Merge pull request #1903 from folkertdev/s390x-llvm-21-fixes

`s390x` llvm 21 improvements

1 files changed, 130 insertions, 93 deletions

diff --git a/library/stdarch/crates/core_arch/src/s390x/vector.rs b/library/stdarch/crates/core_arch/src/s390x/vector.rs
index 9927ff2c625..f6d14c45e0d 100644
--- a/library/stdarch/crates/core_arch/src/s390x/vector.rs
+++ b/library/stdarch/crates/core_arch/src/s390x/vector.rs
@@ -94,8 +94,6 @@ unsafe extern "unadjusted" {
     #[link_name = "llvm.s390.vsrlb"] fn vsrlb(a: vector_signed_char, b: vector_signed_char) -> vector_signed_char;
     #[link_name = "llvm.s390.vslb"] fn vslb(a: vector_signed_char, b: vector_signed_char) -> vector_signed_char;
 
-    #[link_name = "llvm.s390.vsldb"] fn vsldb(a: i8x16, b: i8x16, c: u32) -> i8x16;
-    #[link_name = "llvm.s390.vsld"] fn vsld(a: i8x16, b: i8x16, c: u32) -> i8x16;
     #[link_name = "llvm.s390.vsrd"] fn vsrd(a: i8x16, b: i8x16, c: u32) -> i8x16;
 
     #[link_name = "llvm.s390.verimb"] fn verimb(a: vector_signed_char, b: vector_signed_char, c: vector_signed_char, d: i32) -> vector_signed_char;
@@ -169,13 +167,6 @@ unsafe extern "unadjusted" {
     #[link_name = "llvm.s390.vpklsfs"] fn vpklsfs(a: vector_unsigned_int, b: vector_unsigned_int) -> PackedTuple<vector_unsigned_short, i32>;
     #[link_name = "llvm.s390.vpklsgs"] fn vpklsgs(a: vector_unsigned_long_long, b: vector_unsigned_long_long) -> PackedTuple<vector_unsigned_int, i32>;
 
-    #[link_name = "llvm.s390.vuplb"] fn vuplb (a: vector_signed_char) -> vector_signed_short;
-    #[link_name = "llvm.s390.vuplhw"] fn vuplhw (a: vector_signed_short) -> vector_signed_int;
-    #[link_name = "llvm.s390.vuplf"] fn vuplf (a: vector_signed_int) -> vector_signed_long_long;
-    #[link_name = "llvm.s390.vupllb"] fn vupllb (a: vector_unsigned_char) -> vector_unsigned_short;
-    #[link_name = "llvm.s390.vupllh"] fn vupllh (a: vector_unsigned_short) -> vector_unsigned_int;
-    #[link_name = "llvm.s390.vupllf"] fn vupllf (a: vector_unsigned_int) -> vector_unsigned_long_long;
-
     #[link_name = "llvm.s390.vavgb"] fn vavgb(a: vector_signed_char, b: vector_signed_char) -> vector_signed_char;
     #[link_name = "llvm.s390.vavgh"] fn vavgh(a: vector_signed_short, b: vector_signed_short) -> vector_signed_short;
     #[link_name = "llvm.s390.vavgf"] fn vavgf(a: vector_signed_int, b: vector_signed_int) -> vector_signed_int;
@@ -188,22 +179,6 @@ unsafe extern "unadjusted" {
 
     #[link_name = "llvm.s390.vcksm"] fn vcksm(a: vector_unsigned_int, b: vector_unsigned_int) -> vector_unsigned_int;
 
