diff --git a/.gitmodules b/.gitmodules
index 984113151de4d..5a13d1ccf9180 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -36,8 +36,8 @@
 	url = https://github.com/rust-lang/edition-guide.git
 [submodule "src/llvm-project"]
 	path = src/llvm-project
-	url = https://github.com/rust-lang/llvm-project.git
-	branch = rustc/11.0-2020-10-12
+	url = https://github.com/the8472/llvm-project.git
+	branch = loop-delete-pass
 [submodule "src/doc/embedded-book"]
 	path = src/doc/embedded-book
 	url = https://github.com/rust-embedded/book.git
diff --git a/library/alloc/benches/vec.rs b/library/alloc/benches/vec.rs
index 89893b6209c0a..9fd662318623a 100644
--- a/library/alloc/benches/vec.rs
+++ b/library/alloc/benches/vec.rs
@@ -548,6 +548,16 @@ fn bench_in_place_zip_iter_mut(b: &mut Bencher) {
     black_box(data);
 }
 
+#[inline(never)]
+pub fn vec_cast(input: Vec<usize>) -> Vec<isize> {
+    input.into_iter().map(|e| e as isize).collect()
+}
+
+#[bench]
+fn bench_transmute(b: &mut Bencher) {
+    b.iter(|| vec_cast(black_box(Vec::with_capacity(100))));
+}
+
 #[derive(Clone)]
 struct Droppable(usize);
 
diff --git a/src/llvm-project b/src/llvm-project
index 7ade8dc4b8414..77cd407692544 160000
--- a/src/llvm-project
+++ b/src/llvm-project
@@ -1 +1 @@
-Subproject commit 7ade8dc4b84142abd3e6d1fb8a0f4111b0bbd571
+Subproject commit 77cd40769254491ad3497d2e7e0221619499d8a0