LLVM Weekly - #377, March 22nd 2021

Welcome to the three hundred and seventy-seventh 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 asb@asbradbury.org, or @llvmweekly or @asbradbury on Twitter.

News and articles from around the web

Nothing spotted this week.

On the mailing lists

• Chris Bieneman reported back on the review managers' decision on adding a Bazel build configuration to the LLVM monorepo. A follow-up message provided more detail on the process that resulted in the decision to approve.

• Kai Wang posted an RFC on permitting load/store/alloca for structs containing all scalable vectors.

• Ondrej Sykora provided an update on proposals to implement the BHive methodology in llvm-exegesis, and is seeking feedback on the planned next steps.

• Björn Pettersson summarised the current status of support for fixed point numbers in Clang/LLVM.

• Haowei Wu initiated a discussion on merging llvm-elfabi with the llvm-ifs tool, linking to a draft merge plan.

• John Byrd asked if any work had been done on using TableGen to help generate an emulator core.

• LLVM GPU News Issue #8 is out.

• Johannes Doerfert shared an RFC on adding an ‘implements’ attribute. This provides a way to replace a callee statically, inside the LLVM pipeline.

• Stefan Gränitz proposes changing lli’s default JIT engine to Orc rather than MCJIT.

• Philipp Reames posted an RFC to change the referenceability attributes to imply point in time facts, and to re-infer stronger dereferenceability facts when needed. Respondents so far have supported the change, noting that the existing documented semantics aren’t clear.

LLVM commits

• Lit will now record test execution times and use that to determine the order tests are run in. 1d297f9.

• Support for fixed-length vectors was added to the RISC-V calling convention. 0c5b789.

• Support was added for -fpatchable-fucntion-entry on RISC-V. 6ab8927.

• The OCaml bindings gained DebugInfo support. 506df1b.

• Scalable-vector masked gather and scatter operations are now supported with the RISC-V vector extension. 0331399, 3495031.

• The various LLVM sync-up calls are now documented. 64bb375.

• Intrinsic overloading is now supported for unnamed types, fixing two bugs and laying more groundwork for full restrict. 04790d9.

• VPlan gained plain text dumping, to further aid debugging. 93a9d2d.

• The LangRef was expanded to describe the memory layout for vector types. 5737010.

Clang commits

• -B is no longer overloaded to perform GCC detection. --gcc-toolchain should be used instead. 4c2da86, 94a793f.

• __rndr and __rndrrs intrinsics were added to AArch64 targets supporting Armv8.5-A random number instructions. ab86edb.

• Initial support was introduced for the OpenMP interop directive and use clause. 410f09a, c615927.

Other project commits

• The MLIR memref dialect was created, and a number of operations from the std dialect were moved into it. e231070.

• Helper functions used for the RISC-V -msave-restore option were added to compiler-rt. b136a74.

• LLVM libc gained an implementation of gmtime. eaae52c.

• An MLIR Intel AMX dialect was created. 6ad7b97.