From ca1104f81fe18c065c3747766b29f0f7e654a1ba Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 5 Sep 2026 17:00:56 +0200
Subject: [PATCH 01/27] Revert "Reimplement _mm_mulhi_epi16, _mm_mulhi_epu16,
 _mm256_mulhi_epi16 and _mm256_mulhi_epu16 without LLVM intrinsics"

This reverts commit 7abc64d599fcc93719f17ee08a03390d81424800.
---
 .../stdarch/crates/core_arch/src/x86/avx2.rs  | 24 +++++++------------
 .../stdarch/crates/core_arch/src/x86/sse2.rs  | 24 +++++++------------
 2 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/x86/avx2.rs b/library/stdarch/crates/core_arch/src/x86/avx2.rs
index eb636a4fa0397..cb9ff94c5d74e 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx2.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx2.rs
@@ -2231,14 +2231,8 @@ pub const fn _mm256_mul_epu32(a: __m256i, b: __m256i) -> __m256i {
 #[target_feature(enable = "avx2")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_mulhi_epi16(a: __m256i, b: __m256i) -> __m256i {
-    unsafe {
-        let a = simd_cast::<_, i32x16>(a.as_i16x16());
-        let b = simd_cast::<_, i32x16>(b.as_i16x16());
-        let r = simd_shr(simd_mul(a, b), i32x16::splat(16));
-        transmute(simd_cast::<i32x16, i16x16>(r))
-    }
+pub fn _mm256_mulhi_epi16(a: __m256i, b: __m256i) -> __m256i {
+    unsafe { transmute(pmulhw(a.as_i16x16(), b.as_i16x16())) }
 }
 
 /// Multiplies the packed unsigned 16-bit integers in `a` and `b`, producing
@@ -2250,14 +2244,8 @@ pub const fn _mm256_mulhi_epi16(a: __m256i, b: __m256i) -> __m256i {
 #[target_feature(enable = "avx2")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_mulhi_epu16(a: __m256i, b: __m256i) -> __m256i {
-    unsafe {
-        let a = simd_cast::<_, u32x16>(a.as_u16x16());
-        let b = simd_cast::<_, u32x16>(b.as_u16x16());
-        let r = simd_shr(simd_mul(a, b), u32x16::splat(16));
-        transmute(simd_cast::<u32x16, u16x16>(r))
-    }
+pub fn _mm256_mulhi_epu16(a: __m256i, b: __m256i) -> __m256i {
+    unsafe { transmute(pmulhuw(a.as_u16x16(), b.as_u16x16())) }
 }
 
 /// Multiplies the packed 16-bit integers in `a` and `b`, producing
@@ -3825,6 +3813,10 @@ unsafe extern "llvm-intrinsic" {
     fn pmaddubsw(a: u8x32, b: i8x32) -> i16x16;
     #[link_name = "llvm.x86.avx2.mpsadbw"]
     fn mpsadbw(a: u8x32, b: u8x32, imm8: i8) -> u16x16;
+    #[link_name = "llvm.x86.avx2.pmulhu.w"]
+    fn pmulhuw(a: u16x16, b: u16x16) -> u16x16;
+    #[link_name = "llvm.x86.avx2.pmulh.w"]
+    fn pmulhw(a: i16x16, b: i16x16) -> i16x16;
     #[link_name = "llvm.x86.avx2.pmul.hr.sw"]
     fn pmulhrsw(a: i16x16, b: i16x16) -> i16x16;
     #[link_name = "llvm.x86.avx2.packsswb"]
diff --git a/library/stdarch/crates/core_arch/src/x86/sse2.rs b/library/stdarch/crates/core_arch/src/x86/sse2.rs
index 2c61b095c6b24..108d7510adf1a 100644
--- a/library/stdarch/crates/core_arch/src/x86/sse2.rs
+++ b/library/stdarch/crates/core_arch/src/x86/sse2.rs
@@ -294,14 +294,8 @@ pub const fn _mm_min_epu8(a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "sse2")]
 #[cfg_attr(test, assert_instr(pmulhw))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_mulhi_epi16(a: __m128i, b: __m128i) -> __m128i {
-    unsafe {
-        let a = simd_cast::<_, i32x8>(a.as_i16x8());
-        let b = simd_cast::<_, i32x8>(b.as_i16x8());
-        let r = simd_shr(simd_mul(a, b), i32x8::splat(16));
-        transmute(simd_cast::<i32x8, i16x8>(r))
-    }
+pub fn _mm_mulhi_epi16(a: __m128i, b: __m128i) -> __m128i {
+    unsafe { transmute(pmulhw(a.as_i16x8(), b.as_i16x8())) }
 }
 
 /// Multiplies the packed unsigned 16-bit integers in `a` and `b`.
@@ -314,14 +308,8 @@ pub const fn _mm_mulhi_epi16(a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "sse2")]
 #[cfg_attr(test, assert_instr(pmulhuw))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_mulhi_epu16(a: __m128i, b: __m128i) -> __m128i {
-    unsafe {
-        let a = simd_cast::<_, u32x8>(a.as_u16x8());
-        let b = simd_cast::<_, u32x8>(b.as_u16x8());
-        let r = simd_shr(simd_mul(a, b), u32x8::splat(16));
-        transmute(simd_cast::<u32x8, u16x8>(r))
-    }
+pub fn _mm_mulhi_epu16(a: __m128i, b: __m128i) -> __m128i {
+    unsafe { transmute(pmulhuw(a.as_u16x8(), b.as_u16x8())) }
 }
 
 /// Multiplies the packed 16-bit integers in `a` and `b`.
@@ -3202,6 +3190,10 @@ unsafe extern "llvm-intrinsic" {
     fn mfence();
     #[link_name = "llvm.x86.sse2.pmadd.wd"]
     fn pmaddwd(a: i16x8, b: i16x8) -> i32x4;
+    #[link_name = "llvm.x86.sse2.pmulh.w"]
+    fn pmulhw(a: i16x8, b: i16x8) -> i16x8;
+    #[link_name = "llvm.x86.sse2.pmulhu.w"]
+    fn pmulhuw(a: u16x8, b: u16x8) -> u16x8;
     #[link_name = "llvm.x86.sse2.psad.bw"]
     fn psadbw(a: u8x16, b: u8x16) -> u64x2;
     #[link_name = "llvm.x86.sse2.psll.w"]

From be4e27142a34e3e44750f7e1cc1badf34ecae6b7 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 5 Sep 2026 17:01:07 +0200
Subject: [PATCH 02/27] de-constify dependent intrinsics and tests

---
 .../stdarch/crates/core_arch/src/x86/avx2.rs  |  4 +-
 .../crates/core_arch/src/x86/avx512bw.rs      | 40 ++++++++-----------
 .../stdarch/crates/core_arch/src/x86/sse2.rs  |  4 +-
 3 files changed, 20 insertions(+), 28 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/x86/avx2.rs b/library/stdarch/crates/core_arch/src/x86/avx2.rs
index cb9ff94c5d74e..ead44f29f6a74 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx2.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx2.rs
@@ -4927,7 +4927,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx2")]
-    const fn test_mm256_mulhi_epi16() {
+    fn test_mm256_mulhi_epi16() {
         let a = _mm256_set1_epi16(6535);
         let b = _mm256_set1_epi16(6535);
         let r = _mm256_mulhi_epi16(a, b);
@@ -4936,7 +4936,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx2")]
-    const fn test_mm256_mulhi_epu16() {
+    fn test_mm256_mulhi_epu16() {
         let a = _mm256_set1_epi16(6535);
         let b = _mm256_set1_epi16(6535);
         let r = _mm256_mulhi_epu16(a, b);
diff --git a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
index cda2fad4ef2de..0000b9ebdceb7 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
@@ -1502,8 +1502,7 @@ pub const fn _mm512_maskz_mulhi_epu16(k: __mmask32, a: __m512i, b: __m512i) -> _
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_mask_mulhi_epu16(
+pub fn _mm256_mask_mulhi_epu16(
     src: __m256i,
     k: __mmask16,
     a: __m256i,
@@ -1522,8 +1521,7 @@ pub const fn _mm256_mask_mulhi_epu16(
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_maskz_mulhi_epu16(k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
+pub fn _mm256_maskz_mulhi_epu16(k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let mul = _mm256_mulhi_epu16(a, b).as_u16x16();
         transmute(simd_select_bitmask(k, mul, u16x16::ZERO))
@@ -1537,8 +1535,7 @@ pub const fn _mm256_maskz_mulhi_epu16(k: __mmask16, a: __m256i, b: __m256i) -> _
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_mask_mulhi_epu16(src: __m128i, k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_mask_mulhi_epu16(src: __m128i, k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let mul = _mm_mulhi_epu16(a, b).as_u16x8();
         transmute(simd_select_bitmask(k, mul, src.as_u16x8()))
@@ -1552,8 +1549,7 @@ pub const fn _mm_mask_mulhi_epu16(src: __m128i, k: __mmask8, a: __m128i, b: __m1
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_maskz_mulhi_epu16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_maskz_mulhi_epu16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let mul = _mm_mulhi_epu16(a, b).as_u16x8();
         transmute(simd_select_bitmask(k, mul, u16x8::ZERO))
@@ -1619,8 +1615,7 @@ pub const fn _mm512_maskz_mulhi_epi16(k: __mmask32, a: __m512i, b: __m512i) -> _
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_mask_mulhi_epi16(
+pub fn _mm256_mask_mulhi_epi16(
     src: __m256i,
     k: __mmask16,
     a: __m256i,
@@ -1639,8 +1634,7 @@ pub const fn _mm256_mask_mulhi_epi16(
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_maskz_mulhi_epi16(k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
+pub fn _mm256_maskz_mulhi_epi16(k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let mul = _mm256_mulhi_epi16(a, b).as_i16x16();
         transmute(simd_select_bitmask(k, mul, i16x16::ZERO))
@@ -1654,8 +1648,7 @@ pub const fn _mm256_maskz_mulhi_epi16(k: __mmask16, a: __m256i, b: __m256i) -> _
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_mask_mulhi_epi16(src: __m128i, k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_mask_mulhi_epi16(src: __m128i, k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let mul = _mm_mulhi_epi16(a, b).as_i16x8();
         transmute(simd_select_bitmask(k, mul, src.as_i16x8()))
@@ -1669,8 +1662,7 @@ pub const fn _mm_mask_mulhi_epi16(src: __m128i, k: __mmask8, a: __m128i, b: __m1
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_maskz_mulhi_epi16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_maskz_mulhi_epi16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let mul = _mm_mulhi_epi16(a, b).as_i16x8();
         transmute(simd_select_bitmask(k, mul, i16x8::ZERO))
@@ -13934,7 +13926,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_mask_mulhi_epu16() {
+    fn test_mm256_mask_mulhi_epu16() {
         let a = _mm256_set1_epi16(1);
         let b = _mm256_set1_epi16(1);
         let r = _mm256_mask_mulhi_epu16(a, 0, a, b);
@@ -13945,7 +13937,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_maskz_mulhi_epu16() {
+    fn test_mm256_maskz_mulhi_epu16() {
         let a = _mm256_set1_epi16(1);
         let b = _mm256_set1_epi16(1);
         let r = _mm256_maskz_mulhi_epu16(0, a, b);
@@ -13956,7 +13948,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_mask_mulhi_epu16() {
+    fn test_mm_mask_mulhi_epu16() {
         let a = _mm_set1_epi16(1);
         let b = _mm_set1_epi16(1);
         let r = _mm_mask_mulhi_epu16(a, 0, a, b);
@@ -13967,7 +13959,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_maskz_mulhi_epu16() {
+    fn test_mm_maskz_mulhi_epu16() {
         let a = _mm_set1_epi16(1);
         let b = _mm_set1_epi16(1);
         let r = _mm_maskz_mulhi_epu16(0, a, b);
@@ -14013,7 +14005,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_mask_mulhi_epi16() {
+    fn test_mm256_mask_mulhi_epi16() {
         let a = _mm256_set1_epi16(1);
         let b = _mm256_set1_epi16(1);
         let r = _mm256_mask_mulhi_epi16(a, 0, a, b);
@@ -14024,7 +14016,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_maskz_mulhi_epi16() {
+    fn test_mm256_maskz_mulhi_epi16() {
         let a = _mm256_set1_epi16(1);
         let b = _mm256_set1_epi16(1);
         let r = _mm256_maskz_mulhi_epi16(0, a, b);
@@ -14035,7 +14027,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_mask_mulhi_epi16() {
+    fn test_mm_mask_mulhi_epi16() {
         let a = _mm_set1_epi16(1);
         let b = _mm_set1_epi16(1);
         let r = _mm_mask_mulhi_epi16(a, 0, a, b);
@@ -14046,7 +14038,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_maskz_mulhi_epi16() {
+    fn test_mm_maskz_mulhi_epi16() {
         let a = _mm_set1_epi16(1);
         let b = _mm_set1_epi16(1);
         let r = _mm_maskz_mulhi_epi16(0, a, b);
diff --git a/library/stdarch/crates/core_arch/src/x86/sse2.rs b/library/stdarch/crates/core_arch/src/x86/sse2.rs
index 108d7510adf1a..4d5b23dc7225b 100644
--- a/library/stdarch/crates/core_arch/src/x86/sse2.rs
+++ b/library/stdarch/crates/core_arch/src/x86/sse2.rs
@@ -3539,14 +3539,14 @@ mod tests {
     }
 
     #[simd_test(enable = "sse2")]
-    const fn test_mm_mulhi_epi16() {
+    fn test_mm_mulhi_epi16() {
         let (a, b) = (_mm_set1_epi16(1000), _mm_set1_epi16(-1001));
         let r = _mm_mulhi_epi16(a, b);
         assert_eq_m128i(r, _mm_set1_epi16(-16));
     }
 
     #[simd_test(enable = "sse2")]
-    const fn test_mm_mulhi_epu16() {
+    fn test_mm_mulhi_epu16() {
         let (a, b) = (_mm_set1_epi16(1000), _mm_set1_epi16(1001));
         let r = _mm_mulhi_epu16(a, b);
         assert_eq_m128i(r, _mm_set1_epi16(15));

From 33d0f2633c9e72a93ae8984a737d3c2613c6fe86 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 5 Sep 2026 17:01:13 +0200
Subject: [PATCH 03/27] fmt

---
 .../stdarch/crates/core_arch/src/x86/avx512bw.rs   | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
index 0000b9ebdceb7..f4406f05958a8 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
@@ -1502,12 +1502,7 @@ pub const fn _mm512_maskz_mulhi_epu16(k: __mmask32, a: __m512i, b: __m512i) -> _
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-pub fn _mm256_mask_mulhi_epu16(
-    src: __m256i,
-    k: __mmask16,
-    a: __m256i,
-    b: __m256i,
-) -> __m256i {
+pub fn _mm256_mask_mulhi_epu16(src: __m256i, k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let mul = _mm256_mulhi_epu16(a, b).as_u16x16();
         transmute(simd_select_bitmask(k, mul, src.as_u16x16()))
@@ -1615,12 +1610,7 @@ pub const fn _mm512_maskz_mulhi_epi16(k: __mmask32, a: __m512i, b: __m512i) -> _
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-pub fn _mm256_mask_mulhi_epi16(
-    src: __m256i,
-    k: __mmask16,
-    a: __m256i,
-    b: __m256i,
-) -> __m256i {
+pub fn _mm256_mask_mulhi_epi16(src: __m256i, k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let mul = _mm256_mulhi_epi16(a, b).as_i16x16();
         transmute(simd_select_bitmask(k, mul, src.as_i16x16()))

From 38dff1e9e17b4577fe427937a7fd97d040fa9897 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 5 Sep 2026 21:29:17 +0200
Subject: [PATCH 04/27] also adjust AVX512 intrinsics

