Add SparseBitVector implementation

llvm-svn: 41790
diff --git a/llvm/CREDITS.TXT b/llvm/CREDITS.TXT
index bdd20fb..e1e1af30 100644
--- a/llvm/CREDITS.TXT
+++ b/llvm/CREDITS.TXT
@@ -29,6 +29,7 @@
 N: Daniel Berlin
 E: dberlin@dberlin.org
 D: ET-Forest implementation.
+D: Sparse bitmap
 
 N: Neil Booth
 E: neil@daikokuya.co.uk