[llvm] ConstraintElim: add dry-run routine to fail early (PR #99670)

[Ramkumar Ramachandra via llvm-commits]

artagnon wrote:

So, I had some more time to think about this, and there is one other slightly sub-optimal way forward: I experimented with dropping the dry-run routine entirely, and hard-coding 50 columns in the Matrix. If we feel that the small compile-time regression caused by this is acceptable, and that the dry-run routine is unacceptable, this would be one potential way forward: http://llvm-compile-time-tracker.com/compare.php?from=76e2307e695330912b89e51f65f75ca0f4c8bd24&to=1be3ca30a469ff4b2a45a2eb5bba3db230afe95e&stat=instructions:u.

Otherwise, I can also experiment with column-resizing the Matrix dynamically, although I'm less optimistic about that.

https://github.com/llvm/llvm-project/pull/99670