Work around a coalescer bug.

The coalescer can in very rare cases leave too large live intervals around after
rematerializing cheap-as-a-move instructions.

Linear scan doesn't really care, but live range splitting gets very confused
when a live range is killed by a ghost instruction.

I will fix this properly in the coalescer after 2.9 branches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127096 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index 29c0afc..0e35df0 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -103,7 +103,7 @@
   void analyzeUses();
 
   /// calcLiveBlockInfo - Compute per-block information about CurLI.
-  void calcLiveBlockInfo();
+  bool calcLiveBlockInfo();
 
   /// canAnalyzeBranch - Return true if MBB ends in a branch that can be
   /// analyzed.