From 548ec108244f674d8f0708581f77df80f7e60a6f Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Thu, 3 Jun 2021 00:26:36 -0500
Subject: [PATCH] Fix issue 10306: FP knownConditionTrueFalse with modulo
 result converted to bool (#3282)

---
 lib/valueflow.cpp      |  2 ++
 test/testvalueflow.cpp | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 18590b8a8..c38575bb1 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -723,6 +723,8 @@ static void setTokenValue(Token* tok, const ValueFlow::Value &value, const Setti
         for (const ValueFlow::Value &val : tok->values()) {
             if (!val.isIntValue())
                 continue;
+            if (val.isImpossible() && val.intvalue != 0)
+                continue;
             ValueFlow::Value v(val);
             v.intvalue = !v.intvalue;
             setTokenValue(parent, v, settings);
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index a9e80dabc..772b4e85a 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -141,6 +141,7 @@ private:
         TEST_CASE(valueFlowUnknownMixedOperators);
         TEST_CASE(valueFlowIdempotent);
         TEST_CASE(valueFlowUnsigned);
+        TEST_CASE(valueFlowMod);
     }
 
     static bool isNotTokValue(const ValueFlow::Value &val) {
@@ -2643,6 +2644,20 @@ private:
         ASSERT_EQUALS(false, testValueOfXKnown(code, 5U, 1));
         ASSERT_EQUALS(false, testValueOfXImpossible(code, 5U, 0));
         ASSERT_EQUALS(false, testValueOfXImpossible(code, 5U, 1));
+
+        code = "auto f(int i) {\n"
+               "    if (i == 0) return;\n"
+               "    auto x = !i;\n"
+               "    return x;\n"
+               "}\n";
+        ASSERT_EQUALS(true, testValueOfXImpossible(code, 4U, 1));
+
+        code = "auto f(int i) {\n"
+               "    if (i == 1) return;\n"
+               "    auto x = !i;\n"
+               "    return x;\n"
+               "}\n";
+        ASSERT_EQUALS(false, testValueOfXImpossible(code, 4U, 0));
     }
 
     void valueFlowAfterConditionExpr() {
@@ -5638,6 +5653,23 @@ private:
         ASSERT_EQUALS(false, testValueOfXImpossible(code, 4U, 0));
         ASSERT_EQUALS(true, testValueOfXImpossible(code, 4U, -1));
     }
+
+    void valueFlowMod() {
+        const char *code;
+
+        code = "auto f(int i) {\n"
+               "    auto x = i % 2;\n"
+               "    return x;\n"
+               "}\n";
+        ASSERT_EQUALS(true, testValueOfXImpossible(code, 3U, 2));
+
+        code = "auto f(int i) {\n"
+               "    auto x = !(i % 2);\n"
+               "    return x;\n"
+               "}\n";
+        ASSERT_EQUALS(false, testValueOfXImpossible(code, 3U, 0));
+        ASSERT_EQUALS(false, testValueOfXImpossible(code, 3U, 1));
+    }
 };
 
 REGISTER_TEST(TestValueFlow)