A focused walkthrough of REX's mapper-expansion path: scope-aware `declare mapper` resolution, recursive clause expansion, array-section deferral into dynamic entries, and the shared two-pass builder used by `target`, `target data`, and `target update`.

A focused walkthrough of REX's literal target parameter path: how eligible mapped scalars are tagged, packed into pointer-sized launch arguments, stabilized in the host packet, and reconstructed inside the generated GPU kernel.

A focused walkthrough of REX's non-loop GPU offloading branch: how `transOmpTargetSpmd()` handles `target`, `target teams`, and `target parallel`, outlines the region body, builds offload entries and runtime argument arrays, and launches a simpler SPMD kernel path without worksharing loop rewriting.

A focused walkthrough of the target-loop lowering stage in REX: how `transOmpTargetLoopBlock()` recovers canonical loop structure, rewrites loops into direct grid-stride kernels, keeps a round-robin fallback, and shares loop analysis with host launch shaping.

A walkthrough of REX's top validation layer: building native LLVM and REX binaries side by side, comparing outputs with normalization rules, and catching runtime and performance regressions using real benchmarks.

A focused walkthrough of REX's `checkOmpAnalyzing` layer: `-rose:openmp:analyzing`, targeted AST assertions for schedule defaults and implicit target mapping, and why this semantic-analysis checkpoint sits between frontend AST coverage and lowering tests.

A focused walkthrough of the broad `OpenMP_tests` frontend corpus in REX: `parseOmp` in `ast_only` mode, `rose_*` output generation, OpenMP-line reference diffs, mixed OpenMP/OpenACC cases, multi-file and macro-preservation checks, and the separate Fortran AST-coverage slice.

A focused walkthrough of the standalone `ompparser` stage in REX: lexer and grammar, location-aware `OpenMPIR`, expression callbacks, clause normalization, round-trip unparsing, and the tests that validate the parser before AST construction begins.

A focused walkthrough of REX's `lowering_cpu` suite: why it compares original and lowered OpenMP programs on the same CPU runtime, how exact and sorted comparison modes work, and which semantic regressions this layer catches before GPU benchmarks.

A focused walkthrough of the `lowering_rodinia` suite in REX: reduced Rodinia-like inputs, invariant-based checks on generated host and device files, and the specific regression classes this layer catches.