[PATCH] D49491: [RFC][VPlan, SLP] Add simple SLP analysis on top of VPlan.

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

I have no strong opinions on the best approach. My concern is my current work revolves around a number of issues:

1 - Generalize alternate vectorisation paths (multiple different vector ops + select/shuffle merges).
2 - Supporting 'copyable' elements (PR30787).
3 - Pull TTI/vectorization costs from scheduling models (PR36550).
4 - Using dereferenceable_or_null metadata to vectorise loads with missing elements (PR21780).
5 - Revectorisation of 128-bit vector code to 256-bit vector code (make most of YMM ops now that Jaguar model is treating them nicely).

All of these are large pieces of work and I don't want to find myself implementing them in SLPVectorizer just for all the work to be lost and we're back to a very basic SLP system again.

How quickly do you expect VPlanSLP to be close to current SLPVectorizer codegen? Ideally I'd like to see slp tests run on both asap.


https://reviews.llvm.org/D49491