projects / rustc.git / blame
| Commit | Line | Data |
|---|---|---|
| f20569fa XL |
1 | //! Implements portable horizontal float vector arithmetic reductions. |
| 2 | ||
| 3 | macro_rules! impl_reduction_float_arithmetic { | |
| 4 | ([$elem_ty:ident; $elem_count:expr]: $id:ident | $test_tt:tt) => { | |
| 5 | impl $id { | |
| 6 | /// Horizontal sum of the vector elements. | |
| 7 | /// | |
| 8 | /// The intrinsic performs a tree-reduction of the vector elements. | |
| 9 | /// That is, for an 8 element vector: | |
| 10 | /// | |
| 11 | /// > ((x0 + x1) + (x2 + x3)) + ((x4 + x5) + (x6 + x7)) | |
| 12 | /// | |
| 13 | /// If one of the vector element is `NaN` the reduction returns | |
| 14 | /// `NaN`. The resulting `NaN` is not required to be equal to any | |
| 15 | /// of the `NaN`s in the vector. | |
| 16 | #[inline] | |
| 17 | pub fn sum(self) -> $elem_ty { | |
| 18 | #[cfg(not(target_arch = "aarch64"))] | |
| 19 | { | |
| 20 | use crate::llvm::simd_reduce_add_ordered; | |
| 21 | unsafe { simd_reduce_add_ordered(self.0, 0 as $elem_ty) } | |
| 22 | } | |
| 23 | #[cfg(target_arch = "aarch64")] | |
| 24 | { | |
| 25 | // FIXME: broken on AArch64 | |
| 26 | // https://github.com/rust-lang-nursery/packed_simd/issues/15 | |
| 27 | let mut x = self.extract(0) as $elem_ty; | |
| 28 | for i in 1..$id::lanes() { | |
| 29 | x += self.extract(i) as $elem_ty; | |
| 30 | } | |
| 31 | x | |
| 32 | } | |
| 33 | } | |
| 34 | ||
| 35 | /// Horizontal product of the vector elements. | |
| 36 | /// | |
| 37 | /// The intrinsic performs a tree-reduction of the vector elements. | |
| 38 | /// That is, for an 8 element vector: | |
| 39 | /// | |
| 40 | /// > ((x0 * x1) * (x2 * x3)) * ((x4 * x5) * (x6 * x7)) | |
| 41 | /// | |
| 42 | /// If one of the vector element is `NaN` the reduction returns | |
| 43 | /// `NaN`. The resulting `NaN` is not required to be equal to any | |
| 44 | /// of the `NaN`s in the vector. | |
| 45 | #[inline] | |
| 46 | pub fn product(self) -> $elem_ty { | |
| 47 | #[cfg(not(target_arch = "aarch64"))] | |
| 48 | { | |
| 49 | use crate::llvm::simd_reduce_mul_ordered; | |
| 50 | unsafe { simd_reduce_mul_ordered(self.0, 1 as $elem_ty) } | |
| 51 | } | |
| 52 | #[cfg(target_arch = "aarch64")] | |
| 53 | { | |
| 54 | // FIXME: broken on AArch64 | |
| 55 | // https://github.com/rust-lang-nursery/packed_simd/issues/15 | |
| 56 | let mut x = self.extract(0) as $elem_ty; | |
| 57 | for i in 1..$id::lanes() { | |
| 58 | x *= self.extract(i) as $elem_ty; | |
| 59 | } | |
| 60 | x | |
| 61 | } | |
| 62 | } | |
| 63 | } | |
| 64 | ||
| 65 | impl crate::iter::Sum for $id { | |
| 66 | #[inline] | |
| 67 | fn sum<I: Iterator<Item = $id>>(iter: I) -> $id { | |
| 68 | iter.fold($id::splat(0.), crate::ops::Add::add) | |
| 69 | } | |
| 70 | } | |
