simdref

Use when the user asks to look at, analyse, profile, or optimise ASSEMBLY or the runtime performance of compiled C/C++ — from a source file, CMake/Makefile target, object file, binary, or raw .s listing. TRIGGER on: "look at the asm", "inspect codegen", "why is this loop slow", "can this be vectorised", "what intrinsic replaces this", "annotate this .s", and on any "make this faster / vectorise / tune / maximise throughput" request for C/C++, including hardware-specific ones ("faster on Zen4", "tune for Skylake-X", "use AVX-512", "avoid the port-5 bottleneck"). Default here whenever the goal is runtime performance of compiled C/C++, unless scoped to source-only (readability, algorithmic complexity, API ergonomics). DO NOT TRIGGER for pure source refactoring, style, or C++ semantics questions that don't require reading generated code.

Use when the user asks Codex to inspect, annotate, profile, or optimise generated assembly for C/C++ or raw .s/object/binary inputs. Triggers include "look at the asm", "inspect codegen", "why is this loop slow", "vectorise this", "make this faster", "tune this loop", "use AVX-512", "make this faster on Zen4/Skylake-X/Apple M2", or requests for intrinsic-level replacements with cited latency/CPI. Do not use for pure source-level refactoring, style changes, or C++ semantics questions that do not require generated code.