ValueFlow: better handling of ? when condition result is known

lib/valueflow.cpp

@@ -363,6 +363,14 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value)
     }
 
     else if (parent->str() == "?" && tok->str() == ":" && tok == parent->astOperand2()) {
+        // is condition always true/false?
+        if (parent->astOperand1()->values.size() == 1U && parent->astOperand1()->values.front().isKnown()) {
+            const ValueFlow::Value &condvalue = parent->astOperand1()->values.front();
+            const bool cond(condvalue.tokvalue || condvalue.intvalue != 0);
+            const std::list<ValueFlow::Value> &values = cond ? tok->astOperand1()->values : tok->astOperand2()->values;
+            if (std::find(values.begin(), values.end(), value) != values.end())
+                setTokenValue(parent, value);
+        } else {
             // is condition only depending on 1 variable?
             std::stack<const Token*> tokens;
             tokens.push(parent->astOperand1());
@@ -391,6 +399,7 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value)
 
             setTokenValue(parent, v);
         }
+    }
 
     // Calculations..
     else if ((parent->isArithmeticalOp() || parent->isComparisonOp() || (parent->tokType() == Token::eBitOp)) &&

lib/valueflow.h

@@ -36,6 +36,18 @@ namespace ValueFlow {
         explicit Value(long long val = 0) : intvalue(val), tokvalue(nullptr), varvalue(val), condition(0), varId(0U), conditional(false), inconclusive(false), defaultArg(false), valueKind(ValueKind::Possible) {}
         Value(const Token *c, long long val) : intvalue(val), tokvalue(nullptr), varvalue(val), condition(c), varId(0U), conditional(false), inconclusive(false), defaultArg(false), valueKind(ValueKind::Possible) {}
 
+        bool operator==(const Value &rhs) const {
+            return intvalue == rhs.intvalue &&
+                   tokvalue == rhs.tokvalue &&
+                   varvalue == rhs.varvalue &&
+                   condition == rhs.condition &&
+                   varId == rhs.varId &&
+                   conditional == rhs.conditional &&
+                   inconclusive == rhs.inconclusive &&
+                   defaultArg == rhs.defaultArg &&
+                   valueKind == rhs.valueKind;
+        }
+
         /** int value */
         long long intvalue;
 

test/testvalueflow.cpp

@@ -327,6 +327,11 @@ private:
         ASSERT_EQUALS(2, values.front().intvalue);
         ASSERT_EQUALS(3, values.back().intvalue);
 
+        code = "x = (2<5) ? 2 : 3;\n";
+        values = tokenValues(code, "?");
+        ASSERT_EQUALS(1U, values.size());
+        ASSERT_EQUALS(2, values.front().intvalue);
+
         // !
         code  = "void f(int x) {\n"
                 "    a = !x;\n"