LLVM Weekly - #459, October 17th 2022

Welcome to the four hundred and fifty-ninth 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 http://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.

News and articles from around the web

The build of LLVM used by rustc is now optimised with BOLT, resulting in 3-5% build time improvements of Rust crates.

Reddit user “catcat202x” wrote up notes on additions to GCC so far in the GCC 13 development cycle.

On the forums

• Arthur Eubanks started a discussion about what to do with the ‘legacy’ opt pass syntax as part of the move to the new pass manager.

• Raghavan Raman shared an RFC proposal for broadcasting in the MLIR Tensor Compute Primitive dialect.

• Artem Dergachev commented with thoughts on the tension between encouragement to discuss ideas early and often and the community’s desire for things to be fully worked out.

• Schrodinger Zhu sought feedback on using the ‘swisstable’ hash table implementation for hsearch in LLVM’s libc.

• eop Chen posted an updated RFC for loop vectorisation of width 1.

• The next Berlin LLVM meetup will take place on October 26th.

• Tanya Lattner sent a reminder about LLVM Dev Meeting registration.

LLVM commits

• The LLVM go bindings were removed. bc839b4.

• The RISC-V backend now generates better code for selects with 0 in either arm. 1c41d0c.

• llvm-reduce gained an opcode reduction pass. 573a5de.

• The developer policy on potentially breaking changes was updated to reflect what was agreed on Discourse. 8673444.

Clang commits

• Clang’s thread safety analysis was extended to support copy-elided production of scoped capabilities through arbitrary calls. 54bfd04.

• Work started on record types in the Clang interpreter, as well as a range of other additions. 1942a25, 5421234, c9ad877, d704ba2, and more.

• nullptr and nullptr_t are now supported in C2x mode. 3a31970.

• The redundant -menable-unsafe-fp-math option was removed. 84a9ec2.

• clang-tidy gained a cppcoreguidelines-avoid-do-while check. 1ae33bf.

• The clang(-tools) pseudo-parse approach to parse disambiguation was documented. b13f7f9.

Other project commits

• Documentation was added on a new “HLFIR” (high-level FIR) dialect for Flang. 0623ce1.

• LLVM’s libc gained implementations of functions including getrandom, pthread_atfork, isatty, and getcwd. 9eb1185, 438e591, 7639ba6, 8b0e84a.

• The C++17 <memory_resource> header was added to libcxx. 243da90.

• OpenMP gained documentation on multi-architecture binary handling and for linking OpenMP with CUDA/HIP. 55d043c, 316eaa3.