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LLVM Weekly - #51, Dec 22nd 2014

Welcome to the fifty-first 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 and pass it on to anyone else you think may be interested. Please send any tips or feedback to, or @llvmweekly or @asbradbury on Twitter.

Last week as part of the lowRISC project I was involved in sharing our plans for tagged memory and 'minion' cores in the initial version. We've almost made it a full year of LLVM Weekly with no interruption of service!

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News and articles from around the web

3.5.1-rc2 has been tagged, time to get testing again.

Version 0.15.1 of LDC, the LLVM D Compiler has been released. The most prominent feature is probably the addition of preliminary support for MSVC on Win64.

SN Systems (part of Sony) have written a blog post describing their recently contributed ABI test suite.

Peter Wilmott has benchmarked Ruby across various GCC and Clang releases. The discussion at HN may be of interest.

On the mailing lists

LLVM commits

  • Metadata is now typeless in assembly. r224257.

  • PowerPC instruction selection for bit-permuting operations has been improved. r224318.

  • An optimisation has been added to move sign/zero extends close to loads which causes performance improvements of 2-3% on a few benchmarks on x86. r224351.

  • More overflow arithmetic intrinsics are strength reduced into regular arithmetic operations if possible. r224417.

Clang commits

  • Codegen for 'omp for' has started to be committed. r224233.

  • -save-temps will now emit unoptimized bitcode files. r224688.

Other project commits

  • The libcxx test suite can be run with ccache now. r224603.

  • Breakpoints can now be tagged with a name in lldb. r224392.