---
 .../crates/core_arch/src/x86/avx512bw.rs      | 59 ++++++-------------
 1 file changed, 19 insertions(+), 40 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
index f4406f05958a8..349b46d562592 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
@@ -1450,14 +1450,8 @@ pub const fn _mm_maskz_subs_epi8(k: __mmask16, a: __m128i, b: __m128i) -> __m128
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_mulhi_epu16(a: __m512i, b: __m512i) -> __m512i {
-    unsafe {
-        let a = simd_cast::<_, u32x32>(a.as_u16x32());
-        let b = simd_cast::<_, u32x32>(b.as_u16x32());
-        let r = simd_shr(simd_mul(a, b), u32x32::splat(16));
-        transmute(simd_cast::<u32x32, u16x32>(r))
-    }
+pub fn _mm512_mulhi_epu16(a: __m512i, b: __m512i) -> __m512i {
+    unsafe { transmute(vpmulhuw(a.as_u16x32(), b.as_u16x32())) }
 }
 
 /// Multiply the packed unsigned 16-bit integers in a and b, producing intermediate 32-bit integers, and store the high 16 bits of the intermediate integers in dst using writemask k (elements are copied from src when the corresponding mask bit is not set).
@@ -1467,13 +1461,7 @@ pub const fn _mm512_mulhi_epu16(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_mask_mulhi_epu16(
-    src: __m512i,
-    k: __mmask32,
-    a: __m512i,
-    b: __m512i,
-) -> __m512i {
+pub fn _mm512_mask_mulhi_epu16(src: __m512i, k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let mul = _mm512_mulhi_epu16(a, b).as_u16x32();
         transmute(simd_select_bitmask(k, mul, src.as_u16x32()))
@@ -1487,8 +1475,7 @@ pub const fn _mm512_mask_mulhi_epu16(
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhuw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_maskz_mulhi_epu16(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+pub fn _mm512_maskz_mulhi_epu16(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let mul = _mm512_mulhi_epu16(a, b).as_u16x32();
         transmute(simd_select_bitmask(k, mul, u16x32::ZERO))
@@ -1558,14 +1545,8 @@ pub fn _mm_maskz_mulhi_epu16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_mulhi_epi16(a: __m512i, b: __m512i) -> __m512i {
-    unsafe {
-        let a = simd_cast::<_, i32x32>(a.as_i16x32());
-        let b = simd_cast::<_, i32x32>(b.as_i16x32());
-        let r = simd_shr(simd_mul(a, b), i32x32::splat(16));
-        transmute(simd_cast::<i32x32, i16x32>(r))
-    }
+pub fn _mm512_mulhi_epi16(a: __m512i, b: __m512i) -> __m512i {
+    unsafe { transmute(vpmulhw(a.as_i16x32(), b.as_i16x32())) }
 }
 
 /// Multiply the packed signed 16-bit integers in a and b, producing intermediate 32-bit integers, and store the high 16 bits of the intermediate integers in dst using writemask k (elements are copied from src when the corresponding mask bit is not set).
@@ -1575,13 +1556,7 @@ pub const fn _mm512_mulhi_epi16(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_mask_mulhi_epi16(
-    src: __m512i,
-    k: __mmask32,
-    a: __m512i,
-    b: __m512i,
-) -> __m512i {
+pub fn _mm512_mask_mulhi_epi16(src: __m512i, k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let mul = _mm512_mulhi_epi16(a, b).as_i16x32();
         transmute(simd_select_bitmask(k, mul, src.as_i16x32()))
@@ -1595,8 +1570,7 @@ pub const fn _mm512_mask_mulhi_epi16(
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpmulhw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_maskz_mulhi_epi16(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+pub fn _mm512_maskz_mulhi_epi16(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let mul = _mm512_mulhi_epi16(a, b).as_i16x32();
         transmute(simd_select_bitmask(k, mul, i16x32::ZERO))
@@ -12583,6 +12557,11 @@ unsafe extern "llvm-intrinsic" {
     #[link_name = "llvm.x86.avx512.pmul.hr.sw.512"]
     fn vpmulhrsw(a: i16x32, b: i16x32) -> i16x32;
 
+    #[link_name = "llvm.x86.avx512.pmulhu.w.512"]
+    fn vpmulhuw(a: u16x32, b: u16x32) -> u16x32;
+    #[link_name = "llvm.x86.avx512.pmulh.w.512"]
+    fn vpmulhw(a: i16x32, b: i16x32) -> i16x32;
+
     #[link_name = "llvm.x86.avx512.pmaddw.d.512"]
     fn vpmaddwd(a: i16x32, b: i16x32) -> i32x16;
     #[link_name = "llvm.x86.avx512.pmaddubs.w.512"]
@@ -13881,7 +13860,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_mulhi_epu16() {
+    fn test_mm512_mulhi_epu16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_mulhi_epu16(a, b);
@@ -13890,7 +13869,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_mask_mulhi_epu16() {
+    fn test_mm512_mask_mulhi_epu16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_mask_mulhi_epu16(a, 0, a, b);
@@ -13903,7 +13882,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_maskz_mulhi_epu16() {
+    fn test_mm512_maskz_mulhi_epu16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_maskz_mulhi_epu16(0, a, b);
@@ -13960,7 +13939,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_mulhi_epi16() {
+    fn test_mm512_mulhi_epi16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_mulhi_epi16(a, b);
@@ -13969,7 +13948,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_mask_mulhi_epi16() {
+    fn test_mm512_mask_mulhi_epi16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_mask_mulhi_epi16(a, 0, a, b);
@@ -13982,7 +13961,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_maskz_mulhi_epi16() {
+    fn test_mm512_maskz_mulhi_epi16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_maskz_mulhi_epi16(0, a, b);

From c76d283d24c7f8812d4440e3c593e5774083f7f3 Mon Sep 17 00:00:00 2001
From: WANG Rui <wangrui@loongson.cn>
Date: Fri, 18 Sep 2026 13:43:45 +0800
Subject: [PATCH 05/27] loongarch: Use LLVM intrinsics for vdiv/vmod

Miri reports UB on division by zero with the LSX vdiv/vmod
intrinsics when implemented via the portable simd_div/simd_rem
helpers. [^1]

Per clarification from the LoongArch ISA developers, the hardware
defines that vdiv/vmod return 0 when the divisor is zero (this
will be documented in the SIMD reference). This differs from the
earlier assumption in PR #2078, so the portable helpers are not
a correct match.

Switch back to the corresponding LLVM intrinsics so the Rust
wrappers preserve the defined ISA behavior.

[^1]: https://github.com/rust-lang/stdarch/pull/2221#issuecomment-5688403926
---
 .../src/loongarch64/lasx/generated.rs         | 144 ++++++++++++++++++
 .../src/loongarch64/lasx/portable.rs          |  16 --
 .../src/loongarch64/lsx/generated.rs          | 144 ++++++++++++++++++
 .../core_arch/src/loongarch64/lsx/portable.rs |  16 --
 .../crates/stdarch-gen-loongarch/lasx.spec    |  16 --
 .../crates/stdarch-gen-loongarch/lsx.spec     |  16 --
 .../src/portable-intrinsics.txt               |  32 ----
 7 files changed, 288 insertions(+), 96 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/loongarch64/lasx/generated.rs b/library/stdarch/crates/core_arch/src/loongarch64/lasx/generated.rs
index cfc4aced34173..70560f8b5a68d 100644
--- a/library/stdarch/crates/core_arch/src/loongarch64/lasx/generated.rs
+++ b/library/stdarch/crates/core_arch/src/loongarch64/lasx/generated.rs
@@ -91,6 +91,22 @@ unsafe extern "llvm-intrinsic" {
     fn __lasx_xvsat_wu(a: __v8u32, b: u32) -> __v8u32;
     #[link_name = "llvm.loongarch.lasx.xvsat.du"]
     fn __lasx_xvsat_du(a: __v4u64, b: u32) -> __v4u64;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.b"]
+    fn __lasx_xvdiv_b(a: __v32i8, b: __v32i8) -> __v32i8;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.h"]
+    fn __lasx_xvdiv_h(a: __v16i16, b: __v16i16) -> __v16i16;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.w"]
+    fn __lasx_xvdiv_w(a: __v8i32, b: __v8i32) -> __v8i32;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.d"]
+    fn __lasx_xvdiv_d(a: __v4i64, b: __v4i64) -> __v4i64;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.bu"]
+    fn __lasx_xvdiv_bu(a: __v32u8, b: __v32u8) -> __v32u8;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.hu"]
+    fn __lasx_xvdiv_hu(a: __v16u16, b: __v16u16) -> __v16u16;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.wu"]
+    fn __lasx_xvdiv_wu(a: __v8u32, b: __v8u32) -> __v8u32;
+    #[link_name = "llvm.loongarch.lasx.xvdiv.du"]
+    fn __lasx_xvdiv_du(a: __v4u64, b: __v4u64) -> __v4u64;
     #[link_name = "llvm.loongarch.lasx.xvhaddw.h.b"]
     fn __lasx_xvhaddw_h_b(a: __v32i8, b: __v32i8) -> __v16i16;
     #[link_name = "llvm.loongarch.lasx.xvhaddw.w.h"]
@@ -115,6 +131,22 @@ unsafe extern "llvm-intrinsic" {
     fn __lasx_xvhsubw_wu_hu(a: __v16u16, b: __v16u16) -> __v8i32;
     #[link_name = "llvm.loongarch.lasx.xvhsubw.du.wu"]
     fn __lasx_xvhsubw_du_wu(a: __v8u32, b: __v8u32) -> __v4i64;
+    #[link_name = "llvm.loongarch.lasx.xvmod.b"]
+    fn __lasx_xvmod_b(a: __v32i8, b: __v32i8) -> __v32i8;
+    #[link_name = "llvm.loongarch.lasx.xvmod.h"]
+    fn __lasx_xvmod_h(a: __v16i16, b: __v16i16) -> __v16i16;
+    #[link_name = "llvm.loongarch.lasx.xvmod.w"]
+    fn __lasx_xvmod_w(a: __v8i32, b: __v8i32) -> __v8i32;
+    #[link_name = "llvm.loongarch.lasx.xvmod.d"]
+    fn __lasx_xvmod_d(a: __v4i64, b: __v4i64) -> __v4i64;
+    #[link_name = "llvm.loongarch.lasx.xvmod.bu"]
+    fn __lasx_xvmod_bu(a: __v32u8, b: __v32u8) -> __v32u8;
+    #[link_name = "llvm.loongarch.lasx.xvmod.hu"]
+    fn __lasx_xvmod_hu(a: __v16u16, b: __v16u16) -> __v16u16;
+    #[link_name = "llvm.loongarch.lasx.xvmod.wu"]
+    fn __lasx_xvmod_wu(a: __v8u32, b: __v8u32) -> __v8u32;
+    #[link_name = "llvm.loongarch.lasx.xvmod.du"]
+    fn __lasx_xvmod_du(a: __v4u64, b: __v4u64) -> __v4u64;
     #[link_name = "llvm.loongarch.lasx.xvshuf.b"]
     fn __lasx_xvshuf_b(a: __v32i8, b: __v32i8, c: __v32i8) -> __v32i8;
     #[link_name = "llvm.loongarch.lasx.xvshuf.h"]
@@ -1251,6 +1283,62 @@ pub fn lasx_xvsat_du<const IMM6: u32>(a: m256i) -> m256i {
     unsafe { transmute(__lasx_xvsat_du(transmute(a), IMM6)) }
 }
 
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_b(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_b(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_h(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_h(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_w(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_w(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_d(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_d(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_bu(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_bu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_hu(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_hu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_wu(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_wu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvdiv_du(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvdiv_du(transmute(a), transmute(b))) }
+}
+
 #[inline]
 #[target_feature(enable = "lasx")]
 #[unstable(feature = "stdarch_loongarch", issue = "117427")]
@@ -1335,6 +1423,62 @@ pub fn lasx_xvhsubw_du_wu(a: m256i, b: m256i) -> m256i {
     unsafe { transmute(__lasx_xvhsubw_du_wu(transmute(a), transmute(b))) }
 }
 
