rust/library
Alex Crichton 625462202e Use the trifecta div algorithm for 128-bit div on wasm
This commit updates the `#[cfg]` annotations used to select the
implementation of 128-bit division in compiler-builtins on wasm targets.
This is done with relation to
https://github.com/WebAssembly/128-bit-arithmetic where performance of
128-bit operations is being investigated on WebAssembly. While I don't
know much about the particulars of the two algorithms involved here the
comments indicate that the "trifecta" variant is preferred if possible
but it's not selected on 32-bit architectures. This rationale isn't as
applicable to WebAssembly targets because despite the 32-bit pointer
width there are often wider-than-pointer operations available as it's
typically run on 64-bit machines.

Locally in testing a benchmark that performs division with a Rust-based
bignum libraries whent from 350% slower-than-native to 220%
slower-than-native with this change, a nice increase in speed. While
this was tested with Wasmtime other runtimes are likely to see an
improvement as well.
2024-09-05 09:03:28 -07:00
..
compiler-builtins Use the trifecta div algorithm for 128-bit div on wasm 2024-09-05 09:03:28 -07:00