::::{only} PreRelease :::{warning} These are in-progress notes for the upcoming LLVM {{env.config.release}} release. Release notes for previous releases can be found on the Download Page. ::: ::::
This document contains the release notes for the LLVM Compiler Infrastructure, release {{env.config.release}}. 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.
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LLVM now assigns persistent print IDs to metadata nodes. Reusing these IDs avoids repeated module-wide scans to rebuild metadata numbering, which can significantly speed up debug and pass printing on large modules. Keeping the IDs stable also makes repeated output easier to compare: unchanged metadata keeps the same number as passes modify the module. The numbering and definition order can differ from earlier releases, so tests of intermediate output may need updated expectations.
LLVM's standard final-output paths renumber metadata in canonical order. This gives consecutive IDs with no gaps and makes the final IR easier to read. C++ clients that call Module::print() directly do not renumber automatically. For final IR output, these clients should call Module::renumberMetadataForAssembly() immediately before printing. Keep persistent IDs for intermediate dumps so their numbering remains stable.
Standalone metadata printing now uses numbered definitions such as !1 = !DIFile(...) instead of pointer-based forms such as <0x...> = !DIFile(...). Tools and tests that compare such output may need updating.
Added llvm.vector.reduce.fmaximumnum and llvm.vector.reduce.fminimumnum intrinsics, the reduction variants of llvm.maximumnum and llvm.minimumnum.
Added llvm.smulh and llvm.umulh intrinsics for signed and unsigned multiply returning the high-order half of the 2N-bit product of iN operands.
Added nofreeobj attribute for attributes and returns, which forbids freeing the underlying object (as opposed to only frees through that specific pointer). Renamed !nofree metadata to !nofreeobj, as it has the same semantics.
The following VP intrinsics have been removed:
llvm.vp.select.*llvm.vp.add.*llvm.vp.sub.*llvm.vp.mul.*llvm.vp.ashr.*llvm.vp.lshr.*llvm.vp.shl.*llvm.vp.or.*llvm.vp.and.*llvm.vp.xor.*llvm.vp.abs.*llvm.vp.smax.*llvm.vp.smin.*llvm.vp.umax.*llvm.vp.umin.*llvm.vp.copysign.*llvm.vp.minnum.*llvm.vp.maxnum.*llvm.vp.minimum.*llvm.vp.maximum.*llvm.vp.fadd.*llvm.vp.fsub.*llvm.vp.fmul.*llvm.vp.fdiv.*llvm.vp.frem.*llvm.vp.fneg.*llvm.vp.fabs.*llvm.vp.sqrt.*llvm.vp.fma.*llvm.vp.fmuladd.*llvm.vp.trunc.*llvm.vp.zext.*llvm.vp.sext.*llvm.vp.fptrunc.*llvm.vp.fpext.*llvm.vp.fptoui.*llvm.vp.fptosi.*llvm.vp.uitofp.*llvm.vp.sitofp.*llvm.vp.ptrtoint.*llvm.vp.inttoptr.*llvm.vp.fcmp.*llvm.vp.icmp.*llvm.vp.ceil.*llvm.vp.floor.*llvm.vp.rint.*llvm.vp.nearbyint.*llvm.vp.round.*llvm.vp.roundeven.*llvm.vp.roundtozero.*llvm.vp.lrint.*llvm.vp.llrint.*llvm.vp.bitreverse.*llvm.vp.bswap.*llvm.vp.ctpop.*llvm.vp.ctlz.*llvm.vp.cttz.*llvm.vp.sadd.sat.*llvm.vp.uadd.sat.*llvm.vp.ssub.sat.*llvm.vp.usub.sat.*llvm.vp.fshl.*llvm.vp.fshr.*llvm.vp.is.fpclass.*These intrinsics previously only set masked-off lanes to poison, and will be automatically upgraded to their non-VP equivalent. On RISC-V the VL optimizer should automatically infer vl in most cases from a store or reduction instruction, so passing around an explicit EVL operand shouldn't be required. If needed a “root” EVL can be synthesized with llvm.vp.merge, e.g:
%x = add <vscale x 2 x i32> %y, %z %res = call <vscale x 2 x i32> @llvm.vp.merge(<vscale x 2 x i32> %x, <vscale x 2 x i32> poison, <vscale x 2 x i1> splat (i1 true), i32 %evl)
The llvm.vp.merge will be folded away but the %evl will be propagated to the add instruction.
