Don't pass the "at start" parameter to native RegExp...

src/ia32/codegen-ia32.cc

 // Copyright 2006-2009 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 8453 matching lines @@
   __ mov(ebx, Operand(esp, kPreviousIndexOffset));
   __ mov(ecx, Operand(esp, kJSRegExpOffset));
   __ SmiUntag(ebx);  // Previous index from smi.
 
   // eax: subject string
   // ebx: previous index
   // edx: code
   // All checks done. Now push arguments for native regexp code.
   __ IncrementCounter(&Counters::regexp_entry_native, 1);
 
-  // Argument 8: Indicate that this is a direct call from JavaScript.
+  // Argument 7: Indicate that this is a direct call from JavaScript.
   __ push(Immediate(1));
 
-  // Argument 7: Start (high end) of backtracking stack memory area.
+  // Argument 6: Start (high end) of backtracking stack memory area.
   __ mov(ecx, Operand::StaticVariable(address_of_regexp_stack_memory_address));
   __ add(ecx, Operand::StaticVariable(address_of_regexp_stack_memory_size));
   __ push(ecx);
 
-  // Argument 6: At start of string?
-  __ xor_(Operand(ecx), ecx);  // setcc only operated on cl (lower byte of ecx).
-  __ test(ebx, Operand(ebx));
-  __ setcc(zero, ecx);  // 1 if 0 (start of string), 0 if positive.
-  __ push(ecx);
-
   // Argument 5: static offsets vector buffer.
   __ push(Immediate(ExternalReference::address_of_static_offsets_vector()));
 
   // Argument 4: End of string data
   // Argument 3: Start of string data
   Label push_two_byte, push_rest;
   __ test(edi, Operand(edi));
   __ mov(edi, FieldOperand(eax, String::kLengthOffset));
   __ j(zero, &push_two_byte);
   __ lea(ecx, FieldOperand(eax, edi, times_1, SeqAsciiString::kHeaderSize));
@@ skipping 14 matching lines @@
   // Argument 2: Previous index.
   __ push(ebx);
 
   // Argument 1: Subject string.
   __ push(eax);
 
   // Locate the code entry and call it.
   __ add(Operand(edx), Immediate(Code::kHeaderSize - kHeapObjectTag));
   __ call(Operand(edx));
   // Remove arguments.
-  __ add(Operand(esp), Immediate(8 * kPointerSize));
+  __ add(Operand(esp), Immediate(7 * kPointerSize));
 
   // Check the result.
   Label success;
   __ cmp(eax, NativeRegExpMacroAssembler::SUCCESS);
   __ j(equal, &success, taken);
   Label failure;
   __ cmp(eax, NativeRegExpMacroAssembler::FAILURE);
   __ j(equal, &failure, taken);
   __ cmp(eax, NativeRegExpMacroAssembler::EXCEPTION);
   // If not exception it can only be retry. Handle that in the runtime system.
@@ skipping 1455 matching lines @@
 
   // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
   // tagged as a small integer.
   __ bind(&runtime);
   __ TailCallRuntime(ExternalReference(Runtime::kStringCompare), 2, 1);
 }
 
 #undef __
 
 } }  // namespace v8::internal