Do not throw away bits for no reason

llvm-svn: 19378
diff --git a/llvm/lib/Support/Compressor.cpp b/llvm/lib/Support/Compressor.cpp
index ac6a78a1..886dd7c 100644
--- a/llvm/lib/Support/Compressor.cpp
+++ b/llvm/lib/Support/Compressor.cpp
@@ -328,7 +328,7 @@
 uint64_t 
 Compressor::compressToNewBuffer(const char* in, unsigned size, char*&out) {
   BufferContext bc(size);
-  unsigned result = compress(in,size,BufferContext::callback,(void*)&bc);
+  uint64_t result = compress(in,size,BufferContext::callback,(void*)&bc);
   out = bc.buff;
   return result;
 }