Module route 

The one process-wide switch between the optimized product route and the f32 reference.

The optimized route (int8 projections, the SLEEF SnakeBeta, the worker team) is the DEFAULT everywhere — library and binary alike. Two things override it:

• Environment: FTTS_INT8=0 (or off/false) selects the reference route for a run; the finer-grained FTTS_INT8_CODEC / FTTS_FAST_SNAKE variables tune individual pieces.
• pin_reference: a programmatic, first-call-wins pin used by the conformance harness, so every oracle-parity test measures the reference numerics no matter what the surrounding environment says. A parity suite that silently tested the optimized route would be comparing the wrong thing against the oracle.

The pin is sticky for the process (OnceLock): parity test binaries pin once, product processes never call it.

Functions

optimized_default

The shared default rule for optimized-route switches.

pin_reference

Pins this process to the f32 reference route, regardless of environment defaults.

reference_pinned

Whether pin_reference has been called.