[PATCH] D157509: [LegalizeTypes][RISCV] Enable expanding {S,U}INT_TO_FP for bf16 when bf16 is a legal type

[Alex Bradbury via Phabricator via llvm-commits]

asb added subscribers: pengfei, bkramer.
asb added a comment.

In D157509#4573536 <https://reviews.llvm.org/D157509#4573536>, @craig.topper wrote:

> Doesn't this have potential for double rounding? Though I don't know what to do about that.

I'm not totally sure what the 'ideal' semantics are here, though this two-stage rounding does match what is done for x86_64:

  pushq	%rax
  cvtsi2ss	%rdi, %xmm0
  callq	__truncsfbf2 at PLT
  popq	%rax
  retq

and of course the other RISC-V test cases that aren't impacted by this change (RV64ID and RV32ID check lines).

CC @bkramer @pengfei


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https://reviews.llvm.org/D157509