[llvm] [MemoryBuiltins] Cache the result of ObjectOffsetSizeVisitor::visit. #64796 (PR #65326)

[Nikita Popov via llvm-commits]

nikic wrote:

This change caused a large compile-time regression. I've mostly mitigated this with https://github.com/llvm/llvm-project/commit/c0a64ec13916e420831cee96b48d3ee938f41a66, but there is still some residual regression: http://llvm-compile-time-tracker.com/compare.php?from=0a692b6b9632e1460f9e0e983196f2be5879acd1&to=0bf8763781fa68fa63ee8c1f0d9f6040df97483c&stat=instructions%3Au

https://github.com/llvm/llvm-project/pull/65326