LLVM Weekly - #507, September 18th 2023

Welcome to the five hundred and seventh 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 [email protected], @llvmweekly or @asbradbury on Twitter, or @[email protected] or @[email protected].

News and articles from around the web and events

The next LLVM Bay Area monthly meetup will take place on Mon September 25th.

The call for papers for the MLIR workshop at the LLVM developer meeting is up.

Registration is open for the 2023 Clang-built Linux meetup.

According to the LLVM calendar in the coming week there will be:

• Office hours with the following hosts: Phoebe Wang, Johannes Doerfert.
• Online sync-ups on the following topics: Flang, SYCL, LLVM security group, OpenMP in LLVM, classic flang, C/C++ language working group, loop optimisation, OpenMP in Flang, MLIR, PowerPC, and SPIR-V.
• For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.

On the forums

• Stephen Tozer proposed changes to the textual IR representation for debug values, as part of the proposed direction to change the representation of debug values to no longer use instructions.

• Tom Stellard is seeking feedback on how the move to pull requests for LLVM is going.

• Reid Kleckner shared a new proposed timeline for deprecating reviews.llvm.org.

• Kelbon proposes allowing recursive macros as a Clang extension.

• Vlad Serebrennikov provided guidance on triaging GitHub issues.

• MLIR news #55 is out.

• Anton Rydahl posted an RFC on supporting offloaing C++ parallel algorithms to GPUs.

• Evgenii Kudriashov posted an RFC on improving GlobalISel support for X86.

LLVM commits

• load/store/alloca of arrays of scalable vectors is now allowed. c7d65e44.

• A new triple was added for SPIR-V with the logical addressing model. 53b6a16, 56396b2.

• A scheduling model was added for Power7. 69b056d.

• The InlineAsm class was refactored. 93bd428.

• In-tree tests that use -march= for llvm-mc or llc were updated to use -mtriple=, as using -march alone might result in a non-sensical target triple. 806761a, 252c423, cfc1a87.

• Assembly syntax highlighting was implemented for RISC-V. 4e07262.

• RISC-V’s GlobalISel can now select ALU GPR instructions. ac182de.

Clang commits

• --print-suppported-extensions can now be used for AArch64 and Arm targets. 90db419, 99594ba.

• The __reference_constructs_from_temporary type trait builtin was added. 8f3b0b4.

• An experimental option was introduced to completely omit the RTTI field from the vtable when -fno-rtti is used (rather than wasting a pointer-sized space). 6385c1d.

• The new bugprone-compare-pointer-to-member-virtual-function check will warn on equality comparison between pointer to member virtual function and anything other than a null pointer constant. 72d4d4e.

Other project commits

• BOLT now supports linker relaxation on RISC-V. c5ba619.

• The behaviour of printf in LLVM’s libc was documented. aa1eacd.

• Developer documentation was introduced for adding new LLVM libc config options. 7d7df7f.

• std::jthread was implemented in libcxx. 695138c.

• LLDB’s prompt colour can now be customised. 645a385.

• A new buffer deallocation pass was introduced to MLIR, aiming to offer improvements over the previous one. 01334d1.