[PATCH] D143394: [RISCV] Add performMULcombine to perform strength-reduction

[Philip Reames via Phabricator via llvm-commits]

reames added a comment.

At a high level, it feels wrong for this to be applied only to the t-head versions of the Zba instructions.  If this can be profitably done for the standard extension, I'd encourage you to do so.  If anything, starting with the standard extension specifically so we get the test coverage would seem like a better strategy.

Have you looked at what it would take to share code with another target here?  I glanced at x86, and it seems like there's a bunch of overlap.  Maybe we could introduce a set of generic DAG combines which enabled based on a callback or configuration?  Haven't given this much thought, so take this as a light suggestion only.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D143394/new/

https://reviews.llvm.org/D143394