--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/go/gofrontend/go-optimize.cc	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,53 @@
+// go-optimize.cc -- Go frontend optimizer flags.
+
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "go-system.h"
+
+#include "go-c.h"
+#include "go-optimize.h"
+
+namespace {
+
+// The list of optimizations.
+
+Go_optimize* optimizations;
+
+} // End empty namespace.
+
+// Create a new optimization.
+
+Go_optimize::Go_optimize(const char* name)
+  : next_(optimizations), name_(name), is_enabled_(false)
+{
+  optimizations = this;
+}
+
+// Enable an optimization by name.
+
+bool
+Go_optimize::enable_by_name(const char* name)
+{
+  bool is_all = strcmp(name, "all") == 0;
+  bool found = false;
+  for (Go_optimize* p = optimizations; p != NULL; p = p->next_)
+    {
+      if (is_all || strcmp(name, p->name_) == 0)
+	{
+	  p->is_enabled_ = true;
+	  found = true;
+	}
+    }
+  return found;
+}
+
+// Enable an optimization.  Return 1 if this is a real name, 0 if not.
+
+GO_EXTERN_C
+int
+go_enable_optimize(const char* name)
+{
+  return Go_optimize::enable_by_name(name) ? 1 : 0;
+}