That would make no sense at all (to have a TI DSP soft core) in an FPGA!
It is far less expensive to just buy the part from TI.
As for making TI 'uncomfortable', we consider TI a great partner: they sell their DSPs into many markets, and when they can't do something fast enough, they sell their DSPs and our FPGAs.
If we sell our FPGA into a market, and there is a TI DSP that can do a job where we are not competitive, we encourage the customer to use TI, too.
Are there some jobs that TI wins, or we win exclusively (the other is just not needed)? Sure. That happens if we were partners, or not.
We sell, they sell. It is not a "zero-sum" game where there can only be one winner every time: we are all winning (customer, Xilinx, TI)!
Customer knows that Xilinx and TI are working together to provide them with the best solution to their problems.