Tail duplicate indirect branches for PowerPC, too.

With the testcase for pr3120, the "threaded interpreter" runtime decreases
from 1788 to 1413 with this change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89877 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/PowerPC/PPCInstrInfo.h

@@ -151,6 +151,8 @@ public:
   /// instruction may be.  This returns the maximum number of bytes.
   ///
   virtual unsigned GetInstSizeInBytes(const MachineInstr *MI) const;
+
+  virtual bool isProfitableToDuplicateIndirectBranch() const { return true; }
 };
 
 }