LLVM Weekly - #360, November 23rd 2020

Welcome to the three hundred and sixtieth 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. Subscribe to future issues at https://llvmweekly.org and pass it on to anyone else you think may be interested. Please send any tips or feedback to [email protected], or @llvmweekly or @asbradbury on Twitter.

News and articles from around the web

Support for the Cranelift code generation backend has been merged into Rust as an optional alternative to LLVM offering 20-30% faster build times.

Some previously missing videos from past LLVM Dev Meetings have been uploaded to the LLVM YouTube channel.

On the mailing lists

• Paul C. Anagnostopoulos has posted the second occasional TableGen newsletter, covering recent documentation updates and feature additions.

• Fāng-ruì Sòng proposes adding an -fbinutils-verstion= option to Clang.

• Geoffrey Martin-Noble restarted discussion on contributing Bazel BUILD files to LLVM, framing it in the context of the recently agreed support policy.

• Paulo Matos has shared an RFC on supporting multiple program address spaces in LLVM. This is motivated by the support of reference types in WebAssembly.

• Yuanke Luo authored an RFC on supporting the Intel AMX programming model in LLVM.

• Mike Edwards linked to notes from the GitHub Pull Requests round table at the LLVM Dev Meeting, which led to a sub-thread bout rebase-based CI setups.

• Rong Xu distributed an RFC on control-flow sensitive AutoFDO, which aims to mantain more proced AutoFDO profile counts for duplicated control flow.

• Tom Stellard posted the proposed LLVM 11.0.1 release schedule.

LLVM commits

• A new llvm.pseudoprobe IR intrinsic was introduced for pseudo-probe block instrumentation. See the RFC for more background. f3c4456.

• Support was added for "out of line atomics" on AArch64. 4d7df43.

• A default address space for globals can now be specified in DataLayout. 3bc4157.

• A SchedMachineModel was added for the Cortex-M7. 48b43c9.

• BasicAA's checks for whether two getelementptrs with different offsets alias were generalised and unified. cd3c22c4.

• RISC-V bitmanip GREVI and GORCI are now lowered as custom nodes, allowing more complex patterns to be matched. 1ac9b54.

Clang commits

• The OpenMP 5.1 feature status table was updated. 7046be1

• clangd gained an extension method to dump the AST. 8adc4d1.

Other project commits

• LLDB was extended to show tagged regions on AArch64 Linux when the memory tagging extension (MTE) is enabled. 3254168.

• Sparse tensor compiler support was started in MLIR. eced4a8.

• New builtins were introduced to compiler-rt to convert between fp16 and fp128. 1fb91fc.

• LLVM's libc gained implementations of ldexp[f|l]. bb8f258.

• LLVM's libcxx was ported to the NuttX RTOS. f0785c1.