rewrite lto-empty to rmake

Oneirical · Oneirical · commit 6ba0a84df917 · 2024-06-25T14:27:43.000-04:00
diff --git a/src/tools/tidy/src/allowed_run_make_makefiles.txt b/src/tools/tidy/src/allowed_run_make_makefiles.txt
@@ -97,7 +97,6 @@ run-make/long-linker-command-lines-cmd-exe/Makefile
 run-make/long-linker-command-lines/Makefile
 run-make/longjmp-across-rust/Makefile
 run-make/lto-dylib-dep/Makefile
-run-make/lto-empty/Makefile
 run-make/lto-linkage-used-attr/Makefile
 run-make/lto-no-link-whole-rlib/Makefile
 run-make/lto-smoke-c/Makefile
diff --git a/tests/run-make/lto-empty/Makefile b/tests/run-make/lto-empty/Makefile
diff --git a/tests/run-make/lto-empty/rmake.rs b/tests/run-make/lto-empty/rmake.rs
@@ -0,0 +1,17 @@
+// Compiling Rust code twice in a row with "fat" link-time-optimizations used to cause
+// an internal compiler error (ICE). This was due to how the compiler would cache some modules
+// to make subsequent compilations faster, at least one of which was required for LTO to link
+// into. After this was patched in #63956, this test checks that the bug does not make
+// a resurgence.
+// See https://github.com/rust-lang/rust/issues/63349
+
+//@ ignore-cross-compile
+
+use run_make_support::rustc;
+
+fn main() {
+    rustc().input("lib.rs").arg("-Clto=fat").opt_level("3").incremental("inc-fat").run();
+    rustc().input("lib.rs").arg("-Clto=fat").opt_level("3").incremental("inc-fat").run();
+    rustc().input("lib.rs").arg("-Clto=thin").opt_level("3").incremental("inc-thin").run();
+    rustc().input("lib.rs").arg("-Clto=thin").opt_level("3").incremental("inc-thin").run();
+}
