diff --git a/src/pkg/crypto/sha1/sha1block_decl.go b/src/pkg/crypto/sha1/sha1block_decl.go
index 3512a58299140546b63c179a61b9037ad3322d2b..4cb157fff6d608809f8c63f5f7e28090df406065 100644
--- a/src/pkg/crypto/sha1/sha1block_decl.go
+++ b/src/pkg/crypto/sha1/sha1block_decl.go
@@ -6,4 +6,6 @@
 
 package sha1
 
+//go:noescape
+
 func block(dig *digest, p []byte)