Auto merge of #54554 - RalfJung:maybe-uninit, r=nagisa

Revert most of MaybeUninit, except for the new API itself

This reverts most of https://github.com/rust-lang/rust/pull/53508/ for perf reasons (first commit reverts that entire PR), except for the new API itself (added back in 2nd commit).

1 files changed, 0 insertions, 23 deletions

diff --git a/src/test/codegen/box-maybe-uninit.rs b/src/test/codegen/box-maybe-uninit.rs
deleted file mode 100644
index 168e1a3eba0..00000000000
--- a/src/test/codegen/box-maybe-uninit.rs
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-// compile-flags: -O
-#![crate_type="lib"]
-#![feature(maybe_uninit)]
-
-use std::mem::MaybeUninit;
-
-// Boxing a `MaybeUninit` value should not copy junk from the stack
-#[no_mangle]
-pub fn box_uninitialized() -> Box<MaybeUninit<usize>> {
-    // CHECK-LABEL: @box_uninitialized
-    // CHECK-NOT: store
-    Box::new(MaybeUninit::uninitialized())
-}