[llvm-dev] LLVM Weekly - #325, Mar 23rd 2020
Alex Bradbury via llvm-dev
llvm-dev at lists.llvm.org
Mon Mar 23 13:30:55 PDT 2020
LLVM Weekly - #325, Mar 23rd 2020
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Welcome to the three hundred and twenty-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](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
LLVM 10.0.0-rc6 [has been
## On the mailing lists
* The 3rd MLIR newsletter is [now
* ORC JIT Weekly #9 [is
JITEventListener support (with fixes) has landed.
* Anton Korobeynikov has sent a note out [for students thinking of submitting
proposals for LLVM in
* Rahman Lavaee shared a plan for [handling Intel JCC mitigation using
* Farzad Sadeghi posted an RFC on [adding his cgrep utility to
* Kristóf Umann has [shared a patch implementing reaching definitions
C++](http://lists.llvm.org/pipermail/cfe-dev/2020-March/064913.html) and is
* Ties Stuij proposes [adding a new bfloat IR type for the C bfloat16 format
Respondents discussed whether an IR type was necessary.
* Evandro Menezes shared a [draft proposal for a compact code model for
## LLVM commits
* The register data flow (RDF) framework was moved from the Hexagon backend to
the shared CodeGen library, to enable it to be used by other targets.
* Known bits constant folding was removed on the basis that it is incredibly
expensive but almost never has an impact on generated code. As a further
follow-up, the ExpensiveCombines option was removed altogether.
* Lit gained support for flaky tests through the `ALLOW_RETRIES` keyword.
* Documentation was added to explain loop rotation.
* The second in a series of patches to enable basic block sections (one BB per
ELF section) was committed. [df082ac](https://reviews.llvm.org/rGdf082ac45aa).
* Arm learned to spill extra registers when compiling for `-Oz` in cases where
inter-procedural register allocation may benefit from this.
* The RISC-V backend gained improved codegen for materialising +0.0 floating
point immediates. [3c24aee](https://reviews.llvm.org/rG3c24aee7ee8).
## Clang commits
* A tablegen backend was added to generated builtins and a header for SVE.
* Support was added for the `-mdouble=x` flag to set the width of double types
for AVR. [4add249](https://reviews.llvm.org/rG4add2492055).
* clang-format can now handle C# generic type constraints.
* The Clang driver now accepts and `-mstall-data-limit` argument for RISC-V,
which will put global and static data smaller than the limit into a special
## Other project commits
* libc gained implementations of `memcpy`, `sigaction`, and `signal`.
* libc now has a range of Arm optimised routines.
* MLIR gained support for out of tree projects embedding it using CMake.
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