Added register reassignment prototype to RAGreedy. It's a simple
heuristic to reshuffle register assignments when we can't find an
available reg.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121388 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveIntervalUnion.cpp b/lib/CodeGen/LiveIntervalUnion.cpp
index 1fca034..d5c7bf0 100644
--- a/lib/CodeGen/LiveIntervalUnion.cpp
+++ b/lib/CodeGen/LiveIntervalUnion.cpp
@@ -247,10 +247,13 @@
       if (!IR.LiveUnionI.value()->isSpillable())
         SeenUnspillableVReg = true;
 
-      InterferingVRegs.push_back(IR.LiveUnionI.value());
       if (InterferingVRegs.size() == MaxInterferingRegs)
+        // Leave SeenAllInterferences set to false to indicate that at least one
+        // interference exists beyond those we collected.
         return MaxInterferingRegs;
 
+      InterferingVRegs.push_back(IR.LiveUnionI.value());
+
       // Cache the most recent interfering vreg to bypass isSeenInterference.
       RecentInterferingVReg = IR.LiveUnionI.value();
       ++IR.LiveUnionI;