Charles Crisler <charles.crisler@xxxxxxxxxxx> writes: > Which file contains the definition of this built-in function? It's an intrinsic implemented directly by the compiler. If you mean: which file in the compiler defines it, it will normally be found in gcc/config/CPU/CPU.md or gcc/config/CPU/sync.md. If you happen to be using a toolchain configured for i386, note that you must use -march=i486 or later in order to use these functions successfully. Ian
