Don't create matcher functions when interpreting regex.

runtime/vm/regexp.cc

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/regexp.h"
 
 #include "vm/dart_entry.h"
 #include "vm/regexp_assembler.h"
 #include "vm/regexp_assembler_bytecode.h"
 #include "vm/regexp_assembler_ir.h"
@@ skipping 5299 matching lines @@
   }
   if (ignore_case) {
     regexp.set_is_ignore_case();
   }
 
   // TODO(zerny): We might want to use normal string searching algorithms
   // for simple patterns.
   regexp.set_is_complex();
   regexp.set_is_global();   // All dart regexps are global.
 
-  const Library& lib = Library::Handle(zone, Library::CoreLibrary());
-  const Class& owner = Class::Handle(
-      zone, lib.LookupClass(Symbols::RegExp()));
+  if (!FLAG_interpret_irregexp) {
+    const Library& lib = Library::Handle(zone, Library::CoreLibrary());
+    const Class& owner = Class::Handle(
+        zone, lib.LookupClass(Symbols::RegExp()));
 
-  CreateSpecializedFunction(zone, regexp, kOneByteStringCid, owner);
-  CreateSpecializedFunction(zone, regexp, kTwoByteStringCid, owner);
-  CreateSpecializedFunction(zone, regexp, kExternalOneByteStringCid, owner);
-  CreateSpecializedFunction(zone, regexp, kExternalTwoByteStringCid, owner);
+    CreateSpecializedFunction(zone, regexp, kOneByteStringCid, owner);
+    CreateSpecializedFunction(zone, regexp, kTwoByteStringCid, owner);
+    CreateSpecializedFunction(zone, regexp, kExternalOneByteStringCid, owner);
+    CreateSpecializedFunction(zone, regexp, kExternalTwoByteStringCid, owner);
+  }
 
   return regexp.raw();
 }
 
 
 }  // namespace dart