Why Xcode 5.0 (5A1413) crash only when I build & run on an iPhone 5S?

Why Xcode 5.0 (5A1413) crash only when I build & run on an iPhone 5S?

I am running Mountain Lion with the latest version of Xcode 5. It is
extremely unstable and crashes when I try to build & run on an iPhone 5S.
It does not crash when I build & run on older devices.
It looks like a crash related to "DBGLLDBLauncher Serial Queue", the
debugger maybe?
Process: Xcode [1706]
Path: /Applications/Xcode.app/Contents/MacOS/Xcode
Identifier: com.apple.dt.Xcode
Version: 5.0 (3332.25)
Build Info: IDEApplication-3332025000000000~2
Code Type: X86-64 (Native)
Parent Process: launchd [125]
User ID: 501
Date/Time: 2013-09-28 01:29:23.661 +0200
OS Version: Mac OS X 10.8.5 (12F37)
Report Version: 10
Interval Since Last Report: 1061 sec
Crashes Since Last Report: 3
Per-App Interval Since Last Report: 876 sec
Per-App Crashes Since Last Report: 3
Anonymous UUID: 52DE9388-C7D9-F332-DBDD-9024E9D2ED05
Crashed Thread: 8 Dispatch queue: DBGLLDBLauncher Serial Queue
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Application Specific Information:
ProductBuildVersion: 5A1413
Assertion failed: (pointer_byte_size == m_host_arch.GetAddressByteSize()),
function GetHostInfo, file
/SourceCache/lldb/lldb-300.2.47/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp,
line 1266.
Thread 0:: Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x00007fff86ad9686 mach_msg_trap + 10
1 libsystem_kernel.dylib 0x00007fff86ad8c42 mach_msg + 70
2 com.apple.CoreFoundation 0x00007fff844c1233
__CFRunLoopServiceMachPort + 195
3 com.apple.CoreFoundation 0x00007fff844c6916 __CFRunLoopRun + 1078
4 com.apple.CoreFoundation 0x00007fff844c60e2
CFRunLoopRunSpecific + 290
5 com.apple.HIToolbox 0x00007fff8ce3eeb4
RunCurrentEventLoopInMode + 209
6 com.apple.HIToolbox 0x00007fff8ce3ec52
ReceiveNextEventCommon + 356
7 com.apple.HIToolbox 0x00007fff8ce3eae3
BlockUntilNextEventMatchingListInMode + 62
8 com.apple.AppKit 0x00007fff88df0533 _DPSNextEvent + 685
9 com.apple.AppKit 0x00007fff88defdf2 -[NSApplication
nextEventMatchingMask:untilDate:inMode:dequeue:] + 128
10 com.apple.AppKit 0x00007fff88de71a3 -[NSApplication
run] + 517
11 com.apple.AppKit 0x00007fff88d8bbd6 NSApplicationMain +
869
12 libdyld.dylib 0x00007fff8ca4a7e1 start + 1
Is this related to the new 64 bit architecture of the iPhone 5S? Do I need
to upgrade to OS X Mavericks? Has anyone managed to get an iPhone 5S work
with Xcode 5?