From 62362cd06d42e464e571434cc0939938df9e4e56 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Sun, 14 Aug 2016 22:19:06 +0200
Subject: [PATCH] ValueFlow: improve handling of unary minus

---
 lib/valueflow.cpp      | 12 ++++++++++++
 test/testvalueflow.cpp |  9 +++++++++
 2 files changed, 21 insertions(+)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 3e7b243b5..064a110df 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -521,6 +521,18 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value)
         }
     }
 
+    // unary minus
+    else if (parent->str() == "-" && !parent->astOperand2()) {
+        std::list<ValueFlow::Value>::const_iterator it;
+        for (it = tok->values.begin(); it != tok->values.end(); ++it) {
+            if (it->tokvalue)
+                continue;
+            ValueFlow::Value v(*it);
+            v.intvalue = -v.intvalue;
+            setTokenValue(parent, v);
+        }
+    }
+
     // Array element
     else if (parent->str() == "[" && parent->astOperand1() && parent->astOperand2()) {
         std::list<ValueFlow::Value>::const_iterator value1, value2;
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index 18e9f6f3c..9d85f9a37 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -336,6 +336,15 @@ private:
         ASSERT_EQUALS(1U, values.size());
         ASSERT_EQUALS(1, values.back().intvalue);
 
+        // unary minus
+        code  = "void f(int x) {\n"
+                "    a = -x;\n"
+                "    if (x==10) {}\n"
+                "}";
+        values = tokenValues(code,"-");
+        ASSERT_EQUALS(1U, values.size());
+        ASSERT_EQUALS(-10, values.back().intvalue);
+
         // function call => calculation
         code  = "void f(int x) {\n"
                 "    a = x + 8;\n"