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//! 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);
}
}
}
}
};
}