[PATCH] D116362: [TTI] Support ScalableVectorType in getShuffleCost with SK_Broadcast kind

[Dave Green via Phabricator via llvm-commits]

dmgreen added reviewers: sdesmalen, david-arm, paulwalker-arm.
dmgreen added a comment.

This looks like it would treat the default cost of a broadcast as scalarising the first n elements from a <vscale x n x iM> vector, which doesn't sound right. Unless we are assuming that the default vscale is 1.

I would suspect that the cost should either be invalid or to be "cheap" under assumption that the operation is always present. AArch64 has some cost overrides in its backend for certain types of scalable broadcasts.


Repository:
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  https://reviews.llvm.org/D116362/new/

https://reviews.llvm.org/D116362