LLVM Weekly - #231, June 4th 2018
Welcome to the two hundred and thirty-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 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
Nathan Froyd muses on the possibility of Firefox building using LLVM and Clang across all major platforms, and the advantages/disadvantages/risks of standardising on a single compiler toolchain.
On the mailing lists
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Michael Kruse has written RFCs on extending #pragma clang loop and extending loop metadata in LLVM. As explained in the RFC, the intent is to propose a form of these loop transformation pragmas to the OpenMP standard.
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Sohail Somani proposes a new API to simplify the interface for creating new forms of debug info metadata.
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Anast Gramm reports on an investigation of the impact of the Scalar Replacement of Aggregates pass on debuginfo. Although the DExTer tool showed SROA had a negative impact on debug experience, Anast's experiment indicated that SROA does a good job of preserving debug information. Greg Bedwell offers clarification on some of the subtleties of interpreting DExTer results.
LLVM commits
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A new WebAssembly exception handling prepare pass was added. r333696.
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ADDE/ADDC/SUBE/SUBC have been set to expand by default. Out-of-tree backends that use these deprecated opcodes may need to be updated. r333748.
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The RISC-V backend gained peepholes to improve codegen for some common global address lowering cases. The intent is to replace these peepholes with a more complete MachineFunctionPass. r333455.
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The core logic of LoopInstSimplify has been rewritten to be both simpler and more efficient. r333461.
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The MCSchedModel API was extended with new methods for querying latency and reciprocal throughput information for an MCInst. r333650.
Clang commits
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Initial infrastructure for the HIP language has started to land. As explained in the original RFC, HIP is a language similar to CUDA but with a vendor neutral host API. r333483, r333484.
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The
-compiler-option-dumpflag will dump features/extensions lists to a JSON file. r333653.