Minimize the slot indexes spanned by register ranges created when splitting.

When an interfering live range ends at a dead slot index between two
instructions, make sure that the inserted copy instruction gets a slot index
after the dead ones. This makes it possible to avoid the interference.

Ideally, there shouldn't be interference ending at a deleted instruction, but
physical register coalescing can sometimes do that to sub-registers.

This fixes PR9823.

llvm-svn: 130687
diff --git a/llvm/lib/CodeGen/LiveRangeEdit.h b/llvm/lib/CodeGen/LiveRangeEdit.h
index c008d76..14d227e6 100644
--- a/llvm/lib/CodeGen/LiveRangeEdit.h
+++ b/llvm/lib/CodeGen/LiveRangeEdit.h
@@ -165,7 +165,8 @@
                             const Remat &RM,
                             LiveIntervals&,
                             const TargetInstrInfo&,
-                            const TargetRegisterInfo&);
+                            const TargetRegisterInfo&,
+                            bool Late = false);
 
   /// markRematerialized - explicitly mark a value as rematerialized after doing
   /// it manually.