swiftlang/swift

[SR-10817] Gaps in arithmetic benchmarking / testing

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#53,207 opened on Jun 1, 2019

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benchmarksbuggood first issuestandard library

Description
Previous ID SR-10817
Radar None
Original Reporter @stephentyrone
Type Bug
Votes 0
Component/s Standard Library
Labels Bug, Benchmark, StarterBug, Test
Assignee None
Priority Medium

md5: af326874c16fabc95a608b2cf02675cf

Issue Description:

We are in need of tests and/or benchmarks to ensure that arithmetic operations in Swift compile down to single instructions (when a single instruction on the target captures the necessary semantics).

These could plausibly take the form of either benchmarks or regression tests; regression tests are good because we can directly validate that we get single IR or assembly operations where appropriate, benchmarks are also good in some cases, where we don't necessarily have a single instruction replacement for an operation (integer smart shifts, for example).

Contributor guide

Tech stack
swift
Domain
testingperformance
Issue type
bug
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.
1-2 days
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.
mostly clear
Prerequisites
Swift programmingFamiliarity with XCTestBasic compiler concepts
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65
Research direction
Examine the existing Swift test suite in the 'test' directory for arithmetic related tests. Look at benchmarks in the 'benchmark' directory for examples. The issue specifically mentions ensuring that integer addition compiles to a single add instruction. Start by writing a simple test that compiles a Swift file containing an addition and verify the generated LLVM IR using the Swift compiler's emit ir flag. Alternatively, create a benchmark using the Swift Benchmark Suite to measure performance of arithmetic operations.