[llvm] [VectorCombine] Add initial nodes to the Worklist in VectorCombine (PR #149047)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

Compile-time: https://llvm-compile-time-tracker.com/compare.php?from=60579ec3059b2b6cc9dad90eaac1ed363fc395a7&to=7322d4b393c94af7164439419100d9c25df1e420&stat=instructions:u

Adding the entire function to the worklist at once is quite expensive...

Possibly we could do something more targeted at removing dead instructions early?

https://github.com/llvm/llvm-project/pull/149047