From bdcccba55cddfa2c47ba322efec5dc110865edd1 Mon Sep 17 00:00:00 2001
From: Caleb Zulawski <caleb.zulawski@gmail.com>
Date: Sun, 13 Jun 2021 17:52:44 +0000
Subject: [PATCH] Implement Sum/Product traits

---
 crates/core_simd/src/iter.rs | 52 ++++++++++++++++++++++++++++++++++++
 crates/core_simd/src/lib.rs  |  1 +
 2 files changed, 53 insertions(+)
 create mode 100644 crates/core_simd/src/iter.rs

diff --git a/crates/core_simd/src/iter.rs b/crates/core_simd/src/iter.rs
new file mode 100644
index 000000000000..c49715932b48
--- /dev/null
+++ b/crates/core_simd/src/iter.rs
@@ -0,0 +1,52 @@
+macro_rules! impl_traits {
+    { $type:ident, $scalar:ty } => {
+        impl<const LANES: usize> core::iter::Sum<Self> for crate::$type<LANES>
+        where
+            Self: crate::LanesAtMost32,
+        {
+            fn sum<I: core::iter::Iterator<Item = Self>>(iter: I) -> Self {
+                iter.fold(Default::default(), core::ops::Add::add)
+            }
+        }
+
+        impl<const LANES: usize> core::iter::Product<Self> for crate::$type<LANES>
+        where
+            Self: crate::LanesAtMost32,
+        {
+            fn product<I: core::iter::Iterator<Item = Self>>(iter: I) -> Self {
+                iter.fold(Default::default(), core::ops::Mul::mul)
+            }
+        }
+
+        impl<const LANES: usize> core::iter::Sum<crate::$type<LANES>> for $scalar
+        where
+            crate::$type<LANES>: crate::LanesAtMost32,
+        {
+            fn sum<I: core::iter::Iterator<Item = crate::$type<LANES>>>(iter: I) -> Self {
+                iter.sum::<crate::$type<LANES>>().horizontal_sum()
+            }
+        }
+
+        impl<const LANES: usize> core::iter::Product<crate::$type<LANES>> for $scalar
+        where
+            crate::$type<LANES>: crate::LanesAtMost32,
+        {
+            fn product<I: core::iter::Iterator<Item = crate::$type<LANES>>>(iter: I) -> Self {
+                iter.product::<crate::$type<LANES>>().horizontal_product()
+            }
+        }
+    }
+}
+
+impl_traits! { SimdF32, f32 }
+impl_traits! { SimdF64, f64 }
+impl_traits! { SimdU8, u8 }
+impl_traits! { SimdU16, u16 }
+impl_traits! { SimdU32, u32 }
+impl_traits! { SimdU64, u64 }
+impl_traits! { SimdUsize, usize }
+impl_traits! { SimdI8, i8 }
+impl_traits! { SimdI16, i16 }
+impl_traits! { SimdI32, i32 }
+impl_traits! { SimdI64, i64 }
+impl_traits! { SimdIsize, isize }
diff --git a/crates/core_simd/src/lib.rs b/crates/core_simd/src/lib.rs
index 7fe7d666e8d8..5b74d1d574a6 100644
--- a/crates/core_simd/src/lib.rs
+++ b/crates/core_simd/src/lib.rs
@@ -22,6 +22,7 @@ pub use to_bytes::ToBytes;
 mod comparisons;
 mod fmt;
 mod intrinsics;
+mod iter;
 mod ops;
 mod round;