LLVM Weekly - #556, August 26th 2024

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LLVM Weekly - #556, August 26th 2024

If you prefer, you can read the canonical version of this issue at http://llvmweekly.org/issue/556.

Welcome to the five hundred and fifty-sixth 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

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

  • Office hours with the following hosts: Kristof Beyls, Johannes Doerfert, Amara Emerson.
  • Online sync-ups on the following topics: Pointer authentication, SPIR-V, new contributors, OpenMP, Flang, RISC-V, LLVM’s libc, MLIR.
  • For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.

On the forums

LLVM commits

  • The CPU definition was added for the Hazard3 RISC-V core used in the Raspberry Pi RP2350. 9fa2386.

  • A SME peephole optimiser pass was added for AArch64. 6c189ea.

  • Errata workaround passes were added to the SPARC backend for the Gaisler GR712RC and UT700 cores. 7faf1a0.

  • Vector and vector crypto were added to the RISC-V SiFive P400 scheduler model. 7efa068.

  • CycleAnalysis gained methods to verify cycles and their nesting. b432afc.

  • The C API was extended with support for creating instructions with custom synchronisation scopes. eb7d535.

  • An elect.sync intrinsic was added for NVPTX. d5e9691.

  • Some of the complexity-based canonicalisation was removed from InstCombine on the basis that it’s unreliable / difficult to reason about. a105877.

  • SPIR-V learned to sort basic blocks as required by the SPIR-V spec. 0c07e7c.

  • Lowering of Mul/Div/Shift operations was implemented for the Xtensa backend. fab515c.

  • A new RISC-V peephole was added to reduce VLs based on demanded VL. 26a8a85.

Clang commits

  • Support for the “RealtimeSanitizer” was added. RTSan can be used to detect real-time violations e.g. calls to methods that aren’t safe for use in functions with deterministic runtime requirements. d010ec6.

  • -msmall-data-limit was defaulted to 0. Users of GP relaxation are encouraged to specify the customisation options explicitly. d3864d9.

  • -ffp-model=aggressive was introduced and ffp-model=fast was made more limited in effect. 27e5f50.

  • Support for -fsanitizer-undefined-ignore-overflow-pattern was added, which disables instrumentation around specific common patterns. 295fe0b.

Other project commits

  • LLVM’s libc docs were updated to reflect the new headergen setup. b89fef8.

  • Initial locale.h support was added to LLVM’s libc. 78d8ab2.

  • Materializations are now optional in MLIR’s dialect conversion. d7073c5.