Pass the instruction to the base implementation.
Are there costmodel tests for these? If not can you copy the ones over from ARM?
I copied over the tests in https://reviews.llvm.org/rG751da4d596ea, and this patch doesn't change the results.
Is that missing the load_extends tests? Are they the same?
Bingo. Cheers Dave, with those tests ported over it shows some differences.
They do look like they should be free to me.