[llvm] [LV] Enable considering higher VFs when data extend ops are present i… (PR #137593)

[Sushant Gokhale via llvm-commits]

sushgokh wrote:

>I think the correct place to do this would be in shouldMaximizeVectorBandwidth, since not all targets want to maximise the bandwidth.

ok thanks @david-arm . Will try to make this target specific and make amendment to AArch64 `shouldMaximizeVectorBandwidth` to start with

https://github.com/llvm/llvm-project/pull/137593