[PATCH] D46283: [AArch64] Set vectorizer-maximize-bandwidth as default true

[Renato Golin via Phabricator via llvm-commits]

rengolin added a reviewer: mcrosier.
rengolin added a subscriber: mcrosier.
rengolin added a comment.

This seems like an improvement, but we have to be careful with wide variations and little gain. The geomean is almost null but the standard deviation is higher than 75% of the results.

This is not a good sign and is a reflection of what I have complained about exchanging numbers and not tracking which benchmarks get worse/better, then risking hurting more one side than another in the long term.

The patch sets the default to *all* AArch64 cores, which is a wide range and you have only tested on one.

To enable such flag by default, we'd need to run on more cores (preferably including A53) as well as other vendors (like Apple, Samsung, Qualcomm), which this patch is likely to impact.

@t.p.northover @evandro @mcrosier please have a look.


Repository:
  rL LLVM

https://reviews.llvm.org/D46283