Texas Instruments TMS320C6000 Reference Manual page 19

CSL API Module Introduction
enabling inlining when the functions are very small. This is because the size
of the function is smaller than the state saving code required to call the function
if it were not inlined. The API reference does not state which functions are in-
lined and which are not: this allows for future changes. You should see an in-
crease in CSL code performance when you enable function inlining.
CSL API Module Descriptions 2-5