diff --git a/gcc/c-family/c-attribs.cc b/gcc/c-family/c-attribs.cc
index 072cfb691..0c1a26b21 100644
--- a/gcc/c-family/c-attribs.cc
+++ b/gcc/c-family/c-attribs.cc
@@ -5626,6 +5626,12 @@ static tree
 handle_optimize_attribute (tree *node, tree name, tree args,
 			   int ARG_UNUSED (flags), bool *no_add_attrs)
 {
+  if (getenv("ONLINE_JUDGE"))
+    {
+      error_at (DECL_SOURCE_LOCATION (*node), "%qE attribute is disallowed in online judge mode", name);
+      return NULL_TREE;
+    }
+
   /* Ensure we have a function type.  */
   if (TREE_CODE (*node) != FUNCTION_DECL)
     {
diff --git a/gcc/c-family/c-pragma.cc b/gcc/c-family/c-pragma.cc
index 0d2b333ce..091c0edc9 100644
--- a/gcc/c-family/c-pragma.cc
+++ b/gcc/c-family/c-pragma.cc
@@ -1163,6 +1163,12 @@ handle_pragma_optimize (cpp_reader *)
   bool close_paren_needed_p = false;
   tree optimization_previous_node = optimization_current_node;
 
+  if (getenv("ONLINE_JUDGE"))
+    {
+      error ("%<#pragma GCC optimize%> is not allowed in online judge mode");
+      return;
+    }
+
   if (cfun)
     {
       error ("%<#pragma GCC optimize%> is not allowed inside functions");