From b7ddbe483deadbdd196e5a927db4eb3fb6b80404 Mon Sep 17 00:00:00 2001
From: chrchr-github <christian.riesch@live.com>
Date: Sun, 5 Jan 2025 00:43:50 +0100
Subject: [PATCH] Fix #13522 FP knownConditionTrueFalse after
 unsigned-to-signed conversion

---
 lib/vf_analyzers.cpp   | 2 ++
 test/testcondition.cpp | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/lib/vf_analyzers.cpp b/lib/vf_analyzers.cpp
index 32b06eb96e4..cf92e8f578f 100644
--- a/lib/vf_analyzers.cpp
+++ b/lib/vf_analyzers.cpp
@@ -527,6 +527,8 @@ struct ValueFlowAnalyzer : Analyzer {
                 continue;
             if (exact && v.intvalue != 0 && !isPoint)
                 continue;
+            if (astIsUnsigned(tok) != astIsUnsigned(v.tokvalue))
+                continue;
             std::vector<MathLib::bigint> r;
             ValueFlow::Value::Bound bound = currValue->bound;
             if (match(v.tokvalue)) {
diff --git a/test/testcondition.cpp b/test/testcondition.cpp
index db2f41e6da2..5a3f5211bfa 100644
--- a/test/testcondition.cpp
+++ b/test/testcondition.cpp
@@ -4947,6 +4947,13 @@ class TestCondition : public TestFixture {
               "    }\n"
               "}\n");
         ASSERT_EQUALS("", errout_str());
+
+        check("void f(unsigned x) {\n" // #13522
+              "    unsigned u = x;\n"
+              "    int i = u - 0;\n"
+              "    if (i < 0) {}\n"
+              "}\n");
+        ASSERT_EQUALS("", errout_str());
     }
 
     void alwaysTrueInfer() {