diff --git a/.gitmodules b/.gitmodules
index f9bd42edab3f4..2e73c20a4452b 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -20,7 +20,7 @@
 	shallow = true
 [submodule "library/stdarch"]
 	path = library/stdarch
-	url = https://github.com/rust-lang/stdarch.git
+	url = https://github.com/usamoi/stdarch.git
 	shallow = true
 [submodule "src/doc/edition-guide"]
 	path = src/doc/edition-guide
diff --git a/compiler/rustc_span/src/analyze_source_file.rs b/compiler/rustc_span/src/analyze_source_file.rs
index 47cc16b623d10..4c2e8d7e453ea 100644
--- a/compiler/rustc_span/src/analyze_source_file.rs
+++ b/compiler/rustc_span/src/analyze_source_file.rs
@@ -87,17 +87,17 @@ cfg_match! {
 
                 // For character in the chunk, see if its byte value is < 0, which
                 // indicates that it's part of a UTF-8 char.
-                let multibyte_test = unsafe { _mm_cmplt_epi8(chunk, _mm_set1_epi8(0)) };
+                let multibyte_test = _mm_cmplt_epi8(chunk, _mm_set1_epi8(0));
                 // Create a bit mask from the comparison results.
-                let multibyte_mask = unsafe { _mm_movemask_epi8(multibyte_test) };
+                let multibyte_mask = _mm_movemask_epi8(multibyte_test);
 
                 // If the bit mask is all zero, we only have ASCII chars here:
                 if multibyte_mask == 0 {
                     assert!(intra_chunk_offset == 0);
 
                     // Check for newlines in the chunk
-                    let newlines_test = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8)) };
-                    let mut newlines_mask = unsafe { _mm_movemask_epi8(newlines_test) };
+                    let newlines_test = _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8));
+                    let mut newlines_mask = _mm_movemask_epi8(newlines_test);
 
                     let output_offset = RelativeBytePos::from_usize(chunk_index * CHUNK_SIZE + 1);
 
@@ -212,17 +212,17 @@ cfg_match! {
 
                 // For character in the chunk, see if its byte value is < 0, which
                 // indicates that it's part of a UTF-8 char.
-                let multibyte_test = unsafe { _mm_cmplt_epi8(chunk, _mm_set1_epi8(0)) };
+                let multibyte_test = _mm_cmplt_epi8(chunk, _mm_set1_epi8(0));
                 // Create a bit mask from the comparison results.
-                let multibyte_mask = unsafe { _mm_movemask_epi8(multibyte_test) };
+                let multibyte_mask = _mm_movemask_epi8(multibyte_test);
 
                 // If the bit mask is all zero, we only have ASCII chars here:
                 if multibyte_mask == 0 {
                     assert!(intra_chunk_offset == 0);
 
                     // Check for newlines in the chunk
-                    let newlines_test = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8)) };
-                    let mut newlines_mask = unsafe { _mm_movemask_epi8(newlines_test) };
+                    let newlines_test = _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8));
+                    let mut newlines_mask = _mm_movemask_epi8(newlines_test);
 
                     let output_offset = RelativeBytePos::from_usize(chunk_index * CHUNK_SIZE + 1);
 
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 99d5af9f0ef95..31e9ec395a12a 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -210,12 +210,15 @@
 #![feature(powerpc_target_feature)]
 #![feature(riscv_target_feature)]
 #![feature(rtm_target_feature)]
+#![feature(s390x_target_feature)]
 #![feature(sha512_sm_x86)]
 #![feature(sse4a_target_feature)]
 #![feature(tbm_target_feature)]
 #![feature(wasm_target_feature)]
 #![feature(x86_amx_intrinsics)]
 // tidy-alphabetical-end
+#![allow(stable_features)]
+#![feature(target_feature_11)]
 
 // allow using `core::` in intra-doc links
 #[allow(unused_extern_crates)]
diff --git a/library/stdarch b/library/stdarch
index 684de0d6fef70..d8c341fb2e529 160000
--- a/library/stdarch
+++ b/library/stdarch
@@ -1 +1 @@
-Subproject commit 684de0d6fef708cae08214fef9643dd9ec7296e1
+Subproject commit d8c341fb2e52951913af897686db6e405b86eb6a
diff --git a/src/tools/rust-analyzer/lib/line-index/src/lib.rs b/src/tools/rust-analyzer/lib/line-index/src/lib.rs
index bc87ada3eb55c..ac2e7779c9116 100644
--- a/src/tools/rust-analyzer/lib/line-index/src/lib.rs
+++ b/src/tools/rust-analyzer/lib/line-index/src/lib.rs
@@ -287,17 +287,17 @@ unsafe fn analyze_source_file_sse2(
 
         // For character in the chunk, see if its byte value is < 0, which
         // indicates that it's part of a UTF-8 char.
-        let multibyte_test = unsafe { _mm_cmplt_epi8(chunk, _mm_set1_epi8(0)) };
+        let multibyte_test = _mm_cmplt_epi8(chunk, _mm_set1_epi8(0));
         // Create a bit mask from the comparison results.
-        let multibyte_mask = unsafe { _mm_movemask_epi8(multibyte_test) };
+        let multibyte_mask = _mm_movemask_epi8(multibyte_test);
 
         // If the bit mask is all zero, we only have ASCII chars here:
         if multibyte_mask == 0 {
             assert!(intra_chunk_offset == 0);
 
             // Check for newlines in the chunk
-            let newlines_test = unsafe { _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8)) };
-            let newlines_mask = unsafe { _mm_movemask_epi8(newlines_test) };
+            let newlines_test = _mm_cmpeq_epi8(chunk, _mm_set1_epi8(b'\n' as i8));
+            let newlines_mask = _mm_movemask_epi8(newlines_test);
 
             if newlines_mask != 0 {
                 // All control characters are newlines, record them