llvm dev - Nov 2020 - LLVM Weekly - #359, November 16th 2020

LLVM Weekly - #359, November 16th 2020
=====================================
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<http://llvmweekly.org/issue/359>.

Welcome to the three hundred and fifty-ninth 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
be interested. Please send any tips or feedback to <asb at
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@llvmweekly or @asbradbury on Twitter.


## News and articles from around the web

Herb Sutter shared a [trip report from the Autumn ISO C++ standards
meeting](https://herbsutter.com/2020/11/13/trip-report-autumn-iso-c-standards-meeting-virtual/).


## On the mailing lists

* Mike Edwards shared the [plan and timeline for renaming the default LLVM
branch to
'main'](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146615.html).
The change will take place on December 7th.

* Sander De Smalen shared an [update on scalable vectors in
LLVM](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146547.html),
summarising the current state of support, regulary sync-up meeting timings,
and what's next.

* Florian Hahn brought life back to an old discussion on [better support for
complex
numbers](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146568.html),
e.g. to support lowering to FCMLA on AArch64.

* ORC JIT Weekly #26 [is
out](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146633.html),
covering he Orc library break-up, remote TargetProcessControl, and the
beginnings of a runtime.

* Alexander Yermolovich started a discussion on [supporting DWARF64 with
`debug_info` sorting in
LLD](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146522.html).

* Sean Silva posted an RFC on [adding new `SVec<T> ` and `Vec<T>`
convenience
wrappers for
SmallVector](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146613.html),
aiming to make SmallVector easier to use and more difficult to accidentally
misuse.

* Nathan James suggests [adding support for a defined initialisation order of
plugins in
Support/Registry](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146609.html).

* Paul C. Anagnostopoulos shared thoughts on [improving performance of
TableGen
`-emit-dag-isel`](http://lists.llvm.org/pipermail/llvm-dev/2020-November/146563.html),
at a small cost to code size. This triggered further discussion and proposals.


## LLVM commits

* llvm-build has been replaced by plain CMake.
[9218ff5](https://reviews.llvm.org/rG9218ff50f93).

* TableGen gained a `!filter` bang operator.
[91d2e5c](https://reviews.llvm.org/rG91d2e5c81ae).

* `!annotation` metadata was introduced alongside a pass that emits summary
remarks per function with counts for each annotation kind.
[8bb6347](https://reviews.llvm.org/rG8bb6347939b).

* The AMDGPU backend gained an `amdgpu_gfx` calling convention.
[a022b1c](https://reviews.llvm.org/rGa022b1ccd8d).

* A new Orc-RPC based TargetProcessControl implementation was added.
[1d0676b](https://reviews.llvm.org/rG1d0676b54c4).

* The OpenMPIRBuilder gained a CreateCononicalLoop function.
[f44ee0f](https://reviews.llvm.org/rGf44ee0f5e7d).

* The new `-dot-cfg-mssa` options creates a dot-cfg file visualising MemorySSA
information. [45d459e](https://reviews.llvm.org/rG45d459e7522).


## Clang commits

* Initial TableGen definitions of syntax nodes were added.
[55120f7](https://reviews.llvm.org/rG55120f74ca1),
[98aa067](https://reviews.llvm.org/rG98aa067109e).

* The `-fproc-stat-report` option was introduced, which will generate a report
about memory usage and execution time for each called tool.
[92d7a84](https://reviews.llvm.org/rG92d7a84e128).

* Clang gained support for searching for prebuilt implicit modules.
[58c586e](https://reviews.llvm.org/rG58c586e7018).


## Other project commits

* Flang's documentation gained a description of problems with `DO
CONCURRENT`.
[c2bccd6](https://reviews.llvm.org/rGc2bccd66f63).

* LLD's `--time-trace` functionality was expanded with new categories.
[439341b](https://reviews.llvm.org/rG439341b9bf0).

* The lld-macho linker gained basic support for LTO.
[21f8311](https://reviews.llvm.org/rG21f831134c9).