Check for empty repetitions.

src/interpreter-irregexp.cc

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 361 matching lines @@
           pc += BC_CHECK_REGISTER_LT_LENGTH;
         }
         break;
       BYTECODE(CHECK_REGISTER_GE)
         if (registers[pc[1]] >= Load16(pc + 2)) {
           pc = code_base + Load32(pc + 4);
         } else {
           pc += BC_CHECK_REGISTER_GE_LENGTH;
         }
         break;
+      BYTECODE(CHECK_REGISTER_EQ_POS)
+        if (registers[pc[1]] == current) {
+          pc = code_base + Load32(pc + 2);
+        } else {
+          pc += BC_CHECK_REGISTER_EQ_POS_LENGTH;
+        }
+        break;
       BYTECODE(LOOKUP_MAP1) {
         // Look up character in a bitmap.  If we find a 0, then jump to the
         // location at pc + 7.  Otherwise fall through!
         int index = current_char - Load16(pc + 1);
         byte map = code_base[Load32(pc + 3) + (index >> 3)];
         map = ((map >> (index & 7)) & 1);
         if (map == 0) {
           pc = code_base + Load32(pc + 7);
         } else {
           pc += BC_LOOKUP_MAP1_LENGTH;
@@ skipping 129 matching lines @@
     if (start_position != 0) previous_char = subject_vector[start_position - 1];
     return RawMatch(code_base,
                     subject_vector,
                     registers,
                     start_position,
                     previous_char);
   }
 }
 
 } }  // namespace v8::internal