[PATCH] D151180: [RISCV] select(C0, x, select(C1, x, y)) -> select(C0|C1, x, y)

[Liao Chunyu via Phabricator via llvm-commits]

liaolucy created this revision.
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RV32, ExpandIntRes_MINMAX expanding i64 will generate select + select.

This patch reduces the number of branch instructions for a specific condition:
select(C0, x, select(C1 <https://reviews.llvm.org/C1>, x, y)) -> select(C0|C1 <https://reviews.llvm.org/C1>, x, y)
select(C0, select(C1 <https://reviews.llvm.org/C1>, x, y), y) -> select(C0&C1 <https://reviews.llvm.org/C1>, x, y)


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151180

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/test/CodeGen/RISCV/fpclamptosat.ll
  llvm/test/CodeGen/RISCV/min-max.ll
  llvm/test/CodeGen/RISCV/rvv/fpclamptosat_vec.ll

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