diff --git a/src/test/run-pass/out-of-stack.rs b/src/test/run-pass/out-of-stack.rs
index d1daa1e365e..71fde866703 100644
--- a/src/test/run-pass/out-of-stack.rs
+++ b/src/test/run-pass/out-of-stack.rs
@@ -17,6 +17,9 @@ use std::os;
 use std::str;
 
 // lifted from the test module
+// Inlining to avoid llvm turning the recursive functions into tail calls,
+// which doesn't consume stack.
+#[inline(always)]
 pub fn black_box<T>(dummy: T) { unsafe { asm!("" : : "r"(&dummy)) } }
 
 fn silent_recurse() {