      2 RETURN type=kotlin.Nothing from='minBiRoot(Double, Double, Double): Double'
+OUTGOING -> NONE
+    Function exit: FUN public fun minBiRoot(a: kotlin.Double, b: kotlin.Double, c: kotlin.Double): kotlin.Double
+BB 5
+INCOMING <- BB 3
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+      1 CALL 'unaryMinus(): Double' type=kotlin.Double origin=UMINUS
+      2 RETURN type=kotlin.Nothing from='minBiRoot(Double, Double, Double): Double'
+OUTGOING -> NONE
+    Function exit: FUN public fun minBiRoot(a: kotlin.Double, b: kotlin.Double, c: kotlin.Double): kotlin.Double
+BB 6
+INCOMING <- BB 0
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 CALL 'minus(Double): Double' type=kotlin.Double origin=MINUS
+      2 VAR val d: kotlin.Double
+      3 WHEN type=kotlin.Unit origin=null
+OUTGOING -> BB 7, 8
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+BB 7
+INCOMING <- BB 6
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+      1 CONST Double type=kotlin.Double value='3.0'
+      2 RETURN type=kotlin.Nothing from='minBiRoot(Double, Double, Double): Double'
+OUTGOING -> NONE
+    Function exit: FUN public fun minBiRoot(a: kotlin.Double, b: kotlin.Double, c: kotlin.Double): kotlin.Double
+BB 8
+INCOMING <- BB 6
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+      1 CALL 'div(Double): Double' type=kotlin.Double origin=DIV
+      2 VAR val y1: kotlin.Double
+      3 CALL 'div(Double): Double' type=kotlin.Double origin=DIV
+      4 VAR val y2: kotlin.Double
+      5 WHEN type=kotlin.Double origin=null
+OUTGOING -> BB 9, 10
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+BB 9
+INCOMING <- BB 8
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+CONTENT
+OUTGOING -> BB 11
+    CONST Boolean type=kotlin.Boolean value='true'
+BB 10
+INCOMING <- BB 8
+    CALL 'GT0(Int): Boolean' type=kotlin.Boolean origin=GT
+CONTENT
+      1 GET_VAR 'y1: Double' type=kotlin.Double origin=null
+OUTGOING -> BB 12
+    When exit: WHEN type=kotlin.Double origin=null
+BB 11
+INCOMING <- BB 9
+    CONST Boolean type=kotlin.Boolean value='true'
+CONTENT
+      1 GET_VAR 'y2: Double' type=kotlin.Double origin=null
+OUTGOING -> BB 12
+    When exit: WHEN type=kotlin.Double origin=null
+BB 12
+INCOMING <- BB 10, 11
+    When exit: WHEN type=kotlin.Double origin=null
+CONTENT
+      1 VAR val y3: kotlin.Double
+      2 WHEN type=kotlin.Double origin=null
+OUTGOING -> BB 13, 14
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+BB 13
+INCOMING <- BB 12
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+OUTGOING -> BB 15
+    CONST Boolean type=kotlin.Boolean value='true'
+BB 14
+INCOMING <- BB 12
+    CALL 'LT0(Int): Boolean' type=kotlin.Boolean origin=LT
+CONTENT
+      1 CONST Double type=kotlin.Double value='4.0'
+OUTGOING -> BB 16
+    When exit: WHEN type=kotlin.Double origin=null
+BB 15
+INCOMING <- BB 13
+    CONST Boolean type=kotlin.Boolean value='true'
+CONTENT
+      1 CALL 'unaryMinus(): Double' type=kotlin.Double origin=UMINUS
+OUTGOING -> BB 16
+    When exit: WHEN type=kotlin.Double origin=null
+BB 16
+INCOMING <- BB 14, 15
+    When exit: WHEN type=kotlin.Double origin=null
+CONTENT
+      1 RETURN type=kotlin.Nothing from='minBiRoot(Double, Double, Double): Double'
+OUTGOING -> NONE
+    Function exit: FUN public fun minBiRoot(a: kotlin.Double, b: kotlin.Double, c: kotlin.Double): kotlin.Double
+
+// END FUN: minBiRoot
+
+// END FILE: /ifChain.kt
+
diff --git a/compiler/testData/ir/irCfg/when/whenReturn.kt b/compiler/testData/ir/irCfg/when/whenReturn.kt
new file mode 100644
index 00000000000..b692e1f2dab
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/whenReturn.kt
@@ -0,0 +1,10 @@
+fun toString(grade: String): String {
+    when (grade) {
+        "A" -> return "Excellent"
+        "B" -> return "Good"
+        "C" -> return "Mediocre"
+        "D" -> return "Fair"
+        else -> return "Failure"
+    }
+    return "???"
