This requires DominatorTree be updated, which we do in the ml inliner case, but not in the default case, and the cost of doing so is noticeable to compile time for the latter[1]. So the patch only affects the ML inliner. [1] https://llvm-compile-time-tracker.com/compare.php?from=9fc0aa45e3312944431ba7e1ca0cec99c613992b&to=7af461b1ce0d9138211ef5f883f35d5b9ddf47be&stat=wall-time Differential Revision: https://reviews.llvm.org/D127899
