[PATCH] D155355: [AArch64] Set maximum vscale VF with shouldMaximizeVectorBandwidth

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

For Neon we enabled shouldMaximizeVectorBandwidth so that the backend could make use of instructions like umull/umull2 and the narrowing instructions. Extending into larger types for Neon is quite natural in places, and can lead to less total instructions. SVE has instructions like UMULLB/T that work on the top/bottom lanes in a pair, but I don't believe the backend makes any use of them at the moment.

The description is a bit light on details. What is the reasoning behind enabling this for SVE too? And do you have any benchmark results?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D155355/new/

https://reviews.llvm.org/D155355