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Diffstat (limited to 'third_party/rust/packed_simd/src/api/reductions/integer_arithmetic.rs')
| -rw-r--r-- | third_party/rust/packed_simd/src/api/reductions/integer_arithmetic.rs | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/third_party/rust/packed_simd/src/api/reductions/integer_arithmetic.rs b/third_party/rust/packed_simd/src/api/reductions/integer_arithmetic.rs new file mode 100644 index 0000000000..e99e6cb5d7 --- /dev/null +++ b/third_party/rust/packed_simd/src/api/reductions/integer_arithmetic.rs @@ -0,0 +1,193 @@ +//! Implements portable horizontal integer vector arithmetic reductions. + +macro_rules! impl_reduction_integer_arithmetic { + ([$elem_ty:ident; $elem_count:expr]: $id:ident | $ielem_ty:ident + | $test_tt:tt) => { + impl $id { + /// Horizontal wrapping sum of the vector elements. + /// + /// The intrinsic performs a tree-reduction of the vector elements. + /// That is, for an 8 element vector: + /// + /// > ((x0 + x1) + (x2 + x3)) + ((x4 + x5) + (x6 + x7)) + /// + /// If an operation overflows it returns the mathematical result + /// modulo `2^n` where `n` is the number of times it overflows. + #[inline] + pub fn wrapping_sum(self) -> $elem_ty { + #[cfg(not(target_arch = "aarch64"))] + { + use crate::llvm::simd_reduce_add_ordered; + let v: $ielem_ty = unsafe { simd_reduce_add_ordered(self.0, 0 as $ielem_ty) }; + v as $elem_ty + } + #[cfg(target_arch = "aarch64")] + { + // FIXME: broken on AArch64 + // https://github.com/rust-lang-nursery/packed_simd/issues/15 + let mut x = self.extract(0) as $elem_ty; + for i in 1..$id::lanes() { + x = x.wrapping_add(self.extract(i) as $elem_ty); + } + x + } + } + + /// Horizontal wrapping product of the vector elements. + /// + /// The intrinsic performs a tree-reduction of the vector elements. + /// That is, for an 8 element vector: + /// + /// > ((x0 * x1) * (x2 * x3)) * ((x4 * x5) * (x6 * x7)) + /// + /// If an operation overflows it returns the mathematical result + /// modulo `2^n` where `n` is the number of times it overflows. + #[inline] + pub fn wrapping_product(self) -> $elem_ty { + #[cfg(not(target_arch = "aarch64"))] + { + use crate::llvm::simd_reduce_mul_ordered; + let v: $ielem_ty = unsafe { simd_reduce_mul_ordered(self.0, 1 as $ielem_ty) }; + v as $elem_ty + } + #[cfg(target_arch = "aarch64")] + { + // FIXME: broken on AArch64 + // https://github.com/rust-lang-nursery/packed_simd/issues/15 + let mut x = self.extract(0) as $elem_ty; + for i in 1..$id::lanes() { + x = x.wrapping_mul(self.extract(i) as $elem_ty); + } + x + } + } + } + + impl crate::iter::Sum for $id { + #[inline] + fn sum<I: Iterator<Item = $id>>(iter: I) -> $id { + iter.fold($id::splat(0), crate::ops::Add::add) + } + } + + impl crate::iter::Product for $id { + #[inline] + fn product<I: Iterator<Item = $id>>(iter: I) -> $id { + iter.fold($id::splat(1), crate::ops::Mul::mul) + } + } + + impl<'a> crate::iter::Sum<&'a $id> for $id { + #[inline] + fn sum<I: Iterator<Item = &'a $id>>(iter: I) -> $id { + iter.fold($id::splat(0), |a, b| crate::ops::Add::add(a, *b)) + } + } + + impl<'a> crate::iter::Product<&'a $id> for $id { + #[inline] + fn product<I: Iterator<Item = &'a $id>>(iter: I) -> $id { + iter.fold($id::splat(1), |a, b| crate::ops::Mul::mul(a, *b)) + } + } + + test_if! { + $test_tt: + paste::item! { + pub mod [<$id _reduction_int_arith>] { + use super::*; + + fn alternating(x: usize) -> $id { + let mut v = $id::splat(1 as $elem_ty); + for i in 0..$id::lanes() { + if i % x == 0 { + v = v.replace(i, 2 as $elem_ty); + } + } + v + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] + #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn wrapping_sum() { + let v = $id::splat(0 as $elem_ty); + assert_eq!(v.wrapping_sum(), 0 as $elem_ty); + let v = $id::splat(1 as $elem_ty); + assert_eq!(v.wrapping_sum(), $id::lanes() as $elem_ty); + let v = alternating(2); + if $id::lanes() > 1 { + assert_eq!( + v.wrapping_sum(), + ($id::lanes() / 2 + $id::lanes()) as $elem_ty + ); + } else { + assert_eq!( + v.wrapping_sum(), + 2 as $elem_ty + ); + } + } + #[cfg_attr(not(target_arch = "wasm32"), test)] + #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn wrapping_sum_overflow() { + let start = $elem_ty::max_value() + - ($id::lanes() as $elem_ty / 2); + + let v = $id::splat(start as $elem_ty); + let vwrapping_sum = v.wrapping_sum(); + + let mut wrapping_sum = start; + for _ in 1..$id::lanes() { + wrapping_sum = wrapping_sum.wrapping_add(start); + } + assert_eq!(wrapping_sum, vwrapping_sum, "v = {:?}", v); + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] + #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn wrapping_product() { + let v = $id::splat(0 as $elem_ty); + assert_eq!(v.wrapping_product(), 0 as $elem_ty); + let v = $id::splat(1 as $elem_ty); + assert_eq!(v.wrapping_product(), 1 as $elem_ty); + let f = match $id::lanes() { + 64 => 16, + 32 => 8, + 16 => 4, + _ => 2, + }; + let v = alternating(f); + if $id::lanes() > 1 { + assert_eq!( + v.wrapping_product(), + (2_usize.pow(($id::lanes() / f) as u32) + as $elem_ty) + ); + } else { + assert_eq!( + v.wrapping_product(), + 2 as $elem_ty + ); + } + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] + #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn wrapping_product_overflow() { + let start = $elem_ty::max_value() + - ($id::lanes() as $elem_ty / 2); + + let v = $id::splat(start as $elem_ty); + let vmul = v.wrapping_product(); + + let mut mul = start; + for _ in 1..$id::lanes() { + mul = mul.wrapping_mul(start); + } + assert_eq!(mul, vmul, "v = {:?}", v); + } + } + } + } + }; +} |