LLVM Weekly - #303, October 21st 2019

Welcome to the three hundred and third issue of LLVM Weekly, a weekly newsletter (published every Monday) covering developments in LLVM, Clang, and related projects. LLVM Weekly is brought to you by Alex Bradbury. Subscribe to future issues at https://llvmweekly.org and pass it on to anyone else you think may be interested. Please send any tips or feedback to asb@asbradbury.org, or @llvmweekly or @asbradbury on Twitter.

I'll be at the LLVM Dev Meeting this week - I look forward to seeing many of you there! I'm giving a talk on lessons learned from the RISC-V backend on Tuesday.

News and articles from around the web

Version 1.4 of the of the pocl OpenCL implementation was released, as was v1.20 of the TTA-based Co-Design Environment. In both cases, support was added for LLVM 9.0.

On the mailing lists

• Tom Stellard is seeking feedback on when committing with git-llvm should become optional. The primary motivation of the git-llvm wrapper script was to enforce a linear commit history. GitHub now supports a branch protection rule for this. Most respondents are in favour of retiring the git-llvm script as soon as possible.

• DeForest Richards is looked for feedback on LLVM docs updates done through the Google Season of Docs.

• Stephen Kelly gave a detailed update on AST matcher. The post also discusses current policy on use of auto in the LLVM codebase.

• Galina Kistanova shares details on Zorg migration for the GitHub monorepo. If you run a bot, do check to see if it may be affected.

• Sriraman Tallam has summarised all the concerns raised about merging Propeller.

• Simon Moll is seeking reviewers for initial patches for the NEC SX-Aurora Vector Engine.

• Alina Sbirlea gives a heads up on patches to delete BasicBlockPass/BasicBlockManager.

• Nicolai Hähnle-Montoro suggests redefining 'convergent' in terms of dynamic instances.

• Tom Stellard flags that SVN commit emails will be replaced with git commit emails week.

LLVM commits

• AArch64 now supports stackframe access to SVE objects. r374772.

• A new pass was introduced to lower is.constant and objectisze intrinsics, replacing the previous lowering in the codegen-prepare pass and instruction selection fallbacks. r374743.

• The RISC-V backend now supports the fastcc calling convention. r374857.

• The RISC-V backend now performs immediate verification in the TargetInstrInvo::verifyInstruction hook. r375006.

• Some initial infrastructural changes were merged for profile-guided size optimisations. r375254.

Clang commits

• As part of the C++20 concepts implementation effort, support for Concept Specialization Expressions and associated constraints was added. r374882, r374938.

• Clang's C++20 support was extended to allow rewriting from comparison operators to <=> / ==. r375306.

• Clang now supports the OpenMP 5.0 'parallel master taskloop' construct. r374791.

• Clang learned the -Wa,-W option to suppress warning messages in the GNU assembler. r374822.

• Documentation was written describing the current level of OpenCL support. r375111.

Other project commits

• LLD's COFF linker learned to report source locations for duplicate symbols. r375218.

• Some initial ARC support landed in LLDB. r375122, r375123.