LLVM Weekly - #349, September 7th 2020

Welcome to the three hundred and forty-ninth 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

C++20 has been approved.

On the mailing lists

• Andrew Litteken posted an RFC on a framework for defining, detecting, and deduplicating similar code sections at the IR level. The RFC presents results for an IR outliner implemented on top of this framework.

• Djordje Todorovic posted an RFC on using DW_OP_entry_value within LLVM IR.

• Petr Hosek is seeking advice on adding a HTTP library to LLVM. The use case is to provide an implementation of debuginfod.

• Atmn Patel posted an RFC on introducing a maynotprogress IR attribute. Johannes Doerfert followed up with further explanation of the issues with llvm.sideefffect.

• Lang Hames sent a heads-up that he intends to remove OrcV1 some point after the 14th of September, inviting any questions.

• Thomas Lively thread about inlining with different target features generated further discussion this week.

LLVM commits

• Experimental MachineInstr stable hashing has been committed, bringing stable hashing to MIRVRegNamer and MIRCanonicalizer. 7fff1fb.

• The FileCheck implementation has been moved out of LLVMSupport and into its own library. e9a3d1a.

• An initial canReplacePointersIfEqual helper was written. 0d966ae.

• -lint has been ported to the new pass manager. c977139.

Clang commits

• A partial implementation of #pragma STDC FENV_ROUND was committed. a633da5.

• New readability-prefer-member-initializer and bugprone-redundant-branch-condition checks were added to clang-tidy. f5fd748, 14dd073.

• The initial toolchain driver was added for z/OS. 3e1e5f5.

• CXRewriter was added to the libclang API. 69e5abb.

Other project commits

• Type constraints were introduced for operands of MLIR's LLVM dialect operations. aec9e20.

• libFuzzer gained an option to keep initial seed inputs. 62673c4.

• libFuzzer will now scale the energy assigned to each input based on the input execution time. 5cda4dc.

• Implementations of remquo[f|l] and remainder[f|l] were added to LLVM's libc. 8514ecb.

• A reproducer verifier was added to LLDB, checking for e.g. a missing or invalid working directory. 3746906.