[llvm] [InstCombine]Fold bitcast shuffle ashr v2i64 (PR #206717)

[Simon Pilgrim via llvm-commits]

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RKSimon wrote:

Ensure the variables are descriptive (I was looking for some meaning behind i and j......)
Ti -> DstEltTy
Tj -> SrcEltTy

https://github.com/llvm/llvm-project/pull/206717