emscripten-core/emscripten

Add diagnose_if warnings for slow SIMD stuff?

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#12,871 opened on Nov 24, 2020

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 (3 comments) (1 reaction) (0 assignees)C++ (3,519 forks)batch import
good first bughelp wanted

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Description

The SIMD emulation occasionally drops to scalarized code. In addition to putting a bomb emoji in the doc, we can use something like __attribute__((diagnose_if(__EMSCRIPTEN_SIMD_🐌__ < 4, "💣", "warning")))__ to mark them in the header too. Clang would then emit warnings when a tagged function are called. Doing so might help developers with hunting down slow emulations.

Doc: https://clang.llvm.org/docs/AttributeReference.html#diagnose-if

Contributor guide

Research direction
Identify SIMD functions that fall back to scalar code and add the `diagnose if` attribute to emit warnings when they are called.
Tech stack
cpp
Domain
tooling
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
C++Emscripten
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60