Re: [Linaro-TCWG-CI] gcc-17-2325-g4302e16581b4: 10 regressions on arm
Project / Subsystem
gcc / gcc-17-2325-g4302e16581b4
Date
2026-07-16
Proposer
Richard Biener <richard.guenther@gmail.com>
Source type
public_inbox
Consensus
Proposed
Sentiment
—/10
Technical tradeoffs
- • Enabling trapping math for test coverage conflicts with fast-math optimizations needed for NEON vectorization tests.
- • The interaction between flags leads to unexpected errors in the test suite, indicating a need for better flag management or test case isolation.
All attributes
- project
- gcc
- subsystem
- gcc-17-2325-g4302e16581b4
- patch_id
- —
- discussion_id
- CAFiYyc0rt5sPOBEMxamBHeQo4KMxjrGOLY7bSEVO8YEYZJzccQ@mail.gmail.com
- source_type
- public_inbox
- title
- Re: [Linaro-TCWG-CI] gcc-17-2325-g4302e16581b4: 10 regressions on arm
- headline
- gcc-17-2325-g4302e16581b4: 10 regressions on arm
- tldr
- A commit adding testcases for trapping math with comparisons caused regressions on ARM due to an interaction with -ffast-math.
- proposer
- Richard Biener <richard.guenther@gmail.com>
- consensus
- Proposed
- outcome
- proposed
- sentiment_score
- —
- technical_tradeoffs
-
- • Enabling trapping math for test coverage conflicts with fast-math optimizations needed for NEON vectorization tests.
- • The interaction between flags leads to unexpected errors in the test suite, indicating a need for better flag management or test case isolation.
- series_id
- —
- series_role
- standalone
- series_parts
- []
- tags
-
- • gcc
- • ARM
- • vectorization
- • testing
- • regression
- url
- https://inbox.sourceware.org/gcc/CAFiYyc0rt5sPOBEMxamBHeQo4KMxjrGOLY7bSEVO8YEYZJzccQ@mail.gmail.com
- bugzilla_url
- —
- date
- 2026-07-16T00:00:00.000Z
Re: [Linaro-TCWG-CI] gcc-17-2325-g4302e16581b4: 10 regressions on arm
This thread discusses 10 regressions on ARM architectures caused by commit gcc-17-2325-g4302e16581b4, which introduced test cases for trapping math operations with comparisons. Richard Biener explains that the regressions stem from an interaction between the new test cases using -ftrapping-math and the existing test suite logic, which sets -ffast-math for NEON vectorization support. This combination leads to unexpected behavior, specifically manifesting as ‘excess errors’ in test cases like vect-111.c.