Wilco Dijkstra wrote: > James Greenhalgh wrote: > > > I haven't seen a follow-up to Andrew's point regarding other > > read-modify-write operations. > > > > Did youi investigate the cost of these? > > I looked at whether there are other similar cases, but it appears SHA1 > is unique due to the odd dataflow, the mismatch in latencies and the high > repetition. So it seems best to handle it as a special case. > > What does seem useful is teaching GCC to prefer using the same > register for accumulators. That is a general issue that would improve > performance in many cases.
Any further comments? Wilco