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_b(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_b(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_h(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_h(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_w(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_w(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_d(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_d(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_bu(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_bu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_hu(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_hu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_wu(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_wu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lasx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lasx_xvmod_du(a: m256i, b: m256i) -> m256i {
+    unsafe { transmute(__lasx_xvmod_du(transmute(a), transmute(b))) }
+}
+
 #[inline]
 #[target_feature(enable = "lasx")]
 #[unstable(feature = "stdarch_loongarch", issue = "117427")]
diff --git a/library/stdarch/crates/core_arch/src/loongarch64/lasx/portable.rs b/library/stdarch/crates/core_arch/src/loongarch64/lasx/portable.rs
index d53f21c792626..fe45ed6543dfb 100644
--- a/library/stdarch/crates/core_arch/src/loongarch64/lasx/portable.rs
+++ b/library/stdarch/crates/core_arch/src/loongarch64/lasx/portable.rs
@@ -681,22 +681,6 @@ impl_vvv!("lasx", lasx_xvmul_b, simd_mul, m256i, i8x32);
 impl_vvv!("lasx", lasx_xvmul_h, simd_mul, m256i, i16x16);
 impl_vvv!("lasx", lasx_xvmul_w, simd_mul, m256i, i32x8);
 impl_vvv!("lasx", lasx_xvmul_d, simd_mul, m256i, i64x4);
-impl_vvv!("lasx", lasx_xvdiv_b, simd_div, m256i, i8x32);
-impl_vvv!("lasx", lasx_xvdiv_h, simd_div, m256i, i16x16);
-impl_vvv!("lasx", lasx_xvdiv_w, simd_div, m256i, i32x8);
-impl_vvv!("lasx", lasx_xvdiv_d, simd_div, m256i, i64x4);
-impl_vvv!("lasx", lasx_xvdiv_bu, simd_div, m256i, u8x32);
-impl_vvv!("lasx", lasx_xvdiv_hu, simd_div, m256i, u16x16);
-impl_vvv!("lasx", lasx_xvdiv_wu, simd_div, m256i, u32x8);
-impl_vvv!("lasx", lasx_xvdiv_du, simd_div, m256i, u64x4);
-impl_vvv!("lasx", lasx_xvmod_b, simd_rem, m256i, i8x32);
-impl_vvv!("lasx", lasx_xvmod_h, simd_rem, m256i, i16x16);
-impl_vvv!("lasx", lasx_xvmod_w, simd_rem, m256i, i32x8);
-impl_vvv!("lasx", lasx_xvmod_d, simd_rem, m256i, i64x4);
-impl_vvv!("lasx", lasx_xvmod_bu, simd_rem, m256i, u8x32);
-impl_vvv!("lasx", lasx_xvmod_hu, simd_rem, m256i, u16x16);
-impl_vvv!("lasx", lasx_xvmod_wu, simd_rem, m256i, u32x8);
-impl_vvv!("lasx", lasx_xvmod_du, simd_rem, m256i, u64x4);
 impl_vvv!("lasx", lasx_xvand_v, simd_and, m256i, u8x32);
 impl_vvv!("lasx", lasx_xvandn_v, simd_ext_andn, m256i, u8x32);
 impl_vvv!("lasx", lasx_xvor_v, simd_or, m256i, u8x32);
diff --git a/library/stdarch/crates/core_arch/src/loongarch64/lsx/generated.rs b/library/stdarch/crates/core_arch/src/loongarch64/lsx/generated.rs
index aa4e31ce8da6c..601b40467c6b2 100644
--- a/library/stdarch/crates/core_arch/src/loongarch64/lsx/generated.rs
+++ b/library/stdarch/crates/core_arch/src/loongarch64/lsx/generated.rs
@@ -91,6 +91,22 @@ unsafe extern "llvm-intrinsic" {
     fn __lsx_vsat_wu(a: __v4u32, b: u32) -> __v4u32;
     #[link_name = "llvm.loongarch.lsx.vsat.du"]
     fn __lsx_vsat_du(a: __v2u64, b: u32) -> __v2u64;
+    #[link_name = "llvm.loongarch.lsx.vdiv.b"]
+    fn __lsx_vdiv_b(a: __v16i8, b: __v16i8) -> __v16i8;
+    #[link_name = "llvm.loongarch.lsx.vdiv.h"]
+    fn __lsx_vdiv_h(a: __v8i16, b: __v8i16) -> __v8i16;
+    #[link_name = "llvm.loongarch.lsx.vdiv.w"]
+    fn __lsx_vdiv_w(a: __v4i32, b: __v4i32) -> __v4i32;
+    #[link_name = "llvm.loongarch.lsx.vdiv.d"]
+    fn __lsx_vdiv_d(a: __v2i64, b: __v2i64) -> __v2i64;
+    #[link_name = "llvm.loongarch.lsx.vdiv.bu"]
+    fn __lsx_vdiv_bu(a: __v16u8, b: __v16u8) -> __v16u8;
+    #[link_name = "llvm.loongarch.lsx.vdiv.hu"]
+    fn __lsx_vdiv_hu(a: __v8u16, b: __v8u16) -> __v8u16;
+    #[link_name = "llvm.loongarch.lsx.vdiv.wu"]
+    fn __lsx_vdiv_wu(a: __v4u32, b: __v4u32) -> __v4u32;
+    #[link_name = "llvm.loongarch.lsx.vdiv.du"]
+    fn __lsx_vdiv_du(a: __v2u64, b: __v2u64) -> __v2u64;
     #[link_name = "llvm.loongarch.lsx.vhaddw.h.b"]
     fn __lsx_vhaddw_h_b(a: __v16i8, b: __v16i8) -> __v8i16;
     #[link_name = "llvm.loongarch.lsx.vhaddw.w.h"]
@@ -115,6 +131,22 @@ unsafe extern "llvm-intrinsic" {
     fn __lsx_vhsubw_wu_hu(a: __v8u16, b: __v8u16) -> __v4i32;
     #[link_name = "llvm.loongarch.lsx.vhsubw.du.wu"]
     fn __lsx_vhsubw_du_wu(a: __v4u32, b: __v4u32) -> __v2i64;
+    #[link_name = "llvm.loongarch.lsx.vmod.b"]
+    fn __lsx_vmod_b(a: __v16i8, b: __v16i8) -> __v16i8;
+    #[link_name = "llvm.loongarch.lsx.vmod.h"]
+    fn __lsx_vmod_h(a: __v8i16, b: __v8i16) -> __v8i16;
+    #[link_name = "llvm.loongarch.lsx.vmod.w"]
+    fn __lsx_vmod_w(a: __v4i32, b: __v4i32) -> __v4i32;
+    #[link_name = "llvm.loongarch.lsx.vmod.d"]
+    fn __lsx_vmod_d(a: __v2i64, b: __v2i64) -> __v2i64;
+    #[link_name = "llvm.loongarch.lsx.vmod.bu"]
+    fn __lsx_vmod_bu(a: __v16u8, b: __v16u8) -> __v16u8;
+    #[link_name = "llvm.loongarch.lsx.vmod.hu"]
+    fn __lsx_vmod_hu(a: __v8u16, b: __v8u16) -> __v8u16;
+    #[link_name = "llvm.loongarch.lsx.vmod.wu"]
+    fn __lsx_vmod_wu(a: __v4u32, b: __v4u32) -> __v4u32;
+    #[link_name = "llvm.loongarch.lsx.vmod.du"]
+    fn __lsx_vmod_du(a: __v2u64, b: __v2u64) -> __v2u64;
     #[link_name = "llvm.loongarch.lsx.vreplve.b"]
     fn __lsx_vreplve_b(a: __v16i8, b: i32) -> __v16i8;
     #[link_name = "llvm.loongarch.lsx.vreplve.h"]
@@ -1171,6 +1203,62 @@ pub fn lsx_vsat_du<const IMM6: u32>(a: m128i) -> m128i {
     unsafe { transmute(__lsx_vsat_du(transmute(a), IMM6)) }
 }
 
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_b(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_b(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_h(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_h(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_w(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_w(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_d(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_d(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_bu(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_bu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_hu(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_hu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_wu(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_wu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vdiv_du(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vdiv_du(transmute(a), transmute(b))) }
+}
+
 #[inline]
 #[target_feature(enable = "lsx")]
 #[unstable(feature = "stdarch_loongarch", issue = "117427")]
@@ -1255,6 +1343,62 @@ pub fn lsx_vhsubw_du_wu(a: m128i, b: m128i) -> m128i {
     unsafe { transmute(__lsx_vhsubw_du_wu(transmute(a), transmute(b))) }
 }
 
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_b(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_b(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_h(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_h(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_w(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_w(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_d(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_d(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_bu(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_bu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_hu(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_hu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_wu(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_wu(transmute(a), transmute(b))) }
+}
+
+#[inline]
+#[target_feature(enable = "lsx")]
+#[unstable(feature = "stdarch_loongarch", issue = "117427")]
+pub fn lsx_vmod_du(a: m128i, b: m128i) -> m128i {
+    unsafe { transmute(__lsx_vmod_du(transmute(a), transmute(b))) }
+}
+
 #[inline]
 #[target_feature(enable = "lsx")]
 #[unstable(feature = "stdarch_loongarch", issue = "117427")]
diff --git a/library/stdarch/crates/core_arch/src/loongarch64/lsx/portable.rs b/library/stdarch/crates/core_arch/src/loongarch64/lsx/portable.rs
index 2b5bfe1ab4d2b..f2b86dae00af8 100644
--- a/library/stdarch/crates/core_arch/src/loongarch64/lsx/portable.rs
+++ b/library/stdarch/crates/core_arch/src/loongarch64/lsx/portable.rs
@@ -351,22 +351,6 @@ impl_vvv!("lsx", lsx_vmul_b, simd_mul, m128i, i8x16);
 impl_vvv!("lsx", lsx_vmul_h, simd_mul, m128i, i16x8);
 impl_vvv!("lsx", lsx_vmul_w, simd_mul, m128i, i32x4);
 impl_vvv!("lsx", lsx_vmul_d, simd_mul, m128i, i64x2);
-impl_vvv!("lsx", lsx_vdiv_b, simd_div, m128i, i8x16);
-impl_vvv!("lsx", lsx_vdiv_h, simd_div, m128i, i16x8);
-impl_vvv!("lsx", lsx_vdiv_w, simd_div, m128i, i32x4);
-impl_vvv!("lsx", lsx_vdiv_d, simd_div, m128i, i64x2);
-impl_vvv!("lsx", lsx_vdiv_bu, simd_div, m128i, u8x16);
-impl_vvv!("lsx", lsx_vdiv_hu, simd_div, m128i, u16x8);
-impl_vvv!("lsx", lsx_vdiv_wu, simd_div, m128i, u32x4);
-impl_vvv!("lsx", lsx_vdiv_du, simd_div, m128i, u64x2);
-impl_vvv!("lsx", lsx_vmod_b, simd_rem, m128i, i8x16);
-impl_vvv!("lsx", lsx_vmod_h, simd_rem, m128i, i16x8);
-impl_vvv!("lsx", lsx_vmod_w, simd_rem, m128i, i32x4);
-impl_vvv!("lsx", lsx_vmod_d, simd_rem, m128i, i64x2);
-impl_vvv!("lsx", lsx_vmod_bu, simd_rem, m128i, u8x16);
-impl_vvv!("lsx", lsx_vmod_hu, simd_rem, m128i, u16x8);
-impl_vvv!("lsx", lsx_vmod_wu, simd_rem, m128i, u32x4);
-impl_vvv!("lsx", lsx_vmod_du, simd_rem, m128i, u64x2);
 impl_vvv!("lsx", lsx_vand_v, simd_and, m128i, u8x16);
 impl_vvv!("lsx", lsx_vandn_v, simd_ext_andn, m128i, u8x16);
 impl_vvv!("lsx", lsx_vor_v, simd_or, m128i, u8x16);
diff --git a/library/stdarch/crates/stdarch-gen-loongarch/lasx.spec b/library/stdarch/crates/stdarch-gen-loongarch/lasx.spec
index eb3ff074a3978..63895945948f8 100644
--- a/library/stdarch/crates/stdarch-gen-loongarch/lasx.spec
+++ b/library/stdarch/crates/stdarch-gen-loongarch/lasx.spec
@@ -1260,49 +1260,41 @@ asm-fmts = xd, xj, xk
 data-types = V4DI, V4DI, V4DI, V4DI
 
 /// lasx_xvdiv_b
-impl = portable
 name = lasx_xvdiv_b
 asm-fmts = xd, xj, xk
 data-types = V32QI, V32QI, V32QI
 
 /// lasx_xvdiv_h
-impl = portable
 name = lasx_xvdiv_h
 asm-fmts = xd, xj, xk
 data-types = V16HI, V16HI, V16HI
 
 /// lasx_xvdiv_w
-impl = portable
 name = lasx_xvdiv_w
 asm-fmts = xd, xj, xk
 data-types = V8SI, V8SI, V8SI
 
 /// lasx_xvdiv_d
-impl = portable
 name = lasx_xvdiv_d
 asm-fmts = xd, xj, xk
 data-types = V4DI, V4DI, V4DI
 
 /// lasx_xvdiv_bu
-impl = portable
 name = lasx_xvdiv_bu
 asm-fmts = xd, xj, xk
 data-types = UV32QI, UV32QI, UV32QI
 
 /// lasx_xvdiv_hu
-impl = portable
 name = lasx_xvdiv_hu
 asm-fmts = xd, xj, xk
 data-types = UV16HI, UV16HI, UV16HI
 
 /// lasx_xvdiv_wu
-impl = portable
 name = lasx_xvdiv_wu
 asm-fmts = xd, xj, xk
 data-types = UV8SI, UV8SI, UV8SI
 
 /// lasx_xvdiv_du
-impl = portable
 name = lasx_xvdiv_du
 asm-fmts = xd, xj, xk
 data-types = UV4DI, UV4DI, UV4DI
@@ -1368,49 +1360,41 @@ asm-fmts = xd, xj, xk
 data-types = V4DI, UV8SI, UV8SI
 
 /// lasx_xvmod_b
-impl = portable
 name = lasx_xvmod_b
 asm-fmts = xd, xj, xk
 data-types = V32QI, V32QI, V32QI
 
 /// lasx_xvmod_h
-impl = portable
 name = lasx_xvmod_h
 asm-fmts = xd, xj, xk
 data-types = V16HI, V16HI, V16HI
 
 /// lasx_xvmod_w
-impl = portable
 name = lasx_xvmod_w
 asm-fmts = xd, xj, xk
 data-types = V8SI, V8SI, V8SI
 
 /// lasx_xvmod_d
-impl = portable
 name = lasx_xvmod_d
 asm-fmts = xd, xj, xk
 data-types = V4DI, V4DI, V4DI
 
 /// lasx_xvmod_bu
-impl = portable
 name = lasx_xvmod_bu
 asm-fmts = xd, xj, xk
 data-types = UV32QI, UV32QI, UV32QI
 
 /// lasx_xvmod_hu
-impl = portable
 name = lasx_xvmod_hu
 asm-fmts = xd, xj, xk
 data-types = UV16HI, UV16HI, UV16HI
 
 /// lasx_xvmod_wu
-impl = portable
 name = lasx_xvmod_wu
 asm-fmts = xd, xj, xk
 data-types = UV8SI, UV8SI, UV8SI
 
 /// lasx_xvmod_du
-impl = portable
 name = lasx_xvmod_du
 asm-fmts = xd, xj, xk
 data-types = UV4DI, UV4DI, UV4DI
diff --git a/library/stdarch/crates/stdarch-gen-loongarch/lsx.spec b/library/stdarch/crates/stdarch-gen-loongarch/lsx.spec
index 89970c3657048..e1fb72c7901c9 100644
--- a/library/stdarch/crates/stdarch-gen-loongarch/lsx.spec
+++ b/library/stdarch/crates/stdarch-gen-loongarch/lsx.spec
@@ -1260,49 +1260,41 @@ asm-fmts = vd, vj, vk
 data-types = V2DI, V2DI, V2DI, V2DI
 
 /// lsx_vdiv_b
-impl = portable
 name = lsx_vdiv_b
 asm-fmts = vd, vj, vk
 data-types = V16QI, V16QI, V16QI
 
 /// lsx_vdiv_h
-impl = portable
 name = lsx_vdiv_h
 asm-fmts = vd, vj, vk
 data-types = V8HI, V8HI, V8HI
 
 /// lsx_vdiv_w
-impl = portable
 name = lsx_vdiv_w
 asm-fmts = vd, vj, vk
 data-types = V4SI, V4SI, V4SI
 
 /// lsx_vdiv_d
-impl = portable
 name = lsx_vdiv_d
 asm-fmts = vd, vj, vk
 data-types = V2DI, V2DI, V2DI
 
 /// lsx_vdiv_bu
-impl = portable
 name = lsx_vdiv_bu
 asm-fmts = vd, vj, vk
 data-types = UV16QI, UV16QI, UV16QI
 
 /// lsx_vdiv_hu
-impl = portable
 name = lsx_vdiv_hu
 asm-fmts = vd, vj, vk
 data-types = UV8HI, UV8HI, UV8HI
 
 /// lsx_vdiv_wu
-impl = portable
 name = lsx_vdiv_wu
 asm-fmts = vd, vj, vk
 data-types = UV4SI, UV4SI, UV4SI
 
 /// lsx_vdiv_du
-impl = portable
 name = lsx_vdiv_du
 asm-fmts = vd, vj, vk
 data-types = UV2DI, UV2DI, UV2DI
@@ -1368,49 +1360,41 @@ asm-fmts = vd, vj, vk
 data-types = V2DI, UV4SI, UV4SI
 
 /// lsx_vmod_b
-impl = portable
 name = lsx_vmod_b
 asm-fmts = vd, vj, vk
 data-types = V16QI, V16QI, V16QI
 
 /// lsx_vmod_h
-impl = portable
 name = lsx_vmod_h
 asm-fmts = vd, vj, vk
 data-types = V8HI, V8HI, V8HI
 
 /// lsx_vmod_w
-impl = portable
 name = lsx_vmod_w
 asm-fmts = vd, vj, vk
 data-types = V4SI, V4SI, V4SI
 
 /// lsx_vmod_d
-impl = portable
 name = lsx_vmod_d
 asm-fmts = vd, vj, vk
 data-types = V2DI, V2DI, V2DI
 
 /// lsx_vmod_bu
-impl = portable
 name = lsx_vmod_bu
 asm-fmts = vd, vj, vk
 data-types = UV16QI, UV16QI, UV16QI
 
 /// lsx_vmod_hu
-impl = portable
 name = lsx_vmod_hu
 asm-fmts = vd, vj, vk
 data-types = UV8HI, UV8HI, UV8HI
 
 /// lsx_vmod_wu
-impl = portable
 name = lsx_vmod_wu
 asm-fmts = vd, vj, vk
 data-types = UV4SI, UV4SI, UV4SI
 
