add ppc64/pwr8 as target

includes handling DIR_PWR8 where appropriate
The P7Model Itinerary is currently tied in for use under the P8Model, and will be updated later.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211779 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCSubtarget.cpp

@@ -247,6 +247,7 @@ static bool needsAggressiveScheduling(unsigned Directive) {
   case PPC::DIR_E500mc:
   case PPC::DIR_E5500:
   case PPC::DIR_PWR7:
+  case PPC::DIR_PWR8:
     return true;
   }
 }