[FIR] Fix propagating deadness for loops and when expressions

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/cfg/ControlFlowGraphBuilder.kt

@@ -206,6 +206,7 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
         // we should remove it
         require(lastNodes.pop() is WhenBranchConditionExitNode)
         val whenExitNode = whenExitNodes.pop()
+        whenExitNode.markAsDeadIfNecessary()
         lastNodes.push(whenExitNode)
         return whenExitNode
     }
@@ -247,6 +248,7 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
             addEdge(loopBlockExitNode, conditionEnterNode, propagateDeadness = false)
         }
         val loopExitNode = loopExitNodes.pop()
+        loopExitNode.markAsDeadIfNecessary()
         lastNodes.push(loopExitNode)
         levelCounter--
         return loopBlockExitNode to loopExitNode
@@ -285,7 +287,8 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
         require(blockEnterNode is LoopBlockEnterNode)
         addEdge(conditionExitNode, blockEnterNode, propagateDeadness = false)
         val loopExit = loopExitNodes.pop()
-        addEdge(conditionExitNode, loopExit)
+        addEdge(conditionExitNode, loopExit, propagateDeadness = false)
+        loopExit.markAsDeadIfNecessary()
         lastNodes.push(loopExit)
         levelCounter--
         return loopExit
@@ -310,7 +313,7 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
         return binaryAndExitNodes.pop().also {
             val rightNode = lastNodes.pop()
             addEdge(rightNode, it, propagateDeadness = false, isDead = it.leftOperandNode.booleanConstValue == false)
-            it.isDead = it.previousNodes.all { it.isDead }
+            it.markAsDeadIfNecessary()
             lastNodes.push(it)
         }
     }
@@ -342,7 +345,7 @@ class ControlFlowGraphBuilder : ControlFlowGraphNodeBuilder() {
         return binaryOrExitNodes.pop().also {
             val rightNode = lastNodes.pop()
             addEdge(rightNode, it, propagateDeadness = false)
-            it.isDead = it.previousNodes.all { it.isDead }
+            it.markAsDeadIfNecessary()
             lastNodes.push(it)
         }
     }

compiler/fir/resolve/testData/resolve/cfg/jumps.dot

@@ -163,11 +163,11 @@ subgraph test_4 {
   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[DEAD]"];
-  84 [shape=box label="Access variable R|<local>/x|[DEAD]"];
-  85 [shape=box label="Function call: R|<local>/x|.<Ambiguity: inc, [kotlin/inc, kotlin/inc]>#()[DEAD]"];
-  86 [shape=box label="Exit block[DEAD]"];
-  87 [shape=box label="Exit function test_4[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"];
 
   69 -> {70};
   70 -> {71};
@@ -176,17 +176,18 @@ subgraph test_4 {
   73 -> {74};
   74 -> {75};
   75 -> {76};
-  76 -> {83 77} [style=dotted];
+  76 -> {83};
+  76 -> {77} [style=dotted];
   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} [style=dotted];
-  84 -> {85} [style=dotted];
-  85 -> {86} [style=dotted];
-  86 -> {87} [style=dotted];
+  83 -> {84};
+  84 -> {85};
+  85 -> {86};
+  86 -> {87};
 }
 
 }