From b2e95eebabc54a62abea74651ab603b874ef07f0 Mon Sep 17 00:00:00 2001
From: Dmitriy Novozhilov <dmitriy.novozhilov@jetbrains.com>
Date: Tue, 27 Aug 2019 16:13:17 +0300
Subject: [PATCH] [FIR] Add processing of loops with constant boolean value in
 condition

---
 .../fir/resolve/dfa/cfg/ControlFlowGraph.kt   |   4 +-
 .../dfa/cfg/ControlFlowGraphBuilder.kt        |  31 +-
 .../dfa/cfg/ControlFlowGraphNodeBuilder.kt    |   4 +-
 .../resolve/testData/resolve/cfg/jumps.dot    |  71 +--
 .../fir/resolve/testData/resolve/cfg/jumps.kt |   2 +-
 .../resolve/testData/resolve/cfg/jumps.txt    |   6 +-
 .../resolve/testData/resolve/cfg/loops.dot    | 274 ++++++++++
 .../fir/resolve/testData/resolve/cfg/loops.kt |  47 ++
 .../resolve/testData/resolve/cfg/loops.txt    |  56 ++
 .../resolve/testData/resolve/cfg/tryCatch.dot |  30 +-
 .../resolve/smartcasts/endlessLoops.dot       | 513 ++++++++++++++++++
 .../resolve/smartcasts/endlessLoops.kt        |  74 +++
 .../resolve/smartcasts/endlessLoops.txt       | 111 ++++
 .../fir/FirCfgBuildingTestGenerated.java      |   5 +
 14 files changed, 1158 insertions(+), 70 deletions(-)
 create mode 100644 compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot
 create mode 100644 compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.kt
 create mode 100644 compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.txt

diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt
index 5c159bf0816..887a0e6f78c 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraph.kt
@@ -74,8 +74,8 @@ class WhenBranchResultExitNode(owner: ControlFlowGraph, override val fir: FirWhe
 class LoopEnterNode(owner: ControlFlowGraph, override val fir: FirLoop, level: Int) : CFGNode<FirLoop>(owner, level)
 class LoopBlockEnterNode(owner: ControlFlowGraph, override val fir: FirLoop, level: Int) : CFGNode<FirLoop>(owner, level)
 class LoopBlockExitNode(owner: ControlFlowGraph, override val fir: FirLoop, level: Int) : CFGNode<FirLoop>(owner, level)
-class LoopConditionEnterNode(owner: ControlFlowGraph, override val fir: FirLoop, level: Int) : CFGNode<FirLoop>(owner, level)
-class LoopConditionExitNode(owner: ControlFlowGraph, override val fir: FirLoop, level: Int) : CFGNode<FirLoop>(owner, level)
+class LoopConditionEnterNode(owner: ControlFlowGraph, override val fir: FirExpression, level: Int) : CFGNode<FirExpression>(owner, level)
+class LoopConditionExitNode(owner: ControlFlowGraph, override val fir: FirExpression, level: Int) : CFGNode<FirExpression>(owner, level)
 class LoopExitNode(owner: ControlFlowGraph, override val fir: FirLoop, level: Int) : CFGNode<FirLoop>(owner, level)
 
 // ----------------------------------- Try-catch-finally -----------------------------------
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt
index 0a9b269330b..c7fef99fdc6 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt
@@ -217,7 +217,7 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
         addNewSimpleNode(createLoopEnterNode(loop))
         loopExitNodes.push(createLoopExitNode(loop))
         levelCounter++
-        val node = createLoopConditionEnterNode(loop)
+        val node = createLoopConditionEnterNode(loop.condition)
         levelCounter++
         addNewSimpleNode(node)
         // put conditional node twice so we can refer it after exit from loop block
@@ -228,11 +228,12 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
 
     fun exitWhileLoopCondition(loop: FirLoop): LoopConditionExitNode {
         levelCounter--
-        val conditionExitNode = createLoopConditionExitNode(loop)
+        val conditionExitNode = createLoopConditionExitNode(loop.condition)
         addNewSimpleNode(conditionExitNode)
-        // TODO: here we can check that condition is always true
-        addEdge(conditionExitNode, loopExitNodes.top())
-        addNewSimpleNode(createLoopBlockEnterNode(loop))
+        val conditionConstBooleanValue = conditionExitNode.booleanConstValue
+        addEdge(conditionExitNode, loopExitNodes.top(), isDead = conditionConstBooleanValue == true)
+        val loopBlockEnterNode = createLoopBlockEnterNode(loop)
+        addNewSimpleNode(loopBlockEnterNode, conditionConstBooleanValue == false)
         levelCounter++
         return conditionExitNode
     }
@@ -272,7 +273,7 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
     fun enterDoWhileLoopCondition(loop: FirLoop): Pair<LoopBlockExitNode, LoopConditionEnterNode> {
         levelCounter--
         val blockExitNode = createLoopBlockExitNode(loop).also { addNewSimpleNode(it) }
-        val conditionEnterNode = createLoopConditionEnterNode(loop).also { addNewSimpleNode(it) }
+        val conditionEnterNode = createLoopConditionEnterNode(loop.condition).also { addNewSimpleNode(it) }
         levelCounter++
         return blockExitNode to conditionEnterNode
     }
@@ -280,14 +281,14 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
     fun exitDoWhileLoop(loop: FirLoop): LoopExitNode {
         loopEnterNodes.pop()
         levelCounter--
-        val conditionExitNode = createLoopConditionExitNode(loop)
-        // TODO: here we can check that condition is always false
+        val conditionExitNode = createLoopConditionExitNode(loop.condition)
+        val conditionBooleanValue = conditionExitNode.booleanConstValue
         addEdge(lastNodes.pop(), conditionExitNode)
         val blockEnterNode = lastNodes.pop()
         require(blockEnterNode is LoopBlockEnterNode)
-        addEdge(conditionExitNode, blockEnterNode, propagateDeadness = false)
+        addEdge(conditionExitNode, blockEnterNode, propagateDeadness = false, isDead = conditionBooleanValue == false)
         val loopExit = loopExitNodes.pop()
-        addEdge(conditionExitNode, loopExit, propagateDeadness = false)
+        addEdge(conditionExitNode, loopExit, propagateDeadness = false, isDead = conditionBooleanValue == true)
         loopExit.markAsDeadIfNecessary()
         lastNodes.push(loopExit)
         levelCounter--
@@ -531,22 +532,22 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
         lastNodes.push(stub)
     }
 
-    private fun addNewSimpleNode(newNode: CFGNode<*>): CFGNode<*> {
+    private fun addNewSimpleNode(newNode: CFGNode<*>, isDead: Boolean = false): CFGNode<*> {
         val oldNode = lastNodes.pop()
-        addEdge(oldNode, newNode)
+        addEdge(oldNode, newNode, isDead = isDead)
         lastNodes.push(newNode)
         return oldNode
     }
 
