diff --git a/src/pkg/crypto/sha512/sha512block_decl.go b/src/pkg/crypto/sha512/sha512block_decl.go
index 229e46ba64..bef99de2e4 100644
--- a/src/pkg/crypto/sha512/sha512block_decl.go
+++ b/src/pkg/crypto/sha512/sha512block_decl.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build 386 amd64
+// +build amd64
 
 package sha512