+}
\ No newline at end of file
diff --git a/compiler/testData/ir/irCfg/when/whenReturn.txt b/compiler/testData/ir/irCfg/when/whenReturn.txt
new file mode 100644
index 00000000000..a8c8157a1ad
--- /dev/null
+++ b/compiler/testData/ir/irCfg/when/whenReturn.txt
@@ -0,0 +1,87 @@
+// FILE: /whenReturn.kt
+// FUN: toString
+BB 0
+CONTENT
+      1 FUN public fun toString(grade: kotlin.String): kotlin.String
+      2 GET_VAR 'value-parameter grade: String' type=kotlin.String origin=null
+      3 VAR IR_TEMPORARY_VARIABLE val tmp0_subject: kotlin.String
+      4 WHEN type=kotlin.Nothing origin=WHEN
+OUTGOING -> BB 1, 5
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+BB 1
+INCOMING <- BB 0
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+OUTGOING -> BB 2, 6
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+BB 2
+INCOMING <- BB 1
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+OUTGOING -> BB 3, 7
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+BB 3
+INCOMING <- BB 2
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+OUTGOING -> BB 4, 8
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+BB 4
+INCOMING <- BB 3
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+OUTGOING -> BB 9, 10
+    CONST Boolean type=kotlin.Boolean value='true'
+BB 5
+INCOMING <- BB 0
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 CONST String type=kotlin.String value='Excellent'
+      2 RETURN type=kotlin.Nothing from='toString(String): String'
+OUTGOING -> NONE
+    Function exit: FUN public fun toString(grade: kotlin.String): kotlin.String
+BB 6
+INCOMING <- BB 1
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 CONST String type=kotlin.String value='Good'
+      2 RETURN type=kotlin.Nothing from='toString(String): String'
+OUTGOING -> NONE
+    Function exit: FUN public fun toString(grade: kotlin.String): kotlin.String
+BB 7
+INCOMING <- BB 2
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 CONST String type=kotlin.String value='Mediocre'
+      2 RETURN type=kotlin.Nothing from='toString(String): String'
+OUTGOING -> NONE
+    Function exit: FUN public fun toString(grade: kotlin.String): kotlin.String
+BB 8
+INCOMING <- BB 3
+    CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+CONTENT
+      1 CONST String type=kotlin.String value='Fair'
+      2 RETURN type=kotlin.Nothing from='toString(String): String'
+OUTGOING -> NONE
+    Function exit: FUN public fun toString(grade: kotlin.String): kotlin.String
+BB 9
+INCOMING <- BB 4
+    CONST Boolean type=kotlin.Boolean value='true'
+CONTENT
+      1 CONST String type=kotlin.String value='Failure'
+      2 RETURN type=kotlin.Nothing from='toString(String): String'
+OUTGOING -> NONE
+    Function exit: FUN public fun toString(grade: kotlin.String): kotlin.String
+BB 10
+INCOMING <- BB 4
+    CONST Boolean type=kotlin.Boolean value='true'
+CONTENT
+      1 CONST String type=kotlin.String value='???'
+      2 RETURN type=kotlin.Nothing from='toString(String): String'
+OUTGOING -> NONE
+    Function exit: FUN public fun toString(grade: kotlin.String): kotlin.String
+
+// END FUN: toString
+
+// END FILE: /whenReturn.kt
+
diff --git a/compiler/testData/ir/irText/expressions/whenReturn.kt b/compiler/testData/ir/irText/expressions/whenReturn.kt
new file mode 100644
index 00000000000..b692e1f2dab
--- /dev/null
+++ b/compiler/testData/ir/irText/expressions/whenReturn.kt
@@ -0,0 +1,10 @@
+fun toString(grade: String): String {
+    when (grade) {
+        "A" -> return "Excellent"
+        "B" -> return "Good"
+        "C" -> return "Mediocre"
+        "D" -> return "Fair"
+        else -> return "Failure"
+    }
+    return "???"