-    private fun addDeadEdge(from: CFGNode<*>, to: CFGNode<*>) {
+    private fun addDeadEdge(from: CFGNode<*>, to: CFGNode<*>, propagateDeadness: Boolean) {
         val stub = createStubNode()
         addEdge(from, stub)
-        addEdge(stub, to)
+        addEdge(stub, to, propagateDeadness = propagateDeadness)
     }
 
     private fun addEdge(from: CFGNode<*>, to: CFGNode<*>, propagateDeadness: Boolean = true, isDead: Boolean = false) {
         if (isDead) {
-            addDeadEdge(from, to)
+            addDeadEdge(from, to, propagateDeadness)
             return
         }
         if (propagateDeadness && from.isDead) {
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphNodeBuilder.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphNodeBuilder.kt
index 4e04b5d5973..e8a53ebd289 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphNodeBuilder.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphNodeBuilder.kt
@@ -95,10 +95,10 @@ abstract class ControlFlowGraphNodeBuilder {
     protected fun createWhenBranchResultExitNode(fir: FirWhenBranch): WhenBranchResultExitNode =
         WhenBranchResultExitNode(graph, fir, levelCounter)
 
-    protected fun createLoopConditionExitNode(fir: FirLoop): LoopConditionExitNode =
+    protected fun createLoopConditionExitNode(fir: FirExpression): LoopConditionExitNode =
         LoopConditionExitNode(graph, fir, levelCounter)
 
-    protected fun createLoopConditionEnterNode(fir: FirLoop): LoopConditionEnterNode =
+    protected fun createLoopConditionEnterNode(fir: FirExpression): LoopConditionEnterNode =
         LoopConditionEnterNode(graph, fir, levelCounter)
 
     protected fun createLoopBlockEnterNode(fir: FirLoop): LoopBlockEnterNode =
diff --git a/compiler/fir/resolve/testData/resolve/cfg/jumps.dot b/compiler/fir/resolve/testData/resolve/cfg/jumps.dot
index e07ccc333ef..097c59e714c 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/jumps.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/jumps.dot
@@ -121,73 +121,78 @@ subgraph test_3 {
   61 [shape=box label="Stub[DEAD]"];
   62 [shape=box label="Exit block[DEAD]"];
   63 [shape=box label="Exit loop block[DEAD]"];
-  64 [shape=box label="Exit whileloop"];
-  65 [shape=box label="Access variable R|<local>/x|"];
-  66 [shape=box label="Function call: R|<local>/x|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()"];
-  67 [shape=box label="Exit block"];
-  68 [shape=box label="Exit function test_3"];
+  64 [shape=box label="Stub[DEAD]"];
+  65 [shape=box label="Exit whileloop"];
+  66 [shape=box label="Access variable R|<local>/x|"];
+  67 [shape=box label="Function call: R|<local>/x|.R|kotlin/Int.inc|()"];
+  68 [shape=box label="Exit block"];
+  69 [shape=box label="Exit function test_3"];
 
   50 -> {51};
   51 -> {52};
   52 -> {53};
   53 -> {54};
   54 -> {55};
-  55 -> {64 56};
+  55 -> {56};
+  55 -> {64} [style=dotted];
   56 -> {57};
   57 -> {58};
   58 -> {59};
   59 -> {60};
-  60 -> {64};
+  60 -> {65};
   60 -> {61} [style=dotted];
   61 -> {62} [style=dotted];
   62 -> {63} [style=dotted];
   63 -> {53} [style=dotted];
-  64 -> {65};
+  64 -> {65} [style=dotted];
   65 -> {66};
   66 -> {67};
   67 -> {68};
+  68 -> {69};
 }
 
 subgraph test_4 {
-  69 [shape=box label="Enter function test_4"];
-  70 [shape=box label="Enter block"];
-  71 [shape=box label="Enter do-while loop"];
-  72 [shape=box label="Enter loop block"];
-  73 [shape=box label="Enter block"];
-  74 [shape=box label="Access variable R|<local>/x|"];
-  75 [shape=box label="Type operator: x as int"];
-  76 [shape=box label="Jump: break@@@[Boolean(true)] "];
-  77 [shape=box label="Stub[DEAD]"];
-  78 [shape=box label="Exit block[DEAD]"];
-  79 [shape=box label="Exit loop block[DEAD]"];
-  80 [shape=box label="Enter loop condition[DEAD]"];
-  81 [shape=box label="Const: Boolean(true)[DEAD]"];
-  82 [shape=box label="Exit loop condition[DEAD]"];
-  83 [shape=box label="Exit do-whileloop"];
-  84 [shape=box label="Access variable R|<local>/x|"];
-  85 [shape=box label="Function call: R|<local>/x|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()"];
-  86 [shape=box label="Exit block"];
-  87 [shape=box label="Exit function test_4"];
+  70 [shape=box label="Enter function test_4"];
+  71 [shape=box label="Enter block"];
+  72 [shape=box label="Enter do-while loop"];
+  73 [shape=box label="Enter loop block"];
+  74 [shape=box label="Enter block"];
+  75 [shape=box label="Access variable R|<local>/x|"];
+  76 [shape=box label="Type operator: x as Int"];
+  77 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  78 [shape=box label="Stub[DEAD]"];
+  79 [shape=box label="Exit block[DEAD]"];
+  80 [shape=box label="Exit loop block[DEAD]"];
+  81 [shape=box label="Enter loop condition[DEAD]"];
+  82 [shape=box label="Const: Boolean(true)[DEAD]"];
+  83 [shape=box label="Exit loop condition[DEAD]"];
+  84 [shape=box label="Stub[DEAD]"];
+  85 [shape=box label="Exit do-whileloop"];
+  86 [shape=box label="Access variable R|<local>/x|"];
+  87 [shape=box label="Function call: R|<local>/x|.R|kotlin/Int.inc|()"];
+  88 [shape=box label="Exit block"];
+  89 [shape=box label="Exit function test_4"];
 
-  69 -> {70};
   70 -> {71};
   71 -> {72};
   72 -> {73};
   73 -> {74};
   74 -> {75};
   75 -> {76};
-  76 -> {83};
-  76 -> {77} [style=dotted];
+  76 -> {77};
+  77 -> {85};
   77 -> {78} [style=dotted];
   78 -> {79} [style=dotted];
   79 -> {80} [style=dotted];
   80 -> {81} [style=dotted];
   81 -> {82} [style=dotted];
-  82 -> {72 83} [style=dotted];
-  83 -> {84};
-  84 -> {85};
+  82 -> {83} [style=dotted];
+  83 -> {73 84} [style=dotted];
+  84 -> {85} [style=dotted];
   85 -> {86};
   86 -> {87};
+  87 -> {88};
+  88 -> {89};
 }
 
