diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index a47b97bc3..cdf99a945 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -5939,8 +5939,8 @@ bool Tokenizer::simplifyKnownVariablesSimplify(Token **tok2, Token *tok3, unsign
         if (Token::Match(tok3, "; %type% : ;"))
             break;
 
-        // Stop if return or break is found ..
-        if (tok3->str() == "break")
+        // Stop if break/continue is found ..
+        if (tok3->str() == "break" || tok3->str() == "continue")
             break;
         if ((indentlevel3 > 1 || !Token::simpleMatch(Token::findsimplematch(tok3,";"), "; }")) && tok3->str() == "return")
             ret3 = true;
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index 433f60bca..addf93642 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -152,6 +152,7 @@ private:
         TEST_CASE(simplifyKnownVariables46);    // ticket #3587 - >>
         TEST_CASE(simplifyKnownVariables47);    // ticket #3627 - >>
         TEST_CASE(simplifyKnownVariables48);    // ticket #3754 - wrong simplification in for loop header
+        TEST_CASE(simplifyKnownVariables49);    // #3691 - continue in switch
         TEST_CASE(simplifyKnownVariablesIfEq1); // if (a==5) => a is 5 in the block
         TEST_CASE(simplifyKnownVariablesIfEq2); // if (a==5) { buf[a++] = 0; }
         TEST_CASE(simplifyKnownVariablesBailOutAssign1);
@@ -2300,6 +2301,22 @@ private:
         ASSERT_EQUALS(expected, tokenizeAndStringify(code, true, true, Settings::Unspecified, "test.c"));
     }
 
+    void simplifyKnownVariables49() { // #3691
+        const char code[] = "void f(int sz) {\n"
+                            "    switch (x) {\n"
+                            "    case 1: sz = 2; continue;\n"
+                            "    case 2: x = sz; break;\n"
+                            "    }\n"
+                            "}";
+        const char expected[] = "void f ( int sz ) {\n"
+                                "switch ( x ) {\n"
+                                "case 1 : ; sz = 2 ; continue ;\n"
+                                "case 2 : ; x = sz ; break ;\n"
+                                "}\n"
+                                "}";
+        ASSERT_EQUALS(expected, tokenizeAndStringify(code, true, true, Settings::Unspecified, "test.c"));
+    }
+
     void simplifyKnownVariablesIfEq1() {
         const char code[] = "void f(int x) {\n"
                             "    if (x==5) {\n"