diff --git a/src/util/StringCompare.hxx b/src/util/StringCompare.hxx
index a7aca0ce0..f08b32d6c 100644
--- a/src/util/StringCompare.hxx
+++ b/src/util/StringCompare.hxx
@@ -12,8 +12,8 @@
 
 #include <string_view>
 
-[[gnu::pure]] [[gnu::nonnull]]
-static inline bool
+[[gnu::nonnull]]
+static constexpr bool
 StringIsEmpty(const char *string) noexcept
 {
 	return *string == 0;