[PATCH] D151663: [RISCV] Implement support for bf16 truncate/extend on hard FP targets

[Alex Bradbury via Phabricator via llvm-commits]

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For the same reasons as D151284 <https://reviews.llvm.org/D151284>, this requires custom lowering of the truncate libcall on hard float ABIs (the normal libcall code path is used on soft ABIs).

The extend operation is implemented by a shift just as in the standard legalisation, but needs to be custom lowered because i32 isn't a legal type on RV64.

This patch aims to make the minimal changes that result in correct codegen for the bfloat.ll tests.


https://reviews.llvm.org/D151663

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

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