Unrolled build for #152970

Rollup merge of #152970 - RalfJung:unpin-noalias-tests, r=Mark-Simulacrum

extend unpin noalias tests to cover mutable references

#152946 made a change to the logic for this attribute that the test should have flagged as problematic -- but the test only checked `Box`, not `&mut`, and those have independent code paths. So extend the test to also cover `&mut`.

@b-naber would be nice if you could confirm that the added tests do fail with your PR.

Author: rust-timer

tests/codegen-llvm/function-arguments.rs

@@ -257,18 +257,30 @@ pub fn option_trait_borrow_mut(x: Option<&mut dyn Drop>) {}
 #[no_mangle]
 pub fn trait_raw(_: *const dyn Drop) {}
 
+// Ensure that `Box` gets `noalias` when the right traits are present, but removing *either* `Unpin`
+// or `UnsafeUnpin` is enough to lose the attribute.
 // CHECK: @trait_box(ptr noalias noundef nonnull align 1{{( %0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %1)?}})
 #[no_mangle]
 pub fn trait_box(_: Box<dyn Drop + Unpin + UnsafeUnpin>) {}
-
-// Ensure that removing *either* `Unpin` or `UnsafeUnpin` is enough to lose the attribute.
 // CHECK: @trait_box_pin1(ptr noundef nonnull align 1{{( %0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %1)?}})
 #[no_mangle]
 pub fn trait_box_pin1(_: Box<dyn Drop + Unpin>) {}
 // CHECK: @trait_box_pin2(ptr noundef nonnull align 1{{( %0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %1)?}})
 #[no_mangle]
 pub fn trait_box_pin2(_: Box<dyn Drop + UnsafeUnpin>) {}
 
+// Same for mutable references (with a non-zero minimal size so that we also see the
+// `dereferenceable` disappear).
+// CHECK: @trait_mutref(ptr noalias noundef align 4 dereferenceable(4){{( %_1.0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %_1.1)?}})
+#[no_mangle]
+pub fn trait_mutref(_: &mut (i32, dyn Drop + Unpin + UnsafeUnpin)) {}
+// CHECK: @trait_mutref_pin1(ptr noundef nonnull align 4{{( %_1.0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %_1.1)?}})
+#[no_mangle]
+pub fn trait_mutref_pin1(_: &mut (i32, dyn Drop + Unpin)) {}
+// CHECK: @trait_mutref_pin2(ptr noundef nonnull align 4{{( %_1.0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %_1.1)?}})
+#[no_mangle]
+pub fn trait_mutref_pin2(_: &mut (i32, dyn Drop + UnsafeUnpin)) {}
+
 // CHECK: { ptr, ptr } @trait_option(ptr noalias noundef align 1 %x.0, ptr %x.1)
 #[no_mangle]
 pub fn trait_option(