LLVM 21.1 is out today as the first stable version of the LLVM 21 compiler stack. This half-year stable release to the open-source LLVM compiler software brings new hardware support, new language features, and a lot of other enhancements throughout this massive and widely-used codebase.
LLVM 21.1.0 is released right on schedule following three release candidates over the past month. LLVM 21.1.0 was just tagged and is now available for downloading from GitHub as — similar to the GCC versioning scheme — represents the first stable release of LLVM 21. LLVM 21.1.x point releases will be out in the coming weeks as per their usual release cadence.
LLVM 21 introduces the AMD GFX1250 target for what is expected to be an APU with an RDNA4 refresh (RDNA 4.5?) while the additions for the GFX1250 target remain ongoing. There are also other AMDGPU LLVM back-end enhancements for helping their ROCm stack and other libc-for-GPU efforts. There is also now -mcpu=gb10 support for NVIDIA’s GB10 Superchip, various RISC-V improvements, many RISC-V back-end enhancements, LLDB debugger improvements, and more.
On the LLVM Clang 21 C/C++ compiler front-end side there are new optimizations around pointer arithmetic on null pointers, new C++2c feature additions, various other C++ language features added, new C warnings, additional C2y feature work, and many compiler diagnostic enhancements. Clang 21 also addresses Intel’s changes to AVX10 with dropping the AVX10-256 support to now make 512-bit support unconditional for the maximum vector register size.
LLVM 21.1 can be downloaded from GitHub.
