[llvm] [InstCombine] Optimistically allow multiple shufflevector uses in foldOpPhi (PR #114278)

[Matthias Braun via llvm-commits]

MatzeB wrote:

> If we say that we consider it profitable to replace a shufflevector with a phi in general, then we shouldn't need the check on the uses for shufflevectors at all.

My assumption is that turning one Phi into multiple Phi instructions is not necessarily an improvement.

It could see this being an improvement on average, but it's hard to put that into numbers. But given it's not a clear improvement I am not sure I want to deal with the complaints for the regressions and rather would be more conservative...

https://github.com/llvm/llvm-project/pull/114278