Limit end-anchored regexps to testing end of string where possible.

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 589 matching lines @@
           pc += BC_CHECK_AT_START_LENGTH;
         }
         break;
       BYTECODE(CHECK_NOT_AT_START)
         if (current == 0) {
           pc += BC_CHECK_NOT_AT_START_LENGTH;
         } else {
           pc = code_base + Load32Aligned(pc + 4);
         }
         break;
+      BYTECODE(SET_CURRENT_POSITION_FROM_END) {
+        int by = static_cast<uint32_t>(insn) >> BYTECODE_SHIFT;
+        if (subject.length() - current > by) {
+          current = subject.length() - by;
+          current_char = subject[current - 1];
+        }
+        pc += BC_SET_CURRENT_POSITION_FROM_END_LENGTH;
+        break;
+      }
       default:
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 bool IrregexpInterpreter::Match(Handle<ByteArray> code_array,
                                 Handle<String> subject,
@@ skipping 17 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