[PATCH] D124824: [RISCV] Make use of SHXADD instructions in RVV spill/reload code.

[Craig Topper via Phabricator via llvm-commits]

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We can use SH1ADD, SH2ADD, SH3ADD to multipy by 3, 5, and 9 respectively.

We could extend this to 3, 5, or 9 multiplied by a power 2 by also
emitting a SLLI.

While there remove the code that looks up TII. We're already a
member of RISCV's TII.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D124824

Files:
  llvm/lib/Target/RISCV/RISCVInstrInfo.cpp
  llvm/test/CodeGen/RISCV/rvv/allocate-lmul-2-4-8.ll

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