Switch some getAliasSet clients to MCRegAliasIterator.

MCRegAliasIterator can optionally visit the register itself, allowing
for simpler code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157837 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineCSE.cpp b/lib/CodeGen/MachineCSE.cpp
index a63688e..f2539ba 100644
--- a/lib/CodeGen/MachineCSE.cpp
+++ b/lib/CodeGen/MachineCSE.cpp
@@ -216,11 +216,10 @@
     if (MO.isDef() &&
         (MO.isDead() || isPhysDefTriviallyDead(Reg, I, MBB->end())))
       continue;
-    PhysRefs.insert(Reg);
+    for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+      PhysRefs.insert(*AI);
     if (MO.isDef())
       PhysDefs.push_back(Reg);
-    for (const uint16_t *Alias = TRI->getAliasSet(Reg); *Alias; ++Alias)
-      PhysRefs.insert(*Alias);
   }
 
   return !PhysRefs.empty();