Auto merge of #52958 - pietroalbini:rollup, r=pietroalbini

Rollup of 15 pull requests

Successful merges:

 - #52793 (Add test for NLL: unexpected "free region `` does not outlive" error )
 - #52799 (Use BitVector for global sets of AttrId)
 - #52809 (Add test for unexpected region for local data ReStatic)
 - #52834 ([NLL] Allow conflicting borrows of promoted length zero arrays)
 - #52835 (Fix Alias intra doc ICE)
 - #52854 (fix memrchr in miri)
 - #52899 (tests/ui: Add missing mips{64} ignores)
 - #52908 (Use SetLenOnDrop in Vec::truncate())
 - #52915 (Don't count MIR locals as borrowed after StorageDead when finding locals live across a yield terminator)
 - #52926 (rustc: Trim down the `rust_2018_idioms` lint group)
 - #52930 (rustc_resolve: record single-segment extern crate import resolutions.)
 - #52939 (Make io::Read::read_to_end consider io::Take::limit)
 - #52942 (Another SmallVec.extend optimization)
 - #52947 (1.27 actually added the `armv5te-unknown-linux-musleabi` target)
 - #52954 (async can begin expressions)

Failed merges:

r? @ghost

1 files changed, 21 insertions, 0 deletions

diff --git a/src/test/codegen/vec-clear.rs b/src/test/codegen/vec-clear.rs
new file mode 100644
index 00000000000..a73dd077cea
--- /dev/null
+++ b/src/test/codegen/vec-clear.rs
@@ -0,0 +1,21 @@
+// Copyright 2018 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"]
+
+// CHECK-LABEL: @vec_clear
+#[no_mangle]
+pub fn vec_clear(x: &mut Vec<u32>) {
+    // CHECK-NOT: load
+    // CHECK-NOT: icmp
+    x.clear()
+}