Add LiveIntervalUnion print methods, RegAllocGreedy::trySplit debug spew.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121783 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index 46cfbe7..324340a 100644
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -269,6 +269,14 @@
 unsigned RAGreedy::trySplit(LiveInterval &VirtReg, AllocationOrder &Order,
                             SmallVectorImpl<LiveInterval*>&SplitVRegs) {
   NamedRegionTimer T("Splitter", TimerGroupName, TimePassesIsEnabled);
+  Order.rewind();
+  while (unsigned PhysReg = Order.next()) {
+    DEBUG({
+      query(VirtReg, PhysReg).print(dbgs(), TRI);
+      for (const unsigned *AI = TRI->getAliasSet(PhysReg); *AI; ++AI)
+        query(VirtReg, *AI).print(dbgs(), TRI);
+    });
+  }
   return 0;
 }