LLVM Weekly - #656, July 27th 2026
If you prefer, you can read the canonical version of this issuel at https://llvmweekly.org/issue/656.
Welcome to the six 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 via email: asb@asbradbury.org, or Mastodon: @llvmweekly@fosstodon.org / @asb@fosstodon.org, or Bluesky: @llvmweekly.org / @asbradbury.org.
News and articles from around the web and events
I didn’t spot any particular blog posts or news this time round. As always, feel free to drop me an email if there’s something you think I should include.
According to the LLVM Calendar in the coming week there will be the following:
- Office hours with the following hosts: None this week.
- Online sync-ups on the following topics: formal specification, LLVM pointer authentication, OpenMP in LLVM, Flang, RISC-V, LLVM libc, HLSL, LLVM libc math.
- For more details see the LLVM calendar, getting involved documentation on online sync ups and office hours.
On the forums
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MafĂŞ GuimarĂŁes posted an RFC related to their GSoC work on improving HLSL support in clangd.
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Bojun Seo proposed adding a DoubleFreeSanitizer.
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Tatiana Larina started an RFC thread on adding lightweight instrumentation, " a new Clang/LLVM instrumentation mode that reuses the frontend site selection from -fprofile-instr-generate but lowers instrumentation sites to a user-defined callback instead of inline counters."
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LLVM 23.1.0-rc1 was released.
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Donát Nagy suggests unifying PthreadLockChecker and BlockInCriticalSection checkers in Clang’s static analyser.
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Yaxun (Sam) Liu posted an RFC on adding
__builtin_pointee_address_spaceto clang. Respondents are suggesting that a general__addressspaceof()operator may be better. -
Victor Perez would like to add LLVM IR-style floating point literals to MLIR.
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Bea Healy and Moritz Scherer shared an RFC on adding an AXI4 dialect to CIRCT.
LLVM commits
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A MachineRegisterClassInfo analysis pass was added which can cache the result of RegisterClassInfo to save compile time. a9a25df.
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A scalar replacement of aggregates pass implementation for logical pointers (i.e. those created by llvm.structured.gep and llvm.structured.alloca) was implemented. 03b5c52.
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The RISC-V backend now always enables memcmp/bcmp expansion for pointers known to be aligned. ca276b4.
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A more efficient algorithm for identifying cycles was used. e49aac8.
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Triple::getDefaultFloatABIwas added. 8bbaac6. -
lit was migrated to ProcessPoolExecutor. 14bfc424.
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The deprecated
BranchInstwas removed now the migration toUncondBrandCondBrwas completed. 14304ef.
Clang commits
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A flag
-fdefined-pointer-subtractionwas added for making pointer subtraction defined. 6d8d3f8. -
ClangIR’s lowering learned to generate a cleanup region for loops when needed. e00944c.
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A
performance-expensive-value-orclang-tidy check was added which identifies calls tovalue_oron optional types where the return type is expensive to copy. 2e32c6c.
Other project commits
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LLDB now has a document on platform/target support requirements. b227ed7.
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An MLIR commit was landed introducing full support for raising WASM MLIR to other dialects. f61499b.
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Initial documentation was added on adding a new BOLT backend. a822836.
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float128 emulation was introduced to LLVM’s libc. 7c445ab.
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std::function_refwas implemented in libcxx. a434fe8.