[PATCH] D106277: [SVE] Remove the interface for getMaxVScale in favour of the IR attributes

[Fraser Cormack via Phabricator via cfe-commits]

frasercrmck added a comment.

In D106277#2913136 <https://reviews.llvm.org/D106277#2913136>, @paulwalker-arm wrote:

> @craig.topper can you share RISCV plans around supporting vscale_range?  In essence we'd like to deprecate the TTI method and have LLVM IR contain all relevant information when is comes to interpreting vscale.
>
> Currently the usage is minimal and so checking both interfaces is not too bad but they'll come a point when there's no TTI available and then only the side supporting vscale_range can be considered.  There's also the LTO side of things where relying on opt/llc flags to set register widths becomes fragile.

As it happens I was playing around with adding support for that today at least to get us started. I was going to put something up for review based on this patch, assuming this gets merged first.

However in the TTI method we're currently making use of some `RISCVSubtarget` properties to help refine the vscale range, so we'll need to think about how we'll deal with those.


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  https://reviews.llvm.org/D106277/new/

https://reviews.llvm.org/D106277