 /// lsx_vmod_du
-impl = portable
 name = lsx_vmod_du
 asm-fmts = vd, vj, vk
 data-types = UV2DI, UV2DI, UV2DI
diff --git a/library/stdarch/crates/stdarch-gen-loongarch/src/portable-intrinsics.txt b/library/stdarch/crates/stdarch-gen-loongarch/src/portable-intrinsics.txt
index f47c17b23adea..4005385b75198 100644
--- a/library/stdarch/crates/stdarch-gen-loongarch/src/portable-intrinsics.txt
+++ b/library/stdarch/crates/stdarch-gen-loongarch/src/portable-intrinsics.txt
@@ -111,22 +111,6 @@ lsx_vmul_b
 lsx_vmul_h
 lsx_vmul_w
 lsx_vmul_d
-lsx_vdiv_b
-lsx_vdiv_h
-lsx_vdiv_w
-lsx_vdiv_d
-lsx_vdiv_bu
-lsx_vdiv_hu
-lsx_vdiv_wu
-lsx_vdiv_du
-lsx_vmod_b
-lsx_vmod_h
-lsx_vmod_w
-lsx_vmod_d
-lsx_vmod_bu
-lsx_vmod_hu
-lsx_vmod_wu
-lsx_vmod_du
 lsx_vmadd_b
 lsx_vmadd_h
 lsx_vmadd_w
@@ -426,22 +410,6 @@ lasx_xvmul_b
 lasx_xvmul_h
 lasx_xvmul_w
 lasx_xvmul_d
-lasx_xvdiv_b
-lasx_xvdiv_h
-lasx_xvdiv_w
-lasx_xvdiv_d
-lasx_xvdiv_bu
-lasx_xvdiv_hu
-lasx_xvdiv_wu
-lasx_xvdiv_du
-lasx_xvmod_b
-lasx_xvmod_h
-lasx_xvmod_w
-lasx_xvmod_d
-lasx_xvmod_bu
-lasx_xvmod_hu
-lasx_xvmod_wu
-lasx_xvmod_du
 lasx_xvmadd_b
 lasx_xvmadd_h
 lasx_xvmadd_w

From 84ed32a32588de2398d21737ee9e4544c82c0698 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Tue, 29 Sep 2026 08:27:32 +0200
Subject: [PATCH 06/27] Revert "Reimplement _mm_avg_epu8, _mm_avg_epu16,
 _mm256_avg_epu8 and _mm256_avg_epu16 without LLVM intrinsics"

This reverts commit 87e6703ba1a2c44d27f9e4f55dfcf145bca2834a.
---
 .../stdarch/crates/core_arch/src/x86/avx2.rs  | 28 +++++--------
 .../crates/core_arch/src/x86/avx512bw.rs      | 40 ++++++++-----------
 .../stdarch/crates/core_arch/src/x86/sse2.rs  | 28 +++++--------
 3 files changed, 36 insertions(+), 60 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/x86/avx2.rs b/library/stdarch/crates/core_arch/src/x86/avx2.rs
index 56dacd1f0970c..168871188868b 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx2.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx2.rs
@@ -290,14 +290,8 @@ pub const fn _mm256_andnot_si256(a: __m256i, b: __m256i) -> __m256i {
 #[target_feature(enable = "avx2")]
 #[cfg_attr(test, assert_instr(vpavgw))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_avg_epu16(a: __m256i, b: __m256i) -> __m256i {
-    unsafe {
-        let a = simd_cast::<_, u32x16>(a.as_u16x16());
-        let b = simd_cast::<_, u32x16>(b.as_u16x16());
-        let r = simd_shr(simd_add(simd_add(a, b), u32x16::splat(1)), u32x16::splat(1));
-        transmute(simd_cast::<_, u16x16>(r))
-    }
+pub fn _mm256_avg_epu16(a: __m256i, b: __m256i) -> __m256i {
+    unsafe { transmute(pavgw(a.as_u16x16(), b.as_u16x16())) }
 }
 
 /// Averages packed unsigned 8-bit integers in `a` and `b`.
@@ -307,14 +301,8 @@ pub const fn _mm256_avg_epu16(a: __m256i, b: __m256i) -> __m256i {
 #[target_feature(enable = "avx2")]
 #[cfg_attr(test, assert_instr(vpavgb))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_avg_epu8(a: __m256i, b: __m256i) -> __m256i {
-    unsafe {
-        let a = simd_cast::<_, u16x32>(a.as_u8x32());
-        let b = simd_cast::<_, u16x32>(b.as_u8x32());
-        let r = simd_shr(simd_add(simd_add(a, b), u16x32::splat(1)), u16x32::splat(1));
-        transmute(simd_cast::<_, u8x32>(r))
-    }
+pub fn _mm256_avg_epu8(a: __m256i, b: __m256i) -> __m256i {
+    unsafe { transmute(pavgb(a.as_u8x32(), b.as_u8x32())) }
 }
 
 /// Blends packed 32-bit integers from `a` and `b` using control mask `IMM4`.
@@ -3747,6 +3735,10 @@ pub const fn _mm256_extract_epi16<const INDEX: i32>(a: __m256i) -> i32 {
 
 #[allow(improper_ctypes)]
 unsafe extern "llvm-intrinsic" {
+    #[link_name = "llvm.x86.avx2.pavg.b"]
+    fn pavgb(a: u8x32, b: u8x32) -> u8x32;
+    #[link_name = "llvm.x86.avx2.pavg.w"]
+    fn pavgw(a: u16x16, b: u16x16) -> u16x16;
     #[link_name = "llvm.x86.avx2.pmadd.wd"]
     fn pmaddwd(a: i16x16, b: i16x16) -> i32x8;
     #[link_name = "llvm.x86.avx2.pmadd.ub.sw"]
@@ -4178,14 +4170,14 @@ mod tests {
     }
 
     #[simd_test(enable = "avx2")]
-    const fn test_mm256_avg_epu8() {
+    fn test_mm256_avg_epu8() {
         let (a, b) = (_mm256_set1_epi8(3), _mm256_set1_epi8(9));
         let r = _mm256_avg_epu8(a, b);
         assert_eq_m256i(r, _mm256_set1_epi8(6));
     }
 
     #[simd_test(enable = "avx2")]
-    const fn test_mm256_avg_epu16() {
+    fn test_mm256_avg_epu16() {
         let (a, b) = (_mm256_set1_epi16(3), _mm256_set1_epi16(9));
         let r = _mm256_avg_epu16(a, b);
         assert_eq_m256i(r, _mm256_set1_epi16(6));
diff --git a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
index 46aeaaadbfe33..1d91ccfc0785d 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
@@ -6906,8 +6906,7 @@ pub const fn _mm512_maskz_avg_epu16(k: __mmask32, a: __m512i, b: __m512i) -> __m
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_mask_avg_epu16(src: __m256i, k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
+pub fn _mm256_mask_avg_epu16(src: __m256i, k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let avg = _mm256_avg_epu16(a, b).as_u16x16();
         transmute(simd_select_bitmask(k, avg, src.as_u16x16()))
@@ -6921,8 +6920,7 @@ pub const fn _mm256_mask_avg_epu16(src: __m256i, k: __mmask16, a: __m256i, b: __
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_maskz_avg_epu16(k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
+pub fn _mm256_maskz_avg_epu16(k: __mmask16, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let avg = _mm256_avg_epu16(a, b).as_u16x16();
         transmute(simd_select_bitmask(k, avg, u16x16::ZERO))
@@ -6936,8 +6934,7 @@ pub const fn _mm256_maskz_avg_epu16(k: __mmask16, a: __m256i, b: __m256i) -> __m
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_mask_avg_epu16(src: __m128i, k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_mask_avg_epu16(src: __m128i, k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let avg = _mm_avg_epu16(a, b).as_u16x8();
         transmute(simd_select_bitmask(k, avg, src.as_u16x8()))
@@ -6951,8 +6948,7 @@ pub const fn _mm_mask_avg_epu16(src: __m128i, k: __mmask8, a: __m128i, b: __m128
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_maskz_avg_epu16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_maskz_avg_epu16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let avg = _mm_avg_epu16(a, b).as_u16x8();
         transmute(simd_select_bitmask(k, avg, u16x8::ZERO))
@@ -7013,8 +7009,7 @@ pub const fn _mm512_maskz_avg_epu8(k: __mmask64, a: __m512i, b: __m512i) -> __m5
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgb))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_mask_avg_epu8(src: __m256i, k: __mmask32, a: __m256i, b: __m256i) -> __m256i {
+pub fn _mm256_mask_avg_epu8(src: __m256i, k: __mmask32, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let avg = _mm256_avg_epu8(a, b).as_u8x32();
         transmute(simd_select_bitmask(k, avg, src.as_u8x32()))
@@ -7028,8 +7023,7 @@ pub const fn _mm256_mask_avg_epu8(src: __m256i, k: __mmask32, a: __m256i, b: __m
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgb))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm256_maskz_avg_epu8(k: __mmask32, a: __m256i, b: __m256i) -> __m256i {
+pub fn _mm256_maskz_avg_epu8(k: __mmask32, a: __m256i, b: __m256i) -> __m256i {
     unsafe {
         let avg = _mm256_avg_epu8(a, b).as_u8x32();
         transmute(simd_select_bitmask(k, avg, u8x32::ZERO))
@@ -7043,8 +7037,7 @@ pub const fn _mm256_maskz_avg_epu8(k: __mmask32, a: __m256i, b: __m256i) -> __m2
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgb))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_mask_avg_epu8(src: __m128i, k: __mmask16, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_mask_avg_epu8(src: __m128i, k: __mmask16, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let avg = _mm_avg_epu8(a, b).as_u8x16();
         transmute(simd_select_bitmask(k, avg, src.as_u8x16()))
@@ -7058,8 +7051,7 @@ pub const fn _mm_mask_avg_epu8(src: __m128i, k: __mmask16, a: __m128i, b: __m128
 #[target_feature(enable = "avx512bw,avx512vl")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgb))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_maskz_avg_epu8(k: __mmask16, a: __m128i, b: __m128i) -> __m128i {
+pub fn _mm_maskz_avg_epu8(k: __mmask16, a: __m128i, b: __m128i) -> __m128i {
     unsafe {
         let avg = _mm_avg_epu8(a, b).as_u8x16();
         transmute(simd_select_bitmask(k, avg, u8x16::ZERO))
@@ -17983,7 +17975,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_mask_avg_epu16() {
+    fn test_mm256_mask_avg_epu16() {
         let a = _mm256_set1_epi16(1);
         let b = _mm256_set1_epi16(1);
         let r = _mm256_mask_avg_epu16(a, 0, a, b);
@@ -17994,7 +17986,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_maskz_avg_epu16() {
+    fn test_mm256_maskz_avg_epu16() {
         let a = _mm256_set1_epi16(1);
         let b = _mm256_set1_epi16(1);
         let r = _mm256_maskz_avg_epu16(0, a, b);
@@ -18005,7 +17997,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_mask_avg_epu16() {
+    fn test_mm_mask_avg_epu16() {
         let a = _mm_set1_epi16(1);
         let b = _mm_set1_epi16(1);
         let r = _mm_mask_avg_epu16(a, 0, a, b);
@@ -18016,7 +18008,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_maskz_avg_epu16() {
+    fn test_mm_maskz_avg_epu16() {
         let a = _mm_set1_epi16(1);
         let b = _mm_set1_epi16(1);
         let r = _mm_maskz_avg_epu16(0, a, b);
@@ -18075,7 +18067,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_mask_avg_epu8() {
+    fn test_mm256_mask_avg_epu8() {
         let a = _mm256_set1_epi8(1);
         let b = _mm256_set1_epi8(1);
         let r = _mm256_mask_avg_epu8(a, 0, a, b);
@@ -18088,7 +18080,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm256_maskz_avg_epu8() {
+    fn test_mm256_maskz_avg_epu8() {
         let a = _mm256_set1_epi8(1);
         let b = _mm256_set1_epi8(1);
         let r = _mm256_maskz_avg_epu8(0, a, b);
@@ -18101,7 +18093,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_mask_avg_epu8() {
+    fn test_mm_mask_avg_epu8() {
         let a = _mm_set1_epi8(1);
         let b = _mm_set1_epi8(1);
         let r = _mm_mask_avg_epu8(a, 0, a, b);
@@ -18112,7 +18104,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw,avx512vl")]
-    const fn test_mm_maskz_avg_epu8() {
+    fn test_mm_maskz_avg_epu8() {
         let a = _mm_set1_epi8(1);
         let b = _mm_set1_epi8(1);
         let r = _mm_maskz_avg_epu8(0, a, b);
diff --git a/library/stdarch/crates/core_arch/src/x86/sse2.rs b/library/stdarch/crates/core_arch/src/x86/sse2.rs
index 4d5b23dc7225b..b52fce6765a00 100644
--- a/library/stdarch/crates/core_arch/src/x86/sse2.rs
+++ b/library/stdarch/crates/core_arch/src/x86/sse2.rs
@@ -178,14 +178,8 @@ pub const fn _mm_adds_epu16(a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "sse2")]
 #[cfg_attr(test, assert_instr(pavgb))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_avg_epu8(a: __m128i, b: __m128i) -> __m128i {
-    unsafe {
-        let a = simd_cast::<_, u16x16>(a.as_u8x16());
-        let b = simd_cast::<_, u16x16>(b.as_u8x16());
-        let r = simd_shr(simd_add(simd_add(a, b), u16x16::splat(1)), u16x16::splat(1));
-        transmute(simd_cast::<_, u8x16>(r))
-    }
+pub fn _mm_avg_epu8(a: __m128i, b: __m128i) -> __m128i {
+    unsafe { transmute(pavgb(a.as_u8x16(), b.as_u8x16())) }
 }
 
 /// Averages packed unsigned 16-bit integers in `a` and `b`.
@@ -195,14 +189,8 @@ pub const fn _mm_avg_epu8(a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "sse2")]
 #[cfg_attr(test, assert_instr(pavgw))]
 #[stable(feature = "simd_x86", since = "1.27.0")]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm_avg_epu16(a: __m128i, b: __m128i) -> __m128i {
-    unsafe {
-        let a = simd_cast::<_, u32x8>(a.as_u16x8());
-        let b = simd_cast::<_, u32x8>(b.as_u16x8());
-        let r = simd_shr(simd_add(simd_add(a, b), u32x8::splat(1)), u32x8::splat(1));
-        transmute(simd_cast::<_, u16x8>(r))
-    }
+pub fn _mm_avg_epu16(a: __m128i, b: __m128i) -> __m128i {
+    unsafe { transmute(pavgw(a.as_u16x8(), b.as_u16x8())) }
 }
 
 /// Multiplies and then horizontally add signed 16 bit integers in `a` and `b`.
@@ -3188,6 +3176,10 @@ unsafe extern "llvm-intrinsic" {
     fn lfence();
     #[link_name = "llvm.x86.sse2.mfence"]
     fn mfence();
+    #[link_name = "llvm.x86.sse2.pavg.b"]
+    fn pavgb(a: u8x16, b: u8x16) -> u8x16;
+    #[link_name = "llvm.x86.sse2.pavg.w"]
+    fn pavgw(a: u16x8, b: u16x8) -> u16x8;
     #[link_name = "llvm.x86.sse2.pmadd.wd"]
     fn pmaddwd(a: i16x8, b: i16x8) -> i32x4;
     #[link_name = "llvm.x86.sse2.pmulh.w"]
@@ -3458,14 +3450,14 @@ mod tests {
     }
 
     #[simd_test(enable = "sse2")]
-    const fn test_mm_avg_epu8() {
+    fn test_mm_avg_epu8() {
         let (a, b) = (_mm_set1_epi8(3), _mm_set1_epi8(9));
         let r = _mm_avg_epu8(a, b);
         assert_eq_m128i(r, _mm_set1_epi8(6));
     }
 
     #[simd_test(enable = "sse2")]
-    const fn test_mm_avg_epu16() {
+    fn test_mm_avg_epu16() {
         let (a, b) = (_mm_set1_epi16(3), _mm_set1_epi16(9));
         let r = _mm_avg_epu16(a, b);
         assert_eq_m128i(r, _mm_set1_epi16(6));

From 9bdda899160e34ccb7ac8a21845c11489b8bee4c Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Tue, 29 Sep 2026 08:39:26 +0200
Subject: [PATCH 07/27] also adjust AVX512 intrinsics

