[PATCH] D99142: [RISCV] Add basic cost modelling for fixed vector gather/scatter.

[Luke via Phabricator via llvm-commits]

luke957 added a comment.
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@craig.topper It seems for intrinsic `llvm.masked.gather.xxx`, the backend will produce similar assembly instructions.  
Eg, `llvm.masked.gather.v8f64.v8p0f64` will get

  vsetivli    zero, 8, e64, m4, tu, mu
  vluxei64.v  v12, (zero), v8, v0.t
  vmv4r.v     v8, v12

, and `llvm.masked.gather.v4f64.v4p0f64` will get

  vsetivli    zero, 4, e64, m2, tu, mu
  vluxei64.v  v10, (zero), v8, v0.t
  vmv2r.v     v8, v10

So why the cost is calculated by element number? I'm not quite clear about this. Can you give some reference or clue? Thanks.


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https://reviews.llvm.org/D99142