[PATCH] D84937: [SVE][CodeGen] Fix scalable vector issues in DAGTypeLegalizer::GenWidenVectorStores

[David Sherwood via Phabricator via llvm-commits]

david-arm added a comment.

HI @efriedma. When I first tried fixing this issue I did originally try adapting the original loop, but the patch gradually grew to be bigger and bigger in order to support cases that I believe could never happen. So the original loop conceptually allows for the possibility of fixed width vector and scalar stores being mixed together in any order. By adding scalable vector stores into the mix we then have to support the possibility of scalable vector stores, fixed width vector stores and scalar stores happening in any combination, any order. That even means changing the existing scalar and fixed width stores to support polynomial offsets, since we could have mixtures of fixed and scaled offsets. In addition, I had to change all the parameters such as StWidth, Offset, etc. to TypeSize, then add new "-=" operators to the TypeSize class. So I began to think this seemed like a much more invasive change than was necessary because in reality we can only ever use legal scalable vector stores to store out wider scalable vector values. However, if you think there is real value in adapting the original loop to allow scalable vectors I am happy to take another look?


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