LLVM Weekly - #514, November 6th 2023
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
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.
Mehdi Amini notes that users may now create branches on the LLVM repo.
Anton Lydike kicked off an RFC thread on an MPI MLIR dialect.
LLVM commits
Wording for “what is considered a security issue” in LLVM’s security documentation was clarified. d16d149e.
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.
MC/DC (modified condition/decision coverage) source-based code coverage support was relanded. f95b2f1.
MachineInstr gained an insert operation. a41b149.
The ‘writable’ attribute was added to LLVM IR. 6b8ed78.
zext and sext constant expressions were removed. e4a4122.
Clang commits
APINotesReader was upstreamed from Apple’s Clang tree. bb352b6.
-fassume-nothrow-exception-dtorwas added, which assumes the destructor of a thrown exception object will not throw. c0a7391.