[llvm] [DAGCombiner] Add support for scalarising extracts of a vector setcc (PR #117566)

[David Sherwood via llvm-commits]

david-arm wrote:

> @david-arm Please acknowledge that you noticed the revert.
> 
> Please let me know if you need help with reproducer, but I guess it's quite straight forward either using https://github.com/google/sanitizers/wiki/SanitizerBotReproduceBuild or copy-pasting cmake commands from the bot.

Yep, I'm taking a look now! The error does look suspiciously like it's caused by this patch.

https://github.com/llvm/llvm-project/pull/117566