We have a store barrier elimination strategy mostly based on "clustering" -- moving the barriers to the point where they will actually be meaningful.
Unfortunately, we have PutByOffset listed as DoesGC, so we will not eliminate any store barriers around sequences of PutByOffsets. This appears to be the case because PutByOffset was accidentally added to the DoesGC list in r240991.
Created attachment 430504 [details]
Comment on attachment 430504 [details]
Landed in https://trac.webkit.org/changeset/278424/webkit