naked functions: test that unused naked functions are not emitted

Author: folkertdev

tests/codegen-llvm/naked-fn/dead-code-elimination.rs

@@ -0,0 +1,43 @@
+//@ add-core-stubs
+//@ revisions: linux win_x86_msvc win_x86_gnu win_i686_gnu macos thumb
+//
+//@[linux] compile-flags: --target x86_64-unknown-linux-gnu
+//@[linux] needs-llvm-components: x86
+//@[win_x86_gnu] compile-flags: --target x86_64-pc-windows-gnu
+//@[win_x86_gnu] needs-llvm-components: x86
+//@[win_x86_msvc] compile-flags: --target x86_64-pc-windows-msvc
+//@[win_x86_msvc] needs-llvm-components: x86
+//@[win_i686_gnu] compile-flags: --target i686-pc-windows-gnu
+//@[win_i686_gnu] needs-llvm-components: x86
+//@[macos] compile-flags: --target aarch64-apple-darwin
+//@[macos] needs-llvm-components: aarch64
+//@[thumb] compile-flags: --target thumbv7em-none-eabi
+//@[thumb] needs-llvm-components: arm
+
+#![crate_type = "lib"]
+#![feature(no_core, lang_items, rustc_attrs)]
+#![no_core]
+
+// Test that unused naked functions are not emitted.
+
+extern crate minicore;
+use minicore::*;
+
+#[unsafe(naked)]
+extern "C" fn foo() {
+    naked_asm!("ret")
+}
+
+#[unsafe(naked)]
+extern "C" fn should_be_eliminated() {
+    naked_asm!("ret")
+}
+
+#[unsafe(no_mangle)]
+fn entry() {
+    foo();
+}
+
+// CHECK-NOT: should_be_eliminated
+// CHECK-LABEL: foo
+// CHECK-NOT: should_be_eliminated