This starts moving `X86Builtins.def` to be a tablegen file. It's quite large, so I think it'd be good to move things in multiple steps to avoid a bunch of merge conflicts due to the amount of time this takes to complete.
This starts moving `X86Builtins.def` to be a tablegen file. It's quite large, so I think it'd be good to move things in multiple steps to avoid a bunch of merge conflicts due to the amount of time this takes to complete.