Module `simd`

Portable SIMD module.

This module offers a portable abstraction for SIMD operations that is not bound to any particular hardware architecture.

What is "portable"?

This module provides a SIMD implementation that is fast and predictable on any target.

Portable SIMD works on every target

Unlike target-specific SIMD in std::arch, portable SIMD compiles for every target. In this regard, it is just like "regular" Rust.

Portable SIMD is consistent between targets

A program using portable SIMD can expect identical behavior on any target. In most regards, [Simd<T, N>] can be thought of as a parallelized [T; N] and operates like a sequence of T.

This has one notable exception: a handful of older architectures (e.g. armv7 and powerpc) flush subnormal f32 values to zero. On these architectures, subnormal f32 input values are replaced with zeros, and any operation producing subnormal f32 values produces zeros instead. This doesn't affect most architectures or programs.

Operations use the best instructions available

Operations provided by this module compile to the best available SIMD instructions.

Portable SIMD is not a low-level vendor library, and operations in portable SIMD do not necessarily map to a single instruction. Instead, they map to a reasonable implementation of the operation for the target.

Consistency between targets is not compromised to use faster or fewer instructions. In some cases, std::arch will provide a faster function that has slightly different behavior than the std::simd equivalent. For example, _mm_min_ps¹ can be slightly faster than SimdFloat::simd_min, but does not conform to the IEEE standard also used by f32::min. When necessary, [Simd<T, N>] can be converted to the types provided by std::arch to make use of target-specific functions.

Many targets simply don't have SIMD, or don't support SIMD for a particular element type. In those cases, regular scalar operations are generated instead.

_mm_min_ps(x, y) is equivalent to x.simd_lt(y).select(x, y) ↩

Modules

alloc Memory allocation APIs
any Utilities for dynamic typing or type reflection.
arch SIMD and vendor intrinsics module.
array Utilities for the array primitive type.
ascii Operations on ASCII strings and characters.
assert_matches Unstable module containing the unstable assert_matches macro.
async_iter Composable asynchronous iteration.
autodiff Unstable module containing the unstable autodiff macro.
borrow Utilities for working with borrowed data.
bstr The ByteStr type and trait implementations.
cell Shareable mutable containers.
char Utilities for the char primitive type.
clone The Clone trait for types that cannot be 'implicitly copied'.
cmp Utilities for comparing and ordering values.
contracts Unstable module containing the unstable contracts lang items and attribute macros.
convert Traits for conversions between types.
default The Default trait for types with a default value.
error Interfaces for working with Errors.
f128 Constants for the f128 quadruple-precision floating point type.
f16 Constants for the f16 half-precision floating point type.
f32 Constants for the f32 single-precision floating point type.
f64 Constants for the f64 double-precision floating point type.
ffi Platform-specific types, as defined by C.
fmt Utilities for formatting and printing strings.
from Unstable module containing the unstable From derive macro.
future Asynchronous basic functionality.
hash Generic hashing support.
hint Hints to compiler that affects how code should be emitted or optimized.
index Helper types for indexing slices.
intrinsics Compiler intrinsics.
io Traits, helpers, and type definitions for core I/O functionality.
iter Composable external iteration.
marker Primitive traits and types representing basic properties of types.
mem Basic functions for dealing with memory.
net Networking primitives for IP communication.
num Numeric traits and functions for the built-in numeric types.
ops Overloadable operators.
option Optional values.
os OS-specific functionality.
panic Panic support in the standard library.
panicking Panic support for core
pat Helper module for exporting the pattern_type macro
pin Types that pin data to a location in memory.
prelude The core prelude
primitive This module reexports the primitive types to allow usage that is not possibly shadowed by other declared types.
profiling Profiling markers for compiler instrumentation.
ptr Manually manage memory through raw pointers.
random Random value generation.
range
Experimental replacement range types
result Error handling with the Result type.
simd Portable SIMD module.
slice Slice management and manipulation.
str String manipulation.
sync Synchronization primitives
task Types and Traits for working with asynchronous tasks.
time Temporal quantification.
ub_checks Provides the assert_unsafe_precondition macro as well as some utility functions that cover common preconditions.
unsafe_binder Operators used to turn types into unsafe binders and back.

Macros

assert Asserts that a boolean expression is true at runtime.
assert_eq Asserts that two expressions are equal to each other (using PartialEq).
assert_ne Asserts that two expressions are not equal to each other (using PartialEq).
assert_unsafe_precondition Checks that the preconditions of an unsafe function are followed.
cfg Evaluates boolean combinations of configuration flags at compile-time.
column Expands to the column number at which it was invoked.
compile_error Causes compilation to fail with the given error message when encountered.
concat Concatenates literals into a static string slice.
concat_bytes Concatenates literals into a byte slice.
const_format_args Same as format_args, but can be used in some const contexts.
debug_assert Asserts that a boolean expression is true at runtime.
debug_assert_eq Asserts that two expressions are equal to each other.
debug_assert_ne Asserts that two expressions are not equal to each other.
env Inspects an environment variable at compile time.
file Expands to the file name in which it was invoked.
format_args Constructs parameters for the other string-formatting macros.
include Parses a file as an expression or an item according to the context.
include_bytes Includes a file as a reference to a byte array.
include_str Includes a UTF-8 encoded file as a string.
line Expands to the line number on which it was invoked.
log_syntax Prints passed tokens into the standard output.
matches Returns whether the given expression matches the provided pattern.
module_path Expands to a string that represents the current module path.
option_env Optionally inspects an environment variable at compile time.
panic Panics the current thread.

pattern_type

Creates a pattern type.

type Positive = std::pat::pattern_type!(i32 is 1..);