[PATCH] D106648: [RISCV] Optimize mul in the zba extension with SH*ADD

[Ben Shi via Phabricator via llvm-commits]

benshi001 created this revision.
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This patch makes the following optimization, if the
immediate multiplier is not a simm12.

  (mul x, (power_of_2 + 2)) => (SH1ADD x, (SLLI x, bits))
  (mul x, (power_of_2 + 4)) => (SH2ADD x, (SLLI x, bits))
  (mul x, (power_of_2 + 8)) => (SH3ADD x, (SLLI x, bits))


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D106648

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/test/CodeGen/RISCV/rv32zba.ll
  llvm/test/CodeGen/RISCV/rv64zba.ll

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