 }
diff --git a/compiler/fir/resolve/testData/resolve/cfg/jumps.kt b/compiler/fir/resolve/testData/resolve/cfg/jumps.kt
index 7c073e5afd7..db6ae0af89a 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/jumps.kt
+++ b/compiler/fir/resolve/testData/resolve/cfg/jumps.kt
@@ -26,7 +26,7 @@ fun test_3(x: Int?) {
 
 fun test_4(x: Int?) {
     do {
-        x as int
+        x as Int
         break
     } while (true)
     x.inc()
diff --git a/compiler/fir/resolve/testData/resolve/cfg/jumps.txt b/compiler/fir/resolve/testData/resolve/cfg/jumps.txt
index 52048d3559b..61de8e960fd 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/jumps.txt
+++ b/compiler/fir/resolve/testData/resolve/cfg/jumps.txt
@@ -29,13 +29,13 @@ FILE: jumps.kt
             break@@@[Boolean(true)]
         }
 
-        R|<local>/x|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()
+        R|<local>/x|.R|kotlin/Int.inc|()
     }
     public final fun test_4(x: R|kotlin/Int?|): R|kotlin/Unit| {
         do {
-            (R|<local>/x| as R|class error: Symbol not found, for `int`|)
+            (R|<local>/x| as R|kotlin/Int|)
             break@@@[Boolean(true)]
         }
         while(Boolean(true))
-        R|<local>/x|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()
+        R|<local>/x|.R|kotlin/Int.inc|()
     }
diff --git a/compiler/fir/resolve/testData/resolve/cfg/loops.dot b/compiler/fir/resolve/testData/resolve/cfg/loops.dot
index 33fd3b89a64..01083fbb028 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/loops.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/loops.dot
@@ -138,4 +138,278 @@ subgraph testFor {
   63 -> {64};
 }
 
