How REX added a strict Sage AST JSON checkpoint path that serializes a complete source-file AST, reconstructs it, replaces the live AST, and proves the rest of the compiler still behaves the same.

A detailed debugging retrospective on replacing the first COV4 gfx803 OpenMP offload path with a narrower COV5 implementation that follows LLVM and ROCm's existing pre-gfx9 design.

A debugging retrospective on an LLVM OpenMP AMDGPU offloading failure where a small gfx803 teams-loop printf case exposed a real pre-GFX9 AMDGPU backend m0 preservation bug.

How the initial LoongArch64 gfx803 LLVM OpenMP AMDGPU stack grew to support an MI50 gfx906 device and a mixed gfx803 plus gfx906 OpenMP process.

A beginner-oriented walkthrough of bringing up LLVM 22 OpenMP AMDGPU offloading for a Radeon Pro WX 3200 gfx803 GPU on a LoongArch64 Linux machine.

An end-to-end Ubuntu 26.04 runbook for making CosyVoice3 generate Furina-style speech on Intel Arc Pro B50 with PyTorch XPU, with a verified NVIDIA Quadro M4000 CUDA path for old Maxwell hardware.

How REX used private CMake precompiled headers to reduce clean build time without changing installed headers, downstream usage, ABI, or runtime behavior.

How REX turned upstream ROSE synchronization into a repeatable, verified workflow: read-only upstream evidence, per-commit decisions, one adapted REX commit per useful change, complete ledger coverage, and full CTest validation.

A reflection on the twelve-day REX repair session: why Codex with GPT-5.5 crossed a practical threshold for persistent engineering work, and why verification discipline mattered more than raw generation speed.

A practical guide for reviewing the large REX Clang frontend stabilization PR by evidence, subsystem, and risk instead of reading the diff linearly.