ios - How to make seperate xib for iphone from already existing one for ipad -

i having ipad specific application. want play same on iphone also. app having xib used size class "wregular hregular" many auto layout constraints. want covert wany hany size class. know there 2 way achieve either using auto layout or creating xib file iphone only. want go separate xib files how make files in xcode 7? , how work?

just create new xib file name whatever want give , load uiviewcontroller using following code

viewcontrollername *vc = [[viewcontrollername alloc] initwithnibname:@"" bundle:nil]; 

in viewcontroller override - (id)initwithnibname:(nsstring *)nibnameornil bundle:(nsbundle *)nibbundleornil method in check device iphone or ipad using following code

- (id)initwithnibname:(nsstring *)nibnameornil bundle:(nsbundle *)nibbundleornil {      nsstring * nibnameornil;      if ( ui_user_interface_idiom() == uiuserinterfaceidiompad ){         // ipad         nibnameornil = @“ipad_xib_name”      } else {         // iphone      }      self = [super initwithnibname:nibnameornil bundle:nibbundleornil];      if (self)      {         // custom initialization      }      return self; } 

this call xib according device type.