LLVM 23.0.0git Release Notes ¶

Warning

These are in-progress notes for the upcoming LLVM 23.0.0git release. Release notes for previous releases can be found on the Download Page.

Introduction ¶

This document contains the release notes for the LLVM Compiler Infrastructure, release 23.0.0git. Here we describe the status of LLVM, including major improvements from the previous release, improvements in various subprojects of LLVM, and some of the current users of the code. All LLVM releases may be downloaded from the LLVM releases web site.

For more information about LLVM, including information about the latest release, please check out the main LLVM web site. If you have questions or comments, the Discourse forums is a good place to ask them.

Note that if you are reading this file from a Git checkout or the main LLVM web page, this document applies to the next release, not the current one. To see the release notes for a specific release, please see the releases page.

Non-comprehensive list of changes in this release ¶

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Changes to the LLVM IR ¶

Removed llvm.convert.to.fp16 and llvm.convert.from.fp16 intrinsics. These are equivalent to fptrunc and fpext with half with a bitcast.
“denormal-fp-math” and “denormal-fp-math-f32” string attributes were migrated to first-class denormal_fpenv attribute.
The "nooutline" attribute is now writen as nooutline. Existing IR and bitcode will be automatically updated.

Changes to LLVM infrastructure ¶

Removed Constant::isZeroValue. It was functionally identical to Constant::isNullValue for all types except floating-point negative zero. All callers should use isNullValue instead. isZeroValue will be reintroduced in the future with bitwise-all-zeros semantics to support non-zero null pointers.
Removed TypePromoteFloat legalization from SelectionDAG

Changes to building LLVM ¶

Changes to TableGen ¶

Changes to Interprocedural Optimizations ¶

Changes to Vectorizers ¶

Changes to the AArch64 Backend ¶

The sysp, mrrs, and msrr instructions are now accepted without requiring the +d128 feature gating.

Changes to the AMDGPU Backend ¶

Initial support for gfx1310

Changes to the ARM Backend ¶

The r14 register can now be used as an alias for the link register lr in inline assembly. Clang always canonicalizes the name to lr, but other frontends may not.

Changes to the AVR Backend ¶

Changes to the DirectX Backend ¶

Changes to the Hexagon Backend ¶

Changes to the LoongArch Backend ¶

DWARF fission is now compatible with linker relaxations, allowing -gsplit-dwarf and -mrelax to be used together when building for the LoongArch platform.

Changes to the MIPS Backend ¶

Changes to the NVPTX Backend ¶

The default SM version has been changed from sm_30 to sm_75. sm_75 is the oldest GPU variant compatible with the widest range of recent major CUDA Toolkit versions (11/12/13).

Changes to the PowerPC Backend ¶

Changes to the RISC-V Backend ¶

llvm-objdump now has support for --symbolize-operands with RISC-V.
-mcpu=spacemit-x100 was added.
Change P extension version to match the 019 draft specification. Encoded in -march as 0p19.
Mnemonics for MOP/HINT-based instructions (lpad, pause, ntl.*, c.ntl.*, sspush, sspopchk, ssrdp, c.sspush, c.sspopchk) are now always available in the assembler and disassembler without requiring their respective extensions.
Adds experimental assembler support for the ‘Zvabd` (RISC-V Integer Vector Absolute Difference) extension.
-mcpu=spacemit-a100 was added.

Changes to the WebAssembly Backend ¶

Changes to the Windows Target ¶

The .seh_startchained and .seh_endchained assembly instructions have been removed and replaced with a new .seh_splitchained instruction.

Changes to the X86 Backend ¶

.att_syntax directive is now emitted for assembly files when AT&T syntax is in use. This matches the behaviour of Intel syntax and aids with compatibility when changing the default Clang syntax to the Intel syntax.

Changes to the OCaml bindings ¶

Changes to the Python bindings ¶

Changes to the C API ¶

Changes to the CodeGen infrastructure ¶

Changes to the Metadata Info ¶

Changes to the Debug Info ¶

Changes to the LLVM tools ¶

llvm-objcopy no longer corrupts the symbol table when --update-section is called for ELF files.
FileCheck option -check-prefix now accepts a comma-separated list of prefixes, making it an alias of the existing -check-prefixes option.

Changes to LLDB ¶

Deprecated APIs ¶

SBTarget::GetDataByteSize(), SBTarget::GetCodeByteSize(), and SBSection::GetTargetByteSize() have been deprecated. They always return 1, as before.

FreeBSD ¶

Userspace Debugging ¶

Support for MIPS64 has been removed.
The minimum assumed FreeBSD version is now 14. The effect of which is that watchpoints are assumed to be supported.

Kernel Debugging ¶

Support for libfbsdvmcore has been removed. As a result, FreeBSD kernel dump debugging is now only available on FreeBSD hosts. Live kernel debugging through the GDB remote protocol is still available from any platform.
The crashed thread is now automatically selected on start.
Threads are listed in incrmental order by pid then by tid.
Unread kernel messages saved in msgbufp are now printed when lldb starts. This information is printed only when lldb is in the interactive mode (i.e. not in batch mode).

Changes to BOLT ¶

Changes to Sanitizers ¶

Add a random delay into ThreadSanitizer to help find rare thread interleavings.

Other Changes ¶

External Open Source Projects Using LLVM 23.0.0git ¶

Additional Information ¶

A wide variety of additional information is available on the LLVM web page, in particular in the documentation section. The web page also contains versions of the API documentation which is up-to-date with the Git version of the source code. You can access versions of these documents specific to this release by going into the llvm/docs/ directory in the LLVM tree.

If you have any questions or comments about LLVM, please feel free to contact us via the Discourse forums.