AWS based ARM processor looks to be widely deployed in the cloud.Nvidia, the leader in GPU compute in buying ARM.Intel, which has suffered deeply because of their 10nm fab problems are going to work with TSMC.And AMD's P/E ratio is at 159, higher than Amazon's!
So Maybe AMD is looking to convert some inflated stock with a predictable business.
And it's better to invest in a predictable business that may have possible synergies with yours. Otherwise it looks bad to the stock market.
And Xilinx is probably the biggest company AMD can buy.