Fixed #1646 (False positive: array access after return cannot have default loop value)

lib/tokenize.cpp

@@ -5067,6 +5067,29 @@ bool Tokenizer::simplifyKnownVariables()
 
                 if (Token::Match(tok2->tokAt(-2), "for ( %varid% = %num% ; %varid% <|<= %num% ; ++| %varid% ++| ) {", varid))
                 {
+                    // is there a "break" in the for loop?
+                    bool hasbreak = false;
+                    unsigned int indentlevel4 = 0;   // indentlevel for tok4
+                    for (const Token *tok4 = tok2->previous()->link(); tok4; tok4 = tok4->next())
+                    {
+                        if (tok4->str() == "{")
+                            ++indentlevel4;
+                        else if (tok4->str() == "}")
+                        {
+                            if (indentlevel4 <= 1)
+                                break;
+                            --indentlevel4;
+                        }
+                        else if (tok4->str() == "break")
+                        {
+                            hasbreak = true;
+                            break;
+                        }
+                    }
+                    if (hasbreak)
+                        break;
+
+                    // no break => the value of the counter value is known after the for loop..
                     const std::string compareop = tok2->strAt(5);
                     if (compareop == "<")
                         value = tok2->strAt(6);

test/testtokenize.cpp

@@ -1151,6 +1151,7 @@ private:
     }
 
     void simplifyKnownVariables24()
+    {
         {
             // This testcase is related to ticket #1596
             const char code[] = "void foo()\n"
@@ -1160,7 +1161,6 @@ private:
                                 "    a[c] = 0;\n"
                                 "}\n";
 
-        // Current result
             ASSERT_EQUALS(
                 "void foo ( ) "
                 "{"
@@ -1171,6 +1171,31 @@ private:
                 simplifyKnownVariables(code));
         }
 
+        {
+            // #1692 - unknown counter value after for loop
+            const char code[] = "void foo(const char s[])\n"
+                                "{\n"
+                                "    int x[3];\n"
+                                "    int i;\n"
+                                "    for (i = 0; i < 3; ++i) {\n"
+                                "        if (s[i]) break;\n"
+                                "    }"
+                                "    if (i < 3) x[i] = 0;\n"
+                                "}\n";
+            ASSERT_EQUALS(
+                "void foo ( const char s [ ] ) "
+                "{"
+                " int x [ 3 ] ;"
+                " int i ;"
+                " for ( i = 0 ; i < 3 ; ++ i ) {"
+                " if ( s [ i ] ) { break ; }"
+                " }"
+                " if ( i < 3 ) { x [ i ] = 0 ; } "
+                "}",
+                simplifyKnownVariables(code));
+        }
+    }
+
     void simplifyKnownVariables25()
     {
         {