diff -urN a/src/mongo/db/storage/mmap_v1/btree/key.cpp b/src/mongo/db/storage/mmap_v1/btree/key.cpp
--- a/src/mongo/db/storage/mmap_v1/btree/key.cpp	2015-03-16 09:08:50.000000000 -0600
+++ b/src/mongo/db/storage/mmap_v1/btree/key.cpp	2015-04-02 06:14:33.858972179 -0600
@@ -424,7 +424,7 @@
                     p += 8;
                     break;
                 case cdouble:
-                    b.append("", (double&) *p);
+                    b.append("", (reinterpret_cast< const PackedDouble& >(*p)).d);
                     p += sizeof(double);
                     break;
                 case cint: