First up, a report is making the rounds that claims AMD's marketshare is up from 20.6 percent in Q1 2017 to 31.0 percent in Q2 2017. The origin of the data is the PassMark database, it counts the number of benchmark submissions so it's data that provides a clue about the number of actual systems in use, rather than systems sold. There's a caveat though.
This data is updated on a regularly basis but the last datapoint of the chart shown by WCCF Tech had data of less than one day (July 1) so it wasn't an accurate representation. There's a bit more data now and the latest chart shows a much smaller rise:
So yeah, AMD is recapturing some marketshare but it's nowhere near to getting back to the levels of marketshare it held ten years ago.
Other regularly updated marketshare data can be found at Steam. The latest results of the Steam Hardware Survey show 19.01 percent of Steam gamers used an AMD processor in June. These numbers are not encouraging as they show AMD's marketshare has declined for at least four consecutive months:
More accurate marketshare data is expected in a couple of weeks.