From 5f73af0d0ef14a11879c6ff44fa02e5b019be42c Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Wed, 15 Dec 2021 12:32:14 -0600
Subject: [PATCH] Fix 10625: False positive: known value below do while (#3623)

---
 lib/forwardanalyzer.cpp |  8 ++++++--
 test/testcondition.cpp  | 13 +++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/lib/forwardanalyzer.cpp b/lib/forwardanalyzer.cpp
index 19cd196df..f6fbbf949 100644
--- a/lib/forwardanalyzer.cpp
+++ b/lib/forwardanalyzer.cpp
@@ -284,6 +284,10 @@ struct ForwardTraversal {
         return Token::findsimplematch(endBlock->link(), "goto", endBlock);
     }
 
+    bool hasJump(const Token* endBlock) {
+        return Token::findmatch(endBlock->link(), "goto|break", endBlock);
+    }
+
     bool hasInnerReturnScope(const Token* start, const Token* end) const {
         for (const Token* tok=start; tok != end; tok = tok->previous()) {
             if (Token::simpleMatch(tok, "}")) {
@@ -404,7 +408,7 @@ struct ForwardTraversal {
         bool checkElse = false;
         if (condTok && !Token::simpleMatch(condTok, ":"))
             std::tie(checkThen, checkElse) = evalCond(condTok, isDoWhile ? endBlock->previous() : nullptr);
-        if (checkElse && exit)
+        if (checkElse && exit && !hasJump(endBlock))
             return Progress::Continue;
         Analyzer::Action bodyAnalysis = analyzeScope(endBlock);
         Analyzer::Action allAnalysis = bodyAnalysis;
@@ -417,7 +421,7 @@ struct ForwardTraversal {
             allAnalysis |= analyzeRecursive(stepTok);
         actions |= allAnalysis;
         // do while(false) is not really a loop
-        if (checkElse && isDoWhile &&
+        if (checkElse && isDoWhile && !hasJump(endBlock) &&
             (condTok->hasKnownIntValue() ||
              (!bodyAnalysis.isModified() && !condAnalysis.isModified() && condAnalysis.isRead()))) {
             if (updateRange(endBlock->link(), endBlock) == Progress::Break)
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index 8d66c8e2e..50fde0d5a 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -4211,6 +4211,19 @@ private:
               "  return bFirst;\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("void f() {\n"
+              "   void * pool = NULL;\n"
+              "   do {\n"
+              "      pool = malloc(40);\n"
+              "      if (dostuff())\n"
+              "         break;\n"
+              "      pool = NULL;\n"
+              "   }\n"
+              "   while (0);\n"
+              "   if (pool) {}\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void alwaysTrueTryCatch()