From: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date: Thu, 17 Apr 2025 15:53:15 +0000 (+0200)
Subject: gccrs: Add execute test for black_box intrinsic
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=93c9f9af0aa3356a2a50bf920ad32be5b07f3d59;p=thirdparty%2Fgcc.git

gccrs: Add execute test for black_box intrinsic

gcc/testsuite/ChangeLog:

	* rust/execute/black_box.rs: New test.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
---

diff --git a/gcc/testsuite/rust/execute/black_box.rs b/gcc/testsuite/rust/execute/black_box.rs
new file mode 100644
index 00000000000..7a9920eba94
--- /dev/null
+++ b/gcc/testsuite/rust/execute/black_box.rs
@@ -0,0 +1,30 @@
+/* { dg-output "Value is: 42\r*\n" } */
+#![feature(rustc_attrs)]
+
+extern "C" {
+    fn printf(s: *const i8, ...);
+}
+
+#[lang = "sized"]
+pub trait Sized {}
+
+#[rustc_builtin_macro]
+macro_rules! llvm_asm {
+    () => {};
+}
+
+pub fn black_box<T>(mut dummy: T) -> T {
+    unsafe {
+        llvm_asm!("" : : "r"(&mut dummy) : "memory" : "volatile");
+    }
+
+    dummy
+}
+
+fn main() {
+    let dummy: i32 = 42;
+    let result = black_box(dummy);
+    unsafe {
+        printf("Value is: %i\n\0" as *const str as *const i8, result);
+    }
+}