Fixed #7849 (Tokenizer: Wrong simplification of floating point equality comparison)

lib/tokenize.cpp

@@ -4777,9 +4777,14 @@ bool Tokenizer::simplifyConditions()
                     bool eq = false;
                     if (MathLib::isInt(op1) && MathLib::isInt(op2))
                         eq = (MathLib::toLongNumber(op1) == MathLib::toLongNumber(op2));
-                    else
+                    else {
                         eq = (op1 == op2);
 
+                        // It is inconclusive whether two unequal float representations are numerically equal
+                        if (!eq && MathLib::isFloat(op1))
+                            cmp = "";
+                    }
+
                     if (cmp == "==")
                         result = eq;
                     else

test/testsimplifytokens.cpp

@@ -2624,6 +2624,21 @@ private:
 
             ASSERT_EQUALS("void f ( ) { ; }", tok(code));
         }
+
+        {
+            // #7849
+            const char code[] =
+                    "void f() {\n"
+                    "if (-1e-2 == -0.01) \n"
+                    "    g();\n"
+                    "else\n"
+                    "    h();\n"
+                    "}";
+            // condition cannot be safely be calculated to be true due to numerics
+            TODO_ASSERT_EQUALS("void f ( ) { g ( ) ; }",
+                               "void f ( ) { if ( -1e-2 == -0.01 ) { g ( ) ; } else { h ( ) ; } }",
+                               tok(code));
+        }
     }
 
     void simplify_condition() {