diff --git a/blake2s_386.s b/blake2s_386.s
index 82894e5..603d00c 100644
--- a/blake2s_386.s
+++ b/blake2s_386.s
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build 386 && gc && !purego
 // +build 386,gc,!purego
 
 #include "textflag.h"
diff --git a/blake2s_amd64.s b/blake2s_amd64.s
index 9b8824f..e9df7a7 100644
--- a/blake2s_amd64.s
+++ b/blake2s_amd64.s
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build amd64 && gc && !purego
 // +build amd64,gc,!purego
 
 #include "textflag.h"