1 files changed, 23 insertions, 0 deletions
diff --git a/tests/run-make/pgo-use/main.rs b/tests/run-make/pgo-use/main.rs
new file mode 100644
index 000000000..eb9192c87
--- /dev/null
+++ b/tests/run-make/pgo-use/main.rs
@@ -0,0 +1,23 @@
+#[no_mangle]
+pub fn cold_function(c: u8) {
+    println!("cold {}", c);
+}
+
+#[no_mangle]
+pub fn hot_function(c: u8) {
+    std::env::set_var(format!("var{}", c), format!("hot {}", c));
+}
+
+fn main() {
+    let arg = std::env::args().skip(1).next().unwrap();
+
+    for i in 0 .. 1000_000 {
+        let some_value = arg.as_bytes()[i % arg.len()];
+        if some_value == b'!' {
+            // This branch is never taken at runtime
+            cold_function(some_value);
+        } else {
+            hot_function(some_value);
+        }
+    }
+}