LLVM Weekly - #495, June 26th 2023

LLVM Weekly - #495, June 26th 2023

If you prefer, you can read a HTML version of this email at http://llvmweekly.org/issue/495.

Welcome to the four hundred and ninety-fifth 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, @llvmweekly or @asbradbury on Twitter, or @llvmweekly@fosstodon.org or @asb@fosstodon.org.

News and articles from around the web and events

Fangrui Song blogged about porting LLVM’s XRay to Apple systems and C++ standard library ABI compatibility.

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

  • Office hours with the following hosts: Kirstof Beyls, Johannes Doerfert.
  • Online sync-ups on the following topics: Flang, MLIR C/C++ frontend, pointer authentication, SYCL, OpenMP, classic Flang, loop optimisations, OpenMP in Flang, MLIR open meeting, SPIR-V.
  • For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.

On the forums

LLVM commits

  • An Cortex A510 scheduling model was added. ef9159c.

  • TrigramIndex from the LLVM support library was removed on the basis that it doesn’t appear to make SpecialCaseList::match() faster as intended. 1390675.

  • The -misched-detail-resource-booking flag was added to llc. 37db9ca.

  • The RISCVMoveMerge pass as added to perform peephole optimisation that enabled the Zcmp cm.mvsa01 and cm.mva01s instructions to be used (instructions for moving to/from a0-a1 and s0-s7, defined to help reduce code size). c9e08fa.

  • llvm-exegesis gained a subprocess executor mode. 4d618b5.

  • The CORE-V XCVmac extension is now supported in the RISC-V backend MC layer. e219dd8.

  • LLVM can now generate execute-only code for armv6m. 2273741.

  • The sample profile reader was optimised using MD5 as a key to the sample profile map. 31af18b.

Clang commits

  • The new misc-header-include-cycle check can be used to detect cyclic include dependencies between user-defined headers. 7f6e005.

  • __builtin_elementwise_round was introduced. 2a488b4.

  • Clang learned to warn for invalid Arm or AArch64 target triples. 041ffc1.

Other project commits

  • Support for baremetal 32-bit RISC-V was added to LLVM’s libc. 9fa7998.

  • Large parts of the libc++ codebase were reformatted with clang-format. 5aa03b6.

  • LLD gained support for Arm’s “byte-invariant” big endian configuration. 8cf8956.

  • The new register info command in LLDV will show all information LLDB knows about a register. ba85f20, bcfe5a5.

  • The TransformRewriter was added to MLIR. c63d2b2.

Can you re-check this list? I’m pretty sure the next meeting of Clang C/C++ language working group is scheduled next week.

1 Like

The next Clang C/C++ language WG meeting is July 5th.

1 Like

Thanks - sorry, transcription error where I didn’t fully delete the topics from last week. Fixed now.