ValueFlow: analysis in condition.

lib/valueflow.cpp

@@ -815,6 +815,37 @@ static void valueFlowAfterCondition(TokenList *tokenlist, ErrorLogger *errorLogg
         std::list<ValueFlow::Value> values;
         values.push_back(ValueFlow::Value(tok, numtok ? MathLib::toLongNumber(numtok->str()) : 0LL));
 
+        if (Token::Match(tok->astParent(), "%oror%|&&")) {
+            Token *parent = const_cast<Token*>(tok->astParent());
+            const std::string &op(parent->str());
+
+            if (parent->astOperand1() == tok &&
+                ((op == "&&" && Token::Match(tok, "==|>=|<=|!")) ||
+                 (op == "||" && Token::Match(tok, "%var%|!=")))) {
+                bool assign = false;
+                for (; !assign && parent && parent->str() == op; parent = const_cast<Token*>(parent->astParent())) {
+                    std::stack<Token *> tokens;
+                    tokens.push(const_cast<Token*>(parent->astOperand2()));
+                    while (!tokens.empty()) {
+                        Token *rhstok = tokens.top();
+                        tokens.pop();
+                        if (!rhstok)
+                            continue;
+                        tokens.push(const_cast<Token*>(rhstok->astOperand1()));
+                        tokens.push(const_cast<Token*>(rhstok->astOperand2()));
+                        if (rhstok->varId() == varid)
+                            setTokenValue(rhstok, values.front());
+                        if (Token::Match(rhstok, "++|--|=") && Token::Match(rhstok->astOperand1(),"%varid%",varid)) {
+                            assign = true;
+                            break;
+                        }
+                    }
+                    while (parent->astParent() && parent == parent->astParent()->astOperand2())
+                        parent = const_cast<Token*>(parent->astParent());
+                }
+            }
+        }
+
         const Token *top = tok->astTop();
         if (top && Token::Match(top->previous(), "if|while (") && !top->previous()->isExpandedMacro()) {
             // does condition reassign variable?

test/testnullpointer.cpp

@@ -1059,7 +1059,7 @@ private:
                   "        p = q;\n"
                   "    if (p || *p) { }\n"
                   "}");
-            TODO_ASSERT_EQUALS("error", "", errout.str());
+            ASSERT_EQUALS("[test.cpp:5] -> [test.cpp:5]: (warning) Possible null pointer dereference: p - otherwise it is redundant to check it against null.\n", errout.str());
         }
     }
 

test/testvalueflow.cpp

@@ -777,6 +777,19 @@ private:
                "    a = x;\n"
                "}";
         ASSERT_EQUALS(true, testValueOfX(code, 3U, 3));
+
+        // In condition, after && and ||
+        code = "void f(int x) {\n"
+               "  a = (x != 3 ||\n"
+               "       x);\n"
+               "}";
+        ASSERT_EQUALS(true, testValueOfX(code, 3U, 3));
+
+        code = "void f(int x) {\n"
+               "  a = (x == 4 &&\n"
+               "       x);\n"
+               "}";
+        ASSERT_EQUALS(true, testValueOfX(code, 3U, 4));
     }
 
     void valueFlowBitAnd() {