diff --git a/library/stdarch/crates/core_arch/src/x86/avx2.rs b/library/stdarch/crates/core_arch/src/x86/avx2.rs
index 5a3f88069bd1..9a550fed821f 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx2.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx2.rs
@@ -989,24 +989,22 @@ pub unsafe fn _mm256_cvtepu8_epi64(a: __m128i) -> __m256i {
     transmute::<i64x4, _>(simd_cast(v32))
 }
 
-/// Extracts 128 bits (of integer data) from `a` selected with `imm8`.
+/// Extracts 128 bits (of integer data) from `a` selected with `IMM1`.
 ///
 /// [Intel's documentation](https://software.intel.com/sites/landingpage/IntrinsicsGuide/#text=_mm256_extracti128_si256)
 #[inline]
 #[target_feature(enable = "avx2")]
 #[cfg_attr(
     all(test, not(target_os = "windows")),
-    assert_instr(vextractf128, imm8 = 1)
+    assert_instr(vextractf128, IMM1 = 1)
 )]
-#[rustc_args_required_const(1)]
+#[rustc_legacy_const_generics(1)]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-pub unsafe fn _mm256_extracti128_si256(a: __m256i, imm8: i32) -> __m128i {
+pub unsafe fn _mm256_extracti128_si256<const IMM1: i32>(a: __m256i) -> __m128i {
+    static_assert_imm1!(IMM1);
     let a = a.as_i64x4();
     let b = _mm256_undefined_si256().as_i64x4();
-    let dst: i64x2 = match imm8 & 0b01 {
-        0 => simd_shuffle2(a, b, [0, 1]),
-        _ => simd_shuffle2(a, b, [2, 3]),
-    };
+    let dst: i64x2 = simd_shuffle2(a, b, [[0, 1], [2, 3]][IMM1 as usize]);
     transmute(dst)
 }
 
@@ -4412,7 +4410,7 @@ mod tests {
     #[simd_test(enable = "avx2")]
     unsafe fn test_mm256_extracti128_si256() {
         let a = _mm256_setr_epi64x(1, 2, 3, 4);
-        let r = _mm256_extracti128_si256(a, 0b01);
+        let r = _mm256_extracti128_si256::<1>(a);
         let e = _mm_setr_epi64x(3, 4);
         assert_eq_m128i(r, e);
     }
diff --git a/library/stdarch/crates/core_arch/src/x86/avx512vaes.rs b/library/stdarch/crates/core_arch/src/x86/avx512vaes.rs
index b9d8433b4bf0..8479d64ee666 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512vaes.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512vaes.rs
@@ -155,18 +155,18 @@ mod tests {
             0x978093862CDE7187,
         );
         let mut a_decomp = [_mm_setzero_si128(); 2];
-        a_decomp[0] = _mm256_extracti128_si256(a, 0);
-        a_decomp[1] = _mm256_extracti128_si256(a, 1);
+        a_decomp[0] = _mm256_extracti128_si256::<0>(a);
+        a_decomp[1] = _mm256_extracti128_si256::<1>(a);
         let mut k_decomp = [_mm_setzero_si128(); 2];
-        k_decomp[0] = _mm256_extracti128_si256(k, 0);
-        k_decomp[1] = _mm256_extracti128_si256(k, 1);
+        k_decomp[0] = _mm256_extracti128_si256::<0>(k);
+        k_decomp[1] = _mm256_extracti128_si256::<1>(k);
         let r = vectorized(a, k);
         let mut e_decomp = [_mm_setzero_si128(); 2];
         for i in 0..2 {
             e_decomp[i] = linear(a_decomp[i], k_decomp[i]);
         }
-        assert_eq_m128i(_mm256_extracti128_si256(r, 0), e_decomp[0]);
-        assert_eq_m128i(_mm256_extracti128_si256(r, 1), e_decomp[1]);
+        assert_eq_m128i(_mm256_extracti128_si256::<0>(r), e_decomp[0]);
+        assert_eq_m128i(_mm256_extracti128_si256::<1>(r), e_decomp[1]);
     }
 
     #[target_feature(enable = "sse2")]
diff --git a/library/stdarch/crates/core_arch/src/x86/avx512vpclmulqdq.rs b/library/stdarch/crates/core_arch/src/x86/avx512vpclmulqdq.rs
index b4e472dc3f51..cd6476482feb 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512vpclmulqdq.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512vpclmulqdq.rs
@@ -125,6 +125,10 @@ mod tests {
             assert_eq_m128i($op($vec_res, 1), $lin_res[1]);
             assert_eq_m128i($op($vec_res, 0), $lin_res[0]);
         };
+        (assert_eq_m128i($op:ident::<2>($vec_res:ident),$lin_res:ident[2]);) => {
+            assert_eq_m128i($op::<1>($vec_res), $lin_res[1]);
+            assert_eq_m128i($op::<0>($vec_res), $lin_res[0]);
+        };
     }
 
     // this function tests one of the possible 4 instances
@@ -209,7 +213,7 @@ mod tests {
         for i in 0..2 {
             e_decomp[i] = linear(a_decomp[i], b_decomp[i]);
         }
-        unroll! {assert_eq_m128i(_mm256_extracti128_si256(r,2),e_decomp[2]);}
+        unroll! {assert_eq_m128i(_mm256_extracti128_si256::<2>(r),e_decomp[2]);}
     }
 
     #[simd_test(enable = "avx512vpclmulqdq,avx512f")]