Fix #11434 FP knownConditionTrueFalse with loop over bool array (#4646)

* Fix #11434 FP knownConditionTrueFalse with loop over bool array

* Simplify

Author: chrchr-github

lib/astutils.cpp

@@ -1370,10 +1370,23 @@ static bool isForLoopCondition(const Token * const tok)
            parent->astParent()->astParent()->astOperand1()->str() == "for";
 }
 
+static bool isForLoopIncrement(const Token* const tok)
+{
+    if (!tok)
+        return false;
+    const Token *const parent = tok->astParent();
+    return Token::simpleMatch(parent, ";") && parent->astOperand2() == tok &&
+           Token::simpleMatch(parent->astParent(), ";") &&
+           Token::simpleMatch(parent->astParent()->astParent(), "(") &&
+           parent->astParent()->astParent()->astOperand1()->str() == "for";
+}
+
 bool isUsedAsBool(const Token* const tok)
 {
     if (!tok)
         return false;
+    if (isForLoopIncrement(tok))
+        return false;
     if (astIsBool(tok))
         return true;
     if (Token::Match(tok, "!|&&|%oror%|%comp%"))

test/testcondition.cpp

@@ -4973,6 +4973,13 @@ class TestCondition : public TestFixture {
               "  }\n"
               "}\n");
         ASSERT_EQUALS("", errout.str());
+
+        check("void f() {\n" // #11434
+              "    const int N = 5;\n"
+              "    bool a[N];\n"
+              "    for (int i = 0; i < N; a[i++] = false);\n"
+              "}\n");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void alwaysTrueTryCatch()