[llvm-dev] LLVM Weekly - #324, Mar 16th 2020

Alex Bradbury via llvm-dev llvm-dev at lists.llvm.org
Mon Mar 16 14:47:46 PDT 2020

LLVM Weekly - #324, Mar 16th 2020

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Welcome to the three hundred and twenty-fourth 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 asbradbury.org>, or
@llvmweekly or @asbradbury on Twitter.

## News and articles from around the web

John Regehr and Nuno Lopes have written a [blog post on Alive
2](https://blog.regehr.org/archives/1722). It will take an unoptimised
function in LLVM IR and either proves that it is refined by the optimized
version of the function, or else shows a set of inputs that illustrate a
failure of refinement.

EuroLLVM'20 [has now been cancelled due to

LLVM 10.0.0-rc4 [has now been

## On the mailing lists

* Richard Barton reports that [merging f18 in LLVM as flang has been delayed
until Mon 23rd

* ORC JIT Weekly #8 [is
out](http://lists.llvm.org/pipermail/llvm-dev/2020-March/139938.html). Basic
OrcV2 C Bindings have been added, and a number of MachO and COFF bugs fixed.

* Scott Constable and Zola Bridges
about load value injection mitigation for x86.

* Nigel Perks [sent an update on plans from XMOS for the XCore

* Chris Tetreault wrote an RFC on [refactoring the class hierarchy of
VectorType in the

* Farzad Sadeghi [announced
cgrep](http://lists.llvm.org/pipermail/cfe-dev/2020-March/064836.html), a
grep-like tool for C language source files.

## LLVM commits

* The AVR backend was promoted to a standard backend, built by default.

* Macro fusion was implemented for the PowerPC backend.

* The attributor framework was extended to introduce propagation of known
information based on path exploration.

* CPU definitions were added for the Fujitsu A64FX.

* `IEEEFloat::roundToIntegral` was made more standard conformant.

* Support was added for placing every basic block in a unique ELF text
section, allowing the linker to order them in an arbitrary sequence.

* AssemblerPredicates can now be combined with ORs.

## Clang commits

* Clang will now default to `-fno-common` for all targets, matching the GCC 10
default. [2c36c23](https://reviews.llvm.org/rG2c36c23f347).

* Clang's parsing of GNU C extended asm statement was improved.

* clang-tidy gained a new module to enforce standards specific to the
llvm-libc project. [eb41cc6](https://reviews.llvm.org/rGeb41cc61986).

## Other project commits

* libc now has a Linux implementation of `thrd_create`, `thrd_join`,
`mtc_lock`, and `mtx_unlock`.

* libunwind performance was improved.

* PGO is now disabled for compiler-rt, as it doesn't officially support it.

* In MLIR, HasNoSideEffect was replaced with MemoryEffectInterface.

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