diff --git a/appveyor.yml b/appveyor.yml
index d27883d..06255fa 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -17,6 +17,8 @@ test_script:
   - cargo build --release
   - cargo test
   - cargo test --release
+  - dumpbin /disasm target/debug/librustc_builtins.rlib
+  - dumpbin /disasm target/release/librustc_builtins.rlib
 
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