Try harder to get the hint by preferring to evict hint interference.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126463 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AllocationOrder.h

@@ -47,6 +47,8 @@ public:
   /// rewind - Start over from the beginning.
   void rewind() { Pos = 0; }
 
+  /// isHint - Return true if PhysReg is a preferred register.
+  bool isHint(unsigned PhysReg) const { return PhysReg == Hint; }
 };
 
 } // end namespace llvm

lib/CodeGen/RegAllocGreedy.cpp

@@ -379,6 +379,9 @@ unsigned RAGreedy::tryEvict(LiveInterval &VirtReg,
     // Best so far.
     BestPhys = PhysReg;
     BestWeight = Weight;
+    // Stop if the hint can be used.
+    if (Order.isHint(PhysReg))
+      break;
   }
 
   if (!BestPhys)