+subgraph testWhileTrue {
+  65 [shape=box label="Enter function testWhileTrue"];
+  66 [shape=box label="Enter block"];
+  67 [shape=box label="Enter while loop"];
+  68 [shape=box label="Enter loop condition"];
+  69 [shape=box label="Const: Boolean(true)"];
+  70 [shape=box label="Exit loop condition"];
+  71 [shape=box label="Enter loop block"];
+  72 [shape=box label="Enter block"];
+  73 [shape=box label="Const: Int(1)"];
+  74 [shape=box label="Exit block"];
+  75 [shape=box label="Exit loop block"];
+  76 [shape=box label="Stub[DEAD]"];
+  77 [shape=box label="Exit whileloop[DEAD]"];
+  78 [shape=box label="Const: Int(1)[DEAD]"];
+  79 [shape=box label="Exit block[DEAD]"];
+  80 [shape=box label="Exit function testWhileTrue[DEAD]"];
+
+  65 -> {66};
+  66 -> {67};
+  67 -> {68};
+  68 -> {69};
+  69 -> {70};
+  70 -> {71};
+  70 -> {76} [style=dotted];
+  71 -> {72};
+  72 -> {73};
+  73 -> {74};
+  74 -> {75};
+  75 -> {68};
+  76 -> {77} [style=dotted];
+  77 -> {78} [style=dotted];
+  78 -> {79} [style=dotted];
+  79 -> {80} [style=dotted];
+}
+
+subgraph testWhileTrueWithBreak {
+  81 [shape=box label="Enter function testWhileTrueWithBreak"];
+  82 [shape=box label="Enter block"];
+  83 [shape=box label="Enter while loop"];
+  84 [shape=box label="Enter loop condition"];
+  85 [shape=box label="Const: Boolean(true)"];
+  86 [shape=box label="Exit loop condition"];
+  87 [shape=box label="Enter loop block"];
+  88 [shape=box label="Enter block"];
+  89 [shape=box label="Enter when"];
+  90 [shape=box label="Enter when branch condition "];
+  91 [shape=box label="Access variable R|<local>/b|"];
+  92 [shape=box label="Exit when branch condition"];
+  93 [shape=box label="Enter block"];
+  94 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  95 [shape=box label="Stub[DEAD]"];
+  96 [shape=box label="Exit block[DEAD]"];
+  97 [shape=box label="Exit when branch result[DEAD]"];
+  98 [shape=box label="Enter when branch condition else"];
+  99 [shape=box label="Exit when branch condition"];
+  100 [shape=box label="Enter block"];
+  101 [shape=box label="Exit block"];
+  102 [shape=box label="Exit when branch result"];
+  103 [shape=box label="Exit when"];
+  104 [shape=box label="Exit block"];
+  105 [shape=box label="Exit loop block"];
+  106 [shape=box label="Stub[DEAD]"];
+  107 [shape=box label="Exit whileloop"];
+  108 [shape=box label="Const: Int(1)"];
+  109 [shape=box label="Exit block"];
+  110 [shape=box label="Exit function testWhileTrueWithBreak"];
+
+  81 -> {82};
+  82 -> {83};
+  83 -> {84};
+  84 -> {85};
+  85 -> {86};
+  86 -> {87};
+  86 -> {106} [style=dotted];
+  87 -> {88};
+  88 -> {89};
+  89 -> {90};
+  90 -> {91};
+  91 -> {92};
+  92 -> {93 98};
+  93 -> {94};
+  94 -> {107};
+  94 -> {95} [style=dotted];
+  95 -> {96} [style=dotted];
+  96 -> {97} [style=dotted];
+  97 -> {103} [style=dotted];
+  98 -> {99};
+  99 -> {100};
+  100 -> {101};
+  101 -> {102};
+  102 -> {103};
+  103 -> {104};
+  104 -> {105};
+  105 -> {84};
+  106 -> {107} [style=dotted];
+  107 -> {108};
+  108 -> {109};
+  109 -> {110};
+}
+
+subgraph testWhileFalse {
+  111 [shape=box label="Enter function testWhileFalse"];
+  112 [shape=box label="Enter block"];
+  113 [shape=box label="Enter while loop"];
+  114 [shape=box label="Enter loop condition"];
+  115 [shape=box label="Const: Boolean(false)"];
+  116 [shape=box label="Exit loop condition"];
+  117 [shape=box label="Stub[DEAD]"];
+  118 [shape=box label="Enter loop block[DEAD]"];
+  119 [shape=box label="Enter block[DEAD]"];
+  120 [shape=box label="Const: Int(1)[DEAD]"];
+  121 [shape=box label="Exit block[DEAD]"];
+  122 [shape=box label="Exit loop block[DEAD]"];
+  123 [shape=box label="Exit whileloop"];
+  124 [shape=box label="Const: Int(1)"];
+  125 [shape=box label="Exit block"];
+  126 [shape=box label="Exit function testWhileFalse"];
+
+  111 -> {112};
+  112 -> {113};
+  113 -> {114};
+  114 -> {115};
+  115 -> {116};
+  116 -> {123};
+  116 -> {117} [style=dotted];
+  117 -> {118} [style=dotted];
+  118 -> {119} [style=dotted];
+  119 -> {120} [style=dotted];
+  120 -> {121} [style=dotted];
+  121 -> {122} [style=dotted];
+  122 -> {114} [style=dotted];
+  123 -> {124};
+  124 -> {125};
+  125 -> {126};
+}
+
+subgraph testDoWhileTrue {
+  127 [shape=box label="Enter function testDoWhileTrue"];
+  128 [shape=box label="Enter block"];
+  129 [shape=box label="Enter do-while loop"];
+  130 [shape=box label="Enter loop block"];
+  131 [shape=box label="Enter block"];
+  132 [shape=box label="Const: Int(1)"];
+  133 [shape=box label="Exit block"];
+  134 [shape=box label="Exit loop block"];
+  135 [shape=box label="Enter loop condition"];
+  136 [shape=box label="Const: Boolean(true)"];
+  137 [shape=box label="Exit loop condition"];
+  138 [shape=box label="Stub[DEAD]"];
+  139 [shape=box label="Exit do-whileloop[DEAD]"];
+  140 [shape=box label="Const: Int(1)[DEAD]"];
+  141 [shape=box label="Exit block[DEAD]"];
+  142 [shape=box label="Exit function testDoWhileTrue[DEAD]"];
+
+  127 -> {128};
+  128 -> {129};
+  129 -> {130};
+  130 -> {131};
+  131 -> {132};
+  132 -> {133};
+  133 -> {134};
+  134 -> {135};
+  135 -> {136};
+  136 -> {137};
+  137 -> {130};
+  137 -> {138} [style=dotted];
+  138 -> {139} [style=dotted];
+  139 -> {140} [style=dotted];
+  140 -> {141} [style=dotted];
+  141 -> {142} [style=dotted];
+}
+
+subgraph testDoWhileTrueWithBreak {
+  143 [shape=box label="Enter function testDoWhileTrueWithBreak"];
+  144 [shape=box label="Enter block"];
+  145 [shape=box label="Enter do-while loop"];
+  146 [shape=box label="Enter loop block"];
+  147 [shape=box label="Enter block"];
+  148 [shape=box label="Enter when"];
+  149 [shape=box label="Enter when branch condition "];
+  150 [shape=box label="Access variable R|<local>/b|"];
+  151 [shape=box label="Exit when branch condition"];
+  152 [shape=box label="Enter block"];
+  153 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  154 [shape=box label="Stub[DEAD]"];
+  155 [shape=box label="Exit block[DEAD]"];
+  156 [shape=box label="Exit when branch result[DEAD]"];
+  157 [shape=box label="Enter when branch condition else"];
+  158 [shape=box label="Exit when branch condition"];
+  159 [shape=box label="Enter block"];
+  160 [shape=box label="Exit block"];
+  161 [shape=box label="Exit when branch result"];
+  162 [shape=box label="Exit when"];
+  163 [shape=box label="Exit block"];
+  164 [shape=box label="Exit loop block"];
+  165 [shape=box label="Enter loop condition"];
+  166 [shape=box label="Const: Boolean(true)"];
+  167 [shape=box label="Exit loop condition"];
+  168 [shape=box label="Stub[DEAD]"];
+  169 [shape=box label="Exit do-whileloop"];
+  170 [shape=box label="Const: Int(1)"];
+  171 [shape=box label="Exit block"];
+  172 [shape=box label="Exit function testDoWhileTrueWithBreak"];
+
+  143 -> {144};
+  144 -> {145};
+  145 -> {146};
+  146 -> {147};
+  147 -> {148};
+  148 -> {149};
+  149 -> {150};
+  150 -> {151};
+  151 -> {152 157};
+  152 -> {153};
+  153 -> {169};
+  153 -> {154} [style=dotted];
+  154 -> {155} [style=dotted];
+  155 -> {156} [style=dotted];
+  156 -> {162} [style=dotted];
+  157 -> {158};
+  158 -> {159};
+  159 -> {160};
+  160 -> {161};
+  161 -> {162};
+  162 -> {163};
+  163 -> {164};
+  164 -> {165};
+  165 -> {166};
+  166 -> {167};
+  167 -> {146};
+  167 -> {168} [style=dotted];
+  168 -> {169} [style=dotted];
+  169 -> {170};
+  170 -> {171};
+  171 -> {172};
+}
+
+subgraph testDoWhileFalse {
+  173 [shape=box label="Enter function testDoWhileFalse"];
+  174 [shape=box label="Enter block"];
+  175 [shape=box label="Enter do-while loop"];
+  176 [shape=box label="Enter loop block"];
+  177 [shape=box label="Enter block"];
+  178 [shape=box label="Const: Int(1)"];
+  179 [shape=box label="Exit block"];
+  180 [shape=box label="Exit loop block"];
+  181 [shape=box label="Enter loop condition"];
+  182 [shape=box label="Const: Boolean(false)"];
+  183 [shape=box label="Exit loop condition"];
+  184 [shape=box label="Exit do-whileloop"];
+  185 [shape=box label="Const: Int(1)"];
+  186 [shape=box label="Exit block"];
+  187 [shape=box label="Exit function testDoWhileFalse"];
+  188 [shape=box label="Stub[DEAD]"];
+
+  173 -> {174};
+  174 -> {175};
+  175 -> {176};
+  176 -> {177};
+  177 -> {178};
+  178 -> {179};
+  179 -> {180};
+  180 -> {181};
+  181 -> {182};
+  182 -> {183};
+  183 -> {184};
+  183 -> {188} [style=dotted];
+  184 -> {185};
+  185 -> {186};
+  186 -> {187};
+  188 -> {176} [style=dotted];
+}
+
 }
diff --git a/compiler/fir/resolve/testData/resolve/cfg/loops.kt b/compiler/fir/resolve/testData/resolve/cfg/loops.kt
index a939f97fe25..b52562e0edc 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/loops.kt
+++ b/compiler/fir/resolve/testData/resolve/cfg/loops.kt
@@ -17,4 +17,51 @@ fun testFor(x: Any?) {
         val y = x is String
     }
     x is String
+}
+
+fun testWhileTrue() {
+    while (true) {
+        1
+    }
+    1
+}
+
+fun testWhileTrueWithBreak(b: Boolean) {
+    while (true) {
+        if (b) {
+            break
+        }
+    }
+    1
+}
+
+
+fun testWhileFalse() {
+    while (false) {
+        1
+    }
+    1
+}
+
+fun testDoWhileTrue() {
+    do {
+        1
+    } while (true)
+    1
+}
+
+fun testDoWhileTrueWithBreak(b: Boolean) {
+    do {
+        if (b) {
+            break
+        }
+    } while (true)
+    1
+}
+
+fun testDoWhileFalse() {
+    do {
+        1
+    } while (false)
+    1
 }
\ No newline at end of file
diff --git a/compiler/fir/resolve/testData/resolve/cfg/loops.txt b/compiler/fir/resolve/testData/resolve/cfg/loops.txt
index f13ada73e89..f60a2790fef 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/loops.txt
+++ b/compiler/fir/resolve/testData/resolve/cfg/loops.txt
@@ -23,3 +23,59 @@ FILE: loops.kt
 