| 71 | ||
| 72 | impl crate::iter::Product for $id { | |
| 73 | #[inline] | |
| 74 | fn product<I: Iterator<Item = $id>>(iter: I) -> $id { | |
| 75 | iter.fold($id::splat(1.), crate::ops::Mul::mul) | |
| 76 | } | |
| 77 | } | |
| 78 | ||
| 79 | impl<'a> crate::iter::Sum<&'a $id> for $id { | |
| 80 | #[inline] | |
| 81 | fn sum<I: Iterator<Item = &'a $id>>(iter: I) -> $id { | |
| 82 | iter.fold($id::splat(0.), |a, b| crate::ops::Add::add(a, *b)) | |
| 83 | } | |
| 84 | } | |
| 85 | ||
| 86 | impl<'a> crate::iter::Product<&'a $id> for $id { | |
| 87 | #[inline] | |
| 88 | fn product<I: Iterator<Item = &'a $id>>(iter: I) -> $id { | |
| 89 | iter.fold($id::splat(1.), |a, b| crate::ops::Mul::mul(a, *b)) | |
| 90 | } | |
| 91 | } | |
| 92 | ||
| 93 | test_if! { | |
| 94 | $test_tt: | |
| 95 | paste::item! { | |
| 96 | pub mod [<$id _reduction_float_arith>] { | |
| 97 | use super::*; | |
| 98 | fn alternating(x: usize) -> $id { | |
| 99 | let mut v = $id::splat(1 as $elem_ty); | |
| 100 | for i in 0..$id::lanes() { | |
| 101 | if i % x == 0 { | |
| 102 | v = v.replace(i, 2 as $elem_ty); | |
| 103 | } | |
| 104 | } | |
| 105 | v | |
| 106 | } | |
| 107 | ||
| 108 | #[cfg_attr(not(target_arch = "wasm32"), test)] | |
| 109 | #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] | |
| 110 | fn sum() { | |
| 111 | let v = $id::splat(0 as $elem_ty); | |
| 112 | assert_eq!(v.sum(), 0 as $elem_ty); | |
| 113 | let v = $id::splat(1 as $elem_ty); | |
| 114 | assert_eq!(v.sum(), $id::lanes() as $elem_ty); | |
| 115 | let v = alternating(2); | |
| 116 | assert_eq!( | |
| 117 | v.sum(), | |
| 118 | ($id::lanes() / 2 + $id::lanes()) as $elem_ty | |
| 119 | ); | |
| 120 | } | |
| 121 | #[cfg_attr(not(target_arch = "wasm32"), test)] | |
| 122 | #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] | |
| 123 | fn product() { | |
| 124 | let v = $id::splat(0 as $elem_ty); | |
| 125 | assert_eq!(v.product(), 0 as $elem_ty); | |
| 126 | let v = $id::splat(1 as $elem_ty); | |
| 127 | assert_eq!(v.product(), 1 as $elem_ty); | |
| 128 | let f = match $id::lanes() { | |
| 129 | 64 => 16, | |
| 130 | 32 => 8, | |
| 131 | 16 => 4, | |
| 132 | _ => 2, | |
| 133 | }; | |
| 134 | let v = alternating(f); | |
| 135 | assert_eq!( | |
| 136 | v.product(), | |
| 137 | (2_usize.pow(($id::lanes() / f) as u32) | |
| 138 | as $elem_ty) | |
| 139 | ); | |
| 140 | } | |
| 141 | ||
| 142 | #[cfg_attr(not(target_arch = "wasm32"), test)] | |
| 143 | #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] | |
| 144 | #[allow(unreachable_code)] | |
| 145 | #[allow(unused_mut)] | |
| 146 | // ^^^ FIXME: https://github.com/rust-lang/rust/issues/55344 | |
| 147 | fn sum_nan() { | |
| 148 | // FIXME: https://bugs.llvm.org/show_bug.cgi?id=36732 | |
