[PATCH] D146627: [RISCV] Combine (vrgather src, vid) -> vmerge

[Luke Lau via Phabricator via llvm-commits]

luke added inline comments.


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Comment at: llvm/test/CodeGen/RISCV/rvv/combine-gather.ll:18
 ; CHECK-NEXT:    ret
   %res = shufflevector <8 x i8> %v, <8 x i8> %w, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 10, i32 11>
   ret <8 x i8> %res
----------------
craig.topper wrote:
> Shouldn't we be able to implement this shuffle with vslideup/down?
Yes, I think so. I was working on a patch for this, I’ll put it up later today.
It might actually supersede this patch since it prevents the `vrgather vid` from being generated when lowering vector_shuffle. And I’m not sure if there’s anywhere else where that sequence of nodes is emitted. 


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D146627/new/

https://reviews.llvm.org/D146627