Internal Functions (GNU Compiler Collection (GCC) Internals)

## 13 Internal Functions in GENERIC and GIMPLE ¶

In addition to builtin functions specified in `builtins.def` and friends, the GENERIC and GIMPLE intermediate languages use calls with pre-defined semantics that are inline expanded to RTL rather than to calls or lowered at some point during optimization.

Internal functions work like tree operation codes in that they are not strongly typed so there are no variants like `BUILT_IN_SIN` and `BUILT_IN_SINF`; just a single `IFN_SIN`.

Internal functions are declared in `internal-fn.def`.