Rollup merge of #123474 - jieyouxu:issue-7349-port, r=Mark-Simulacrum

Port `run-make/issue-7349` to a codegen test

The test does not need to be a run-make test, it can use the codegen test infrastructure.

Also took the opportunity to rename the test to `no-redundant-item-monomorphization` so it's not just some opaque issue number.

Part of #121876.

Author: GuillaumeGomez

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -130,7 +130,6 @@ run-make/issue-53964/Makefile
 run-make/issue-64153/Makefile
 run-make/issue-68794-textrel-on-minimal-lib/Makefile
 run-make/issue-69368/Makefile
-run-make/issue-7349/Makefile
 run-make/issue-83045/Makefile
 run-make/issue-83112-incr-test-moved-file/Makefile
 run-make/issue-84395-lto-embed-bitcode/Makefile

tests/codegen/no-redundant-item-monomorphization.rs

@@ -0,0 +1,33 @@
+// Test to make sure that inner functions within a polymorphic outer function
+// don't get re-codegened when the outer function is monomorphized. The test
+// code monomorphizes the outer functions several times, but the magic constants
+// used in the inner functions should each appear only once in the generated IR.
+
+// issue: rust-lang/rust#7349
+//@ compile-flags: -Cno-prepopulate-passes -Copt-level=0
+
+// CHECK-COUNT-1: ret i32 8675309
+// CHECK-COUNT-1: ret i32 11235813
+
+fn outer<T>() {
+    #[allow(dead_code)]
+    fn inner() -> u32 {
+        8675309
+    }
+    inner();
+}
+
+extern "C" fn outer_foreign<T>() {
+    #[allow(dead_code)]
+    fn inner() -> u32 {
+        11235813
+    }
+    inner();
+}
+
+fn main() {
+    outer::<isize>();
+    outer::<usize>();
+    outer_foreign::<isize>();
+    outer_foreign::<usize>();
+}