Introduced the generic !atomic.ignore.denormal.mode metadata for floating-point atomicrmw instructions, generalizing the previously AMDGPU-specific !amdgpu.ignore.denormal.mode.
Removed TargetOptions::FloatABIType. The soft float ABI should be controlled by setting the "float-abi" module flag.
Removed TargetOptions::EABIVersion and the llc/opt -meabi flag. The GNU-vs-EABI distinction is now derived entirely from the target triple's environment (e.g. arm-none-gnueabi vs arm-none-eabi).
The DirectX backend is now an official target and has moved from LLVM_ALL_EXPERIMENTAL_TARGETS to LLVM_ALL_TARGETS. It is now built by default and no longer requires LLVM_EXPERIMENTAL_TARGETS_TO_BUILD.
Clang and MLIR projects enabled implicitly as Flang dependencies now omit unrelated build and test targets. Installation retains the dependency libraries, headers, resources, and CMake targets needed by Flang. Explicitly enabling Clang or MLIR retains the project's complete build, test, and install behavior.
!cond operator short-circuits at the first true condition. Subsequent condition : value pairs, along with their corresponding side effects, are left unresolved.Interprocedural passes no longer rewrite the signature of functions marked optnone, so their argument list, return type, and calling convention are preserved. Interprocedural analysis and transformation of such functions is otherwise unaffected.
The IR Outliner has been removed, due to lack of a maintainer and the presence of correctness issues.
Replaced xnack and sramecc target features with amdgpu.xnack and amdgpu.sramecc module flags.
llvm.amdgcn.make.buffer.rsrc now accepts any integer width for its numRecords argument to account for targets that use 32-bit and 45-bit numRecords widths more accurately. If an integer of the incorrect width is used, it will be zero-extended or truncated as needed.
These intrinsics have been removed in favour of llvm.amdgcn.ballot:
llvm.amdgcn.icmpllvm.amdgcn.fcmpSmidctrl, Ssidctrl, Smnip, Ssnip, Smijt, Ssijt, Smehv, Ssehv, Smcsps, Sscsps, Smip, and Ssip.Zilx (Indexed Integer Load) extension.Sspmp, Sspmpen and Smpmpdeleg extensions.Ventana Conditional Operations extension.tail symbol, rt form that takes an address (materialisation) register, that is used when software guarded branch is needed.Zvzip extension to the v0.3 draft specification.RVA23P1S64 and RVB23P1S64 profiles.@llvm.wasm.memory.copy and @llvm.wasm.memory.fill intrinsics for the WebAssembly memory.copy and memory.fill instructions.size_of and align_of functions. Create a constant based on the result of DataLayout.abi_size or DataLayout.abi_align instead.LLVMAlignOf() and LLVMSizeOf() have been deprecated. Create a constant based on the result of LLVMABIAlignmentOfType() or LLVMABISizeOfType() instead.(size_t)-1 bytes, whose size collided with the sentinel value MachineFrameInfo used to mark dead stack objects.llvm-mca no longer defaults -mcpu to “native”
llvm-rc now supports /showIncludes to report header and resource-file dependencies in a format compatible with Ninja's deps = msvc mode.
platform.plugin.wasm.runtime-args now precede the port argument on the Wasm runtime's command line instead of following it. A runtime that dispatches on a leading subcommand can therefore name that subcommand through this setting, rather than needing a wrapper script.GetIndexOfChildWithName and GetChildMemberWithName were incorrectly looking up values in all register sets. This meant that GetIndexOfChildWithName could return an index greater than the size of the set, and that GetChildMemberWithName could return values that were actually in a different set. Both methods are now fixed so that they are limited to the registers within the register set. Scripts using these methods may have to be updated as a result.platform.plugin.windows.disable-debug-heap to false.cas::ObjectStore::getMemoryBuffer() was documented as returning a buffer whose lifetime is independent of the CAS, but the buffer it returns may alias storage the CAS owns and so cannot outlive it. The documentation now matches the behavior, and the new getStandaloneMemoryBuffer() provides a buffer that does stay valid after the ObjectStore is destroyed.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.
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