[PATCH] D48172: [CostModel][AArch64] Add some initial costs for SK_Select and SK_PermuteSingleSrc

[Eli Friedman via Phabricator via llvm-commits]

efriedma accepted this revision.
efriedma added a comment.
This revision is now accepted and ready to land.

LGTM



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Comment at: lib/Target/AArch64/AArch64TargetTransformInfo.cpp:966
+      { TTI::SK_PermuteSingleSrc, MVT::v2i32, 1 }, // mov.
+      { TTI::SK_PermuteSingleSrc, MVT::v4i32, 2 }, // rev+trn or similar.
+      { TTI::SK_PermuteSingleSrc, MVT::v2i64, 1 }, // mov.
----------------
RKSimon wrote:
> efriedma wrote:
> > `egrep -c "[0-3],[0-3],[0-3],[0-3].*Cost [3-4]" lib/Target/AArch64/AArch64PerfectShuffle.h` says there are 182 permutes which cost more than 2.  But I guess this is a reasonable estimate not knowing anything else.
> Out of interest, are those perfect shuffle costs based off throughput or number of instructions?
All the shuffles it uses have the same throughput on an A57, so there isn't really any difference.


Repository:
  rL LLVM

https://reviews.llvm.org/D48172