diff --git a/lib/tokenize.cpp b/lib/tokenize.cpp
index 1f7fa463e..c52c0d514 100644
--- a/lib/tokenize.cpp
+++ b/lib/tokenize.cpp
@@ -6115,6 +6115,22 @@ bool Tokenizer::simplifyKnownVariables()
                 ret |= simplifyKnownVariablesSimplify(&tok2, tok3, varid, structname, value, valueVarId, valueIsPointer, valueToken, indentlevel);
             }
 
+            else if (Token::Match(tok2, "( %var% == %num% ) {")) {
+                const unsigned int varid = tok2->next()->varId();
+                if (varid == 0)
+                    continue;
+
+                const std::string structname = "";
+
+                const Token *valueToken = tok2->tokAt(3);
+                std::string value(tok2->strAt(3));
+                const unsigned int valueVarId = 0;
+                const bool valueIsPointer = false;
+
+                Token *scopeStart = tok2->tokAt(6);
+                ret |= simplifyKnownVariablesSimplify(&scopeStart, scopeStart, varid, structname, value, valueIsPointer, valueVarId, valueToken, 0);
+            }
+
             else if (Token::Match(tok2, "strcpy ( %var% , %str% ) ;")) {
                 const unsigned int varid(tok2->tokAt(2)->varId());
                 if (varid == 0)
diff --git a/test/testtokenize.cpp b/test/testtokenize.cpp
index 24f89aa91..35c15c7d5 100644
--- a/test/testtokenize.cpp
+++ b/test/testtokenize.cpp
@@ -149,6 +149,7 @@ private:
         TEST_CASE(simplifyKnownVariables44);    // ticket #3117 - don't simplify static variables
         TEST_CASE(simplifyKnownVariables45);    // ticket #3281 - static constant variable not simplified
         TEST_CASE(simplifyKnownVariables46);    // ticket #3587 - >>
+        TEST_CASE(simplifyKnownVariablesIfEq);  // if (a==5) => a is 5 in the block
         TEST_CASE(simplifyKnownVariablesBailOutAssign1);
         TEST_CASE(simplifyKnownVariablesBailOutAssign2);
         TEST_CASE(simplifyKnownVariablesBailOutFor1);
@@ -2306,6 +2307,20 @@ private:
         }
     }
 
+    void simplifyKnownVariablesIfEq() {
+        const char code[] = "void f(int x) {\n"
+                            "    if (x==5) {\n"
+                            "        return x;\n"
+                            "    }\n"
+                            "}";
+        const char expected[] = "void f ( int x ) {\n"
+                                "if ( x == 5 ) {\n"
+                                "return 5 ;\n"
+                                "}\n"
+                                "}";
+        ASSERT_EQUALS(expected, tokenizeAndStringify(code, true, true, Settings::Unspecified, "test.c"));
+    }
+
     void simplifyKnownVariablesBailOutAssign1() {
         const char code[] = "int foo() {\n"
                             "    int i; i = 0;\n"