[llvm-dev] SETCC ISD node question

[Friedman, Eli via llvm-dev]

On 10/25/2018 5:20 PM, Craig Topper wrote:
> Should SETCC result types and input types always have the same number 
> of vector elements or both be scalar?

No. At least, the documentation for ISD::SETCC doesn't indicate it's 
allowed, and it's not obvious what it would mean.

> I ask because it appears DAGTypeLegalizer::WidenVSELECTAndMask can 
> create a setcc where this isn't true.

This comes from https://reviews.llvm.org/D29489 .  Looking over my 
comments from that review, the patch isn't intentionally creating 
mismatched SETCCs, though.

-Eli

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