Eliminate the last use of InterferenceResult.

The Query class now holds two iterators instead of an InterferenceResult
instance. The iterators are used as bookmarks for repeated
collectInterferingVRegs calls.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137380 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalUnion.h b/lib/CodeGen/LiveIntervalUnion.h
index 570ad94..8f4bb00 100644
--- a/lib/CodeGen/LiveIntervalUnion.h
+++ b/lib/CodeGen/LiveIntervalUnion.h
@@ -142,7 +142,8 @@
   class Query {
     LiveIntervalUnion *LiveUnion;
     LiveInterval *VirtReg;
-    InterferenceResult FirstInterference;
+    LiveInterval::iterator VirtRegI; // current position in VirtReg
+    SegmentIter LiveUnionI;          // current position in LiveUnion
     SmallVector<LiveInterval*,4> InterferingVRegs;
     bool CheckedFirstInterference;
     bool SeenAllInterferences;
@@ -217,8 +218,7 @@
     void operator=(const Query&); // DO NOT IMPLEMENT
 
     // Private interface for queries
-    const InterferenceResult &firstInterference();
-    void findIntersection(InterferenceResult &IR) const;
+    void findIntersection();
   };
 };