[PATCH] D151719: Add special case for (select_cc 0, x, setlt, 0.0, 1.0) to lowerSELECT

[Liao Chunyu via Phabricator via llvm-commits]

liaolucy created this revision.
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Use sint_to_fp instead of select. 
Reduce the number of branch instructions and 
avoid generating TargetConstantPool for double.

(select (setcc x, 1, setlt), 1.0, 0.0) -> (sint_to_fp (zext (setcc x, 1, setlt)))
https://alive2.llvm.org/ce/z/TYMMSD
https://godbolt.org/z/n543Y9v3e

(select (setcc x, 0, setgt), 0.0, 1.0) -> (sint_to_fp (zext (setcc x, 1, setlt)))
https://alive2.llvm.org/ce/z/L32zaJ
https://godbolt.org/z/GG4jWTPKK


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151719

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp
  llvm/test/CodeGen/RISCV/double-select-icmp.ll
  llvm/test/CodeGen/RISCV/float-select-icmp.ll
  llvm/test/CodeGen/RISCV/half-select-icmp.ll

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