From: Xin Long ... > Hi, David, Sorry, I'm not sure we're worrying about the cpu cost or > codes style now ? > > For cpu cost, I think 0x848(%r13) operation must be better than the > generated code of if-else.
Nope - the call xxx(%ryyy) is likely to be a data cache miss and a complete cpu pipeline stall. The conditional will be a data cache hit and the code (for one branch) will be prefetched and speculatively executed. Some very modern cpu might manage to predict indirect jumps, but for most it is a full pipeline stall. David