diff --git a/src/cmd/internal/obj/s390x/asmz.go b/src/cmd/internal/obj/s390x/asmz.go
index 7db714c204..ba8cff4e6d 100644
--- a/src/cmd/internal/obj/s390x/asmz.go
+++ b/src/cmd/internal/obj/s390x/asmz.go
@@ -4563,7 +4563,7 @@ func (c *ctxtz) zopload(a obj.As) uint32 {
 		return op_LRVH
 	}
 
-	c.ctxt.Diag("unknown store opcode %v", a)
+	c.ctxt.Diag("unknown zopload opcode %v", a)
 	return 0
 }