From 0e0b60749129927edb2bab83f684bedf859b2cda Mon Sep 17 00:00:00 2001
From: Andrey Zgarbul <zgarbul.andrey@gmail.com>
Date: Wed, 24 Jan 2024 20:01:34 +0300
Subject: [PATCH] nextafter fix

---
 src/f64.rs  |  4 ++--
 src/f64x.rs | 45 ++++++---------------------------------------
 2 files changed, 8 insertions(+), 41 deletions(-)

diff --git a/src/f64.rs b/src/f64.rs
index e66456b..20b6cd7 100644
--- a/src/f64.rs
+++ b/src/f64.rs
@@ -873,7 +873,7 @@ pub fn nextafter(x: f64, y: f64) -> f64 {
     let mut cxi = x.to_bits() as i64;
     let c = (cxi < 0) == (y < x);
     if c {
-        cxi = -(cxi ^ (1 << 63));
+        cxi = -(cxi ^ i64::MIN);
     }
 
     if x != y {
@@ -881,7 +881,7 @@ pub fn nextafter(x: f64, y: f64) -> f64 {
     }
 
     if c {
-        cxi = -(((cxi as u64) ^ (1u64 << 63)) as i64);
+        cxi = -(cxi ^ i64::MIN);
     }
 
     let cxf = f64::from_bits(cxi as u64);
diff --git a/src/f64x.rs b/src/f64x.rs
index 9836740..c1921e8 100644
--- a/src/f64x.rs
+++ b/src/f64x.rs
@@ -912,47 +912,14 @@ where
     LaneCount<N>: SupportedLaneCount,
 {
     let x = x.simd_eq(F64x::ZERO).select(F64x::ZERO.mul_sign(y), x);
-    let mut xi2 = x.to_bits().cast::<i64>();
+    let xi2 = x.to_bits().cast::<i64>();
     let c = x.is_sign_negative() ^ y.simd_ge(x);
 
-    let mut t = (xi2 ^ I64x::splat(0x_7fff_ffff_ffff_ffff_u64 as _)) + I64x::splat(1);
-    t += swap_upper_lower(
-        I64x::splat(1)
-            & t.simd_eq(I64x::splat(0x_ffff_ffff_0000_0000_u64 as _))
-                .to_int(),
-    );
-    xi2 = c
-        .select(F64x::from_bits(t.cast()), F64x::from_bits(xi2.cast()))
-        .to_bits()
-        .cast();
-
-    xi2 -= (x.simd_ne(y).to_int().cast() & U64x::splat(1)).cast();
-
-    xi2 = x
-        .simd_ne(y)
-        .select(
-            F64x::from_bits(
-                (xi2 + swap_upper_lower(
-                    I64x::splat(0x_ffff_ffff_u64 as _)
-                        & xi2.simd_eq(I64x::splat(0x_ffff_ffff_u64 as _)).to_int(),
-                ))
-                .cast(),
-            ),
-            F64x::from_bits(xi2.cast()),
-        )
-        .to_bits()
-        .cast();
-
-    let mut t = (xi2 ^ I64x::splat(0x_7fff_ffff_ffff_ffff_u64 as _)) + I64x::splat(1);
-    t += swap_upper_lower(
-        I64x::splat(1)
-            & t.simd_eq(I64x::splat(0x_ffff_ffff_0000_0000_u64 as _))
-                .to_int(),
-    );
-    xi2 = c
-        .select(F64x::from_bits(t.cast()), F64x::from_bits(xi2.cast()))
-        .to_bits()
-        .cast();
+    let xi2 = c.select(-(xi2 ^ I64x::splat(i64::MIN)), xi2);
+
+    let xi2 = x.simd_ne(y).select(xi2 - I64x::splat(1), xi2);
+
+    let xi2 = c.select(-(xi2 ^ I64x::splat(i64::MIN)), xi2);
 
     let mut ret = F64x::from_bits(xi2.cast());