I'd be interested to learn about such closed-source important bits and invite them to MLIR workshop / open developer meeting. Having worked on the project essentially since its inception, I am quite positive that the bits the original MLIR team considered important are completely open source.
Certainly, there are closed-source downstream dialects, that was one of the actual design goals of the project, but they are rarely as useful as one might think. I'd expect every big company with a hardware to have an ISA/intrinsic-level dialect, at least as a prototype, that they won't open source for the same reason they won't open source the ISA.
What I find sad is the lack is that end-to-end flows from, e.g., PyTorch to binaries are usually living outside of the LLVM project, and often in each company's downstream. There is some slow motion to fix that.
Certainly, there are closed-source downstream dialects, that was one of the actual design goals of the project, but they are rarely as useful as one might think. I'd expect every big company with a hardware to have an ISA/intrinsic-level dialect, at least as a prototype, that they won't open source for the same reason they won't open source the ISA.
What I find sad is the lack is that end-to-end flows from, e.g., PyTorch to binaries are usually living outside of the LLVM project, and often in each company's downstream. There is some slow motion to fix that.