LLVM Weekly - #514, November 6th 2023
If you prefer, you can read a HTML version of this email at http://llvmweekly.org/issue/514.
Welcome to the five hundred and fourteenth 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 http://llvmweekly.org and pass it on to anyone else you think may be interested. Please send any tips or feedback to asb@asbradbury.org, @llvmweekly or @asbradbury on Twitter, or @llvmweekly@fosstodon.org or @asb@fosstodon.org.
News and articles from around the web and events
LLVM 17.0.4 was released.
According to the LLVM calendar in the coming week there will be:
- Office hours with the following hosts: Tobias Grosser, Kristof Beyls, Johannes Doerfert, BOLT maintainers.
- Online sync-ups on the following topics: Pointer authentication, OpenMP, RISC-V, MLIR open meeting, embedded toolchains…
- For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.
On the forums
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Louis Dionne shared a note on an upcoming ABI break in std::expected and parts of
<ranges>in LLVM 18. -
Mingming Liu posted an RFC on dynamic type profiling and optimisations in LLVM, noting this improved throughput by 0.3% on some internal workloads.
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Mehdi Amini notes that users may now create branches on the LLVM repo.
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Anton Lydike kicked off an RFC thread on an MPI MLIR dialect.
LLVM commits
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Wording for “what is considered a security issue” in LLVM’s security documentation was clarified. d16d149e.
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The
nnegflag was introduced for thezextinstruction, which asserts that the argument is non-negative. This allows zext to be converted back into sext later, if deemed profitable. ed3f06b, 3f2ed81. -
Some post-isel RISC-V vector peepholes were moved to a MachineFunction pass. 72e6c1c.
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MC/DC (modified condition/decision coverage) source-based code coverage support was relanded. f95b2f1.
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MachineInstr gained an insert operation. a41b149.
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The ‘writable’ attribute was added to LLVM IR. 6b8ed78.
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zext and sext constant expressions were removed. e4a4122.
Clang commits
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APINotesReader was upstreamed from Apple’s Clang tree. bb352b6.
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-fassume-nothrow-exception-dtorwas added, which assumes the destructor of a thrown exception object will not throw. c0a7391.