[MLIR] add linalg.argmax and linalg.argmin

[yuanfz98]

Hello,

I wonder if it is possbile to add linalg.argmax and linalg.argmin to better describe such computation rather than making it as a series of selection and compare.

[llvmbot]

@llvm/issue-subscribers-mlir

Author: yuanfz (yuanfz98)

Hello,

I wonder if it is possbile to add linalg.argmax and linalg.argmin to better describe such computation rather than making it as a series of selection and compare.