diff --git a/library/stdarch/src/macros.rs b/library/stdarch/src/macros.rs
index 87f1242619e4..b3cf8ecf4e85 100644
--- a/library/stdarch/src/macros.rs
+++ b/library/stdarch/src/macros.rs
@@ -36,6 +36,28 @@ macro_rules! define_impl {
                 assert!(idx < $nelems);
                 unsafe { simd_insert(self, idx, val) }
             }
+
+            #[inline(always)]
+            pub fn load(slice: &[$elemty], offset: usize) -> $name {
+                assert!(slice[offset..].len() >= $nelems);
+                unsafe { $name::load_unchecked(slice, offset) }
+            }
+
+            #[inline(always)]
+            pub unsafe fn load_unchecked(
+                slice: &[$elemty],
+                offset: usize,
+            ) -> $name {
+                use std::mem::size_of;
+                use std::ptr;
+
+                let mut x = $name::splat(0 as $elemty);
+                ptr::copy_nonoverlapping(
+                    slice.get_unchecked(offset) as *const $elemty as *const u8,
+                    &mut x as *mut $name as *mut u8,
+                    size_of::<$name>());
+                x
+            }
         }
     }
 }
diff --git a/library/stdarch/src/x86/mod.rs b/library/stdarch/src/x86/mod.rs
index a6b4cbd803ba..8bc93f73ec70 100644
--- a/library/stdarch/src/x86/mod.rs
+++ b/library/stdarch/src/x86/mod.rs
@@ -8,3 +8,4 @@ pub type __m128i = ::v128::i8x16;
 // mod sse;
 mod sse2;
 mod ssse3;
+mod sse42;
diff --git a/library/stdarch/src/x86/sse42.rs b/library/stdarch/src/x86/sse42.rs
new file mode 100644
index 000000000000..be1d97edf9e6
--- /dev/null
+++ b/library/stdarch/src/x86/sse42.rs
@@ -0,0 +1,56 @@
+// use v128::*;
+use x86::__m128i;
+
+pub const _SIDD_UBYTE_OPS: i8 = 0b00000000;
+pub const _SIDD_UWORD_OPS: i8 = 0b00000001;
+pub const _SIDD_SBYTE_OPS: i8 = 0b00000010;
+pub const _SIDD_SWORD_OPS: i8 = 0b00000011;
+
+pub const _SIDD_CMP_EQUAL_ANY: i8 = 0b00000000;
+pub const _SIDD_CMP_RANGES: i8 = 0b00000100;
+pub const _SIDD_CMP_EQUAL_EACH: i8 = 0b00001000;
+pub const _SIDD_CMP_EQUAL_ORDERED: i8 = 0b00001100;
+
+pub const _SIDD_POSITIVE_POLARITY: i8 = 0b00000000;
+pub const _SIDD_NEGATIVE_POLARITY: i8 = 0b00010000;
+pub const _SIDD_MASKED_NEGATIVE_POLARITY: i8 = 0b00110000;
+
+pub const _SIDD_LEAST_SIGNIFICANT: i8 = 0b00000000;
+pub const _SIDD_MOST_SIGNIFICANT: i8 = 0b01000000;
+
+#[inline(always)]
+#[target_feature = "+sse4.2"]
+pub fn _mm_cmpestri(
+    a: __m128i,
+    la: i32,
+    b: __m128i,
+    lb: i32,
+    imm8: i8,
+) -> i32 {
+    unsafe { pcmpestri128(a, la, b, lb, imm8) }
+}
+
+#[allow(improper_ctypes)]
+extern {
+    #[link_name = "llvm.x86.sse42.pcmpestri128"]
+    fn pcmpestri128(a: __m128i, la: i32, b: __m128i, lb: i32, imm8: i8) -> i32;
+}
+
+#[cfg(test)]
+mod tests {
+    use v128::*;
+    use x86::{__m128i, sse42};
+
+    #[test]
+    #[target_feature = "+sse4.2"]
+    fn _mm_cmpestri() {
+        let a = &b"bar             "[..];
+        let b = &b"foobar          "[..];
+        let va = __m128i::from(u8x16::load(a, 0));
+        let vb = __m128i::from(u8x16::load(b, 0));
+        let i = sse42::_mm_cmpestri(
+            va, 3, vb, 6,
+            sse42::_SIDD_CMP_EQUAL_ORDERED | sse42::_SIDD_MOST_SIGNIFICANT);
+        assert_eq!(3, i);
+    }
+}
diff --git a/library/stdarch/src/x86/ssse3.rs b/library/stdarch/src/x86/ssse3.rs
index 006069b1ec54..8f45c2ec4c2d 100644
--- a/library/stdarch/src/x86/ssse3.rs
+++ b/library/stdarch/src/x86/ssse3.rs
@@ -11,7 +11,7 @@ pub fn _mm_abs_epi8(a: i8x16) -> u8x16 {
 #[allow(improper_ctypes)]
 extern {
     #[link_name = "llvm.x86.ssse3.pabs.b.128"]
-    pub fn pabsb128(a: i8x16) -> u8x16;
+    fn pabsb128(a: i8x16) -> u8x16;
 }
 
 #[cfg(test)]