---
 .../crates/core_arch/src/x86/avx512bw.rs      | 49 +++++++------------
 1 file changed, 19 insertions(+), 30 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
index 1d91ccfc0785d..bc119870fa99a 100644
--- a/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
+++ b/library/stdarch/crates/core_arch/src/x86/avx512bw.rs
@@ -6859,14 +6859,8 @@ pub fn _mm_maskz_packus_epi16(k: __mmask16, a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_avg_epu16(a: __m512i, b: __m512i) -> __m512i {
-    unsafe {
-        let a = simd_cast::<_, u32x32>(a.as_u16x32());
-        let b = simd_cast::<_, u32x32>(b.as_u16x32());
-        let r = simd_shr(simd_add(simd_add(a, b), u32x32::splat(1)), u32x32::splat(1));
-        transmute(simd_cast::<_, u16x32>(r))
-    }
+pub fn _mm512_avg_epu16(a: __m512i, b: __m512i) -> __m512i {
+    unsafe { transmute(vpavgw(a.as_u16x32(), b.as_u16x32())) }
 }
 
 /// Average packed unsigned 16-bit integers in a and b, and store the results in dst using writemask k (elements are copied from src when the corresponding mask bit is not set).
@@ -6876,8 +6870,7 @@ pub const fn _mm512_avg_epu16(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_mask_avg_epu16(src: __m512i, k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+pub fn _mm512_mask_avg_epu16(src: __m512i, k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let avg = _mm512_avg_epu16(a, b).as_u16x32();
         transmute(simd_select_bitmask(k, avg, src.as_u16x32()))
@@ -6891,8 +6884,7 @@ pub const fn _mm512_mask_avg_epu16(src: __m512i, k: __mmask32, a: __m512i, b: __
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgw))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_maskz_avg_epu16(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
+pub fn _mm512_maskz_avg_epu16(k: __mmask32, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let avg = _mm512_avg_epu16(a, b).as_u16x32();
         transmute(simd_select_bitmask(k, avg, u16x32::ZERO))
@@ -6962,14 +6954,8 @@ pub fn _mm_maskz_avg_epu16(k: __mmask8, a: __m128i, b: __m128i) -> __m128i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgb))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_avg_epu8(a: __m512i, b: __m512i) -> __m512i {
-    unsafe {
-        let a = simd_cast::<_, u16x64>(a.as_u8x64());
-        let b = simd_cast::<_, u16x64>(b.as_u8x64());
-        let r = simd_shr(simd_add(simd_add(a, b), u16x64::splat(1)), u16x64::splat(1));
-        transmute(simd_cast::<_, u8x64>(r))
-    }
+pub fn _mm512_avg_epu8(a: __m512i, b: __m512i) -> __m512i {
+    unsafe { transmute(vpavgb(a.as_u8x64(), b.as_u8x64())) }
 }
 
 /// Average packed unsigned 8-bit integers in a and b, and store the results in dst using writemask k (elements are copied from src when the corresponding mask bit is not set).
@@ -6979,8 +6965,7 @@ pub const fn _mm512_avg_epu8(a: __m512i, b: __m512i) -> __m512i {
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgb))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_mask_avg_epu8(src: __m512i, k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
+pub fn _mm512_mask_avg_epu8(src: __m512i, k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let avg = _mm512_avg_epu8(a, b).as_u8x64();
         transmute(simd_select_bitmask(k, avg, src.as_u8x64()))
@@ -6994,8 +6979,7 @@ pub const fn _mm512_mask_avg_epu8(src: __m512i, k: __mmask64, a: __m512i, b: __m
 #[target_feature(enable = "avx512bw")]
 #[stable(feature = "stdarch_x86_avx512", since = "1.89")]
 #[cfg_attr(test, assert_instr(vpavgb))]
-#[rustc_const_unstable(feature = "stdarch_const_x86", issue = "149298")]
-pub const fn _mm512_maskz_avg_epu8(k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
+pub fn _mm512_maskz_avg_epu8(k: __mmask64, a: __m512i, b: __m512i) -> __m512i {
     unsafe {
         let avg = _mm512_avg_epu8(a, b).as_u8x64();
         transmute(simd_select_bitmask(k, avg, u8x64::ZERO))
@@ -12534,6 +12518,11 @@ unsafe extern "llvm-intrinsic" {
 
     #[link_name = "llvm.x86.avx512.mask.pmovus.wb.mem.512"]
     fn vpmovuswbmem(mem_addr: *mut i8, a: i16x32, mask: u32);
+
+    #[link_name = "llvm.x86.avx512.pavg.b.512"]
+    fn vpavgb(a: u8x64, b: u8x64) -> u8x64;
+    #[link_name = "llvm.x86.avx512.pavg.w.512"]
+    fn vpavgw(a: u16x32, b: u16x32) -> u16x32;
 }
 
 #[cfg(test)]
@@ -17940,7 +17929,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_avg_epu16() {
+    fn test_mm512_avg_epu16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_avg_epu16(a, b);
@@ -17949,7 +17938,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_mask_avg_epu16() {
+    fn test_mm512_mask_avg_epu16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_mask_avg_epu16(a, 0, a, b);
@@ -17962,7 +17951,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_maskz_avg_epu16() {
+    fn test_mm512_maskz_avg_epu16() {
         let a = _mm512_set1_epi16(1);
         let b = _mm512_set1_epi16(1);
         let r = _mm512_maskz_avg_epu16(0, a, b);
@@ -18019,7 +18008,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_avg_epu8() {
+    fn test_mm512_avg_epu8() {
         let a = _mm512_set1_epi8(1);
         let b = _mm512_set1_epi8(1);
         let r = _mm512_avg_epu8(a, b);
@@ -18028,7 +18017,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_mask_avg_epu8() {
+    fn test_mm512_mask_avg_epu8() {
         let a = _mm512_set1_epi8(1);
         let b = _mm512_set1_epi8(1);
         let r = _mm512_mask_avg_epu8(a, 0, a, b);
@@ -18048,7 +18037,7 @@ mod tests {
     }
 
     #[simd_test(enable = "avx512bw")]
-    const fn test_mm512_maskz_avg_epu8() {
+    fn test_mm512_maskz_avg_epu8() {
         let a = _mm512_set1_epi8(1);
         let b = _mm512_set1_epi8(1);
         let r = _mm512_maskz_avg_epu8(0, a, b);

From bd9f2cfc45cb219197ef083a41fb7d91478282a6 Mon Sep 17 00:00:00 2001
From: Folkert de Vries <folkert@folkertdev.nl>
Date: Wed, 30 Sep 2026 21:34:34 +0200
Subject: [PATCH 08/27] Prepare for merging from rust-lang/rust

This updates the rust-version file to 21b707e3f97e0b522ebd2f277a862339625ad83f.
---
 library/stdarch/rust-version | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/stdarch/rust-version b/library/stdarch/rust-version
index 368cecc0b82f9..e7e9921e4903b 100644
--- a/library/stdarch/rust-version
+++ b/library/stdarch/rust-version
@@ -1 +1 @@
-220b36c420c49c59923f54cd4a76634fac98a067
+21b707e3f97e0b522ebd2f277a862339625ad83f

From 98af1795afb3634f91b4c310fa0d352a31367688 Mon Sep 17 00:00:00 2001
From: ltdk <usr@ltdk.xyz>
Date: Wed, 30 Sep 2026 10:07:35 -0400
Subject: [PATCH 09/27] Add libs-nominated triagebot config

---
 library/stdarch/triagebot.toml | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/library/stdarch/triagebot.toml b/library/stdarch/triagebot.toml
index 149646aa65f01..ea711630662a5 100644
--- a/library/stdarch/triagebot.toml
+++ b/library/stdarch/triagebot.toml
@@ -88,3 +88,13 @@ Thanks!
 # Documentation at: https://forge.rust-lang.org/triagebot/issue-links.html
 [issue-links]
 check-commits = false
+
+[notify-zulip."I-libs-nominated"]
+zulip_stream = 639962 # #t-libs/nominated
+topic = "stdarch#{number}: {title}"
+message_on_add = """\
+@*T-libs-ping* [stdarch#{number} "{title}"](https://github.com/rust-lang/stdarch/pull/{number}) has been nominated for discussion.
+"""
+message_on_remove = """\
+stdarch#{number} is no longer nominated.
+"""

From 42f00d9d67cdfc17e72bfe22607b5cb85bc1c43e Mon Sep 17 00:00:00 2001
From: ltdk <usr@ltdk.xyz>
Date: Wed, 30 Sep 2026 19:08:22 -0400
Subject: [PATCH 10/27] Don't ping

---
 library/stdarch/triagebot.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/stdarch/triagebot.toml b/library/stdarch/triagebot.toml
index ea711630662a5..45005bafad314 100644
--- a/library/stdarch/triagebot.toml
+++ b/library/stdarch/triagebot.toml
@@ -93,7 +93,7 @@ check-commits = false
 zulip_stream = 639962 # #t-libs/nominated
 topic = "stdarch#{number}: {title}"
 message_on_add = """\
-@*T-libs-ping* [stdarch#{number} "{title}"](https://github.com/rust-lang/stdarch/pull/{number}) has been nominated for discussion.
+[stdarch#{number} "{title}"](https://github.com/rust-lang/stdarch/pull/{number}) has been nominated for discussion.
 """
 message_on_remove = """\
 stdarch#{number} is no longer nominated.

From 5a396834f9186fdb999069a1a5b413bd008f5d36 Mon Sep 17 00:00:00 2001
From: Liber <liberxue@gmail.com>
Date: Fri, 2 Oct 2026 09:47:57 +0800
Subject: [PATCH 11/27] Fix the nvptx f16x2 intrinsic annotations

The add expectation reads add.rn.f16x22, which is no PTX instruction.
LLVM's own NVPTX codegen test, llvm/test/CodeGen/NVPTX/f16x2-instructions.ll,
expects add.rn.f16x2 for fadd <2 x half>, and the sub, mul, fma and neg
expectations in this file already match what it emits. Nothing caught the
typo because assert_instr never runs on nvptx: CI builds that target with
NORUN=1 and NOSTD=1.

The neg docs name __hmin2 and the fma docs name __fma2 and __fma2_rn.
cuda_fp16.h (CUDA 12.4) declares __hneg2 and __hfma2, and none of the
other three names exist; the fma link already resolved to __hfma2.
---
 library/stdarch/crates/core_arch/src/nvptx/packed.rs | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/nvptx/packed.rs b/library/stdarch/crates/core_arch/src/nvptx/packed.rs
index 4933a601231f5..99220038e23a2 100644
--- a/library/stdarch/crates/core_arch/src/nvptx/packed.rs
+++ b/library/stdarch/crates/core_arch/src/nvptx/packed.rs
@@ -30,7 +30,7 @@ types! {
 ///  - [`__hadd2`](https://docs.nvidia.com/cuda/cuda-math-api/group__CUDA__MATH____HALF2__ARITHMETIC.html#group__CUDA__MATH____HALF2__ARITHMETIC_1g921c795176eaa31265bd80ef4fe4b8e6)
 ///  - [`__hadd2_rn`](https://docs.nvidia.com/cuda/cuda-math-api/group__CUDA__MATH____HALF2__ARITHMETIC.html#group__CUDA__MATH____HALF2__ARITHMETIC_1g6cd8ddb2c3d670e1a10c3eb2e7644f82)
 #[inline]
-#[cfg_attr(test, assert_instr(add.rn.f16x22))]
+#[cfg_attr(test, assert_instr(add.rn.f16x2))]
 #[unstable(feature = "stdarch_nvptx", issue = "111199")]
 pub unsafe fn f16x2_add(a: f16x2, b: f16x2) -> f16x2 {
     simd_add(a, b)
@@ -68,9 +68,7 @@ pub unsafe fn f16x2_mul(a: f16x2, b: f16x2) -> f16x2 {
 ///
 /// <https://docs.nvidia.com/cuda/parallel-thread-execution/#half-precision-floating-point-instructions-fma>
 ///
-/// Corresponds to the CUDA C intrinsics:
-///  - [`__fma2`](https://docs.nvidia.com/cuda/cuda-math-api/group__CUDA__MATH____HALF2__ARITHMETIC.html#group__CUDA__MATH____HALF2__ARITHMETIC_1g43628ba21ded8b1e188a367348008dab)
-///  - [`__fma2_rn`](https://docs.nvidia.com/cuda/cuda-math-api/group__CUDA__MATH____HALF2__ARITHMETIC.html#group__CUDA__MATH____HALF2__ARITHMETIC_1g43628ba21ded8b1e188a367348008dab)
+/// Corresponds to the CUDA C intrinsic [`__hfma2`](https://docs.nvidia.com/cuda/cuda-math-api/group__CUDA__MATH____HALF2__ARITHMETIC.html#group__CUDA__MATH____HALF2__ARITHMETIC_1g43628ba21ded8b1e188a367348008dab)
 #[inline]
 #[cfg_attr(test, assert_instr(fma.rn.f16x2))]
 #[unstable(feature = "stdarch_nvptx", issue = "111199")]
@@ -82,7 +80,7 @@ pub unsafe fn f16x2_fma(a: f16x2, b: f16x2, c: f16x2) -> f16x2 {
 ///
 /// <https://docs.nvidia.com/cuda/parallel-thread-execution/#half-precision-floating-point-instructions-neg>
 ///
-/// Corresponds to the CUDA C intrinsic [`__hmin2`](https://docs.nvidia.com/cuda/cuda-math-api/group__CUDA__MATH____HALF2__COMPARISON.html#group__CUDA__MATH____HALF2__COMPARISON_1g9e17a33f96061804166f3fbd395422b6)
+/// Corresponds to the CUDA C intrinsic [`__hneg2`](https://docs.nvidia.com/cuda/cuda-math-api/group__CUDA__MATH____HALF2__ARITHMETIC.html#group__CUDA__MATH____HALF2__ARITHMETIC_1g90e216094729014f541fa1e5a5aaeaf7)
 #[inline]
 #[cfg_attr(test, assert_instr(neg.f16x2))]
 #[unstable(feature = "stdarch_nvptx", issue = "111199")]

From edcf15aabe2421eedd6dd1a01496b4a0de793069 Mon Sep 17 00:00:00 2001
From: The rustc-josh-sync Cronjob Bot <github-actions@github.com>
Date: Mon, 5 Oct 2026 04:24:12 +0000
Subject: [PATCH 12/27] Prepare for merging from rust-lang/rust

This updates the rust-version file to 260f1acad9d7f70b5b56a636a9dc5a7f76150417.
---
 library/stdarch/rust-version | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/stdarch/rust-version b/library/stdarch/rust-version
index e7e9921e4903b..271b3a644cfb8 100644
--- a/library/stdarch/rust-version
+++ b/library/stdarch/rust-version
@@ -1 +1 @@
-21b707e3f97e0b522ebd2f277a862339625ad83f
+260f1acad9d7f70b5b56a636a9dc5a7f76150417

From 6b36af2fde0dba320b1268953585b62e8cf75df9 Mon Sep 17 00:00:00 2001
From: hashcatHitman <155700084+hashcatHitman@users.noreply.github.com>
Date: Wed, 7 Oct 2026 18:41:24 +0000
Subject: [PATCH 13/27] ci: Ignore `unpinned-uses` for `josh-sync/rustc-pull`

See: https://rust-lang.zulipchat.com/#narrow/channel/242791-t-infra/topic/josh-sync.20pull.20workflow.20version.20pinning/near/629742031

Signed-off-by: hashcatHitman <155700084+hashcatHitman@users.noreply.github.com>
---
 library/stdarch/.github/workflows/rustc-pull.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/library/stdarch/.github/workflows/rustc-pull.yml b/library/stdarch/.github/workflows/rustc-pull.yml
index d2feb1add6344..96cf9285ec10b 100644
--- a/library/stdarch/.github/workflows/rustc-pull.yml
+++ b/library/stdarch/.github/workflows/rustc-pull.yml
@@ -10,6 +10,7 @@ on:
 jobs:
   pull:
     if: github.repository == 'rust-lang/stdarch'
+    # zizmor: ignore[unpinned-uses] We explicitly want to track the main branch.
     uses: rust-lang/josh-sync/.github/workflows/rustc-pull.yml@main
     with:
       github-app-id: ${{ vars.APP_CLIENT_ID }}

From 7345c38e9c0f4ab4e862ec778750a56cbf21598c Mon Sep 17 00:00:00 2001
From: hashcatHitman <155700084+hashcatHitman@users.noreply.github.com>
Date: Wed, 7 Oct 2026 18:43:19 +0000
Subject: [PATCH 14/27] ci: Pin `actions/checkout` to 6.1.0 hash

See: https://github.com/actions/checkout/releases/tag/v6.1.0

This is the same version we were already using as of writing this.

