From d4169f04d58e3985b05f77d4afcf80e100ab6bb6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Marjam=C3=A4ki?= <daniel.marjamaki@gmail.com>
Date: Fri, 8 May 2020 17:42:56 +0200
Subject: [PATCH] Bug hunting; Avoid false warnings for impossible values

---
 lib/exprengine.cpp |  2 ++
 lib/token.h        | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/lib/exprengine.cpp b/lib/exprengine.cpp
index 8ec3a8ab9..95bdd8209 100644
--- a/lib/exprengine.cpp
+++ b/lib/exprengine.cpp
@@ -2108,6 +2108,8 @@ void ExprEngine::runChecks(ErrorLogger *errorLogger, const Tokenizer *tokenizer,
             return;
         if (tok->hasKnownIntValue() && tok->getKnownIntValue() != 0)
             return;
+        if (tok->isImpossibleIntValue(0))
+            return;
         if (value.isUninit())
             return;
         float f = getKnownFloatValue(tok, 0.0f);
diff --git a/lib/token.h b/lib/token.h
index cb571093f..0ad9f3672 100644
--- a/lib/token.h
+++ b/lib/token.h
@@ -1032,6 +1032,19 @@ public:
         return mImpl->mValues->front().intvalue;
     }
 
+    bool isImpossibleIntValue(const MathLib::bigint val) const {
+        if (!mImpl->mValues)
+            return false;
+        for (const auto &v: *mImpl->mValues) {
+            if (v.isIntValue() && v.isImpossible() && v.intvalue == val)
+                return true;
+            if (v.isIntValue() && v.bound == ValueFlow::Value::Bound::Lower && v.intvalue > val)
+                return true;
+            if (v.isIntValue() && v.bound == ValueFlow::Value::Bound::Upper && v.intvalue < val)
+                return true;
+        }
+    }
+
     const ValueFlow::Value * getValue(const MathLib::bigint val) const {
         if (!mImpl->mValues)
             return nullptr;