diff --git a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
index 8c7921fc1801..b41f8576cfe5 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
@@ -6523,10 +6523,11 @@ pub fn _mm_maskz_maddubs_epi16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackssdw))]
-pub fn _mm512_packs_epi32(a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_packs_epi32(a: __m512i, b: __m512i) -> __m512i {
     unsafe {
-        let max = simd_splat(i32::from(i16::MAX));
-        let min = simd_splat(i32::from(i16::MIN));
+        let max = simd_splat(i16::MAX as i32);
+        let min = simd_splat(i16::MIN as i32);
 
         let clamped_a = simd_imax(simd_imin(a.as_i32x16(), max), min)
             .as_m512i()
@@ -6559,7 +6560,13 @@ pub fn _mm512_packs_epi32(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackssdw))]
-pub fn _mm512_mask_packs_epi32(src: __m512i, k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_mask_packs_epi32(
+    src: __m512i,
+    k: __mmask32,
+    a: __m512i,
+    b: __m512i,
+) -> __m512i {
     unsafe {
         let pack = _mm512_packs_epi32(a, b).as_i16x32();
         transmute(simd_select_bitmask(k, pack, src.as_i16x32()))
@@ -6573,7 +6580,8 @@ pub fn _mm512_mask_packs_epi32(src: __m512i, k: __mmask32, a: __m512i, b: __m512
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackssdw))]
-pub fn _mm512_maskz_packs_epi32(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_maskz_packs_epi32(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let pack = _mm512_packs_epi32(a, b).as_i16x32();
         transmute(simd_select_bitmask(k, pack, i16x32::ZERO))
@@ -6651,10 +6659,11 @@ pub const fn _mm_maskz_packs_epi32(k: __mmask8, a: __m128i, b: __m128i) -> __m12
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpacksswb))]
-pub fn _mm512_packs_epi16(a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_packs_epi16(a: __m512i, b: __m512i) -> __m512i {
     unsafe {
-        let max = simd_splat(i16::from(i8::MAX));
-        let min = simd_splat(i16::from(i8::MIN));
+        let max = simd_splat(i8::MAX as i16);
+        let min = simd_splat(i8::MIN as i16);
 
         let clamped_a = simd_imax(simd_imin(a.as_i16x32(), max), min)
             .as_m512i()
@@ -6687,7 +6696,13 @@ pub fn _mm512_packs_epi16(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpacksswb))]
-pub fn _mm512_mask_packs_epi16(src: __m512i, k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_mask_packs_epi16(
+    src: __m512i,
+    k: __mmask64,
+    a: __m512i,
+    b: __m512i,
+) -> __m512i {
     unsafe {
         let pack = _mm512_packs_epi16(a, b).as_i8x64();
         transmute(simd_select_bitmask(k, pack, src.as_i8x64()))
@@ -6701,7 +6716,8 @@ pub fn _mm512_mask_packs_epi16(src: __m512i, k: __mmask64, a: __m512i, b: __m512
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpacksswb))]
-pub fn _mm512_maskz_packs_epi16(k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_maskz_packs_epi16(k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let pack = _mm512_packs_epi16(a, b).as_i8x64();
         transmute(simd_select_bitmask(k, pack, i8x64::ZERO))
@@ -6780,10 +6796,11 @@ pub const fn _mm_maskz_packs_epi16(k: __mmask16, a: __m128i, b: __m128i) -> __m1
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackusdw))]
-pub fn _mm512_packus_epi32(a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_packus_epi32(a: __m512i, b: __m512i) -> __m512i {
     unsafe {
-        let max = simd_splat(i32::from(u16::MAX));
-        let min = simd_splat(i32::from(u16::MIN));
+        let max = simd_splat(u16::MAX as i32);
+        let min = simd_splat(u16::MIN as i32);
 
         let clamped_a = simd_imax(simd_imin(a.as_i32x16(), max), min)
             .as_m512i()
@@ -6816,7 +6833,13 @@ pub fn _mm512_packus_epi32(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackusdw))]
-pub fn _mm512_mask_packus_epi32(src: __m512i, k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_mask_packus_epi32(
+    src: __m512i,
+    k: __mmask32,
+    a: __m512i,
+    b: __m512i,
+) -> __m512i {
     unsafe {
         let pack = _mm512_packus_epi32(a, b).as_i16x32();
         transmute(simd_select_bitmask(k, pack, src.as_i16x32()))
@@ -6830,7 +6853,8 @@ pub fn _mm512_mask_packus_epi32(src: __m512i, k: __mmask32, a: __m512i, b: __m51
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackusdw))]
-pub fn _mm512_maskz_packus_epi32(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_maskz_packus_epi32(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let pack = _mm512_packus_epi32(a, b).as_i16x32();
         transmute(simd_select_bitmask(k, pack, i16x32::ZERO))
@@ -6909,10 +6933,11 @@ pub const fn _mm_maskz_packus_epi32(k: __mmask8, a: __m128i, b: __m128i) -> __m1
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackuswb))]
-pub fn _mm512_packus_epi16(a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_packus_epi16(a: __m512i, b: __m512i) -> __m512i {
     unsafe {
-        let max = simd_splat(i16::from(u8::MAX));
-        let min = simd_splat(i16::from(u8::MIN));
+        let max = simd_splat(u8::MAX as i16);
+        let min = simd_splat(u8::MIN as i16);
 