-    #[link_name = "llvm.s390.vmeb"] fn vmeb(a: vector_signed_char, b: vector_signed_char) -> vector_signed_short;
-    #[link_name = "llvm.s390.vmeh"] fn vmeh(a: vector_signed_short, b: vector_signed_short) -> vector_signed_int;
-    #[link_name = "llvm.s390.vmef"] fn vmef(a: vector_signed_int, b: vector_signed_int) -> vector_signed_long_long;
-
-    #[link_name = "llvm.s390.vmleb"] fn vmleb(a: vector_unsigned_char, b: vector_unsigned_char) -> vector_unsigned_short;
-    #[link_name = "llvm.s390.vmleh"] fn vmleh(a: vector_unsigned_short, b: vector_unsigned_short) -> vector_unsigned_int;
-    #[link_name = "llvm.s390.vmlef"] fn vmlef(a: vector_unsigned_int, b: vector_unsigned_int) -> vector_unsigned_long_long;
-
-    #[link_name = "llvm.s390.vmob"] fn vmob(a: vector_signed_char, b: vector_signed_char) -> vector_signed_short;
-    #[link_name = "llvm.s390.vmoh"] fn vmoh(a: vector_signed_short, b: vector_signed_short) -> vector_signed_int;
-    #[link_name = "llvm.s390.vmof"] fn vmof(a: vector_signed_int, b: vector_signed_int) -> vector_signed_long_long;
-
-    #[link_name = "llvm.s390.vmlob"] fn vmlob(a: vector_unsigned_char, b: vector_unsigned_char) -> vector_unsigned_short;
-    #[link_name = "llvm.s390.vmloh"] fn vmloh(a: vector_unsigned_short, b: vector_unsigned_short) -> vector_unsigned_int;
-    #[link_name = "llvm.s390.vmlof"] fn vmlof(a: vector_unsigned_int, b: vector_unsigned_int) -> vector_unsigned_long_long;
-
     #[link_name = "llvm.s390.vmhb"] fn vmhb(a: vector_signed_char, b: vector_signed_char) -> vector_signed_char;
     #[link_name = "llvm.s390.vmhh"] fn vmhh(a: vector_signed_short, b: vector_signed_short) -> vector_signed_short;
     #[link_name = "llvm.s390.vmhf"] fn vmhf(a: vector_signed_int, b: vector_signed_int) -> vector_signed_int;
@@ -379,7 +354,20 @@ impl<const N: usize> ShuffleMask<N> {
         ShuffleMask(mask)
     }
 
-    const fn pack() -> Self {
+    const fn even() -> Self {
+        let mut mask = [0; N];
+        let mut i = 0;
+        let mut index = 0;
+        while index < N {
+            mask[index] = i as u32;
+
+            i += 2;
+            index += 1;
+        }
+        ShuffleMask(mask)
+    }
+
+    const fn odd() -> Self {
         let mut mask = [0; N];
         let mut i = 1;
         let mut index = 0;
@@ -392,6 +380,10 @@ impl<const N: usize> ShuffleMask<N> {
         ShuffleMask(mask)
     }
 
+    const fn pack() -> Self {
+        Self::odd()
+    }
+
     const fn unpack_low() -> Self {
         let mut mask = [0; N];
         let mut i = 0;
@@ -1201,10 +1193,8 @@ mod sealed {
     test_impl! { vec_roundc_f32 (a: vector_float) -> vector_float [nearbyint_v4f32,  "vector-enhancements-1" vfisb] }
     test_impl! { vec_roundc_f64 (a: vector_double) -> vector_double [nearbyint_v2f64, vfidb] }
 
-    // FIXME(llvm) llvm trunk already lowers roundeven to vfidb, but rust does not use it yet
-    // use https://godbolt.org/z/cWq95fexe to check, and enable the instruction test when it works
-    test_impl! { vec_round_f32 (a: vector_float) -> vector_float [roundeven_v4f32, _] }
-    test_impl! { vec_round_f64 (a: vector_double) -> vector_double [roundeven_v2f64, _] }
+    test_impl! { vec_round_f32 (a: vector_float) -> vector_float [roundeven_v4f32, "vector-enhancements-1" vfisb] }
+    test_impl! { vec_round_f64 (a: vector_double) -> vector_double [roundeven_v2f64, vfidb] }
 
     #[unstable(feature = "stdarch_s390x", issue = "135681")]
     pub trait VectorRoundc {
@@ -2362,6 +2352,9 @@ mod sealed {
         unsafe fn vec_packs(self, b: Other) -> Self::Result;
     }
 
+    // FIXME(llvm): https://github.com/llvm/llvm-project/issues/153655
+    // Other targets can use a min/max for the saturation + a truncation.
+
     impl_vec_trait! { [VectorPacks vec_packs] vpksh (vector_signed_short, vector_signed_short) -> vector_signed_char }
     impl_vec_trait! { [VectorPacks vec_packs] vpklsh (vector_unsigned_short, vector_unsigned_short) -> vector_unsigned_char }
     impl_vec_trait! { [VectorPacks vec_packs] vpksf (vector_signed_int, vector_signed_int) -> vector_signed_short }
@@ -2583,8 +2576,14 @@ mod sealed {
         unsafe fn vec_unpackl(self) -> Self::Result;
     }
 
