[llvm] [LoopUnswitch] Improve algorithm of unswitch cost estimation (PR #106544)

[Nikita Popov via llvm-commits]

nikic wrote:

Compile-time: https://llvm-compile-time-tracker.com/compare.php?from=7f59264d469d690fcd1cead0a2dfc02739d17db4&to=08c530ba55a2b78aaec879609e848ad72ac473b8&stat=instructions:u
Code size: https://llvm-compile-time-tracker.com/compare.php?from=7f59264d469d690fcd1cead0a2dfc02739d17db4&to=08c530ba55a2b78aaec879609e848ad72ac473b8&stat=size-text

Compile-time increase likely correlated with code size increase.

https://github.com/llvm/llvm-project/pull/106544