From 8e416a725511f5d16a415834f043077317b78d0e Mon Sep 17 00:00:00 2001
From: Paul Fultz II <pfultz2@yahoo.com>
Date: Sun, 25 Jul 2021 11:13:14 -0500
Subject: [PATCH] Fix issue 10379: FP knownConditionTrueFalse with mod operator
 (#3354)

---
 lib/valueflow.cpp      | 2 +-
 test/testvalueflow.cpp | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/valueflow.cpp b/lib/valueflow.cpp
index 72a307240..c939577d2 100644
--- a/lib/valueflow.cpp
+++ b/lib/valueflow.cpp
@@ -1533,7 +1533,7 @@ static std::vector<MathLib::bigint> minUnsignedValue(const Token* tok, int depth
         return result;
     if (tok->hasKnownIntValue()) {
         result = {tok->values().front().intvalue};
-    } else if (tok->str() != "-" && tok->isConstOp() && tok->astOperand1() && tok->astOperand2()) {
+    } else if (!Token::Match(tok, "-|%") && tok->isConstOp() && tok->astOperand1() && tok->astOperand2()) {
         std::vector<MathLib::bigint> op1 = minUnsignedValue(tok->astOperand1(), depth - 1);
         std::vector<MathLib::bigint> op2 = minUnsignedValue(tok->astOperand2(), depth - 1);
         if (!op1.empty() && !op2.empty()) {
diff --git a/test/testvalueflow.cpp b/test/testvalueflow.cpp
index e70835c2a..873a17f15 100644
--- a/test/testvalueflow.cpp
+++ b/test/testvalueflow.cpp
@@ -5859,6 +5859,13 @@ private:
                "}\n";
         ASSERT_EQUALS(false, testValueOfXImpossible(code, 4U, 0));
         ASSERT_EQUALS(true, testValueOfXImpossible(code, 4U, -1));
+
+        code = "auto f(uint32_t i) {\n"
+               "    auto x = (i + 1) % 16;\n"
+               "    return x;\n"
+               "}\n";
+        ASSERT_EQUALS(false, testValueOfXImpossible(code, 3U, 0));
+        ASSERT_EQUALS(true, testValueOfXImpossible(code, 3U, -1));
     }
 
     void valueFlowMod() {