-    // FIXME(llvm): a shuffle + simd_as does not currently optimize into a single instruction like
-    // unpachk above. Tracked in https://github.com/llvm/llvm-project/issues/129576.
+    // NOTE: `vuplh` is used for "unpack logical high", hence `vuplhw`.
+    impl_vec_unpack!(unpack_low vuplb vector_signed_char i8x8 vector_signed_short 8);
+    impl_vec_unpack!(unpack_low vuplhw vector_signed_short i16x4 vector_signed_int 4);
+    impl_vec_unpack!(unpack_low vuplf vector_signed_int i32x2 vector_signed_long_long 2);
+
+    impl_vec_unpack!(unpack_low vupllb vector_unsigned_char u8x8 vector_unsigned_short 8);
+    impl_vec_unpack!(unpack_low vupllh vector_unsigned_short u16x4 vector_unsigned_int 4);
+    impl_vec_unpack!(unpack_low vupllf vector_unsigned_int u32x2 vector_unsigned_long_long 2);
 
     impl_vec_trait! {[VectorUnpackl vec_unpackl] vuplb (vector_signed_char) -> vector_signed_short}
     impl_vec_trait! {[VectorUnpackl vec_unpackl] vuplhw (vector_signed_short) -> vector_signed_int}
@@ -2645,61 +2644,65 @@ mod sealed {
         unsafe fn vec_mule(self, b: Self) -> Result;
     }
 
-    // FIXME(llvm) sadly this does not yet work https://github.com/llvm/llvm-project/issues/129705
-    //    #[target_feature(enable = "vector")]
-    //    #[cfg_attr(test, assert_instr(vmleh))]
-    //    unsafe fn vec_vmleh(a: vector_unsigned_short, b: vector_unsigned_short) -> vector_unsigned_int {
-    //        let even_a: vector_unsigned_int = simd_as(simd_shuffle::<_, _, u16x4>(
-    //            a,
-    //            a,
-    //            const { ShuffleMask([0, 2, 4, 6]) },
-    //        ));
-    //
-    //        let even_b: vector_unsigned_int = simd_as(simd_shuffle::<_, _, u16x4>(
-    //            b,
-    //            b,
-    //            const { ShuffleMask([0, 2, 4, 6]) },
-    //        ));
-    //
-    //        simd_mul(even_a, even_b)
-    //    }
+    macro_rules! impl_vec_mul_even_odd {
+        ($mask:ident $instr:ident $src:ident $shuffled:ident $dst:ident $width:literal) => {
+            #[inline]
+            #[target_feature(enable = "vector")]
+            #[cfg_attr(test, assert_instr($instr))]
+            unsafe fn $instr(a: $src, b: $src) -> $dst {
+                let elems_a: $dst = simd_as(simd_shuffle::<_, _, $shuffled>(
+                    a,
+                    a, // this argument is ignored entirely.
+                    const { ShuffleMask::<$width>::$mask() },
+                ));
+
+                let elems_b: $dst = simd_as(simd_shuffle::<_, _, $shuffled>(
+                    b,
+                    b, // this argument is ignored entirely.
+                    const { ShuffleMask::<$width>::$mask() },
+                ));
+
+                simd_mul(elems_a, elems_b)
+            }
+        };
+    }
 
-    test_impl! { vec_vmeb(a: vector_signed_char, b: vector_signed_char) -> vector_signed_short [ vmeb, vmeb ] }
-    test_impl! { vec_vmeh(a: vector_signed_short, b: vector_signed_short) -> vector_signed_int[ vmeh, vmeh ] }
-    test_impl! { vec_vmef(a: vector_signed_int, b: vector_signed_int) -> vector_signed_long_long [ vmef, vmef ] }
+    impl_vec_mul_even_odd! { even vmeb vector_signed_char i8x8 vector_signed_short 8 }
+    impl_vec_mul_even_odd! { even vmeh vector_signed_short i16x4 vector_signed_int 4 }
+    impl_vec_mul_even_odd! { even vmef vector_signed_int i32x2 vector_signed_long_long 2 }
 
