From 1f698ca49387703a5dd542d29edb8c85d827e162 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Mon, 5 Jan 2015 16:39:47 +0100
Subject: [PATCH] ValueFlow: Fixed valueFlowForward, when condition is false
 and else-block returns dont set values below the else-code

---
 lib/valueflow.cpp      | 17 ++++++++++++++---
 test/testvalueflow.cpp | 11 ++++++++++-
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 2d953afc4..8686207b4 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -690,8 +690,15 @@ static bool valueFlowForward(Token * const               startToken,
             ++indentlevel;
         else if (indentlevel >= 0 && tok2->str() == "}") {
             --indentlevel;
-            if (indentlevel == 0 && isReturn(tok2) && Token::simpleMatch(tok2->link()->previous(), ") {")) {
-                const Token *condition = tok2->link()->linkAt(-1)->astOperand2();
+            if (indentlevel == 0 && isReturn(tok2) && Token::Match(tok2->link()->previous(), "else|) {")) {
+                const Token *condition = tok2->link();
+                const bool iselse = Token::simpleMatch(condition->tokAt(-2), "} else {");
+                if (iselse)
+                    condition = condition->linkAt(-2);
+                if (condition && Token::simpleMatch(condition->previous(), ") {"))
+                    condition = condition->linkAt(-1)->astOperand2();
+                else
+                    condition = nullptr;
                 if (!condition) {
                     if (settings->debugwarnings)
                         bailout(tokenlist, errorLogger, tok2, "variable " + var->name() + " valueFlowForward, bailing out since it's unknown if conditional return is executed");
@@ -700,7 +707,11 @@ static bool valueFlowForward(Token * const               startToken,
 
                 bool bailoutflag = false;
                 for (std::list<ValueFlow::Value>::const_iterator it = values.begin(); it != values.end(); ++it) {
-                    if (conditionIsTrue(condition, getProgramMemory(condition->astParent(), varid, *it))) {
+                    if (!iselse && conditionIsTrue(condition, getProgramMemory(condition->astParent(), varid, *it))) {
+                        bailoutflag = true;
+                        break;
+                    }
+                    if (iselse && conditionIsFalse(condition, getProgramMemory(condition->astParent(), varid, *it))) {
                         bailoutflag = true;
                         break;
                     }
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index fd44c38dc..91dc9f2d9 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -1295,10 +1295,19 @@ private:
                "  if (x == 5) {\n"
                "    panic();\n"
                "  }\n"
-               "  a = x;\n"
+               "  a = x;\n" // <- x can't be 5
                "}";
         ASSERT_EQUALS(false, testValueOfX(code, 7U, 5));
 
+        code = "void f() {\n"
+               "  int x;\n"
+               "  for (x = 0; x < 5; x++) {}\n"
+               "  if (x < 5) {}\n"
+               "  else return;\n"
+               "  a = x;\n" // <- x can't be 5
+               "}";
+        ASSERT_EQUALS(false, testValueOfX(code, 6U, 5));
+
         // hang
         code = "void f() {\n"
                "  for(int i = 0; i < 20; i++)\n"