[PATCH] D94546: [RISCV] Optimize select_cc after fp compare expansion

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
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Some FP compares expand to a sequence ending with (xor X, 1). If
the consumer select_cc we can likely get rid of this xor by fixing
up the select_cc condition.

This patch combines (select_cc (xor X, 1), 0, setne, trueV, falseV) -
(select_cc X, 0, seteq, trueV, falseV) if we can prove X is 0/1.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D94546

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

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