[llvm] [VectorCombine] Fold deinterleave/interleave pairs (PR #211022)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

@jacob-crawley This test breaks the profcheck (`-DLLVM_ENABLE_PROFCHECK=ON`) configuration (see the above buildbot failure link). I've opted it out in #217612 to get the bot back to green, but could you please work on ensuring that profile information is either propagated correctly/we mark actually newly synthesized branches where we cannot infer weights as unknown?

https://github.com/llvm/llvm-project/pull/211022