From 3b9c399f72e7d2c94bf06a8cafc5b27affd646d2 Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Wed, 7 Jul 2021 01:20:32 -0500
Subject: [PATCH] Fix 10338: Hang/Crash in valueflow (#3328)

---
 lib/astutils.cpp        | 2 +-
 lib/forwardanalyzer.cpp | 2 +-
 test/testvalueflow.cpp  | 9 +++++++++
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/astutils.cpp b/lib/astutils.cpp
index a220cfb99..891a836ee 100644
--- a/lib/astutils.cpp
+++ b/lib/astutils.cpp
@@ -597,7 +597,7 @@ bool precedes(const Token * tok1, const Token * tok2)
     if (!tok1)
         return false;
     if (!tok2)
-        return false;
+        return true;
     return tok1->index() < tok2->index();
 }
 
diff --git a/lib/forwardanalyzer.cpp b/lib/forwardanalyzer.cpp
index 75035728b..91122f504 100644
--- a/lib/forwardanalyzer.cpp
+++ b/lib/forwardanalyzer.cpp
@@ -471,7 +471,7 @@ struct ForwardTraversal {
         if (depth < 0)
             return Break(Analyzer::Terminate::Bail);
         std::size_t i = 0;
-        for (Token* tok = start; tok && tok != end; tok = tok->next()) {
+        for (Token* tok = start; precedes(tok, end); tok = tok->next()) {
             Token* next = nullptr;
             if (tok->index() <= i)
                 throw InternalError(tok, "Cyclic forward analysis.");
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index 52b351282..295b3a73e 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -5630,6 +5630,15 @@ private:
                "  return e;\n"
                "}\n";
         valueOfTok(code, "x");
+
+        code = "void a() {\n"
+               "  int b = 0;\n"
+               "  do {\n"
+               "    for (;;)\n"
+               "      break;\n"
+               "  } while (b < 1);\n"
+               "}\n";
+        valueOfTok(code, "b");
     }
 
     void valueFlowCrashConstructorInitialization() { // #9577