update LLVM with fix for PR32379

Fixes #40593.

src/llvm

@@ -1 +1 @@
-Subproject commit d5ef27a79661d4f0d57d7b7d2cdbe9204f790a4a
+Subproject commit 2e951c3ae354bcbd2e50b30798e232949a926b75

src/rustllvm/llvm-rebuild-trigger

@@ -1,4 +1,4 @@
 # If this file is modified, then llvm will be (optionally) cleaned and then rebuilt.
 # The actual contents of this file do not matter, but to trigger a change on the
 # build bots then the contents should be changed so git updates the mtime.
-2017-03-19
+2017-03-23

src/test/run-pass/auxiliary/llvm_pr32379.rs

@@ -0,0 +1,15 @@
+// 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.
+
+pub fn pr32379(mut data: u64, f1: bool, f2: bool) -> u64 {
+    if f1 { data &= !2; }
+    if f2 { data |= 2; }
+    data
+}

src/test/run-pass/llvm-pr32379.rs

@@ -0,0 +1,23 @@
+// 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.
+
+// aux-build:llvm_pr32379.rs
+
+// LLVM PR #32379 (https://bugs.llvm.org/show_bug.cgi?id=32379), which
+// applies to upstream LLVM 3.9.1, is known to cause rustc itself to be
+// miscompiled on ARM (Rust issue #40593). Because cross builds don't test
+// our *compiler* on ARM, have a test for the miscompilation directly.
+
+extern crate llvm_pr32379;
+
+pub fn main() {
+    let val = llvm_pr32379::pr32379(2, false, false);
+    assert_eq!(val, 2);
+}