| 149 | // https://github.com/rust-lang-nursery/packed_simd/issues/6 | |
| 150 | return; | |
| 151 | ||
| 152 | let n0 = crate::$elem_ty::NAN; | |
| 153 | let v0 = $id::splat(-3.0); | |
| 154 | for i in 0..$id::lanes() { | |
| 155 | let mut v = v0.replace(i, n0); | |
| 156 | // If the vector contains a NaN the result is NaN: | |
| 157 | assert!( | |
| 158 | v.sum().is_nan(), | |
| 159 | "nan at {} => {} | {:?}", | |
| 160 | i, | |
| 161 | v.sum(), | |
| 162 | v | |
| 163 | ); | |
| 164 | for j in 0..i { | |
| 165 | v = v.replace(j, n0); | |
| 166 | assert!(v.sum().is_nan()); | |
| 167 | } | |
| 168 | } | |
| 169 | let v = $id::splat(n0); | |
| 170 | assert!(v.sum().is_nan(), "all nans | {:?}", v); | |
| 171 | } | |
| 172 | ||
| 173 | #[cfg_attr(not(target_arch = "wasm32"), test)] | |
| 174 | #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] | |
| 175 | #[allow(unreachable_code)] | |
| 176 | #[allow(unused_mut)] | |
| 177 | // ^^^ FIXME: https://github.com/rust-lang/rust/issues/55344 | |
| 178 | fn product_nan() { | |
| 179 | // FIXME: https://bugs.llvm.org/show_bug.cgi?id=36732 | |
| 180 | // https://github.com/rust-lang-nursery/packed_simd/issues/6 | |
| 181 | return; | |
| 182 | ||
| 183 | let n0 = crate::$elem_ty::NAN; | |
| 184 | let v0 = $id::splat(-3.0); | |
| 185 | for i in 0..$id::lanes() { | |
| 186 | let mut v = v0.replace(i, n0); | |
| 187 | // If the vector contains a NaN the result is NaN: | |
| 188 | assert!( | |
| 189 | v.product().is_nan(), | |
| 190 | "nan at {} => {} | {:?}", | |
| 191 | i, | |
| 192 | v.product(), | |
| 193 | v | |
| 194 | ); | |
| 195 | for j in 0..i { | |
| 196 | v = v.replace(j, n0); | |
| 197 | assert!(v.product().is_nan()); | |
| 198 | } | |
| 199 | } | |
| 200 | let v = $id::splat(n0); | |
| 201 | assert!(v.product().is_nan(), "all nans | {:?}", v); | |
| 202 | } | |
| 203 | ||
| 204 | #[cfg_attr(not(target_arch = "wasm32"), test)] | |
| 205 | #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] | |
| 206 | #[allow(unused, dead_code)] | |
| 207 | fn sum_roundoff() { | |
| 208 | // Performs a tree-reduction | |
| 209 | fn tree_reduce_sum(a: &[$elem_ty]) -> $elem_ty { | |
| 210 | assert!(!a.is_empty()); | |
| 211 | if a.len() == 1 { | |
| 212 | a[0] | |
| 213 | } else if a.len() == 2 { | |
| 214 | a[0] + a[1] | |
| 215 | } else { | |
| 216 | let mid = a.len() / 2; | |
| 217 | let (left, right) = a.split_at(mid); | |
| 218 | tree_reduce_sum(left) + tree_reduce_sum(right) | |
| 219 | } | |
| 220 | } | |
| 221 | ||
| 222 | let mut start = crate::$elem_ty::EPSILON; | |
| 223 | let mut scalar_reduction = 0. as $elem_ty; | |
| 224 | ||
| 225 | let mut v = $id::splat(0. as $elem_ty); | |
| 226 | for i in 0..$id::lanes() { | |
| 227 | let c = if i % 2 == 0 { 1e3 } else { -1. }; | |
| 228 | start *= 3.14 * c; | |