         let clamped_a = simd_imax(simd_imin(a.as_i16x32(), max), min)
             .as_m512i()
@@ -6945,7 +6970,13 @@ pub fn _mm512_packus_epi16(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackuswb))]
-pub fn _mm512_mask_packus_epi16(src: __m512i, k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_mask_packus_epi16(
+    src: __m512i,
+    k: __mmask64,
+    a: __m512i,
+    b: __m512i,
+) -> __m512i {
     unsafe {
         let pack = _mm512_packus_epi16(a, b).as_i8x64();
         transmute(simd_select_bitmask(k, pack, src.as_i8x64()))
@@ -6959,7 +6990,8 @@ pub fn _mm512_mask_packus_epi16(src: __m512i, k: __mmask64, a: __m512i, b: __m51
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpackuswb))]
-pub fn _mm512_maskz_packus_epi16(k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
+#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
+pub const fn _mm512_maskz_packus_epi16(k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let pack = _mm512_packus_epi16(a, b).as_i8x64();
         transmute(simd_select_bitmask(k, pack, i8x64::ZERO))
@@ -17828,7 +17860,7 @@ fn test_mm_maskz_maddubs_epi16() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_packs_epi32() {
+    const fn test_mm512_packs_epi32() {
         let a = _mm512_set1_epi32(i32::MAX);
         let b = _mm512_set1_epi32(1);
         let r = _mm512_packs_epi32(a, b);
@@ -17839,7 +17871,7 @@ fn test_mm512_packs_epi32() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_mask_packs_epi32() {
+    const fn test_mm512_mask_packs_epi32() {
         let a = _mm512_set1_epi32(i32::MAX);
         let b = _mm512_set1_epi32(1 << 16 | 1);
         let r = _mm512_mask_packs_epi32(a, 0, a, b);
@@ -17852,7 +17884,7 @@ fn test_mm512_mask_packs_epi32() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_maskz_packs_epi32() {
+    const fn test_mm512_maskz_packs_epi32() {
         let a = _mm512_set1_epi32(i32::MAX);
         let b = _mm512_set1_epi32(1);
         let r = _mm512_maskz_packs_epi32(0, a, b);
@@ -17911,7 +17943,7 @@ const fn test_mm_maskz_packs_epi32() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_packs_epi16() {
+    const fn test_mm512_packs_epi16() {
         let a = _mm512_set1_epi16(i16::MAX);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_packs_epi16(a, b);
@@ -17924,7 +17956,7 @@ fn test_mm512_packs_epi16() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_mask_packs_epi16() {
+    const fn test_mm512_mask_packs_epi16() {
         let a = _mm512_set1_epi16(i16::MAX);
         let b = _mm512_set1_epi16(1 << 8 | 1);
         let r = _mm512_mask_packs_epi16(a, 0, a, b);
@@ -17944,7 +17976,7 @@ fn test_mm512_mask_packs_epi16() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_maskz_packs_epi16() {
+    const fn test_mm512_maskz_packs_epi16() {
         let a = _mm512_set1_epi16(i16::MAX);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_maskz_packs_epi16(0, a, b);
@@ -18013,7 +18045,7 @@ const fn test_mm_maskz_packs_epi16() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_packus_epi32() {
+    const fn test_mm512_packus_epi32() {
         let a = _mm512_set1_epi32(-1);
         let b = _mm512_set1_epi32(1);
         let r = _mm512_packus_epi32(a, b);
@@ -18024,7 +18056,7 @@ fn test_mm512_packus_epi32() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_mask_packus_epi32() {
+    const fn test_mm512_mask_packus_epi32() {
         let a = _mm512_set1_epi32(-1);
         let b = _mm512_set1_epi32(1 << 16 | 1);
         let r = _mm512_mask_packus_epi32(a, 0, a, b);
@@ -18037,7 +18069,7 @@ fn test_mm512_mask_packus_epi32() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_maskz_packus_epi32() {
+    const fn test_mm512_maskz_packus_epi32() {
         let a = _mm512_set1_epi32(-1);
         let b = _mm512_set1_epi32(1);
         let r = _mm512_maskz_packus_epi32(0, a, b);
@@ -18094,7 +18126,7 @@ const fn test_mm_maskz_packus_epi32() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_packus_epi16() {
+    const fn test_mm512_packus_epi16() {
         let a = _mm512_set1_epi16(-1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_packus_epi16(a, b);
@@ -18107,7 +18139,7 @@ fn test_mm512_packus_epi16() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_mask_packus_epi16() {
+    const fn test_mm512_mask_packus_epi16() {
         let a = _mm512_set1_epi16(-1);
         let b = _mm512_set1_epi16(1 << 8 | 1);
         let r = _mm512_mask_packus_epi16(a, 0, a, b);
@@ -18127,7 +18159,7 @@ fn test_mm512_mask_packus_epi16() {
     }
 
     #[simd_test(enable = "avx512bw")]
-    fn test_mm512_maskz_packus_epi16() {
+    const fn test_mm512_maskz_packus_epi16() {
         let a = _mm512_set1_epi16(-1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_maskz_packus_epi16(0, a, b);