Merge pull request #4058 from CamWass:fix-cfa

PiperOrigin-RevId: 509559837

Author: copybara-github

src/com/google/javascript/jscomp/ControlFlowAnalysis.java

@@ -476,10 +476,11 @@ private void handleWhile(Node node) {
   }
 
   private void handleDo(Node node) {
-    Node cond = node.getFirstChild();
+    Node body = node.getFirstChild();
     // The first edge can be the initial iteration as well as the iterations
     // after.
-    createEdge(node, Branch.ON_TRUE, computeFallThrough(cond));
+    createEdge(node, Branch.ON_TRUE, computeFallThrough(body));
+    Node cond = body.getNext();
     if (!cond.isTrue()) {
       // The edge that leaves the do loop if the condition fails.
       createEdge(node, Branch.ON_FALSE, computeFollowNode(node, this));

test/com/google/javascript/jscomp/ControlFlowAnalysisTest.java

@@ -336,6 +336,14 @@ public void testInifiteLoopWhile() {
     assertNoEdge(cfg, Token.WHILE, Token.EXPR_RESULT);
   }
 
+  @Test
+  public void testInifiteLoopDoWhile() {
+    String src = "var x; do { } while (true); x();";
+    ControlFlowGraph<Node> cfg = createCfg(src);
+    assertDownEdge(cfg, Token.DO, Token.BLOCK, Branch.ON_TRUE);
+    assertNoEdge(cfg, Token.DO, Token.EXPR_RESULT);
+  }
+
   @Test
   public void testInifiteLoopFor_emptyCond() {
     String src = "var x; for(;;) { } x();";