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Merge pull request #31 from thomcc/negxor

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Use xor to implement Neg::neg for floats
This commit is contained in:
Lokathor 2020-10-07 22:15:30 -06:00 • committed by GitHub
commit 0a46ca43e2
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2 changed files with 24 additions and 2 deletions
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17
crates/core_simd/src/ops.rs
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@ -212,7 +212,20 @@ macro_rules! impl_op {
impl core::ops::Neg for $type {
type Output = Self;
fn neg(self) -> Self::Output {
<$type>::splat(-<$scalar>::default()) - self
<$type>::splat(0) - self
}
}
}
};
{ impl Neg for $type:ty, $scalar:ty, @float } => {
impl_ref_ops! {
impl core::ops::Neg for $type {
type Output = Self;
fn neg(self) -> Self::Output {
// FIXME: Replace this with fneg intrinsic once available.
// https://github.com/rust-lang/stdsimd/issues/32
Self::from_bits(<$type>::splat(-0.0).to_bits() ^ self.to_bits())
}
}
}
@ -310,7 +323,7 @@ macro_rules! impl_float_ops {
impl_op! { impl Mul for $vector, $scalar }
impl_op! { impl Div for $vector, $scalar }
impl_op! { impl Rem for $vector, $scalar }
impl_op! { impl Neg for $vector, $scalar }
impl_op! { impl Neg for $vector, $scalar, @float }
impl_op! { impl Index for $vector, $scalar }
)*
)*

9
crates/core_simd/tests/ops_impl/float_macros.rs
View file

@ -289,6 +289,15 @@ macro_rules! float_tests {
assert_biteq!(-v, expected);
}
#[test]
#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
fn neg_odd_floats() {
for v in slice_chunks(&C) {
let expected = apply_unary_lanewise(v, core::ops::Neg::neg);
assert_biteq!(-v, expected);
}
}
#[test]
#[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
fn abs_negative() {