-    test_impl! { vec_vmleb(a: vector_unsigned_char, b: vector_unsigned_char) -> vector_unsigned_short [ vmleb, vmleb ] }
-    test_impl! { vec_vmleh(a: vector_unsigned_short, b: vector_unsigned_short) -> vector_unsigned_int[ vmleh, vmleh ] }
-    test_impl! { vec_vmlef(a: vector_unsigned_int, b: vector_unsigned_int) -> vector_unsigned_long_long [ vmlef, vmlef ] }
+    impl_vec_mul_even_odd! { even vmleb vector_unsigned_char u8x8 vector_unsigned_short 8 }
+    impl_vec_mul_even_odd! { even vmleh vector_unsigned_short u16x4 vector_unsigned_int 4 }
+    impl_vec_mul_even_odd! { even vmlef vector_unsigned_int u32x2 vector_unsigned_long_long 2 }
 
-    impl_mul!([VectorMule vec_mule] vec_vmeb (vector_signed_char, vector_signed_char) -> vector_signed_short );
-    impl_mul!([VectorMule vec_mule] vec_vmeh (vector_signed_short, vector_signed_short) -> vector_signed_int);
-    impl_mul!([VectorMule vec_mule] vec_vmef (vector_signed_int, vector_signed_int) -> vector_signed_long_long );
+    impl_mul!([VectorMule vec_mule] vmeb (vector_signed_char, vector_signed_char) -> vector_signed_short );
+    impl_mul!([VectorMule vec_mule] vmeh (vector_signed_short, vector_signed_short) -> vector_signed_int);
+    impl_mul!([VectorMule vec_mule] vmef (vector_signed_int, vector_signed_int) -> vector_signed_long_long );
 
-    impl_mul!([VectorMule vec_mule] vec_vmleb (vector_unsigned_char, vector_unsigned_char) -> vector_unsigned_short );
-    impl_mul!([VectorMule vec_mule] vec_vmleh (vector_unsigned_short, vector_unsigned_short) -> vector_unsigned_int);
-    impl_mul!([VectorMule vec_mule] vec_vmlef (vector_unsigned_int, vector_unsigned_int) -> vector_unsigned_long_long );
+    impl_mul!([VectorMule vec_mule] vmleb (vector_unsigned_char, vector_unsigned_char) -> vector_unsigned_short );
+    impl_mul!([VectorMule vec_mule] vmleh (vector_unsigned_short, vector_unsigned_short) -> vector_unsigned_int);
+    impl_mul!([VectorMule vec_mule] vmlef (vector_unsigned_int, vector_unsigned_int) -> vector_unsigned_long_long );
 
     #[unstable(feature = "stdarch_s390x", issue = "135681")]
     pub trait VectorMulo<Result> {
         unsafe fn vec_mulo(self, b: Self) -> Result;
     }
 
-    test_impl! { vec_vmob(a: vector_signed_char, b: vector_signed_char) -> vector_signed_short [ vmob, vmob ] }
-    test_impl! { vec_vmoh(a: vector_signed_short, b: vector_signed_short) -> vector_signed_int[ vmoh, vmoh ] }
-    test_impl! { vec_vmof(a: vector_signed_int, b: vector_signed_int) -> vector_signed_long_long [ vmof, vmof ] }
+    impl_vec_mul_even_odd! { odd vmob vector_signed_char i8x8 vector_signed_short 8 }
+    impl_vec_mul_even_odd! { odd vmoh vector_signed_short i16x4 vector_signed_int 4 }
+    impl_vec_mul_even_odd! { odd vmof vector_signed_int i32x2 vector_signed_long_long 2 }
 
-    test_impl! { vec_vmlob(a: vector_unsigned_char, b: vector_unsigned_char) -> vector_unsigned_short [ vmlob, vmlob ] }
-    test_impl! { vec_vmloh(a: vector_unsigned_short, b: vector_unsigned_short) -> vector_unsigned_int[ vmloh, vmloh ] }
-    test_impl! { vec_vmlof(a: vector_unsigned_int, b: vector_unsigned_int) -> vector_unsigned_long_long [ vmlof, vmlof ] }
+    impl_vec_mul_even_odd! { odd vmlob vector_unsigned_char u8x8 vector_unsigned_short 8 }
+    impl_vec_mul_even_odd! { odd vmloh vector_unsigned_short u16x4 vector_unsigned_int 4 }
+    impl_vec_mul_even_odd! { odd vmlof vector_unsigned_int u32x2 vector_unsigned_long_long 2 }
 
