On Fri, 2018-11-30 at 15:37 +0000, Kyrill Tkachov wrote: > > In thunderx2t99.md the reservation changes from thunderx2t99_mul to > thunderx2t99_madd. > > Steve, can you share whether the AArch64 MUL and MNEG instructions > really do have different latencies and reservations from MADD and > MSUB > on Thunderx2? If so, then this change is wrong :( and we'll want to > model these forms differently indeed. > > Thanks, > Kyrill
According to the thunderx2 documents I looked at, the mul/mneg instructions do have the same latencies as madd/msub. So this patch is OK from that standpoint and fixes an existing problem on Thunderx2. Steve Ellcey
