diff --git a/stack-old.yaml b/stack-old.yaml
index 6f02f49c8..8c00d6f16 100644
--- a/stack-old.yaml
+++ b/stack-old.yaml
@@ -20,6 +20,7 @@ extra-deps:
 - splitmix-0.0.4@sha256:fb9bb8b54a2e76c8a021fe5c4c3798047e1f60e168379a1f80693047fe00ad0e,4813
 - doctest-0.16.2@sha256:2f96e9bbe9aee11b47453c82c24b3dc76cdbb8a2a7c984dfd60b4906d08adf68,6942
 - cabal-doctest-1.0.8@sha256:34dff6369d417df2699af4e15f06bc181d495eca9c51efde173deae2053c197c,1491
+- rdtsc-1.3.0.1@sha256:0a6e8dc715ba82ad72c7e2b1c2f468999559bec059d50540719a80b00dcc4e66,1557
 flags:
   splitmix:
     random: false