From 4c48771da2f64489426a8cbebadf9aa6aac601ed Mon Sep 17 00:00:00 2001
From: Folkert de Vries <folkert@folkertdev.nl>
Date: Sat, 22 Feb 2025 19:40:02 +0100
Subject: [PATCH] add `vec_nabs`

---
 .../crates/core_arch/src/s390x/macros.rs      |  3 +-
 .../crates/core_arch/src/s390x/vector.rs      | 40 +++++++++++++++++++
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/library/stdarch/crates/core_arch/src/s390x/macros.rs b/library/stdarch/crates/core_arch/src/s390x/macros.rs
index 565465c348fe..2c40fedae24f 100644
--- a/library/stdarch/crates/core_arch/src/s390x/macros.rs
+++ b/library/stdarch/crates/core_arch/src/s390x/macros.rs
@@ -436,8 +436,7 @@ macro_rules! impl_neg {
         impl crate::ops::Neg for s_t_l!($s) {
             type Output = s_t_l!($s);
             fn neg(self) -> Self::Output {
-                let zero = $s::splat($zero);
-                unsafe { transmute(simd_sub(zero, transmute(self))) }
+                unsafe { simd_neg(self) }
             }
         }
     };
diff --git a/library/stdarch/crates/core_arch/src/s390x/vector.rs b/library/stdarch/crates/core_arch/src/s390x/vector.rs
index 27153ae9ae90..22e0eb5ec997 100644
--- a/library/stdarch/crates/core_arch/src/s390x/vector.rs
+++ b/library/stdarch/crates/core_arch/src/s390x/vector.rs
@@ -506,6 +506,31 @@ mod sealed {
     impl_vec_trait! { [VectorAbs vec_abs] vec_abs_f32 (vector_float) }
     impl_vec_trait! { [VectorAbs vec_abs] vec_abs_f64 (vector_double) }
 
+    #[unstable(feature = "stdarch_s390x", issue = "135681")]
+    pub trait VectorNabs {
+        unsafe fn vec_nabs(self) -> Self;
+    }
+
+    #[inline]
+    #[target_feature(enable = "vector")]
+    #[cfg_attr(
+        all(test, target_feature = "vector-enhancements-1"),
+        assert_instr(vflnsb)
+    )]
+    unsafe fn vec_nabs_f32(a: vector_float) -> vector_float {
+        simd_neg(simd_fabs(a))
+    }
+
+    #[inline]
+    #[target_feature(enable = "vector")]
+    #[cfg_attr(test, assert_instr(vflndb))]
+    unsafe fn vec_nabs_f64(a: vector_double) -> vector_double {
+        simd_neg(simd_fabs(a))
+    }
+
+    impl_vec_trait! { [VectorNabs vec_nabs] vec_nabs_f32 (vector_float) }
+    impl_vec_trait! { [VectorNabs vec_nabs] vec_nabs_f64 (vector_double) }
+
     #[unstable(feature = "stdarch_s390x", issue = "135681")]
     pub trait VectorSplats<Output> {
         unsafe fn vec_splats(self) -> Output;
@@ -1528,6 +1553,17 @@ where
     a.vec_abs()
 }
 
+/// Vector negative abs.
+#[inline]
+#[target_feature(enable = "vector")]
+#[unstable(feature = "stdarch_s390x", issue = "135681")]
+pub unsafe fn vec_nabs<T>(a: T) -> T
+where
+    T: sealed::VectorNabs,
+{
+    a.vec_nabs()
+}
+
 /// Vector splats.
 #[inline]
 #[target_feature(enable = "vector")]
@@ -2351,6 +2387,10 @@ mod tests {
     test_vec_abs! { test_vec_abs_f32, f32x4, -42f32, 42f32 }
     test_vec_abs! { test_vec_abs_f64, f64x2, -42f64, 42f64 }
 
+    test_vec_1! { test_vec_nabs, vec_nabs, f32x4,
+    [core::f32::consts::PI, 1.0, 0.0, -1.0],
+    [-core::f32::consts::PI, -1.0, 0.0, -1.0] }
+
     test_vec_2! { test_vec_andc, vec_andc, i32x4,
     [0b11001100, 0b11001100, 0b11001100, 0b11001100],
     [0b00110011, 0b11110011, 0b00001100, 0b10000000],