         (R|<local>/x| is R|kotlin/String|)
     }
+    public final fun testWhileTrue(): R|kotlin/Unit| {
+        while(Boolean(true)) {
+            Int(1)
+        }
+
+        Int(1)
+    }
+    public final fun testWhileTrueWithBreak(b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        while(Boolean(true)) {
+            when () {
+                R|<local>/b| ->  {
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+        }
+
+        Int(1)
+    }
+    public final fun testWhileFalse(): R|kotlin/Unit| {
+        while(Boolean(false)) {
+            Int(1)
+        }
+
+        Int(1)
+    }
+    public final fun testDoWhileTrue(): R|kotlin/Unit| {
+        do {
+            Int(1)
+        }
+        while(Boolean(true))
+        Int(1)
+    }
+    public final fun testDoWhileTrueWithBreak(b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        do {
+            when () {
+                R|<local>/b| ->  {
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+        }
+        while(Boolean(true))
+        Int(1)
+    }
+    public final fun testDoWhileFalse(): R|kotlin/Unit| {
+        do {
+            Int(1)
+        }
+        while(Boolean(false))
+        Int(1)
+    }
diff --git a/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot b/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot
index 6c0e64362c0..e4511921d9f 100644
--- a/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot
+++ b/compiler/fir/resolve/testData/resolve/cfg/tryCatch.dot
@@ -151,29 +151,31 @@ subgraph test_3 {
   101 [shape=box label="Variable declaration: lval y: R|kotlin/Int|"];
   102 [shape=box label="Exit block"];
   103 [shape=box label="Exit loop block"];
-  104 [shape=box label="Exit whileloop"];
-  105 [shape=box label="Const: Int(3)"];
-  106 [shape=box label="Variable declaration: lval z: R|kotlin/Int|"];
-  107 [shape=box label="Exit block"];
-  108 [shape=box label="Exit function test_3"];
+  104 [shape=box label="Stub[DEAD]"];
+  105 [shape=box label="Exit whileloop"];
+  106 [shape=box label="Const: Int(3)"];
+  107 [shape=box label="Variable declaration: lval z: R|kotlin/Int|"];
+  108 [shape=box label="Exit block"];
+  109 [shape=box label="Exit function test_3"];
 
   41 -> {42};
   42 -> {43};
   43 -> {44};
   44 -> {45};
   45 -> {46};
-  46 -> {104 47};
+  46 -> {47};
+  46 -> {104} [style=dotted];
   47 -> {48};
   48 -> {49};
   49 -> {50};
-  50 -> {108 93 87 51};
+  50 -> {109 93 87 51};
   51 -> {52};
   52 -> {53};
   53 -> {54};
   54 -> {55};
   55 -> {56 61};
   56 -> {57};
-  57 -> {108};
+  57 -> {109};
   57 -> {58} [style=dotted];
   58 -> {59} [style=dotted];
   59 -> {60} [style=dotted];
@@ -192,7 +194,7 @@ subgraph test_3 {
   72 -> {73};
   73 -> {74 79};
   74 -> {75};
-  75 -> {104};
+  75 -> {105};
   75 -> {76} [style=dotted];
   76 -> {77} [style=dotted];
   77 -> {78} [style=dotted];
@@ -205,16 +207,15 @@ subgraph test_3 {
   84 -> {85};
   85 -> {86};
   86 -> {99};
-  87 -> {108 88};
+  87 -> {109 88};
   88 -> {89};
-  89 -> {104};
+  89 -> {105};
   89 -> {90} [style=dotted];
   90 -> {91} [style=dotted];
   91 -> {92} [style=dotted];
   92 -> {99} [style=dotted];
-  93 -> {108 94};
+  93 -> {109 94};
   94 -> {95};
-  95 -> {44};
   95 -> {96} [style=dotted];
   96 -> {97} [style=dotted];
   97 -> {98} [style=dotted];
@@ -224,10 +225,11 @@ subgraph test_3 {
   101 -> {102};
   102 -> {103};
   103 -> {44};
-  104 -> {105};
+  104 -> {105} [style=dotted];
   105 -> {106};
   106 -> {107};
   107 -> {108};
+  108 -> {109};
 }
 
