LLVM Weekly - #156, Dec 26th 2016

Welcome to the one hundred and fifty-sixth 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 bug-fix LLVM 3.9.1 release has taken place.

GCC 6.3 has been released. This is a bug-fix release from the GCC 6 branch.

RamFuzz is a Clang-based tool for fuzzing method parameters. Logging and replay (with mutation) is supported.

On the mailing lists

• Piotr Padlewski kicked off a discussion on canonicalising getelementptr with zero-offset. Chandler Carruth made a case for canonicalising towards gep 0,0 rather than a bitcast.

• George Burgess IV shared an RFC on allowing @llvm.objectsize to be more conservative with null.

• Paul Robinson queried a case where the compiler appeared to be zero-initialising a struct twice. Richard Smith helpfully clarified what is going on.

LLVM commits

• The initial version of the 'NewGVN' global value numbering algorithm implementation has landed. r290346.

• GlobalISel implementation work continues, with the addition of a basic tablegen backend. r290284.

• A POWER9 processor model was added for scheduling. r290102.

• ARM and PPC support has been added to the update_llc_test_checks.py script. r290144, r290370.

• The GlobPattern class has been imported into LLVM from LLD. r290212.

• Codegen for the x86 vectorcall calling convention has landed. r290240.

Clang commits

• It is now possible to use the (still experimental) new pass manager with Clang. r290450.

• The alloc_size attribute has been introduced. This allows the number of bytes that will be returned by malloc/realloc/calloc or similar functions to be inferred. r290297.

• -disable-llvm-optzns is now an alias for -disable-llvm-passes. r290392.

Other project commits

• LLD learned the --retain-symbols-file option. r290122.

• polly will now align newly-created arrays to the first-level cache line boundary. r290253.