Alex Bradbury via llvm-dev
2020-Mar-23 20:30 UTC
[llvm-dev] LLVM Weekly - #325, Mar 23rd 2020
LLVM Weekly - #325, Mar 23rd 2020 ================================ If you prefer, you can read a HTML version of this email at <http://llvmweekly.org/issue/325>. 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 tagged](http://lists.llvm.org/pipermail/llvm-dev/2020-March/140191.html). ## On the mailing lists * The 3rd MLIR newsletter is [now out](https://llvm.discourse.group/t/mlir-news-3rd-edition-3-20-2020/670). * ORC JIT Weekly #9 [is out](http://lists.llvm.org/pipermail/llvm-dev/2020-March/140162.html). OrcV2 JITEventListener support (with fixes) has landed. * Anton Korobeynikov has sent a note out [for students thinking of submitting proposals for LLVM in GSoC](http://lists.llvm.org/pipermail/llvm-dev/2020-March/140029.html). * Rahman Lavaee shared a plan for [handling Intel JCC mitigation using Propeller](http://lists.llvm.org/pipermail/llvm-dev/2020-March/140134.html). * Farzad Sadeghi posted an RFC on [adding his cgrep utility to clang-tools-extra](http://lists.llvm.org/pipermail/cfe-dev/2020-March/064878.html). * Kristóf Umann has [shared a patch implementing reaching definitions calculation for C++](http://lists.llvm.org/pipermail/cfe-dev/2020-March/064913.html) and is seeking feedback. * Ties Stuij proposes [adding a new bfloat IR type for the C bfloat16 format in Armv8.6-a](http://lists.llvm.org/pipermail/cfe-dev/2020-March/064948.html). Respondents discussed whether an IR type was necessary. * Evandro Menezes shared a [draft proposal for a compact code model for RISC-V](http://lists.llvm.org/pipermail/llvm-dev/2020-March/140109.html). ## 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. [080dd10](https://reviews.llvm.org/rG080dd10f7df). * 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. [2b52e4e](https://reviews.llvm.org/rG2b52e4e629e), [dc81923](https://reviews.llvm.org/rGdc81923659c). * Lit gained support for flaky tests through the `ALLOW_RETRIES` keyword. [f951b0f](https://reviews.llvm.org/rGf951b0f82df). * Documentation was added to explain loop rotation. [7fa2045](https://reviews.llvm.org/rG7fa204580df). * 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. [73cea83](https://reviews.llvm.org/rG73cea83a6f5). * 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. [8b409ea](https://reviews.llvm.org/rG8b409eabaf7). * 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. [dcbcec4](https://reviews.llvm.org/rGdcbcec4822f). * 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 section. [fc37526](https://reviews.llvm.org/rGfc3752665f4). ## Other project commits * libc gained implementations of `memcpy`, `sigaction`, and `signal`. [04a309d](https://reviews.llvm.org/rG04a309dd0be), [4d35055](https://reviews.llvm.org/rG4d35055635a), [ca04d0c](https://reviews.llvm.org/rGca04d0c8fd2). * libc now has a range of Arm optimised routines. [0928368](https://reviews.llvm.org/rG0928368f623). * MLIR gained support for out of tree projects embedding it using CMake. [7ca473a](https://reviews.llvm.org/rG7ca473a27bd).