LLVM Weekly - #350, September 14th 2020
Welcome to the three hundred and fiftieth 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
I didn't spot any relevant news this week. As always, feel free to email in tips.
On the mailing lists
-
Hans Wennborg provided an update on the 11.0.0 release status. There are still release blockers that are awaiting resolution.
-
Stephen Neuendorffer restarted discussion on the use of GitHub PRs, sharing observations from use of PRs by LLVM incubator projects.
-
Min-Yih Hsu shared an RFC on de-optimising cold functions using PGO info. This is motivated by improve compile time performance without heavily impacting the performance of the generated code.
-
ORC JIT Weekly #21 is out. This week: Preview branches for OrcV1 removal, removable code support, and new out-of-process execution support.
LLVM commits
-
An initial GlobalISel skeleton was added for PowerPC. 009cd4e.
-
DeadStoreElimination moved to using MemorySSA by default. fb109c4.
-
A PreserveCFG check was added to the new pass manager which checks all passes that report they preserve CFGs actually do. 28012e00.
-
The Arm cost model was tweaked to make i1 operations expensive in terms of code size for Thumb, as they often involve combining predicates. SimplifyCFG was also updated to consider the cost of combining predicates. 0af4147, 65f78e7.
-
The PowerPC backend now supports clustering stores to adjacent target addresses together. 3c0b325.
-
isKnownNonZero and computeKnownBits were implemented for the freeze instruction. a6183d0.
Clang commits
-
clang-tidy gained a new altera-struct-pack-align checker which finds structs that are inefficiently packed or aligned. This is part of work to add checks related to Altera's OpenCL for FPGA coding guidelines. 156b127.
-
Implementation has started on
[[likely]]and[[unlikely]]attributes. 08196e0. -
Sema support was added for
__attribute__((__swift_error__)), used to translate the error semantics for a function to a compatible Swift interface. f5ab5b2.