diff --git a/library/stdarch/src/arm/mod.rs b/library/stdarch/src/arm/mod.rs
new file mode 100644
index 000000000000..9472441ae4fe
--- /dev/null
+++ b/library/stdarch/src/arm/mod.rs
@@ -0,0 +1,10 @@
+//! ARM intrinsics.
+pub use self::v6::*;
+pub use self::v7::*;
+#[cfg(target_arch = "aarch64")]
+pub use self::v8::*;
+
+mod v6;
+mod v7;
+#[cfg(target_arch = "aarch64")]
+mod v8;
diff --git a/library/stdarch/src/arm/v6.rs b/library/stdarch/src/arm/v6.rs
new file mode 100644
index 000000000000..95442b374f8c
--- /dev/null
+++ b/library/stdarch/src/arm/v6.rs
@@ -0,0 +1,25 @@
+//! ARMv6 intrinsics.
+//!
+//! The reference is [ARMv6-M Architecture Reference
+//! Manual](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0419c/index.html).
+
+/// Reverse the order of the bytes.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(rev))]
+pub fn _rev_u8(x: u8) -> u8 {
+    x.swap_bytes() as u8
+}
+
+/// Reverse the order of the bytes.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(rev))]
+pub fn _rev_u16(x: u16) -> u16 {
+    x.swap_bytes() as u16
+}
+
+/// Reverse the order of the bytes.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(rev))]
+pub fn _rev_u32(x: u32) -> u32 {
+    x.swap_bytes() as u32
+}
diff --git a/library/stdarch/src/arm/v7.rs b/library/stdarch/src/arm/v7.rs
new file mode 100644
index 000000000000..1052b8477a92
--- /dev/null
+++ b/library/stdarch/src/arm/v7.rs
@@ -0,0 +1,40 @@
+//! ARMv7 intrinsics.
+//!
+//! The reference is [ARMv7-M Architecture Reference Manual (Issue
+//! E.b)](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0403e.b/index.html).
+
+pub use super::v6::*;
+
+/// Count Leading Zeros.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(clz))]
+pub fn _clz_u8(x: u8) -> u8 {
+    x.leading_zeros() as u8
+}
+
+/// Count Leading Zeros.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(clz))]
+pub fn _clz_u16(x: u16) -> u16 {
+    x.leading_zeros() as u16
+}
+
+/// Count Leading Zeros.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(clz))]
+pub fn _clz_u32(x: u32) -> u32 {
+    x.leading_zeros() as u32
+}
+
+#[allow(dead_code)]
+extern "C" {
+    #[link_name="llvm.bitreverse.i32"]
+    fn rbit_u32(i: i32) -> i32;
+}
+
+/// Reverse the bit order.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(rbit))]
+pub fn _rbit_u32(x: u32) -> u32 {
+    unsafe { rbit_u32(x as i32) as u32 }
+}
diff --git a/library/stdarch/src/arm/v8.rs b/library/stdarch/src/arm/v8.rs
new file mode 100644
index 000000000000..92b1507aada1
--- /dev/null
+++ b/library/stdarch/src/arm/v8.rs
@@ -0,0 +1,54 @@
+//! ARMv8 intrinsics.
+//!
+//! The reference is [ARMv8-A Reference Manual](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0487a.k_10775/index.html).
+
+pub use super::v7::*;
+
+/// Reverse the order of the bytes.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(rev))]
+pub fn _rev_u64(x: u64) -> u64 {
+    x.swap_bytes() as u64
+}
+
+/// Count Leading Zeros.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(clz))]
+pub fn _clz_u64(x: u64) -> u64 {
+    x.leading_zeros() as u64
+}
+
+#[allow(dead_code)]
+extern "C" {
+    #[link_name="llvm.bitreverse.i64"]
+    fn rbit_u64(i: i64) -> i64;
+}
+
+/// Reverse the bit order.
+#[inline(always)]
+#[cfg_attr(test, assert_instr(rbit))]
+pub fn _rbit_u64(x: u64) -> u64 {
+    unsafe { rbit_u64(x as i64) as u64 }
+}
+
+/// Counts the leading most significant bits set.
+///
+/// When all bits of the operand are set it returns the size of the operand in
+/// bits.
+#[inline(always)]
+// #[cfg_attr(test, assert_instr(cls))] // LLVM Bug: https://bugs.llvm.org/show_bug.cgi?id=31802
+#[cfg_attr(test, assert_instr(clz))] 
+pub fn _cls_u32(x: u32) -> u32 {
+    u32::leading_zeros(!x) as u32
+}
+
+/// Counts the leading most significant bits set.
+///
+/// When all bits of the operand are set it returns the size of the operand in
+/// bits.
+#[inline(always)]
+// #[cfg_attr(test, assert_instr(cls))] // LLVM Bug: https://bugs.llvm.org/show_bug.cgi?id=31802
+#[cfg_attr(test, assert_instr(clz))] 
+pub fn _cls_u64(x: u64) -> u64 {
+    u64::leading_zeros(!x) as u64
+}
diff --git a/library/stdarch/src/lib.rs b/library/stdarch/src/lib.rs
index e2ec27688409..2e75c3e833d0 100644
--- a/library/stdarch/src/lib.rs
+++ b/library/stdarch/src/lib.rs
@@ -20,6 +20,9 @@ pub mod simd {
 pub mod vendor {
     #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
     pub use x86::*;
+
+    #[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
+    pub use arm::*;
 }
 
 #[macro_use]
@@ -31,3 +34,6 @@ mod v512;
 mod v64;
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 mod x86;
+
+#[cfg(any(target_arch = "arm", target_arch = "aarch64"))]
+ mod arm;