 }
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot
new file mode 100644
index 00000000000..c1d2f007071
--- /dev/null
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.dot
@@ -0,0 +1,513 @@
+digraph endlessLoops_kt {
+graph [splines=ortho]
+
+subgraph foo {
+  0 [shape=box label="Enter function foo"];
+  1 [shape=box label="Exit function foo"];
+
+  0 -> {1};
+}
+
+subgraph test_1 {
+  2 [shape=box label="Enter function test_1"];
+  3 [shape=box label="Enter block"];
+  4 [shape=box label="Enter while loop"];
+  5 [shape=box label="Enter loop condition"];
+  6 [shape=box label="Const: Boolean(true)"];
+  7 [shape=box label="Exit loop condition"];
+  8 [shape=box label="Enter loop block"];
+  9 [shape=box label="Enter block"];
+  10 [shape=box label="Access variable R|<local>/x|"];
+  11 [shape=box label="Type operator: x as A"];
+  12 [shape=box label="Enter when"];
+  13 [shape=box label="Enter when branch condition "];
+  14 [shape=box label="Access variable R|<local>/b|"];
+  15 [shape=box label="Exit when branch condition"];
+  16 [shape=box label="Enter block"];
+  17 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  18 [shape=box label="Stub[DEAD]"];
+  19 [shape=box label="Exit block[DEAD]"];
+  20 [shape=box label="Exit when branch result[DEAD]"];
+  21 [shape=box label="Enter when branch condition else"];
+  22 [shape=box label="Exit when branch condition"];
+  23 [shape=box label="Enter block"];
+  24 [shape=box label="Exit block"];
+  25 [shape=box label="Exit when branch result"];
+  26 [shape=box label="Exit when"];
+  27 [shape=box label="Exit block"];
+  28 [shape=box label="Exit loop block"];
+  29 [shape=box label="Stub[DEAD]"];
+  30 [shape=box label="Exit whileloop"];
+  31 [shape=box label="Access variable R|<local>/x|"];
+  32 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
+  33 [shape=box label="Exit block"];
+  34 [shape=box label="Exit function test_1"];
+
+  2 -> {3};
+  3 -> {4};
+  4 -> {5};
+  5 -> {6};
+  6 -> {7};
+  7 -> {8};
+  7 -> {29} [style=dotted];
+  8 -> {9};
+  9 -> {10};
+  10 -> {11};
+  11 -> {12};
+  12 -> {13};
+  13 -> {14};
+  14 -> {15};
+  15 -> {16 21};
+  16 -> {17};
+  17 -> {30};
+  17 -> {18} [style=dotted];
+  18 -> {19} [style=dotted];
+  19 -> {20} [style=dotted];
+  20 -> {26} [style=dotted];
+  21 -> {22};
+  22 -> {23};
+  23 -> {24};
+  24 -> {25};
+  25 -> {26};
+  26 -> {27};
+  27 -> {28};
+  28 -> {5};
+  29 -> {30} [style=dotted];
+  30 -> {31};
+  31 -> {32};
+  32 -> {33};
+  33 -> {34};
+}
+
+subgraph test_2 {
+  35 [shape=box label="Enter function test_2"];
+  36 [shape=box label="Enter block"];
+  37 [shape=box label="Enter while loop"];
+  38 [shape=box label="Enter loop condition"];
+  39 [shape=box label="Const: Boolean(true)"];
+  40 [shape=box label="Exit loop condition"];
+  41 [shape=box label="Enter loop block"];
+  42 [shape=box label="Enter block"];
+  43 [shape=box label="Enter when"];
+  44 [shape=box label="Enter when branch condition "];
+  45 [shape=box label="Access variable R|<local>/b|"];
+  46 [shape=box label="Exit when branch condition"];
+  47 [shape=box label="Enter block"];
+  48 [shape=box label="Access variable R|<local>/x|"];
+  49 [shape=box label="Type operator: x as A"];
+  50 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  51 [shape=box label="Stub[DEAD]"];
+  52 [shape=box label="Exit block[DEAD]"];
+  53 [shape=box label="Exit when branch result[DEAD]"];
+  54 [shape=box label="Enter when branch condition else"];
+  55 [shape=box label="Exit when branch condition"];
+  56 [shape=box label="Enter block"];
+  57 [shape=box label="Exit block"];
+  58 [shape=box label="Exit when branch result"];
+  59 [shape=box label="Exit when"];
+  60 [shape=box label="Exit block"];
+  61 [shape=box label="Exit loop block"];
+  62 [shape=box label="Stub[DEAD]"];
+  63 [shape=box label="Exit whileloop"];
+  64 [shape=box label="Access variable R|<local>/x|"];
+  65 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
+  66 [shape=box label="Exit block"];
+  67 [shape=box label="Exit function test_2"];
+
+  35 -> {36};
+  36 -> {37};
+  37 -> {38};
+  38 -> {39};
+  39 -> {40};
+  40 -> {41};
+  40 -> {62} [style=dotted];
+  41 -> {42};
+  42 -> {43};
+  43 -> {44};
+  44 -> {45};
+  45 -> {46};
+  46 -> {47 54};
+  47 -> {48};
+  48 -> {49};
+  49 -> {50};
+  50 -> {63};
+  50 -> {51} [style=dotted];
+  51 -> {52} [style=dotted];
+  52 -> {53} [style=dotted];
+  53 -> {59} [style=dotted];
+  54 -> {55};
+  55 -> {56};
+  56 -> {57};
+  57 -> {58};
+  58 -> {59};
+  59 -> {60};
+  60 -> {61};
+  61 -> {38};
+  62 -> {63} [style=dotted];
+  63 -> {64};
+  64 -> {65};
+  65 -> {66};
+  66 -> {67};
+}
+
+subgraph test_3 {
+  68 [shape=box label="Enter function test_3"];
+  69 [shape=box label="Enter block"];
+  70 [shape=box label="Enter while loop"];
+  71 [shape=box label="Enter loop condition"];
+  72 [shape=box label="Const: Boolean(true)"];
+  73 [shape=box label="Exit loop condition"];
+  74 [shape=box label="Enter loop block"];
+  75 [shape=box label="Enter block"];
+  76 [shape=box label="Access variable R|<local>/x|"];
+  77 [shape=box label="Type operator: x as A"];
+  78 [shape=box label="Enter when"];
+  79 [shape=box label="Enter when branch condition "];
+  80 [shape=box label="Access variable R|<local>/b|"];
+  81 [shape=box label="Exit when branch condition"];
+  82 [shape=box label="Enter block"];
+  83 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  84 [shape=box label="Stub[DEAD]"];
+  85 [shape=box label="Exit block[DEAD]"];
+  86 [shape=box label="Exit when branch result[DEAD]"];
+  87 [shape=box label="Enter when branch condition else"];
+  88 [shape=box label="Exit when branch condition"];
+  89 [shape=box label="Enter block"];
+  90 [shape=box label="Exit block"];
+  91 [shape=box label="Exit when branch result"];
+  92 [shape=box label="Exit when"];
+  93 [shape=box label="Enter when"];
+  94 [shape=box label="Enter when branch condition "];
+  95 [shape=box label="Access variable R|<local>/b|"];
+  96 [shape=box label="Exit when branch condition"];
+  97 [shape=box label="Enter block"];
+  98 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  99 [shape=box label="Stub[DEAD]"];
+  100 [shape=box label="Exit block[DEAD]"];
+  101 [shape=box label="Exit when branch result[DEAD]"];
+  102 [shape=box label="Enter when branch condition else"];
+  103 [shape=box label="Exit when branch condition"];
+  104 [shape=box label="Enter block"];
+  105 [shape=box label="Exit block"];
+  106 [shape=box label="Exit when branch result"];
+  107 [shape=box label="Exit when"];
+  108 [shape=box label="Exit block"];
+  109 [shape=box label="Exit loop block"];
+  110 [shape=box label="Stub[DEAD]"];
+  111 [shape=box label="Exit whileloop"];
+  112 [shape=box label="Access variable R|<local>/x|"];
+  113 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
+  114 [shape=box label="Exit block"];
+  115 [shape=box label="Exit function test_3"];
+
+  68 -> {69};
+  69 -> {70};
+  70 -> {71};
+  71 -> {72};
+  72 -> {73};
+  73 -> {74};
+  73 -> {110} [style=dotted];
+  74 -> {75};
+  75 -> {76};
