diff --git a/checkllvm.sh b/checkllvm.sh
index 2498ffa..ed0b5ab 100755
--- a/checkllvm.sh
+++ b/checkllvm.sh
@@ -1,9 +1,11 @@
 #!/usr/bin/env bash
 
-rustc code.rs --crate-name ll -Zmir-enable-passes=-ConstProp --emit llvm-ir -Cno-prepopulate-passes --crate-type=lib
+set -eu
 
-clang ll.ll helper.c -O1 -o good
-clang ll.ll helper.c -O2 -o bad
+# rustc code.rs --crate-name ll -Zmir-enable-passes=-ConstProp --emit llvm-ir -Cno-prepopulate-passes --crate-type=lib
+
+clang $1 helper.c -O1 -o good
+clang $1 helper.c -O2 -o bad
 
 bad=$(./bad)
 good=$(./good)
@@ -12,4 +14,5 @@ if [ "$good" != "$bad" ]; then
     echo "MISCOMPILATION"
 else
     echo "no repro"
+    exit 1
 fi
\ No newline at end of file