[llvm] [X86] Narrow BT/BTC/BTR/BTS compare + RMW patterns on very large integers (PR #165540)

[Vitaly Buka via llvm-commits]

vitalybuka wrote:

> @durin42 Please do you have the test case yet? Are you sure this wasn't fixed by #165755 / #165850?

https://lab.llvm.org/buildbot/#/builders/66/builds/21507 should be reasonably easy to reproduce from build bot logs.
However minimizing requires some effort. So I'd like to postpone that, with hope that you can guess what could go wrong just from your patch :)

Maybe another easier than minimizing repro option is just to decompose #165540 into even smaller pieces? I am not sure how feasible it is.

https://github.com/llvm/llvm-project/pull/165540