The patch adds very basic cost model for masked memory op on scalable vector.
How come we're not adding support for fixed-length vectors at the same time? The commit title/description should make it clear that this is scalable-only.
What do you mean by "legal" here? The test isn't testing a configuration in which fixed-length vectors are supported by the backend.
Again, what's illegal about these types?
This comment says that these types are legal, but the expected output is that there's an "Invalid cost"? That doesn't sound quite right.
Again, what's illegal about these?