Transfer simply defined values directly without recomputing liveness and SSA.

Values that map to a single new value in a new interval after splitting don't
need new PHIDefs, and if the parent value was never rematerialized the live
range will be the same.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126894 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h
index 3a4d710..05de1505 100644
--- a/lib/CodeGen/SplitKit.h
+++ b/lib/CodeGen/SplitKit.h
@@ -246,12 +246,16 @@
                     SlotIndex Idx,
                     const MachineBasicBlock *IdxMBB);
 
+  /// transferSimpleValues - Transfer simply defined values to the new ranges.
+  /// Return true if any complex ranges were skipped.
+  bool transferSimpleValues();
+
   /// extendPHIKillRanges - Extend the ranges of all values killed by original
   /// parent PHIDefs.
   void extendPHIKillRanges();
 
   /// rewriteAssigned - Rewrite all uses of Edit.getReg() to assigned registers.
-  void rewriteAssigned();
+  void rewriteAssigned(bool ExtendRanges);
 
   /// rewriteComponents - Rewrite all uses of Intv[0] according to the eq
   /// classes in ConEQ.