CISC processors have sometimes huge instruction sets. This makes assembly programming somehow easier. But it reduces overall effectivness of the whole chip.

But how many of those instructions are used by modern compilers?

I'm especialy interested in relation of CISC vs. RISC where in CISC, compiler can use specialised instructions, that might increase effectivness. But do compilers use those instructions? If yes, then how many of them are used?