diff --git a/include/etl/private/delegate_cpp11.h b/include/etl/private/delegate_cpp11.h
index 9664797b..27b443c0 100644
--- a/include/etl/private/delegate_cpp11.h
+++ b/include/etl/private/delegate_cpp11.h
@@ -566,6 +566,14 @@ namespace etl
     //*************************************************************************
     ETL_NODISCARD ETL_CONSTEXPR14 bool is_valid() const ETL_NOEXCEPT
     {
+      // GCC's UBSan instruments function pointer comparisons, which prevents
+      // constexpr evaluation. Use implicit bool conversion at compile time
+      // to avoid the instrumented != comparison while still checking validity.
+      if (etl::is_constant_evaluated())
+      {
+        return static_cast<bool>(invocation.stub);
+      }
+
       return invocation.stub != ETL_NULLPTR;
     }
 
diff --git a/test/test_bsd_checksum.cpp b/test/test_bsd_checksum.cpp
index 9274b112..f95dcf12 100644
--- a/test/test_bsd_checksum.cpp
+++ b/test/test_bsd_checksum.cpp
@@ -50,7 +50,7 @@ namespace
 
       for (size_t i = 0UL; i < sizeof(value_type); ++i)
       {
-        uint8_t byte = static_cast<uint8_t>((static_cast<unsigned char>(value) >> (i * 8UL)) & 0xFFU);
+        uint8_t byte = static_cast<uint8_t>((static_cast<unsigned int>(value) >> (i * 8U)) & 0xFFU);
         checksum     = etl::rotate_right(checksum) + byte;
       }
     }