We lost about 6% on Zen with -O2 -mtune=generic in between these 2 releases. It's quite hard to bisect a single revision.
Created attachment 42525 [details]
Created attachment 42526 [details]
Created attachment 42528 [details]
Caluculix also sees smaller regression on Haswell due to the vectorization costmodel change. I will try to take a look.
GCC 7.3 is being released, adjusting target milestone.
January trunk revision 257023 improved a little but still loses 3.25% on gcc 6 (on Zen).
According to my latest numbers. 454.alculix compiled with gcc 7 is 3% slower than gcc 6 at -O2 but trunk (r259234) is as fast as gcc 6.
According to my latest GCC 8 measurements, we have caught up at some point in the final stages of GCC 8 development and in all but one option combination are noticeably faster than GCC 6. In the only case where we aren't (-O2 and generic march/mtune), we are not really slower (only 1%). So I'd consider this FIXED.