+  76 -> {77};
+  77 -> {78};
+  78 -> {79};
+  79 -> {80};
+  80 -> {81};
+  81 -> {82 87};
+  82 -> {83};
+  83 -> {111};
+  83 -> {84} [style=dotted];
+  84 -> {85} [style=dotted];
+  85 -> {86} [style=dotted];
+  86 -> {92} [style=dotted];
+  87 -> {88};
+  88 -> {89};
+  89 -> {90};
+  90 -> {91};
+  91 -> {92};
+  92 -> {93};
+  93 -> {94};
+  94 -> {95};
+  95 -> {96};
+  96 -> {97 102};
+  97 -> {98};
+  98 -> {111};
+  98 -> {99} [style=dotted];
+  99 -> {100} [style=dotted];
+  100 -> {101} [style=dotted];
+  101 -> {107} [style=dotted];
+  102 -> {103};
+  103 -> {104};
+  104 -> {105};
+  105 -> {106};
+  106 -> {107};
+  107 -> {108};
+  108 -> {109};
+  109 -> {71};
+  110 -> {111} [style=dotted];
+  111 -> {112};
+  112 -> {113};
+  113 -> {114};
+  114 -> {115};
+}
+
+subgraph test_4 {
+  116 [shape=box label="Enter function test_4"];
+  117 [shape=box label="Enter block"];
+  118 [shape=box label="Enter while loop"];
+  119 [shape=box label="Enter loop condition"];
+  120 [shape=box label="Const: Boolean(true)"];
+  121 [shape=box label="Exit loop condition"];
+  122 [shape=box label="Enter loop block"];
+  123 [shape=box label="Enter block"];
+  124 [shape=box label="Enter when"];
+  125 [shape=box label="Enter when branch condition "];
+  126 [shape=box label="Access variable R|<local>/b|"];
+  127 [shape=box label="Exit when branch condition"];
+  128 [shape=box label="Enter block"];
+  129 [shape=box label="Access variable R|<local>/x|"];
+  130 [shape=box label="Type operator: x as A"];
+  131 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  132 [shape=box label="Stub[DEAD]"];
+  133 [shape=box label="Exit block[DEAD]"];
+  134 [shape=box label="Exit when branch result[DEAD]"];
+  135 [shape=box label="Enter when branch condition else"];
+  136 [shape=box label="Exit when branch condition"];
+  137 [shape=box label="Enter block"];
+  138 [shape=box label="Exit block"];
+  139 [shape=box label="Exit when branch result"];
+  140 [shape=box label="Exit when"];
+  141 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  142 [shape=box label="Stub[DEAD]"];
+  143 [shape=box label="Exit block[DEAD]"];
+  144 [shape=box label="Exit loop block[DEAD]"];
+  145 [shape=box label="Stub[DEAD]"];
+  146 [shape=box label="Exit whileloop"];
+  147 [shape=box label="Access variable R|<local>/x|"];
+  148 [shape=box label="Function call: R|<local>/x|.<Unresolved name: foo>#()"];
+  149 [shape=box label="Exit block"];
+  150 [shape=box label="Exit function test_4"];
+
+  116 -> {117};
+  117 -> {118};
+  118 -> {119};
+  119 -> {120};
+  120 -> {121};
+  121 -> {122};
+  121 -> {145} [style=dotted];
+  122 -> {123};
+  123 -> {124};
+  124 -> {125};
+  125 -> {126};
+  126 -> {127};
+  127 -> {128 135};
+  128 -> {129};
+  129 -> {130};
+  130 -> {131};
+  131 -> {146};
+  131 -> {132} [style=dotted];
+  132 -> {133} [style=dotted];
+  133 -> {134} [style=dotted];
+  134 -> {140} [style=dotted];
+  135 -> {136};
+  136 -> {137};
+  137 -> {138};
+  138 -> {139};
+  139 -> {140};
+  140 -> {141};
+  141 -> {146};
+  141 -> {142} [style=dotted];
+  142 -> {143} [style=dotted];
+  143 -> {144} [style=dotted];
+  144 -> {119} [style=dotted];
+  145 -> {146} [style=dotted];
+  146 -> {147};
+  147 -> {148};
+  148 -> {149};
+  149 -> {150};
+}
+
+subgraph test_5 {
+  151 [shape=box label="Enter function test_5"];
+  152 [shape=box label="Enter block"];
+  153 [shape=box label="Enter do-while loop"];
+  154 [shape=box label="Enter loop block"];
+  155 [shape=box label="Enter block"];
+  156 [shape=box label="Enter when"];
+  157 [shape=box label="Enter when branch condition "];
+  158 [shape=box label="Access variable R|<local>/b|"];
+  159 [shape=box label="Exit when branch condition"];
+  160 [shape=box label="Enter block"];
+  161 [shape=box label="Access variable R|<local>/x|"];
+  162 [shape=box label="Type operator: x as A"];
+  163 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  164 [shape=box label="Stub[DEAD]"];
+  165 [shape=box label="Exit block[DEAD]"];
+  166 [shape=box label="Exit when branch result[DEAD]"];
+  167 [shape=box label="Enter when branch condition else"];
+  168 [shape=box label="Exit when branch condition"];
+  169 [shape=box label="Enter block"];
+  170 [shape=box label="Exit block"];
+  171 [shape=box label="Exit when branch result"];
+  172 [shape=box label="Exit when"];
+  173 [shape=box label="Exit block"];
+  174 [shape=box label="Exit loop block"];
+  175 [shape=box label="Enter loop condition"];
+  176 [shape=box label="Const: Boolean(true)"];
+  177 [shape=box label="Exit loop condition"];
+  178 [shape=box label="Stub[DEAD]"];
+  179 [shape=box label="Exit do-whileloop"];
+  180 [shape=box label="Access variable R|<local>/x|"];
+  181 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
+  182 [shape=box label="Exit block"];
+  183 [shape=box label="Exit function test_5"];
+
+  151 -> {152};
+  152 -> {153};
+  153 -> {154};
+  154 -> {155};
+  155 -> {156};
+  156 -> {157};
+  157 -> {158};
+  158 -> {159};
+  159 -> {160 167};
+  160 -> {161};
+  161 -> {162};
+  162 -> {163};
+  163 -> {179};
+  163 -> {164} [style=dotted];
+  164 -> {165} [style=dotted];
+  165 -> {166} [style=dotted];
+  166 -> {172} [style=dotted];
+  167 -> {168};
+  168 -> {169};
+  169 -> {170};
+  170 -> {171};
+  171 -> {172};
+  172 -> {173};
+  173 -> {174};
+  174 -> {175};
+  175 -> {176};
+  176 -> {177};
+  177 -> {154};
+  177 -> {178} [style=dotted];
+  178 -> {179} [style=dotted];
+  179 -> {180};
+  180 -> {181};
+  181 -> {182};
+  182 -> {183};
+}
+
+subgraph test_6 {
+  184 [shape=box label="Enter function test_6"];
+  185 [shape=box label="Enter block"];
+  186 [shape=box label="Enter do-while loop"];
+  187 [shape=box label="Enter loop block"];
+  188 [shape=box label="Enter block"];
+  189 [shape=box label="Access variable R|<local>/x|"];
+  190 [shape=box label="Type operator: x as A"];
+  191 [shape=box label="Enter when"];
+  192 [shape=box label="Enter when branch condition "];
+  193 [shape=box label="Access variable R|<local>/b|"];
+  194 [shape=box label="Exit when branch condition"];
+  195 [shape=box label="Enter block"];
+  196 [shape=box label="Jump: break@@@[Boolean(true)] "];
+  197 [shape=box label="Stub[DEAD]"];
+  198 [shape=box label="Exit block[DEAD]"];
+  199 [shape=box label="Exit when branch result[DEAD]"];
+  200 [shape=box label="Enter when branch condition else"];
+  201 [shape=box label="Exit when branch condition"];
+  202 [shape=box label="Enter block"];
+  203 [shape=box label="Exit block"];
+  204 [shape=box label="Exit when branch result"];
+  205 [shape=box label="Exit when"];
+  206 [shape=box label="Exit block"];
+  207 [shape=box label="Exit loop block"];
+  208 [shape=box label="Enter loop condition"];
+  209 [shape=box label="Const: Boolean(true)"];
+  210 [shape=box label="Exit loop condition"];
+  211 [shape=box label="Stub[DEAD]"];
+  212 [shape=box label="Exit do-whileloop"];
+  213 [shape=box label="Access variable R|<local>/x|"];
+  214 [shape=box label="Function call: R|<local>/x|.R|/A.foo|()"];
+  215 [shape=box label="Exit block"];
