Irregexp-ia32: Fixed backref-matching (works, and advances current position).

src/jsregexp.cc

 // Copyright 2006-2008 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 1523 matching lines @@
       UNREACHABLE();
       return false;
   }
   return on_success()->GoTo(compiler);
 }
 
 
 bool BackReferenceNode::Emit(RegExpCompiler* compiler) {
   RegExpMacroAssembler* macro = compiler->macro_assembler();
   Bind(macro);
-  // Check whether the registers are uninitialized and always
-  // succeed if they are.
-  macro->IfRegisterLT(start_reg_, 0, on_success()->label());
-  macro->IfRegisterLT(end_reg_, 0, on_success()->label());
   ASSERT_EQ(start_reg_ + 1, end_reg_);
   if (info()->at_end) {
     // If we are constrained to match at the end of the input then succeed
     // iff the back reference is empty.
     macro->CheckNotRegistersEqual(start_reg_, end_reg_, on_failure_->label());
   } else {
     if (compiler->ignore_case()) {
       macro->CheckNotBackReferenceIgnoreCase(start_reg_, on_failure_->label());
     } else {
       macro->CheckNotBackReference(start_reg_, on_failure_->label());
@@ skipping 1475 matching lines @@
   }
   EmbeddedVector<byte, 1024> codes;
   RegExpMacroAssemblerIrregexp macro_assembler(codes);
   return compiler.Assemble(&macro_assembler,
                            node,
                            input->capture_count);
 }
 
 
 }}  // namespace v8::internal