A focused walkthrough of the outlining stage in REX GPU lowering: how target bodies become device kernels, how capture sets are classified, and why loop lowering happens after outlining.

A focused walkthrough of the first stage inside the GPU lowerer: how REX routes many `SgOmpTarget*` surface constructs into a small number of core lowering paths, and why that dispatch boundary keeps the compiler generic.

A deep look at the layered OpenMP test system in REX: parser tests, frontend compile and analyzer tests, invariant-based lowering checks, CPU equivalence, and full benchmark validation.

An architectural deep dive into one of the central REX design choices: why a ROSE/Sage source-to-source compiler cannot treat Clang's OpenMP AST as the source of truth, and why OpenMP has to become `SgOmp*` inside REX instead.

A focused walkthrough of Stage 1 in the REX OpenMP pipeline: `processOpenMP()`, clause normalization control, raw directive text recovery, C/C++ pragma parsing, Fortran comment handling, and the handoff into OpenMPIR.

A focused walkthrough of Stage 2 in the REX OpenMP pipeline: converting ompparser's OpenMPIR into Sage/ROSE `SgOmp*` nodes with correct nesting, clause structure, and scope-aware expression parsing.

When LLVM offloading changes, a source-to-source compiler can keep building but stop running. This post explains the failure modes, the debugging workflow, and the compatibility strategy REX uses to stay stable across LLVM toolchain migrations.

A deep look at the REX helper/runtime boundary: how offload entries are emitted, how a CUBIN image is registered with libomptarget, how rex_kmp.h rewrites runtime calls, and why init/fini are handled the way they are.

A deep walkthrough of the REX OpenMP GPU lowerer: directive dispatch, outlining, runtime map arrays, `__tgt_kernel_arguments` construction, generated files, and the tests that keep multi-kernel lowering correct.

An end-to-end walkthrough of REX's OpenMP architecture: why it owns OpenMP parsing, how ompparser feeds Sage AST construction, how lowering generates host and device code, and how the test system keeps the pipeline honest.