[llvm-dev] LLVM Weekly - #377, March 22nd 2021

Mon Mar 22 11:16:15 PDT 2021

LLVM Weekly - #377, March 22nd 2021
===================================

If you prefer, you can read a HTML version of this email at
<http://llvmweekly.org/issue/377>.

Welcome to the three hundred and seventy-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](https://www.linkedin.com/in/alex-bradbury/). Subscribe to future
issues at <http://llvmweekly.org> and pass it on to anyone else you think may
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@llvmweekly or @asbradbury on Twitter.

## News and articles from around the web

Nothing spotted this week.

## On the mailing lists

* Chris Bieneman [reported
  back](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149220.html) on
  the review managers' decision on adding a Bazel build configuration to the
  LLVM monorepo. A [follow-up
  message](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149226.html)
  provided more detail on the process that resulted in the decision to
  approve.

* Kai Wang posted an RFC on [permitting load/store/alloca for structs
  containing all scalable
  vectors](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149296.html/).

* Ondrej Sykora provided an [update on proposals to implement the BHive
  methodology in
  llvm-exegesis](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149299.html),
  and is seeking feedback on the planned next steps.

* Björn Pettersson [summarised the current status of support for fixed point
  numbers in
  Clang/LLVM](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149216.html).

* Haowei Wu initiated a discussion on [merging llvm-elfabi
  with the llvm-ifs
  tool](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149263.html),
  linking to a [draft merge
  plan](https://gist.github.com/zeroomega/dd3ad98f60a8e601091974d139b85790).

* John Byrd asked if any work had been done on [using TableGen to help
  generate an emulator
  core](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149262.html).

* LLVM GPU News Issue #8 [is
  out](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149302.html).

* Johannes Doerfert shared an RFC on [adding an 'implements'
  attribute](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149310.html).
  This provides a way to replace a callee statically, inside the LLVM
  pipeline.

* Stefan Gränitz
  [proposes](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149300.html)
  changing lli's default JIT engine to Orc rather than MCJIT.

* Philipp Reames posted an RFC to [change the referenceability attributes to
  imply point in time
  facts](https://lists.llvm.org/pipermail/llvm-dev/2021-March/149260.html),
  and to re-infer stronger dereferenceability facts when needed. Respondents
  so far have supported the change, noting that the existing documented
  semantics aren't clear.

## LLVM commits

* Lit will now record test execution times and use that to determine the
  order tests are run in. [1d297f9](https://reviews.llvm.org/rG1d297f90649d).

* Support for fixed-length vectors was added to the RISC-V calling convention.
  [0c5b789](https://reviews.llvm.org/rG0c5b789c7342).

* Support was added for `-fpatchable-fucntion-entry` on RISC-V.
  [6ab8927](https://reviews.llvm.org/rG6ab892793185).

* The OCaml bindings gained DebugInfo support.
  [506df1b](https://reviews.llvm.org/rG506df1bbfd16).

* Scalable-vector masked gather and scatter operations are now supported with
  the RISC-V vector extension.
  [0331399](https://reviews.llvm.org/rG0331399dc934),
  [3495031](https://reviews.llvm.org/rG3495031a39b7).

* The various LLVM sync-up calls are now documented.
  [64bb375](https://reviews.llvm.org/rG64bb3759dda5).

* Intrinsic overloading is now supported for unnamed types, fixing two bugs
  and laying more groundwork for full restrict.
  [04790d9](https://reviews.llvm.org/rG04790d9cfba3).

* VPlan gained plain text dumping, to further aid debugging.
  [93a9d2d](https://reviews.llvm.org/rG93a9d2de8f4f).

* The LangRef was expanded to describe the memory layout for vector types.
  [5737010](https://reviews.llvm.org/rG5737010a7948).

## Clang commits

* `-B` is no longer overloaded to perform GCC detection. `--gcc-toolchain`
  should be used instead. [4c2da86](https://reviews.llvm.org/rG4c2da8641087),
  [94a793f](https://reviews.llvm.org/rG94a793f09665).

* `__rndr` and `__rndrrs` intrinsics were added to AArch64 targets supporting
  Armv8.5-A random number instructions.
  [ab86edb](https://reviews.llvm.org/rGab86edbc88fa).

* Initial support was introduced for the OpenMP interop directive and use
  clause. [410f09a](https://reviews.llvm.org/rG410f09af09b9),
  [c615927](https://reviews.llvm.org/rGc615927c8e38).

## Other project commits

* The MLIR memref dialect was created, and a number of operations from the std
  dialect were moved into it.
  [e231070](https://reviews.llvm.org/rGe2310704d890).

* Helper functions used for the RISC-V `-msave-restore` option were added to
  compiler-rt. [b136a74](https://reviews.llvm.org/rGb136a74efc54).

* LLVM libc gained an implementation of `gmtime`.
  [eaae52c](https://reviews.llvm.org/rGeaae52c1fd45).

* An MLIR Intel AMX dialect was created.
  [6ad7b97](https://reviews.llvm.org/rG6ad7b97e20c2).