| 229 | scalar_reduction += start; | |
| 230 | v = v.replace(i, start); | |
| 231 | } | |
| 232 | let simd_reduction = v.sum(); | |
| 233 | ||
| 234 | let mut a = [0. as $elem_ty; $id::lanes()]; | |
| 235 | v.write_to_slice_unaligned(&mut a); | |
| 236 | let tree_reduction = tree_reduce_sum(&a); | |
| 237 | ||
| 238 | // tolerate 1 ULP difference: | |
| 239 | let red_bits = simd_reduction.to_bits(); | |
| 240 | let tree_bits = tree_reduction.to_bits(); | |
| 241 | assert!( | |
| 242 | if red_bits > tree_bits { | |
| 243 | red_bits - tree_bits | |
| 244 | } else { | |
| 245 | tree_bits - red_bits | |
| 246 | } < 2, | |
| 247 | "vector: {:?} | simd_reduction: {:?} | \ | |
| 248 | tree_reduction: {} | scalar_reduction: {}", | |
| 249 | v, | |
| 250 | simd_reduction, | |
| 251 | tree_reduction, | |
| 252 | scalar_reduction | |
| 253 | ); | |
| 254 | } | |
| 255 | ||
| 256 | #[cfg_attr(not(target_arch = "wasm32"), test)] | |
| 257 | #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] | |
| 258 | #[allow(unused, dead_code)] | |
| 259 | fn product_roundoff() { | |
| 260 | // Performs a tree-reduction | |
| 261 | fn tree_reduce_product(a: &[$elem_ty]) -> $elem_ty { | |
| 262 | assert!(!a.is_empty()); | |
| 263 | if a.len() == 1 { | |
| 264 | a[0] | |
| 265 | } else if a.len() == 2 { | |
| 266 | a[0] * a[1] | |
| 267 | } else { | |
| 268 | let mid = a.len() / 2; | |
| 269 | let (left, right) = a.split_at(mid); | |
| 270 | tree_reduce_product(left) | |
| 271 | * tree_reduce_product(right) | |
| 272 | } | |
| 273 | } | |
| 274 | ||
| 275 | let mut start = crate::$elem_ty::EPSILON; | |
| 276 | let mut scalar_reduction = 1. as $elem_ty; | |
| 277 | ||
| 278 | let mut v = $id::splat(0. as $elem_ty); | |
| 279 | for i in 0..$id::lanes() { | |
| 280 | let c = if i % 2 == 0 { 1e3 } else { -1. }; | |
| 281 | start *= 3.14 * c; | |
| 282 | scalar_reduction *= start; | |
| 283 | v = v.replace(i, start); | |
| 284 | } | |
| 285 | let simd_reduction = v.product(); | |
| 286 | ||
| 287 | let mut a = [0. as $elem_ty; $id::lanes()]; | |
| 288 | v.write_to_slice_unaligned(&mut a); | |
| 289 | let tree_reduction = tree_reduce_product(&a); | |
| 290 | ||
| 291 | // tolerate 1 ULP difference: | |
| 292 | let red_bits = simd_reduction.to_bits(); | |
| 293 | let tree_bits = tree_reduction.to_bits(); | |
| 294 | assert!( | |
| 295 | if red_bits > tree_bits { | |
| 296 | red_bits - tree_bits | |
| 297 | } else { | |
| 298 | tree_bits - red_bits | |
| 299 | } < 2, | |
| 300 | "vector: {:?} | simd_reduction: {:?} | \ | |
| 301 | tree_reduction: {} | scalar_reduction: {}", | |
| 302 | v, | |
| 303 | simd_reduction, | |
| 304 | tree_reduction, | |
| 305 | scalar_reduction | |
| 306 | ); | |
| 307 | } | |
| 308 | } | |
| 309 | } | |
| 310 | } | |
| 311 | }; | |
| 312 | } |