-    impl_mul!([VectorMulo vec_mulo] vec_vmob (vector_signed_char, vector_signed_char) -> vector_signed_short );
-    impl_mul!([VectorMulo vec_mulo] vec_vmoh (vector_signed_short, vector_signed_short) -> vector_signed_int);
-    impl_mul!([VectorMulo vec_mulo] vec_vmof (vector_signed_int, vector_signed_int) -> vector_signed_long_long );
+    impl_mul!([VectorMulo vec_mulo] vmob (vector_signed_char, vector_signed_char) -> vector_signed_short );
+    impl_mul!([VectorMulo vec_mulo] vmoh (vector_signed_short, vector_signed_short) -> vector_signed_int);
+    impl_mul!([VectorMulo vec_mulo] vmof (vector_signed_int, vector_signed_int) -> vector_signed_long_long );
 
-    impl_mul!([VectorMulo vec_mulo] vec_vmlob (vector_unsigned_char, vector_unsigned_char) -> vector_unsigned_short );
-    impl_mul!([VectorMulo vec_mulo] vec_vmloh (vector_unsigned_short, vector_unsigned_short) -> vector_unsigned_int);
-    impl_mul!([VectorMulo vec_mulo] vec_vmlof (vector_unsigned_int, vector_unsigned_int) -> vector_unsigned_long_long );
+    impl_mul!([VectorMulo vec_mulo] vmlob (vector_unsigned_char, vector_unsigned_char) -> vector_unsigned_short );
+    impl_mul!([VectorMulo vec_mulo] vmloh (vector_unsigned_short, vector_unsigned_short) -> vector_unsigned_int);
+    impl_mul!([VectorMulo vec_mulo] vmlof (vector_unsigned_int, vector_unsigned_int) -> vector_unsigned_long_long );
 
     #[unstable(feature = "stdarch_s390x", issue = "135681")]
     pub trait VectorMulh<Result> {
@@ -3322,8 +3325,7 @@ mod sealed {
 
     #[inline]
     #[target_feature(enable = "vector")]
-    // FIXME(llvm): https://github.com/llvm/llvm-project/issues/129899
-    // #[cfg_attr(test, assert_instr(vsegb))]
+    #[cfg_attr(test, assert_instr(vsegb))]
     pub unsafe fn vsegb(a: vector_signed_char) -> vector_signed_long_long {
         simd_as(simd_shuffle::<_, _, i8x2>(
             a,
@@ -3334,8 +3336,7 @@ mod sealed {
 
     #[inline]
     #[target_feature(enable = "vector")]
-    // FIXME(llvm): https://github.com/llvm/llvm-project/issues/129899
-    // #[cfg_attr(test, assert_instr(vsegh))]
+    #[cfg_attr(test, assert_instr(vsegh))]
     pub unsafe fn vsegh(a: vector_signed_short) -> vector_signed_long_long {
         simd_as(simd_shuffle::<_, _, i16x2>(
             a,
@@ -3346,8 +3347,7 @@ mod sealed {
 
     #[inline]
     #[target_feature(enable = "vector")]
-    // FIXME(llvm): https://github.com/llvm/llvm-project/issues/129899
-    // #[cfg_attr(test, assert_instr(vsegf))]
+    #[cfg_attr(test, assert_instr(vsegf))]
     pub unsafe fn vsegf(a: vector_signed_int) -> vector_signed_long_long {
         simd_as(simd_shuffle::<_, _, i32x2>(
             a,
@@ -3485,10 +3485,44 @@ mod sealed {
         unsafe fn vec_sldb<const C: u32>(self, b: Self) -> Self;
     }
 
