LLVM Weekly - #372, February 15th 2021

Welcome to the three hundred and seventy-second 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

The LLVM Foundation have announced the first virtual Community.o Summit. Taking place March 8th to March 10th, this three day virtual event aims to provide an inclusive space for underrepresented groups and newcomers. For more information on Community.o, see the recent LLVM blog post on it.

The schedule for the 5th LLVM workshop at CGO is out.

Stephen Kelly has blogged about a new AST traversal mode available in Clang 12 that makes it easier to write AST matchers.

On the mailing lists

• Geoffrey Martin-Noble has posted a proposal for adding a Bazel build configuration to the LLVM monorepo.

• Cassie Jones shares Vim syntax hightling support for MIR.

• Ricky Taylor kicked off a discussion on 'code beads' for M68k machine code generation.

LLVM commits

• -print-changed=[diff | diff-quiet] will show IR changes between passes in a patch-like format. 4b661b4.

• FileCheck now defaults to allow-unused-prefixes=false. 87dbdd2.

• Scalable vector fused multiply-add (FMA) on RISC-V were made commutable to improve register allocation. b7b4f4c.

• Initial support as added for converting fixed vectors to scalable vectors in the RISC-V backend. a719b66, and more.

• opt's new --print-passes flag will print all available passes. 5d960cb.

• Alignment attributes are now supported for atomicrmw and cmpxchg. d06ab79, 17517f3.

Clang commits

• The -f[no-]finite-loops options were added to control when Clang adds the mustprogress attribute. 51bf4c0.

• Support was added for the swift_async_error attribute. 1e8afba.

Other project commits

• lld-macho received initial ARM64 target support. 87104fa.

• LLD gained support for big endian AArch64. 7605a9a.

• An initial alias analysis framework was added to MLIR. b9c876b.

• The flang driver gained support for -fopenmp and -fopenacc. 6d48a1a.

• Various C++20 concepts were added to libcxx. 8caf835, 2b2f36a, 2193e8b, and more.

• The LLDB FreeBSD plugin gained support for mips64 and powerpc. 8244fc5, bd03f6d.

• Dialect interfaces were introduced to MLIR for translation to LLVM IR, and the OpenMP to LLVM IR translation was migrated to use this infrastructure. b77bac0, 66900b3.