[PATCH] D123975: [RISCV] Add rvv codegen support for vp.fpext.

[Jianjian Guan via Phabricator via llvm-commits]

jacquesguan added a comment.

In D123975#3467825 <https://reviews.llvm.org/D123975#3467825>, @frasercrmck wrote:

> If I've read this correctly, this isn't strictly the same behaviour for fixed-length `ISD::FP_EXTEND` because it used to use `ISD::FP_EXTEND` for intermediate extends, whereas now it consistently uses `RISCVISD::FP_EXTEND_VL`. I wonder if we silently went through the same change when `ISD::FP_ROUND` was merged with `ISD::VP_FP_ROUND`.
>
> This isn't necessarily a problem as evidently the existing tests haven't changed, but it should probably be noted in the commit description at least.

I think you mean the scalable vector?  Yes, there is some logic change. Because `ISD::FP_EXTEND` and `ISD::FP_ROUND` has no mask and VL operands, if we want to keep the old way, maybe will import some complicated if-conditions. I am thinking should we remove those patterns in the `RISCVInstrInfoVSDPatterns.td` and let the function handle all lowering cases including fixed-length and scalable vector type? What's your opinion?


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