LLVM Weekly - #319, Feb 10th 2020

Welcome to the three hundred and nineteenth 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

Videos from the FOSDEM LLVM devroom are now available online.

Bartlomiej Filipek has posted a blog in preparation for the Prague ISO C++ meeting highlighting a selection of papers and current status.

On the mailing lists

• Erich Keane proposes supporting an extended integer type in Clang, allowing use of LLVM's iN. Much of the following discussion was about whether to be consistent with C's promotion rules, or to have no promotion rules and require everything be explicit.

• Gábor Márton started an RFC thread on supporting function summaries in the Clang Static Analyzer.

• Petr Penzin has attempted to summarise the various Fortran LLVM front-end projects and their status.

• Eli Friedman's RFC on extending shufflevector for vscale vectors generated more discussion this week, e.g. feedback from Chris Lattner and from Sander De Smalen.

• The 4th installment of the ORC JIT Weekly is out: A preview of the new JIT initializer system has been posted in D74300.

• Fangrui Song provided further feedback on the proposed Propeller post-link optimisation framework from an LLD perspective.

• Nikita Popov is seeking feedback on moving IRBuilder to use virtual dispatch, moving away from the current design that is templated over a constant folder and an instruction inserter.

• Fangrui Song proposes adding a preprocessor to yaml2obj and other YAML tools.

• Christopher Di Bella is interested in contributing a ranges implementation to libcxx.

LLVM commits

• -stack-clash-protection was implemented for X86. e67cbac.

• VectorCombine, a new pass for partial vector ops was implemented. a17f03b.

• Initial work started to land to allow preserving information from assumes. a7bbe45.

• The VE backend now supports vararg function callers and callees. 07c9f75.

• ThinLTO was made more efficient when performing export computation, especially when constant variable importing is enabled. bed4d9c.

• A replaceOperand() helper was introduced to InstCombine. 878cb38.

• The SystemZ backend gained support for -msoft-float. 563e847.

• The AVR backend started to gain some disassembly tests. ea8b2cb.

• AsmPrinter will now print floating point constants in hex instead of decimal form. 01edae1.

• A CallGraph updater helper class was introduced. 72277ec.

Clang commits

• The Clang Static Analyzer started to model STL algorithms, in order to improve the iterator checkers. b198f16.

• Support was added for the OpenMP 5.0 order(concurrent) clause cb8e691, a781521.

• As part of the C++20 implementation effort, consteval-specific semantics were added for functions. 008e7bf.

Other project commits

• The MLIR declarative assembly format was documented. c1bcdb9.

• MLIR gained initial support for emitting line table information when exporting to LLVM IR. c33d697.

• ELF LLD started to make use of the LLVM time tracing infrastructure. e7cb374.

• The NetBSD Process plugin for LLDB gained support for i386. 5cc817b.

• LLDB's NetBSD status was documented. 273f638.