Signed-off-by: hashcatHitman <155700084+hashcatHitman@users.noreply.github.com>
---
 library/stdarch/.github/workflows/main.yml | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/library/stdarch/.github/workflows/main.yml b/library/stdarch/.github/workflows/main.yml
index d7539fe2e8ebd..bf8ad2e293e7f 100644
--- a/library/stdarch/.github/workflows/main.yml
+++ b/library/stdarch/.github/workflows/main.yml
@@ -8,7 +8,7 @@ jobs:
     name: Check Style
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
       - name: Install Rust
         run: rustup update nightly --no-self-update && rustup default nightly
       - run: ci/style.sh
@@ -18,7 +18,7 @@ jobs:
     needs: [ style ]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
       - name: Install Rust
         run: rustup update nightly --no-self-update && rustup default nightly
       - run: ci/dox.sh
@@ -30,7 +30,7 @@ jobs:
     needs: [ style ]
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
       - name: Install Rust
         run: rustup update nightly --no-self-update && rustup default nightly
       - run: cargo test --manifest-path crates/stdarch-verify/Cargo.toml
@@ -218,7 +218,7 @@ jobs:
         #   build_std: true
 
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
       - name: Install Rust
         run: |
           rustup update nightly --no-self-update
@@ -298,7 +298,7 @@ jobs:
           - target: armv7-unknown-linux-gnueabihf
             cc: gcc
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
       - name: Install Rust
         run: |
           rustup update nightly --no-self-update
@@ -326,7 +326,7 @@ jobs:
     env:
       STDARCH_GEN_MODE: check
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
       - name: Install Rust
         run: rustup update nightly && rustup default nightly && rustup component add rustfmt
       - name: Check arm spec
@@ -352,7 +352,7 @@ jobs:
     name: Run some tests with miri
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@d23441a48e516b6c34aea4fa41551a30e30af803 # v6.1.0
       - name: Install Rust
         run: rustup update nightly && rustup default nightly && rustup component add miri
       - name: Run miri tests

From 2f1130c1cb8da27034bfa449c439b817d5e89846 Mon Sep 17 00:00:00 2001
From: Sayantan Chakraborty <142906350+sayantn@users.noreply.github.com>
Date: Tue, 13 Oct 2026 13:17:41 +0530
Subject: [PATCH 15/27] Remove myself from the review rotation

---
 library/stdarch/triagebot.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/stdarch/triagebot.toml b/library/stdarch/triagebot.toml
index 45005bafad314..c4a4b02b0179e 100644
--- a/library/stdarch/triagebot.toml
+++ b/library/stdarch/triagebot.toml
@@ -33,7 +33,7 @@ allow-unauthenticated = [
 [assign]
 
 [assign.owners]
-"*" = ["@Amanieu", "@folkertdev", "@sayantn", "@davidtwco", "@adamgemmell"]
+"*" = ["@Amanieu", "@folkertdev", "@davidtwco", "@adamgemmell"]
 
 [ping.windows]
 message = """\

From 8a61540bd67f6f1a21f061801ee3f7f34de9bebb Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 3 Oct 2026 10:51:36 +0200
Subject: [PATCH 16/27] breakpoint: more explicit guidance regarding SIGTRAP
 handling

---
 library/core/src/arch.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/library/core/src/arch.rs b/library/core/src/arch.rs
index 04fc16f50085b..d6871690e710d 100644
--- a/library/core/src/arch.rs
+++ b/library/core/src/arch.rs
@@ -68,7 +68,11 @@ pub macro global_asm("assembly template", $(operands,)* $(options($(option),*))?
 /// The precise behavior is not guaranteed, it depends on the architecture and operating system.
 /// Not all architectures guarantee that a breakpoint instruction interrupts execution in the absence
 /// of a debugger, and not all operating systems and execution environments guarantee that such an
-/// interrupt aborts the current process.
+/// interrupt aborts the current process. On operating systems where the behavior of the interrupt
+/// can be overwritten by the application (e.g. via a SIGTRAP signal handler), the application
+/// *should* make sure to still abort the process, but we recommend not relying on that for
+/// soundness unless you actually know for sure that the application running your code keeps the
+/// default (or equivalent) behavior.
 ///
 /// The precise instruction is guaranteed only on the following targets:
 /// - On x86 targets, this produces an `int3` instruction.

From 99af6957aa57ab0de65bdfddc47e84cdc04a40ab Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Wed, 14 Oct 2026 17:38:26 +0200
Subject: [PATCH 17/27] edits by Josh

Co-authored-by: Josh Triplett <josh@joshtriplett.org>
---
 library/core/src/arch.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/library/core/src/arch.rs b/library/core/src/arch.rs
index d6871690e710d..92ff55ecc75c0 100644
--- a/library/core/src/arch.rs
+++ b/library/core/src/arch.rs
@@ -70,9 +70,10 @@ pub macro global_asm("assembly template", $(operands,)* $(options($(option),*))?
 /// of a debugger, and not all operating systems and execution environments guarantee that such an
 /// interrupt aborts the current process. On operating systems where the behavior of the interrupt
 /// can be overwritten by the application (e.g. via a SIGTRAP signal handler), the application
-/// *should* make sure to still abort the process, but we recommend not relying on that for
-/// soundness unless you actually know for sure that the application running your code keeps the
-/// default (or equivalent) behavior.
+/// *should* make sure to still abort the process. However, code not fully in control of that
+/// application state (e.g. signal handlers) cannot always rely on that for soundness.
+/// If you do rely on this, such that your code's soundness requires applications to not continue
+/// from your breakpoints, please document that for your users.
 ///
 /// The precise instruction is guaranteed only on the following targets:
 /// - On x86 targets, this produces an `int3` instruction.

From c7ea602b621fc26f34d44b2ec713c4787be9679d Mon Sep 17 00:00:00 2001
From: annieversary <annie@versary.town>
Date: Sat, 17 Oct 2026 23:23:40 +0200
Subject: [PATCH 18/27] add test for literals in lint attributes

---
 tests/ui/lint/lint-attribute-literals.rs     | 7 +++++++
 tests/ui/lint/lint-attribute-literals.stderr | 9 +++++++++
 2 files changed, 16 insertions(+)
 create mode 100644 tests/ui/lint/lint-attribute-literals.rs
 create mode 100644 tests/ui/lint/lint-attribute-literals.stderr

diff --git a/tests/ui/lint/lint-attribute-literals.rs b/tests/ui/lint/lint-attribute-literals.rs
new file mode 100644
index 0000000000000..6cbae8e1e9fcf
--- /dev/null
+++ b/tests/ui/lint/lint-attribute-literals.rs
@@ -0,0 +1,7 @@
+// Checks that lint attributes with literals have an explanatory error
+
+//@ compile-flags: -Zdeduplicate-diagnostics=yes
+
+#[allow("literal")]
+//~^ ERROR malformed lint attribute input [E0452]
+fn main() {}
diff --git a/tests/ui/lint/lint-attribute-literals.stderr b/tests/ui/lint/lint-attribute-literals.stderr
new file mode 100644
index 0000000000000..34d7fbfc9b968
--- /dev/null
+++ b/tests/ui/lint/lint-attribute-literals.stderr
@@ -0,0 +1,9 @@
+error[E0452]: malformed lint attribute input
+  --> $DIR/lint-attribute-literals.rs:5:9
+   |
+LL | #[allow("literal")]
+   |         ^^^^^^^^^ bad attribute argument
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0452`.

From 7142f9a635a049f1248d860062d86df2cbf159af Mon Sep 17 00:00:00 2001
From: annieversary <annie@versary.town>
Date: Sat, 17 Oct 2026 21:19:21 +0200
Subject: [PATCH 19/27] improve diagnostic for literals in lint attributes

---
 .../rustc_attr_parsing/src/attributes/lint.rs | 112 ++++++++++--------
 .../rustc_attr_parsing/src/diagnostics.rs     |  18 +++
 ...deduplicate-diagnostics.deduplicate.stderr |   7 +-
 .../deduplicate-diagnostics.duplicate.stderr  |  17 +--
 .../deduplicate-diagnostics.rs                |   6 +-
 tests/ui/lint/lint-attribute-literals.rs      |   2 +-
 tests/ui/lint/lint-attribute-literals.stderr  |   7 +-
 7 files changed, 102 insertions(+), 67 deletions(-)

diff --git a/compiler/rustc_attr_parsing/src/attributes/lint.rs b/compiler/rustc_attr_parsing/src/attributes/lint.rs
index e1221ecbb96d8..51b0578d83688 100644
--- a/compiler/rustc_attr_parsing/src/attributes/lint.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/lint.rs
@@ -7,7 +7,7 @@ use thin_vec::ThinVec;
 
 use crate::attributes::{AcceptMapping, AttributeParser, AttributeStability};
 use crate::context::{AcceptContext, ExpectStringLiteral, FinalizeContext};
-use crate::parser::ArgParser;
+use crate::parser::{ArgParser, MetaItemOrLitParser};
 use crate::target_checking::AllowedTargets;
 use crate::target_checking::Policy::{Allow, Warn};
 use crate::{AttributeTemplate, diagnostics, template};
@@ -48,58 +48,70 @@ impl LintParser {
             };
 
             for item in parsers {
-                if let Some(p) = item.meta_item() {
-                    match p.args() {
-                        ArgParser::NoArgs => {
-                            let (tool, lint_name, rest) = match &*p.path().0.segments {
-                                [] => unreachable!(),
-                                [lint_name] => (None, lint_name.ident.name, None),
-                                [tool, lint_name] => (Some(tool.ident), lint_name.ident.name, None),
-                                [tool, lint_name, rest @ ..] => {
-                                    let rest = rest
-                                        .iter()
-                                        .map(|s| s.ident.name)
-                                        .collect::<Vec<_>>()
-                                        .into();
-                                    (Some(tool.ident), lint_name.ident.name, Some(rest))
-                                }
-                            };
+                match item {
+                    MetaItemOrLitParser::MetaItemParser(p) => {
+                        match p.args() {
+                            ArgParser::NoArgs => {
+                                let (tool, lint_name, rest) = match &*p.path().0.segments {
+                                    [] => unreachable!(),
+                                    [lint_name] => (None, lint_name.ident.name, None),
+                                    [tool, lint_name] => {
+                                        (Some(tool.ident), lint_name.ident.name, None)
+                                    }
+                                    [tool, lint_name, rest @ ..] => {
+                                        let rest = rest
+                                            .iter()
+                                            .map(|s| s.ident.name)
+                                            .collect::<Vec<_>>()
+                                            .into();
+                                        (Some(tool.ident), lint_name.ident.name, Some(rest))
+                                    }
+                                };
 
-                            self.lints.push(LintCheck {
-                                tool,
-                                lint_name,
-                                lint_span: p.span(),
-                                kind,
-                                attr_id,
-                                reason,
-                                attr_span,
-                                rest,
-                            })
-                        }
-                        // We're found a `reason = "reason"` but we're not the last element.
-                        ArgParser::NameValue(nv) if p.path().word_is(sym::reason) => {
-                            cx.emit_err(diagnostics::MalformedAttribute {
-                                span: p.span(),
-                                sub: diagnostics::MalformedAttributeSub::ReasonMustComeLast(
-                                    item.span(),
-                                ),
-                            });
-                            nv.expect_string_literal(cx);
-                        }
-                        ArgParser::NameValue(_) | ArgParser::List(_) => {
-                            cx.emit_err(diagnostics::MalformedAttribute {
-                                span: p.span(),
-                                sub: diagnostics::MalformedAttributeSub::BadAttributeArgument(
-                                    item.span(),
-                                ),
-                            });
+                                self.lints.push(LintCheck {
+                                    tool,
+                                    lint_name,
+                                    lint_span: p.span(),
+                                    kind,
+                                    attr_id,
+                                    reason,
+                                    attr_span,
+                                    rest,
+                                })
+                            }
+                            // We've found a `reason = "reason"` but we're not the last element.
+                            ArgParser::NameValue(nv) if p.path().word_is(sym::reason) => {
+                                cx.emit_err(diagnostics::MalformedAttribute {
+                                    span: p.span(),
+                                    sub: diagnostics::MalformedAttributeSub::ReasonMustComeLast(
+                                        item.span(),
+                                    ),
+                                });
+                                nv.expect_string_literal(cx);
+                            }
+                            ArgParser::NameValue(_) | ArgParser::List(_) => {
+                                cx.emit_err(diagnostics::MalformedAttribute {
+                                    span: p.span(),
+                                    sub: diagnostics::MalformedAttributeSub::BadAttributeArgument(
+                                        item.span(),
+                                    ),
+                                });
+                            }
                         }
                     }
-                } else {
-                    cx.emit_err(diagnostics::MalformedAttribute {
-                        span: item.span(),
-                        sub: diagnostics::MalformedAttributeSub::BadAttributeArgument(item.span()),
-                    });
+                    MetaItemOrLitParser::Lit(lit) => {
+                        cx.emit_err(diagnostics::BadAttributeLit {
+                            span: item.span(),
+                            sub: if lit.kind.is_str() {
+                                diagnostics::BadAttributeLitHelp::StrLit {
+                                    sym: lit.symbol,
+                                    kind: kind.sym(),
+                                }
+                            } else {
+                                diagnostics::BadAttributeLitHelp::Other { kind: kind.sym() }
+                            },
+                        });
+                    }
                 }
             }
             if parsers.is_empty() {
diff --git a/compiler/rustc_attr_parsing/src/diagnostics.rs b/compiler/rustc_attr_parsing/src/diagnostics.rs
index b55d7e476896b..6e517b3f7085a 100644
--- a/compiler/rustc_attr_parsing/src/diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/diagnostics.rs
@@ -2150,6 +2150,24 @@ pub(crate) enum MalformedAttributeSub {
     ReasonMustComeLast(#[primary_span] Span),
 }
 
+#[derive(Diagnostic)]
+#[diag("expected path to a lint, found literal")]
+pub(crate) struct BadAttributeLit {
+    #[primary_span]
+    #[label("not a lint")]
+    pub span: Span,
+    #[subdiagnostic]
+    pub sub: BadAttributeLitHelp,
+}
+
+#[derive(Subdiagnostic)]
+pub(crate) enum BadAttributeLitHelp {
+    #[help("try using `#[{$kind}({$sym})]`")]
+    StrLit { sym: Symbol, kind: Symbol },
+    #[help("for example, write `#[{$kind}(dead_code)]` for `dead_code`")]
+    Other { kind: Symbol },
+}
+
 #[derive(Subdiagnostic)]
 pub(crate) enum UnusedNote {
     #[note("attribute `{$name}` with an empty list has no effect")]
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr b/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
index c0d568eb5384e..7e962b20a63f6 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
@@ -1,8 +1,10 @@
-error[E0452]: malformed lint attribute input
+error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ bad attribute argument
+   |        ^^^^^^^^^ not a lint
+   |
+   = help: try using `#[deny(literal)]`
 
 error: cannot find derive macro `Unresolved` in this scope
   --> $DIR/deduplicate-diagnostics.rs:6:10
@@ -12,4 +14,3 @@ LL | #[derive(Unresolved)]
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0452`.
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr b/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
index 74d7066293f30..142333d750b4c 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
@@ -1,8 +1,10 @@
-error[E0452]: malformed lint attribute input
+error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ bad attribute argument
+   |        ^^^^^^^^^ not a lint
+   |
+   = help: try using `#[deny(literal)]`
 
 error: cannot find derive macro `Unresolved` in this scope
   --> $DIR/deduplicate-diagnostics.rs:6:10
@@ -18,22 +20,23 @@ LL | #[derive(Unresolved)]
    |
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error[E0452]: malformed lint attribute input
+error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ bad attribute argument
+   |        ^^^^^^^^^ not a lint
    |
+   = help: try using `#[deny(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error[E0452]: malformed lint attribute input
+error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ bad attribute argument
+   |        ^^^^^^^^^ not a lint
    |
+   = help: try using `#[deny(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0452`.
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs b/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs
index 48705266e3584..27b033b346307 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs
@@ -7,7 +7,7 @@
                       //[duplicate]~| ERROR cannot find derive macro `Unresolved` in this scope
 struct S;
 
