I think the cost would be something like: + case POPCOUNT: + *total = COSTS_N_INSNS (3); + return false;Segher> Is that the cost when using popcountb? It is a lot more Segher> expensive when that instruction isn't available (like on Segher> most current machines). Yes, but do we even create POPCOUNT rtx if the insn isn't supported? Wouldn't we expand or create libcall early?
I don't know, there's only one way to find out... :-) Segher
