[llvm-dev] Clang for the PlayStation 2

[Daniel Sanders via llvm-dev]

> On 6 Sep 2018, at 08:00, Dan Ravensloft via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> 
> On Mon, 3 Sep 2018 at 13:31, Tim Northover <t.p.northover at gmail.com <mailto:t.p.northover at gmail.com>> wrote:
> So the next step is to debug where Mips is producing those TruncIntFP
> nodes. There'll be some constraint it's not checking or an unexpected
> node type, probably related to -msingle-float. I'm afraid I'm not sure
> what yet.

FWIW, I'm not sure how well tested -msingle-float was on MIPS. I don't think we had any bots testing it.

> I'm reasonably sure the function producing that node is lowerFP_TO_SINT_STORE in lib/Target/Mips/MipsISelLowering.cpp.
> 
> The node before that function executes has an fp_to_sint node which seems to want to convert an i64 to an f32 which seems...rather odd to me, honestly. The PS2, for what it's worth, only has an i32 -> f32 instruction, so I think there's an impedance mismatch somewhere.

Did you mean those types to be the other way around? fp_to_sint is supposed to take a floating point type and produce an integer type so if you're seeing them backwards like this then that would definitely be a bug.

If you're referring to the size mismatch though, that's ok within the IR and DAG nodes. There's no relationship between the size of the input and output. 

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