diff --git a/src/tag/Builder.cxx b/src/tag/Builder.cxx
index 3dbb5a383..f7a283d9d 100644
--- a/src/tag/Builder.cxx
+++ b/src/tag/Builder.cxx
@@ -236,11 +236,6 @@ TagBuilder::AddItem(TagType type, StringView value) noexcept
 void
 TagBuilder::AddItem(TagType type, const char *value) noexcept
 {
-#if !CLANG_CHECK_VERSION(3,6)
-	/* disabled on clang due to -Wtautological-pointer-compare */
-	assert(value != nullptr);
-#endif
-
 	AddItem(type, StringView(value));
 }
 
diff --git a/src/tag/Builder.hxx b/src/tag/Builder.hxx
index b7b983e63..3920ec76e 100644
--- a/src/tag/Builder.hxx
+++ b/src/tag/Builder.hxx
@@ -22,7 +22,6 @@
 
 #include "Type.h"
 #include "Chrono.hxx"
-#include "util/Compiler.h"
 
 #include <vector>
 #include <memory>
@@ -83,7 +82,7 @@ public:
 	/**
 	 * Returns true if the object contains any information.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool IsDefined() const noexcept {
 		return !duration.IsNegative() || has_playlist || !empty();
 	}
@@ -125,7 +124,7 @@ public:
 	 * Checks whether the tag contains one or more items with
 	 * the specified type.
 	 */
-	gcc_pure
+	[[gnu::pure]]
 	bool HasType(TagType type) const noexcept;
 
 	/**
@@ -147,7 +146,6 @@ public:
 	 * @param value the value of the tag item (not null-terminated)
 	 * @param length the length of #value
 	 */
-	gcc_nonnull_all
 	void AddItem(TagType type, StringView value) noexcept;
 
 	/**
@@ -156,7 +154,7 @@ public:
 	 * @param type the type of the new tag item
 	 * @param value the value of the tag item (null-terminated)
 	 */
-	gcc_nonnull_all
+	[[gnu::nonnull]]
 	void AddItem(TagType type, const char *value) noexcept;
 
 	/**
@@ -177,7 +175,6 @@ public:
 	void RemoveType(TagType type) noexcept;
 
 private:
-	gcc_nonnull_all
 	void AddItemInternal(TagType type, StringView value) noexcept;
 };