-    // FIXME(llvm) https://github.com/llvm/llvm-project/issues/129955
-    // ideally we could implement this in terms of llvm.fshl.i128
-    // #[link_name = "llvm.fshl.i128"] fn fshl_i128(a: u128, b: u128, c: u128) -> u128;
-    // transmute(fshl_i128(transmute(a), transmute(b), const { C * 8 } ))
+    #[inline]
+    #[target_feature(enable = "vector")]
+    #[cfg_attr(test, assert_instr(vsldb))]
+    unsafe fn test_vec_sld(a: vector_signed_int, b: vector_signed_int) -> vector_signed_int {
+        a.vec_sld::<13>(b)
+    }
+
+    #[inline]
+    #[target_feature(enable = "vector")]
+    #[cfg_attr(test, assert_instr(vsldb))]
+    unsafe fn test_vec_sldw(a: vector_signed_int, b: vector_signed_int) -> vector_signed_int {
+        a.vec_sldw::<3>(b)
+    }
+
+    #[inline]
+    #[target_feature(enable = "vector-enhancements-2")]
+    #[cfg_attr(test, assert_instr(vsld))]
+    unsafe fn test_vec_sldb(a: vector_signed_int, b: vector_signed_int) -> vector_signed_int {
+        a.vec_sldb::<7>(b)
+    }
+
+    #[inline]
+    #[target_feature(enable = "vector-enhancements-2")]
+    #[cfg_attr(test, assert_instr(vsrd))]
+    unsafe fn test_vec_srdb(a: vector_signed_int, b: vector_signed_int) -> vector_signed_int {
+        a.vec_srdb::<7>(b)
+    }
+
+    unsafe fn funnel_shl_u128(a: u128, b: u128, c: u128) -> u128 {
+        #[repr(simd)]
+        struct Single([u128; 1]);
+
+        transmute(simd_funnel_shl::<Single>(
+            transmute(a),
+            transmute(b),
+            transmute(c),
+        ))
+    }
 
     macro_rules! impl_vec_sld {
         ($($ty:ident)*) => {
@@ -3499,21 +3533,21 @@ mod sealed {
                     #[target_feature(enable = "vector")]
                     unsafe fn vec_sld<const C: u32>(self, b: Self) -> Self {
                         static_assert_uimm_bits!(C, 4);
-                        transmute(vsldb(transmute(self), transmute(b), C))
+                        transmute(funnel_shl_u128(transmute(self), transmute(b), const { C as u128 * 8 }))
                     }
 
                     #[inline]
                     #[target_feature(enable = "vector")]
                     unsafe fn vec_sldw<const C: u32>(self, b: Self) -> Self {
                         static_assert_uimm_bits!(C, 2);
-                        transmute(vsldb(transmute(self), transmute(b), const { 4 * C }))
+                        transmute(funnel_shl_u128(transmute(self), transmute(b), const { C as u128 * 4 * 8 }))
                     }
 
                     #[inline]
                     #[target_feature(enable = "vector-enhancements-2")]
                     unsafe fn vec_sldb<const C: u32>(self, b: Self) -> Self {
                         static_assert_uimm_bits!(C, 3);
-                        transmute(vsld(transmute(self), transmute(b), C))
+                        transmute(funnel_shl_u128(transmute(self), transmute(b), const { C as u128 }))
                     }
                 }
 
@@ -3524,6 +3558,11 @@ mod sealed {
                     unsafe fn vec_srdb<const C: u32>(self, b: Self) -> Self {
                         static_assert_uimm_bits!(C, 3);
                         transmute(vsrd(transmute(self), transmute(b), C))
+                        // FIXME(llvm): https://github.com/llvm/llvm-project/issues/129955#issuecomment-3207488190
+                        // LLVM currently rewrites `fshr` to `fshl`, and the logic in the s390x
+                        // backend cannot deal with that yet.
+                        // #[link_name = "llvm.fshr.i128"] fn fshr_i128(a: u128, b: u128, c: u128) -> u128;
+                        // transmute(fshr_i128(transmute(self), transmute(b), const { C as u128 }))
                     }
                 }
             )*
@@ -4679,11 +4718,9 @@ pub unsafe fn vec_subc_u128(
     a: vector_unsigned_char,
     b: vector_unsigned_char,
 ) -> vector_unsigned_char {
-    // FIXME(llvm) sadly this does not work https://github.com/llvm/llvm-project/issues/129608
-    // let a: u128 = transmute(a);
-    // let b: u128 = transmute(b);
-    // transmute(!a.overflowing_sub(b).1 as u128)
-    transmute(vscbiq(transmute(a), transmute(b)))
+    let a: u128 = transmute(a);
+    let b: u128 = transmute(b);
+    transmute(!a.overflowing_sub(b).1 as u128)
 }
 
 /// Vector Add Compute Carryout unsigned 128-bits
@@ -4715,7 +4752,7 @@ pub unsafe fn vec_adde_u128(
     let a: u128 = transmute(a);
     let b: u128 = transmute(b);
     let c: u128 = transmute(c);
-    // FIXME(llvm) sadly this does not work
+    // FIXME(llvm) https://github.com/llvm/llvm-project/pull/153557
     //     let (d, _carry) = a.carrying_add(b, c & 1 != 0);
     //     transmute(d)
     transmute(vacq(a, b, c))