[all-commits] [llvm/llvm-project] a9ffb7: [RISCV] Don't promote f16 FNEG/FABS with Zfhmin/Zh...

[Craig Topper via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: a9ffb719bc323588b6b60fbf227db8104a81310e
      https://github.com/llvm/llvm-project/commit/a9ffb719bc323588b6b60fbf227db8104a81310e
  Author: Craig Topper <craig.topper at sifive.com>
  Date:   2024-08-29 (Thu, 29 Aug 2024)

  Changed paths:
    M llvm/lib/Target/RISCV/RISCVISelLowering.cpp
    M llvm/test/CodeGen/RISCV/bfloat-arith.ll
    M llvm/test/CodeGen/RISCV/half-arith-strict.ll
    M llvm/test/CodeGen/RISCV/half-arith.ll
    M llvm/test/CodeGen/RISCV/half-bitmanip-dagcombines.ll
    M llvm/test/CodeGen/RISCV/half-intrinsics.ll
    M llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp.ll

  Log Message:
  -----------
  [RISCV] Don't promote f16 FNEG/FABS with Zfhmin/Zhinxmin. (#106474)

fneg/fabs are not supposed to canonicalize nans. Promoting to f32 will
go through an fp_extend which will canonicalize. The generic Promote
handler needs to be removed from LegalizeDAG.

We need to use integer bit manip to clear the bit instead.

Unfortunately, this is going through the stack due to i16 not being a
legal type. Fixing that will require custom legalization or some other
generic SelectionDAG change.



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