Tried cleaning, restart and reboot did not work.
XCode 5 has several "occasionally hangs" which bug fixed in letter version (Xcode 6 or Xcode 7)
So, it is better to upgrade your Xcode to Xcode 7.(may need to update mac OS X )
Or, uninstall and install your again your xcode
or, disable autolayout and try again
I have switched to xcode 6 ; problem solved; thanks everyone for your valuable inputs.
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