+}
\ No newline at end of file
diff --git a/compiler/testData/ir/irText/expressions/whenReturn.txt b/compiler/testData/ir/irText/expressions/whenReturn.txt
new file mode 100644
index 00000000000..eca3f4385bd
--- /dev/null
+++ b/compiler/testData/ir/irText/expressions/whenReturn.txt
@@ -0,0 +1,37 @@
+FILE /whenReturn.kt
+  FUN public fun toString(grade: kotlin.String): kotlin.String
+    BLOCK_BODY
+      BLOCK type=kotlin.Nothing origin=WHEN
+        VAR IR_TEMPORARY_VARIABLE val tmp0_subject: kotlin.String
+          GET_VAR 'value-parameter grade: String' type=kotlin.String origin=null
+        WHEN type=kotlin.Nothing origin=WHEN
+          BRANCH
+            if: CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+              arg0: GET_VAR 'tmp0_subject: String' type=kotlin.String origin=null
+              arg1: CONST String type=kotlin.String value='A'
+            then: RETURN type=kotlin.Nothing from='toString(String): String'
+              CONST String type=kotlin.String value='Excellent'
+          BRANCH
+            if: CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+              arg0: GET_VAR 'tmp0_subject: String' type=kotlin.String origin=null
+              arg1: CONST String type=kotlin.String value='B'
+            then: RETURN type=kotlin.Nothing from='toString(String): String'
+              CONST String type=kotlin.String value='Good'
+          BRANCH
+            if: CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+              arg0: GET_VAR 'tmp0_subject: String' type=kotlin.String origin=null
+              arg1: CONST String type=kotlin.String value='C'
+            then: RETURN type=kotlin.Nothing from='toString(String): String'
+              CONST String type=kotlin.String value='Mediocre'
+          BRANCH
+            if: CALL 'EQEQ(Any?, Any?): Boolean' type=kotlin.Boolean origin=EQEQ
+              arg0: GET_VAR 'tmp0_subject: String' type=kotlin.String origin=null
+              arg1: CONST String type=kotlin.String value='D'
+            then: RETURN type=kotlin.Nothing from='toString(String): String'
+              CONST String type=kotlin.String value='Fair'
+          BRANCH
+            if: CONST Boolean type=kotlin.Boolean value='true'
+            then: RETURN type=kotlin.Nothing from='toString(String): String'
+              CONST String type=kotlin.String value='Failure'
+      RETURN type=kotlin.Nothing from='toString(String): String'
+        CONST String type=kotlin.String value='???'
diff --git a/compiler/tests/org/jetbrains/kotlin/ir/IrCfgTestCaseGenerated.java b/compiler/tests/org/jetbrains/kotlin/ir/IrCfgTestCaseGenerated.java
index 704fb54c424..0c46977f6fd 100644
--- a/compiler/tests/org/jetbrains/kotlin/ir/IrCfgTestCaseGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/ir/IrCfgTestCaseGenerated.java
@@ -70,4 +70,43 @@ public class IrCfgTestCaseGenerated extends AbstractIrCfgTestCase {
         String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irCfg/simpleReturn.kt");
         doTest(fileName);
     }
+
+    @TestMetadata("compiler/testData/ir/irCfg/when")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class When extends AbstractIrCfgTestCase {
+        public void testAllFilesPresentInWhen() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/ir/irCfg/when"), Pattern.compile("^(.+)\\.kt$"), true);
+        }
+
+        @TestMetadata("cascadeIf.kt")
+        public void testCascadeIf() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irCfg/when/cascadeIf.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("emptyWhen.kt")
+        public void testEmptyWhen() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irCfg/when/emptyWhen.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("expressionIf.kt")
+        public void testExpressionIf() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irCfg/when/expressionIf.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("ifChain.kt")
+        public void testIfChain() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irCfg/when/ifChain.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("whenReturn.kt")
+        public void testWhenReturn() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irCfg/when/whenReturn.kt");
+            doTest(fileName);
+        }
+    }
 }
diff --git a/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java b/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java
index 2353efc3814..c771f997f3e 100644
--- a/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/ir/IrTextTestCaseGenerated.java
@@ -658,6 +658,12 @@ public class IrTextTestCaseGenerated extends AbstractIrTextTestCase {
             doTest(fileName);
         }
 
+        @TestMetadata("whenReturn.kt")
+        public void testWhenReturn() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irText/expressions/whenReturn.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("whileDoWhile.kt")
         public void testWhileDoWhile() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/ir/irText/expressions/whileDoWhile.kt");