-#[deny("literal")] //~ ERROR malformed lint attribute input
-                   //[duplicate]~| ERROR malformed lint attribute input
-                   //[duplicate]~| ERROR malformed lint attribute input
+#[deny("literal")] //~ ERROR expected path to a lint, found literal
+                   //[duplicate]~| ERROR expected path to a lint, found literal
+                   //[duplicate]~| ERROR expected path to a lint, found literal
 fn main() {}
diff --git a/tests/ui/lint/lint-attribute-literals.rs b/tests/ui/lint/lint-attribute-literals.rs
index 6cbae8e1e9fcf..1d104644c71bc 100644
--- a/tests/ui/lint/lint-attribute-literals.rs
+++ b/tests/ui/lint/lint-attribute-literals.rs
@@ -3,5 +3,5 @@
 //@ compile-flags: -Zdeduplicate-diagnostics=yes
 
 #[allow("literal")]
-//~^ ERROR malformed lint attribute input [E0452]
+//~^ ERROR expected path to a lint, found literal
 fn main() {}
diff --git a/tests/ui/lint/lint-attribute-literals.stderr b/tests/ui/lint/lint-attribute-literals.stderr
index 34d7fbfc9b968..ca6832a0cdad8 100644
--- a/tests/ui/lint/lint-attribute-literals.stderr
+++ b/tests/ui/lint/lint-attribute-literals.stderr
@@ -1,9 +1,10 @@
-error[E0452]: malformed lint attribute input
+error: expected path to a lint, found literal
   --> $DIR/lint-attribute-literals.rs:5:9
    |
 LL | #[allow("literal")]
-   |         ^^^^^^^^^ bad attribute argument
+   |         ^^^^^^^^^ not a lint
+   |
+   = help: try using `#[allow(literal)]`
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0452`.

From 1cb7727098ec3c8aa9758e2a18718a3532f0e3d3 Mon Sep 17 00:00:00 2001
From: annieversary <annie@versary.town>
Date: Sat, 17 Oct 2026 23:35:39 +0200
Subject: [PATCH 20/27] rename sub to kind in attribute diagnostics

---
 compiler/rustc_attr_parsing/src/attributes/lint.rs | 8 ++++----
 compiler/rustc_attr_parsing/src/diagnostics.rs     | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/compiler/rustc_attr_parsing/src/attributes/lint.rs b/compiler/rustc_attr_parsing/src/attributes/lint.rs
index 51b0578d83688..0c603faa4b5f9 100644
--- a/compiler/rustc_attr_parsing/src/attributes/lint.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/lint.rs
@@ -37,7 +37,7 @@ impl LintParser {
                 if !p.path().word_is(sym::reason) {
                     cx.emit_err(diagnostics::MalformedAttribute {
                         span: p.span(),
-                        sub: diagnostics::MalformedAttributeSub::BadAttributeArgument(p.span()),
+                        kind: diagnostics::MalformedAttributeKind::BadAttributeArgument(p.span()),
                     });
                 } else {
                     parsers = &parsers[..(parsers.len() - 1)];
@@ -83,7 +83,7 @@ impl LintParser {
                             ArgParser::NameValue(nv) if p.path().word_is(sym::reason) => {
                                 cx.emit_err(diagnostics::MalformedAttribute {
                                     span: p.span(),
-                                    sub: diagnostics::MalformedAttributeSub::ReasonMustComeLast(
+                                    kind: diagnostics::MalformedAttributeKind::ReasonMustComeLast(
                                         item.span(),
                                     ),
                                 });
@@ -92,7 +92,7 @@ impl LintParser {
                             ArgParser::NameValue(_) | ArgParser::List(_) => {
                                 cx.emit_err(diagnostics::MalformedAttribute {
                                     span: p.span(),
-                                    sub: diagnostics::MalformedAttributeSub::BadAttributeArgument(
+                                    kind: diagnostics::MalformedAttributeKind::BadAttributeArgument(
                                         item.span(),
                                     ),
                                 });
@@ -102,7 +102,7 @@ impl LintParser {
                     MetaItemOrLitParser::Lit(lit) => {
                         cx.emit_err(diagnostics::BadAttributeLit {
                             span: item.span(),
-                            sub: if lit.kind.is_str() {
+                            help: if lit.kind.is_str() {
                                 diagnostics::BadAttributeLitHelp::StrLit {
                                     sym: lit.symbol,
                                     kind: kind.sym(),
diff --git a/compiler/rustc_attr_parsing/src/diagnostics.rs b/compiler/rustc_attr_parsing/src/diagnostics.rs
index 6e517b3f7085a..259b2e5d8425f 100644
--- a/compiler/rustc_attr_parsing/src/diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/diagnostics.rs
@@ -2139,11 +2139,11 @@ pub(crate) struct MalformedAttribute {
     #[primary_span]
     pub span: Span,
     #[subdiagnostic]
-    pub sub: MalformedAttributeSub,
+    pub kind: MalformedAttributeKind,
 }
 
 #[derive(Subdiagnostic)]
-pub(crate) enum MalformedAttributeSub {
+pub(crate) enum MalformedAttributeKind {
     #[label("bad attribute argument")]
     BadAttributeArgument(#[primary_span] Span),
     #[label("reason in lint attribute must come last")]
@@ -2157,7 +2157,7 @@ pub(crate) struct BadAttributeLit {
     #[label("not a lint")]
     pub span: Span,
     #[subdiagnostic]
-    pub sub: BadAttributeLitHelp,
+    pub help: BadAttributeLitHelp,
 }
 
 #[derive(Subdiagnostic)]

From 3c7ed77b5e4e4a9d464233dd3ad27d39a80ccfa8 Mon Sep 17 00:00:00 2001
From: SabrinaJewson <sejewson@gmail.com>
Date: Sun, 18 Oct 2026 01:24:09 +0100
Subject: [PATCH 21/27] Add more syscall doc aliases to std docs

---
 library/alloc/src/io/copy.rs     | 1 +
 library/std/src/fs.rs            | 7 +++++--
 library/std/src/os/windows/fs.rs | 2 ++
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/library/alloc/src/io/copy.rs b/library/alloc/src/io/copy.rs
index 798bd2c1ec0a0..f414078d3a0b5 100644
--- a/library/alloc/src/io/copy.rs
+++ b/library/alloc/src/io/copy.rs
@@ -75,6 +75,7 @@ pub enum CopyState {
 /// descriptors if possible.
 ///
 /// Note that platform-specific behavior may change in the future.
+#[doc(alias = "copy_file_range", alias = "sendfile", alias = "splice")]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub fn copy<R: ?Sized, W: ?Sized>(reader: &mut R, writer: &mut W) -> Result<u64>
 where
diff --git a/library/std/src/fs.rs b/library/std/src/fs.rs
index c668e6216fd4b..f922696298fff 100644
--- a/library/std/src/fs.rs
+++ b/library/std/src/fs.rs
@@ -3039,7 +3039,7 @@ pub fn remove_file<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///     Ok(())
 /// }
 /// ```
-#[doc(alias = "stat")]
+#[doc(alias = "stat", alias = "GetFileAttributes", alias = "GetFileAttributesEx")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "fs_metadata")]
 pub fn metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
@@ -3080,7 +3080,7 @@ pub fn metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
 ///     Ok(())
 /// }
 /// ```
-#[doc(alias = "lstat")]
+#[doc(alias = "lstat", alias = "GetFileAttributes", alias = "GetFileAttributesEx")]
 #[stable(feature = "symlink_metadata", since = "1.1.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "fs_symlink_metadata")]
 pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
@@ -3262,6 +3262,7 @@ pub fn rename_noreplace<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::R
 /// }
 /// ```
 #[doc(alias = "cp")]
+#[doc(alias = "copy_file_range")]
 #[doc(alias = "CopyFile", alias = "CopyFileEx")]
 #[doc(alias = "fclonefileat", alias = "fcopyfile")]
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -3511,6 +3512,7 @@ pub fn create_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///     Ok(())
 /// }
 /// ```
+#[doc(alias = "mkdir", alias = "CreateDirectory")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "fs_create_dir_all")]
 pub fn create_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
@@ -3626,6 +3628,7 @@ pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
 ///     Ok(())
 /// }
 /// ```
+#[doc(alias = "rm")]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "fs_remove_dir_all")]
 pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
diff --git a/library/std/src/os/windows/fs.rs b/library/std/src/os/windows/fs.rs
index 4c2506ffae66c..865cc90e83156 100644
--- a/library/std/src/os/windows/fs.rs
+++ b/library/std/src/os/windows/fs.rs
@@ -908,6 +908,7 @@ impl FileTimesExt for fs::FileTimes {
 /// the process as an administrator.
 ///
 /// [symlink-security]: https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/create-symbolic-links
+#[doc(alias = "CreateSymbolicLink", alias = "CreateSymbolicLinkW")]
 #[stable(feature = "symlink", since = "1.1.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "fs_symlink_file")]
 pub fn symlink_file<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
@@ -949,6 +950,7 @@ pub fn symlink_file<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io:
 /// the process as an administrator.
 ///
 /// [symlink-security]: https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/create-symbolic-links
+#[doc(alias = "CreateSymbolicLink", alias = "CreateSymbolicLinkW")]
 #[stable(feature = "symlink", since = "1.1.0")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "fs_symlink_dir")]
 pub fn symlink_dir<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {

From 4245f27b542a0370fecb1691fe931d3d4f7bc6fb Mon Sep 17 00:00:00 2001
From: annieversary <annie@versary.town>
Date: Sun, 18 Oct 2026 07:46:15 +0200
Subject: [PATCH 22/27] change label in BadAttributeLit to be more descriptive

---
 compiler/rustc_attr_parsing/src/diagnostics.rs              | 2 +-
 .../deduplicate-diagnostics.deduplicate.stderr              | 2 +-
 .../deduplicate-diagnostics.duplicate.stderr                | 6 +++---
 3 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_attr_parsing/src/diagnostics.rs b/compiler/rustc_attr_parsing/src/diagnostics.rs
index 259b2e5d8425f..47ea9a2c08517 100644
--- a/compiler/rustc_attr_parsing/src/diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/diagnostics.rs
@@ -2154,7 +2154,7 @@ pub(crate) enum MalformedAttributeKind {
 #[diag("expected path to a lint, found literal")]
 pub(crate) struct BadAttributeLit {
     #[primary_span]
-    #[label("not a lint")]
+    #[label("not the name of a lint")]
     pub span: Span,
     #[subdiagnostic]
     pub help: BadAttributeLitHelp,
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr b/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
index 7e962b20a63f6..c35a239f7e062 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
@@ -2,7 +2,7 @@ error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ not a lint
+   |        ^^^^^^^^^ not the name of a lint
    |
    = help: try using `#[deny(literal)]`
 
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr b/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
index 142333d750b4c..ff782a8d80cca 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
@@ -2,7 +2,7 @@ error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ not a lint
+   |        ^^^^^^^^^ not the name of a lint
    |
    = help: try using `#[deny(literal)]`
 
@@ -24,7 +24,7 @@ error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ not a lint
+   |        ^^^^^^^^^ not the name of a lint
    |
    = help: try using `#[deny(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
@@ -33,7 +33,7 @@ error: expected path to a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
-   |        ^^^^^^^^^ not a lint
+   |        ^^^^^^^^^ not the name of a lint
    |
    = help: try using `#[deny(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`

From 1c9a4b7396042bbc50761be18821fa4d3086c945 Mon Sep 17 00:00:00 2001
From: annieversary <annie@versary.town>
Date: Sun, 18 Oct 2026 07:46:49 +0200
Subject: [PATCH 23/27] change t/u/l/lint-attribute-literals to not
 deduplicate-diagnostics

---
 tests/ui/lint/lint-attribute-literals.rs     |  4 ++--
 tests/ui/lint/lint-attribute-literals.stderr | 24 +++++++++++++++++---
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/tests/ui/lint/lint-attribute-literals.rs b/tests/ui/lint/lint-attribute-literals.rs
index 1d104644c71bc..137b5b94ea7b7 100644
--- a/tests/ui/lint/lint-attribute-literals.rs
+++ b/tests/ui/lint/lint-attribute-literals.rs
@@ -1,7 +1,7 @@
 // Checks that lint attributes with literals have an explanatory error
 
-//@ compile-flags: -Zdeduplicate-diagnostics=yes
-
 #[allow("literal")]
 //~^ ERROR expected path to a lint, found literal
+//~| ERROR expected path to a lint, found literal
+//~| ERROR expected path to a lint, found literal
 fn main() {}
diff --git a/tests/ui/lint/lint-attribute-literals.stderr b/tests/ui/lint/lint-attribute-literals.stderr
index ca6832a0cdad8..161800c09a869 100644
--- a/tests/ui/lint/lint-attribute-literals.stderr
+++ b/tests/ui/lint/lint-attribute-literals.stderr
@@ -1,10 +1,28 @@
 error: expected path to a lint, found literal
-  --> $DIR/lint-attribute-literals.rs:5:9
+  --> $DIR/lint-attribute-literals.rs:3:9
    |
 LL | #[allow("literal")]
-   |         ^^^^^^^^^ not a lint
+   |         ^^^^^^^^^ not the name of a lint
    |
    = help: try using `#[allow(literal)]`
 
-error: aborting due to 1 previous error
+error: expected path to a lint, found literal
+  --> $DIR/lint-attribute-literals.rs:3:9
+   |
+LL | #[allow("literal")]
+   |         ^^^^^^^^^ not the name of a lint
+   |
+   = help: try using `#[allow(literal)]`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: expected path to a lint, found literal
+  --> $DIR/lint-attribute-literals.rs:3:9
+   |
+LL | #[allow("literal")]
+   |         ^^^^^^^^^ not the name of a lint
+   |
+   = help: try using `#[allow(literal)]`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 3 previous errors
 

From db8f02fa178c09cd4fd05f8dc12a68c04f2685ba Mon Sep 17 00:00:00 2001
From: Michael Howell <michael@notriddle.com>
Date: Sat, 17 Oct 2026 22:04:35 -0700
Subject: [PATCH 24/27] Generate redirect pages for hidden modules

This fixes an intra-doc link, shown in the test case,
where the private path gets used as the link target.
---
 src/librustdoc/html/render/context.rs         | 14 +++++-------
 tests/rustdoc-html/file-creation-111249.rs    |  5 +++--
 .../auxiliary/doc-hidden-reexported.rs        | 10 +++++++++
 ...-to-item-thats-reexport-from-doc-hidden.rs | 22 +++++++++++++++++++
 .../reexport-trait-from-hidden-111064-2.rs    |  5 +++--
 5 files changed, 44 insertions(+), 12 deletions(-)
 create mode 100644 tests/rustdoc-html/intra-doc/auxiliary/doc-hidden-reexported.rs
 create mode 100644 tests/rustdoc-html/intra-doc/link-to-item-thats-reexport-from-doc-hidden.rs

diff --git a/src/librustdoc/html/render/context.rs b/src/librustdoc/html/render/context.rs
index f828327b4b985..96b735b08a894 100644
--- a/src/librustdoc/html/render/context.rs
+++ b/src/librustdoc/html/render/context.rs
@@ -725,14 +725,12 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
 
         info!("Recursing into {}", self.dst.display());
 