+  216 [shape=box label="Exit function test_6"];
+
+  184 -> {185};
+  185 -> {186};
+  186 -> {187};
+  187 -> {188};
+  188 -> {189};
+  189 -> {190};
+  190 -> {191};
+  191 -> {192};
+  192 -> {193};
+  193 -> {194};
+  194 -> {195 200};
+  195 -> {196};
+  196 -> {212};
+  196 -> {197} [style=dotted];
+  197 -> {198} [style=dotted];
+  198 -> {199} [style=dotted];
+  199 -> {205} [style=dotted];
+  200 -> {201};
+  201 -> {202};
+  202 -> {203};
+  203 -> {204};
+  204 -> {205};
+  205 -> {206};
+  206 -> {207};
+  207 -> {208};
+  208 -> {209};
+  209 -> {210};
+  210 -> {187};
+  210 -> {211} [style=dotted];
+  211 -> {212} [style=dotted];
+  212 -> {213};
+  213 -> {214};
+  214 -> {215};
+  215 -> {216};
+}
+
+subgraph test_7 {
+  217 [shape=box label="Enter function test_7"];
+  218 [shape=box label="Enter block"];
+  219 [shape=box label="Enter do-while loop"];
+  220 [shape=box label="Enter loop block"];
+  221 [shape=box label="Enter block"];
+  222 [shape=box label="Access variable R|<local>/x|"];
+  223 [shape=box label="Type operator: x as A"];
+  224 [shape=box label="Exit block"];
+  225 [shape=box label="Exit loop block"];
+  226 [shape=box label="Enter loop condition"];
+  227 [shape=box label="Const: Boolean(true)"];
+  228 [shape=box label="Exit loop condition"];
+  229 [shape=box label="Stub[DEAD]"];
+  230 [shape=box label="Exit do-whileloop[DEAD]"];
+  231 [shape=box label="Access variable R|<local>/x|[DEAD]"];
+  232 [shape=box label="Function call: R|<local>/x|.<Unresolved name: foo>#()[DEAD]"];
+  233 [shape=box label="Exit block[DEAD]"];
+  234 [shape=box label="Exit function test_7[DEAD]"];
+
+  217 -> {218};
+  218 -> {219};
+  219 -> {220};
+  220 -> {221};
+  221 -> {222};
+  222 -> {223};
+  223 -> {224};
+  224 -> {225};
+  225 -> {226};
+  226 -> {227};
+  227 -> {228};
+  228 -> {220};
+  228 -> {229} [style=dotted];
+  229 -> {230} [style=dotted];
+  230 -> {231} [style=dotted];
+  231 -> {232} [style=dotted];
+  232 -> {233} [style=dotted];
+  233 -> {234} [style=dotted];
+}
+
+}
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.kt b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.kt
new file mode 100644
index 00000000000..32ee9a395cf
--- /dev/null
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.kt
@@ -0,0 +1,74 @@
+interface A {
+    fun foo()
+}
+
+fun test_1(x: Any, b: Boolean) {
+    while (true) {
+        x as A
+        if (b) {
+            break
+        }
+    }
+    x.foo()
+}
+
+fun test_2(x: Any, b: Boolean) {
+    while (true) {
+        if (b) {
+            x as A
+            break
+        }
+    }
+    x.foo()
+}
+
+fun test_3(x: Any, b: Boolean) {
+    while (true) {
+        x as A
+        if (b) {
+            break
+        }
+        if (b) {
+            break
+        }
+    }
+    x.foo()
+}
+
+fun test_4(x: Any, b: Boolean) {
+    while (true) {
+        if (b) {
+            x as A
+            break
+        }
+        break
+    }
+    x.foo() // No smartcast
+}
+
+fun test_5(x: Any, b: Boolean) {
+    do {
+        if (b) {
+            x as A
+            break
+        }
+    } while (true)
+    x.foo()
+}
+
+fun test_6(x: Any, b: Boolean) {
+    do {
+        x as A
+        if (b) {
+            break
+        }
+    } while (true)
+    x.foo()
+}
+
+fun test_7(x: Any) {
+    do {
+        x as A
+    } while (true)
+    x.foo() // No smartcast
+}
diff --git a/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.txt b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.txt
new file mode 100644
index 00000000000..80fc13dc5ad
--- /dev/null
+++ b/compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.txt
@@ -0,0 +1,111 @@
+FILE: endlessLoops.kt
+    public abstract interface A : R|kotlin/Any| {
+        public abstract fun foo(): R|kotlin/Unit|
+
+    }
+    public final fun test_1(x: R|kotlin/Any|, b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        while(Boolean(true)) {
+            (R|<local>/x| as R|A|)
+            when () {
+                R|<local>/b| ->  {
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+        }
+
+        R|<local>/x|.R|/A.foo|()
+    }
+    public final fun test_2(x: R|kotlin/Any|, b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        while(Boolean(true)) {
+            when () {
+                R|<local>/b| ->  {
+                    (R|<local>/x| as R|A|)
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+        }
+
+        R|<local>/x|.R|/A.foo|()
+    }
+    public final fun test_3(x: R|kotlin/Any|, b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        while(Boolean(true)) {
+            (R|<local>/x| as R|A|)
+            when () {
+                R|<local>/b| ->  {
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+            when () {
+                R|<local>/b| ->  {
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+        }
+
+        R|<local>/x|.R|/A.foo|()
+    }
+    public final fun test_4(x: R|kotlin/Any|, b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        while(Boolean(true)) {
+            when () {
+                R|<local>/b| ->  {
+                    (R|<local>/x| as R|A|)
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+            break@@@[Boolean(true)]
+        }
+
+        R|<local>/x|.<Unresolved name: foo>#()
+    }
+    public final fun test_5(x: R|kotlin/Any|, b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        do {
+            when () {
+                R|<local>/b| ->  {
+                    (R|<local>/x| as R|A|)
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+        }
+        while(Boolean(true))
+        R|<local>/x|.R|/A.foo|()
+    }
+    public final fun test_6(x: R|kotlin/Any|, b: R|kotlin/Boolean|): R|kotlin/Unit| {
+        do {
+            (R|<local>/x| as R|A|)
+            when () {
+                R|<local>/b| ->  {
+                    break@@@[Boolean(true)]
+                }
+                else ->  {
+                }
+            }
+
+        }
+        while(Boolean(true))
+        R|<local>/x|.R|/A.foo|()
+    }
+    public final fun test_7(x: R|kotlin/Any|): R|kotlin/Unit| {
+        do {
+            (R|<local>/x| as R|A|)
+        }
+        while(Boolean(true))
+        R|<local>/x|.<Unresolved name: foo>#()
+    }
diff --git a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java
index 856f966fbaf..ce2596e0541 100644
--- a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java
+++ b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirCfgBuildingTestGenerated.java
@@ -119,6 +119,11 @@ public class FirCfgBuildingTestGenerated extends AbstractFirCfgBuildingTest {
             runTest("compiler/fir/resolve/testData/resolve/smartcasts/elvis.kt");
         }
 
+        @TestMetadata("endlessLoops.kt")
+        public void testEndlessLoops() throws Exception {
+            runTest("compiler/fir/resolve/testData/resolve/smartcasts/endlessLoops.kt");
+        }
+
         @TestMetadata("equalsAndIdentity.kt")
         public void testEqualsAndIdentity() throws Exception {
             runTest("compiler/fir/resolve/testData/resolve/smartcasts/equalsAndIdentity.kt");