diff --git a/appveyor.yml b/appveyor.yml
index d27883d..4bb03de 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -17,6 +17,9 @@ test_script:
   - cargo build --release
   - cargo test
   - cargo test --release
+  - CALL "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"
+  - dumpbin /disasm target/debug/librustc_builtins.rlib || exit 0
+  - dumpbin /disasm target/release/librustc_builtins.rlib || exit 0
 
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