-        if !item.is_stripped() {
-            let buf = self.render_item(item, true);
-            // buf will be empty if the module is stripped and there is no redirect for it
-            if !buf.is_empty() {
-                self.shared.ensure_dir(&self.dst)?;
-                let joint_dst = self.dst.join("index.html");
-                self.shared.fs.write(joint_dst, buf)?;
-            }
+        let buf = self.render_item(item, true);
+        // buf will be empty if the module is stripped and there is no redirect for it
+        if !buf.is_empty() {
+            self.shared.ensure_dir(&self.dst)?;
+            let joint_dst = self.dst.join("index.html");
+            self.shared.fs.write(joint_dst, buf)?;
         }
         if !self.info.is_inside_inlined_module {
             if let Some(def_id) = item.def_id()
diff --git a/tests/rustdoc-html/file-creation-111249.rs b/tests/rustdoc-html/file-creation-111249.rs
index 7a075a1583f30..e745d59b10132 100644
--- a/tests/rustdoc-html/file-creation-111249.rs
+++ b/tests/rustdoc-html/file-creation-111249.rs
@@ -17,11 +17,12 @@ pub trait Sized: MetaSized {}
 //        'struct.Bar.html', 'trait.Sized.html', 'trait.MetaSized.html', 'trait.PointeeSized.html']"
 //@ files "foo/visible" "['trait.Foo.html', 'index.html', 'sidebar-items.js']"
 //@ files "foo/hidden" "['inner']"
-//@ files "foo/hidden/inner" "['trait.Foo.html']"
+//@ files "foo/hidden/inner" "['index.html', 'trait.Foo.html']"
 
 // The following five should not fail!
 //@ !has 'foo/hidden/index.html'
-//@ !has 'foo/hidden/inner/index.html'
+//@ has 'foo/hidden/inner/index.html'
+//@ matchesraw - '<meta http-equiv="refresh" content="0;URL=../../../foo/visible/index.html">'
 // FIXME: Should be `@!has`: https://github.com/rust-lang/rust/issues/111249
 //@ has 'foo/hidden/inner/trait.Foo.html'
 //@ matchesraw - '<meta http-equiv="refresh" content="0;URL=../../../foo/visible/trait.Foo.html">'
diff --git a/tests/rustdoc-html/intra-doc/auxiliary/doc-hidden-reexported.rs b/tests/rustdoc-html/intra-doc/auxiliary/doc-hidden-reexported.rs
new file mode 100644
index 0000000000000..096e958395f94
--- /dev/null
+++ b/tests/rustdoc-html/intra-doc/auxiliary/doc-hidden-reexported.rs
@@ -0,0 +1,10 @@
+#[doc(hidden)]
+pub mod docs {
+    /// Foo
+    pub mod io_uring_provided_buffers {}
+    /// Bar
+    pub struct IoUringProvidedBuffers;
+}
+
+pub use docs::io_uring_provided_buffers;
+pub use docs::IoUringProvidedBuffers;
diff --git a/tests/rustdoc-html/intra-doc/link-to-item-thats-reexport-from-doc-hidden.rs b/tests/rustdoc-html/intra-doc/link-to-item-thats-reexport-from-doc-hidden.rs
new file mode 100644
index 0000000000000..0f9fc3e358ff3
--- /dev/null
+++ b/tests/rustdoc-html/intra-doc/link-to-item-thats-reexport-from-doc-hidden.rs
@@ -0,0 +1,22 @@
+//@ aux-build:doc-hidden-reexported.rs
+//@ build-aux-docs
+
+//@ has doc_hidden_reexported/docs/io_uring_provided_buffers/index.html
+//@ matchesraw - '<meta http-equiv="refresh" content="0;URL=../../../doc_hidden_reexported/io_uring_provided_buffers/index.html">'
+//@ has doc_hidden_reexported/io_uring_provided_buffers/index.html
+
+//@ has doc_hidden_reexported/docs/struct.IoUringProvidedBuffers.html
+//@ matchesraw - '<meta http-equiv="refresh" content="0;URL=../../doc_hidden_reexported/struct.IoUringProvidedBuffers.html">'
+//@ has doc_hidden_reexported/struct.IoUringProvidedBuffers.html
+
+//! Link to [doc_hidden_reexported::io_uring_provided_buffers] and
+//! [doc_hidden_reexported::IoUringProvidedBuffers]
+//!
+//! Because these cross-crate links point at the internal, private path,
+//! we need to make sure the redirect gets generated.
+
+//@ has link_to_item_thats_reexport_from_doc_hidden/index.html
+//@ count - '//a[@href="../doc_hidden_reexported/docs/io_uring_provided_buffers/index.html"]' 1
+//@ count - '//a[@href="../doc_hidden_reexported/docs/struct.IoUringProvidedBuffers.html"]' 1
+
+extern crate doc_hidden_reexported;
diff --git a/tests/rustdoc-html/reexport/reexport-trait-from-hidden-111064-2.rs b/tests/rustdoc-html/reexport/reexport-trait-from-hidden-111064-2.rs
index 8f0a5806b0918..e8d96cb19b6bd 100644
--- a/tests/rustdoc-html/reexport/reexport-trait-from-hidden-111064-2.rs
+++ b/tests/rustdoc-html/reexport/reexport-trait-from-hidden-111064-2.rs
@@ -15,11 +15,12 @@ pub trait Sized: MetaSized {}
 //@ files "foo" "['sidebar-items.js', 'all.html', 'hidden', 'index.html', 'struct.Bar.html', \
 //        'visible', 'trait.Sized.html', 'trait.MetaSized.html', 'trait.PointeeSized.html']"
 //@ files "foo/hidden" "['inner']"
-//@ files "foo/hidden/inner" "['trait.Foo.html']"
+//@ files "foo/hidden/inner" "['index.html', 'trait.Foo.html']"
 //@ files "foo/visible" "['index.html', 'sidebar-items.js', 'trait.Foo.html']"
 
 //@ !has 'foo/hidden/index.html'
-//@ !has 'foo/hidden/inner/index.html'
+//@ has 'foo/hidden/inner/index.html'
+//@ matchesraw - '<meta http-equiv="refresh" content="0;URL=../../../foo/visible/index.html">'
 // FIXME: Should be `@!has`: https://github.com/rust-lang/rust/issues/111249
 //@ has 'foo/hidden/inner/trait.Foo.html'
 //@ matchesraw - '<meta http-equiv="refresh" content="0;URL=../../../foo/visible/trait.Foo.html">'

From 7213e553733a4c1c3a0bf27937f83df0518323dd Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 18 Oct 2026 12:20:47 +0200
Subject: [PATCH 25/27] abort_on_unwind: clarify docs

---
 library/core/src/panic.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/library/core/src/panic.rs b/library/core/src/panic.rs
index 4fcd5f615e993..52fcfebd1111c 100644
--- a/library/core/src/panic.rs
+++ b/library/core/src/panic.rs
@@ -97,8 +97,9 @@ pub macro unreachable_2021 {
 /// Invokes a closure, aborting if the closure unwinds.
 ///
 /// When compiled with aborting panics, this function is effectively a no-op.
-/// With unwinding panics, an unwind results in another call into the panic
-/// hook followed by a process abort.
+/// With unwinding panics, an unwind that would leave the closure results in another call into the
+/// panic handler / panic hook followed by a process abort. (Locals in the closure get dropped as
+/// usual.) Unwinds that get caught inside the closure still behave as normal.
 ///
 /// # Notes
 ///
@@ -114,7 +115,7 @@ pub macro unreachable_2021 {
 /// to prevent unwinds. However, note that `extern "C" fn` will automatically
 /// convert unwinds to aborts, so using this function isn't necessary for FFI.
 #[unstable(feature = "abort_unwind", issue = "130338")]
-#[rustc_nounwind]
+#[rustc_nounwind] // this attribute does all the actual work here
 pub fn abort_on_unwind<F: FnOnce() -> R, R>(f: F) -> R {
     f()
 }

From f9d044c80089a17b746d14173d6c51480813b56f Mon Sep 17 00:00:00 2001
From: annieversary <annie@versary.town>
Date: Sun, 18 Oct 2026 15:13:46 +0200
Subject: [PATCH 26/27] simplify BadAttributeLit diagnostic message

---
 compiler/rustc_attr_parsing/src/diagnostics.rs              | 2 +-
 .../deduplicate-diagnostics.deduplicate.stderr              | 2 +-
 .../deduplicate-diagnostics.duplicate.stderr                | 6 +++---
 tests/ui/diagnostic-flags/deduplicate-diagnostics.rs        | 6 +++---
 tests/ui/lint/lint-attribute-literals.rs                    | 6 +++---
 tests/ui/lint/lint-attribute-literals.stderr                | 6 +++---
 6 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/compiler/rustc_attr_parsing/src/diagnostics.rs b/compiler/rustc_attr_parsing/src/diagnostics.rs
index 47ea9a2c08517..848ab845dc7f6 100644
--- a/compiler/rustc_attr_parsing/src/diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/diagnostics.rs
@@ -2151,7 +2151,7 @@ pub(crate) enum MalformedAttributeKind {
 }
 
 #[derive(Diagnostic)]
-#[diag("expected path to a lint, found literal")]
+#[diag("expected a lint, found literal")]
 pub(crate) struct BadAttributeLit {
     #[primary_span]
     #[label("not the name of a lint")]
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr b/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
index c35a239f7e062..114c37188a9ef 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.deduplicate.stderr
@@ -1,4 +1,4 @@
-error: expected path to a lint, found literal
+error: expected a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr b/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
index ff782a8d80cca..66d0d94c0e815 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.duplicate.stderr
@@ -1,4 +1,4 @@
-error: expected path to a lint, found literal
+error: expected a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
@@ -20,7 +20,7 @@ LL | #[derive(Unresolved)]
    |
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: expected path to a lint, found literal
+error: expected a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
@@ -29,7 +29,7 @@ LL | #[deny("literal")]
    = help: try using `#[deny(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: expected path to a lint, found literal
+error: expected a lint, found literal
   --> $DIR/deduplicate-diagnostics.rs:10:8
    |
 LL | #[deny("literal")]
diff --git a/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs b/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs
index 27b033b346307..b070ec0f7dd93 100644
--- a/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs
+++ b/tests/ui/diagnostic-flags/deduplicate-diagnostics.rs
@@ -7,7 +7,7 @@
                       //[duplicate]~| ERROR cannot find derive macro `Unresolved` in this scope
 struct S;
 
-#[deny("literal")] //~ ERROR expected path to a lint, found literal
-                   //[duplicate]~| ERROR expected path to a lint, found literal
-                   //[duplicate]~| ERROR expected path to a lint, found literal
+#[deny("literal")] //~ ERROR expected a lint, found literal
+                   //[duplicate]~| ERROR expected a lint, found literal
+                   //[duplicate]~| ERROR expected a lint, found literal
 fn main() {}
diff --git a/tests/ui/lint/lint-attribute-literals.rs b/tests/ui/lint/lint-attribute-literals.rs
index 137b5b94ea7b7..69fb7f76007a0 100644
--- a/tests/ui/lint/lint-attribute-literals.rs
+++ b/tests/ui/lint/lint-attribute-literals.rs
@@ -1,7 +1,7 @@
 // Checks that lint attributes with literals have an explanatory error
 
 #[allow("literal")]
-//~^ ERROR expected path to a lint, found literal
-//~| ERROR expected path to a lint, found literal
-//~| ERROR expected path to a lint, found literal
+//~^ ERROR expected a lint, found literal
+//~| ERROR expected a lint, found literal
+//~| ERROR expected a lint, found literal
 fn main() {}
diff --git a/tests/ui/lint/lint-attribute-literals.stderr b/tests/ui/lint/lint-attribute-literals.stderr
index 161800c09a869..188a941918c8d 100644
--- a/tests/ui/lint/lint-attribute-literals.stderr
+++ b/tests/ui/lint/lint-attribute-literals.stderr
@@ -1,4 +1,4 @@
-error: expected path to a lint, found literal
+error: expected a lint, found literal
   --> $DIR/lint-attribute-literals.rs:3:9
    |
 LL | #[allow("literal")]
@@ -6,7 +6,7 @@ LL | #[allow("literal")]
    |
    = help: try using `#[allow(literal)]`
 
-error: expected path to a lint, found literal
+error: expected a lint, found literal
   --> $DIR/lint-attribute-literals.rs:3:9
    |
 LL | #[allow("literal")]
@@ -15,7 +15,7 @@ LL | #[allow("literal")]
    = help: try using `#[allow(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: expected path to a lint, found literal
+error: expected a lint, found literal
   --> $DIR/lint-attribute-literals.rs:3:9
    |
 LL | #[allow("literal")]

From 31b27ab32c6a6b09825e3f937661b4e0baceca7f Mon Sep 17 00:00:00 2001
From: annieversary <annie@versary.town>
Date: Sun, 18 Oct 2026 14:17:33 +0100
Subject: [PATCH 27/27] add test for the BadAttributeLitHelp::Other case

---
 tests/ui/lint/lint-attribute-literals.rs     |  4 +++
 tests/ui/lint/lint-attribute-literals.stderr | 28 +++++++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/tests/ui/lint/lint-attribute-literals.rs b/tests/ui/lint/lint-attribute-literals.rs
index 69fb7f76007a0..34a4757adec3c 100644
--- a/tests/ui/lint/lint-attribute-literals.rs
+++ b/tests/ui/lint/lint-attribute-literals.rs
@@ -4,4 +4,8 @@
 //~^ ERROR expected a lint, found literal
 //~| ERROR expected a lint, found literal
 //~| ERROR expected a lint, found literal
+#[deny(1.0)]
+//~^ ERROR expected a lint, found literal
+//~| ERROR expected a lint, found literal
+//~| ERROR expected a lint, found literal
 fn main() {}
diff --git a/tests/ui/lint/lint-attribute-literals.stderr b/tests/ui/lint/lint-attribute-literals.stderr
index 188a941918c8d..7434f8b5c5d4b 100644
--- a/tests/ui/lint/lint-attribute-literals.stderr
+++ b/tests/ui/lint/lint-attribute-literals.stderr
@@ -6,6 +6,14 @@ LL | #[allow("literal")]
    |
    = help: try using `#[allow(literal)]`
 
+error: expected a lint, found literal
+  --> $DIR/lint-attribute-literals.rs:7:8
+   |
+LL | #[deny(1.0)]
+   |        ^^^ not the name of a lint
+   |
+   = help: for example, write `#[deny(dead_code)]` for `dead_code`
+
 error: expected a lint, found literal
   --> $DIR/lint-attribute-literals.rs:3:9
    |
@@ -15,6 +23,15 @@ LL | #[allow("literal")]
    = help: try using `#[allow(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
+error: expected a lint, found literal
+  --> $DIR/lint-attribute-literals.rs:7:8
+   |
+LL | #[deny(1.0)]
+   |        ^^^ not the name of a lint
+   |
+   = help: for example, write `#[deny(dead_code)]` for `dead_code`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error: expected a lint, found literal
   --> $DIR/lint-attribute-literals.rs:3:9
    |
@@ -24,5 +41,14 @@ LL | #[allow("literal")]
    = help: try using `#[allow(literal)]`
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: aborting due to 3 previous errors
+error: expected a lint, found literal
+  --> $DIR/lint-attribute-literals.rs:7:8
+   |
+LL | #[deny(1.0)]
+   |        ^^^ not the name of a lint
+   |
+   = help: for example, write `#[deny(dead_code)]` for `dead_code`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 6 previous errors