[PATCH] D119316: [RISCV] Add a really basic cost model for SK_Splice.

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


================
Comment at: llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp:168
+
+  unsigned Cost = 2; // vslidedown+vslideup.
+  // TODO: LMUL should increase cost.
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ABataev wrote:
> Shall we include the cost of extra calculations for slidedown+slideup offsets?
Other than the vsetvlis, the read of vlenb and the addi end up being loop invariant and hoisted by LICM.

Should we cost all of the instructions? Should we cost the vsetvlis?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119316/new/

https://reviews.llvm.org/D119316