LLVM Weekly - #448, August 1st 2022

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LLVM Weekly - #448, August 1st 2022

If you prefer, you can read a HTML version of this email at http://llvmweekly.org/issue/448.

Welcome to the four hundred and forty-eighth 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 high level agenda for 2022 US LLVM Dev Meeting has been announced.

On the forums

LLVM commits

  • The trunk major version is now 16. 809855b.

  • Scalable vectorisation was enabled by default on RISC-V with the V extension. 15c645f.

  • The LangRef and GetElementPtr docs were updated to use opaque pointers for examples. 7ac7ec8, b66ca91.

  • It’s now possible to implement a target-specific policy for disassembler “resyncing” when encountering an instruction that can’t be decoded. 55f1fbf.

  • Arm and AArch64 objdump now uses a prettyprinter to print an instruction encoding as a 32-bit word, rather than bytewise little-endian. 2b38f58.

  • New automation was introduced to automatically assign reviewers for backport requests. f673dcc.

  • The Arm backend now supports an +atomic-32 target feature, which forces LLVM to assume lock-free 32-bit atomics are available even if they usually wouldn’t be. b1b1086.

  • If possible, instructions that are between two adjacent loops will be sunk or hoisted in order to faciliate fusion of the loops. dd3ca65.

  • A target hook was added to allow data prefetches into non-default address spaces. 0562cf4.

Clang commits

  • The soversion for libclang will now change for each new LLVM major release (as it did for LLVM 13 and below). bc39d7bd.

  • RISC-V Vector intrinsics are now lazily generated rather than placed in a huge header file, leading to large speedups. 7a5cb15.

  • A library interface was added for ClangOffloadBunder. 0f3f357.

  • clang-format learned more about handling Verilog inputs. f93182a, 67480b3, 6db0c18, b67ee18, c887194, 60e1206.

  • The maybe_undef attribute was introduced. a35c64c.

  • A new misc-const-correctness clang-tidy check was added, which will add const to unmodified variables. 46ae26e.

Other project commits

  • Implementations of opendir, readdir, closedir, and dirfd were added to LLVM’s libc. 35ea84a.

  • P1004R2 (constexpr std::vector) was implemented in libcxx. 98d3d5b.

  • The API of GEPOp in MLIR’s LLVM dialect was reworked. 37da2a1.

  • A new utility was added to MLIR to sort the operands of commutative operations. This is intended to be used to simplify their matching. b508c56.

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Also, an interesting discussion on coordinating LLVM commits across different projects that has raised several issues with testing, validation and how to share “stable green windows” across LLVM components for related projects.

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Thanks and sorry for missing that - I’ve added a note about it to the copy here and on llvmweekly.org

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