[PATCH] D157836: [RFC][IR] Correct lowering of `f128` intrinsics

[Trevor Gross via Phabricator via llvm-commits]

tmgross added a comment.

In D157836#4586599 <https://reviews.llvm.org/D157836#4586599>, @efriedma wrote:

> If there's literally no implementation of sinf128 available, I don't think we can do much better than just letting the linker produce a "sinf128 not found" error.  I mean, a compiler error might be slightly better, but not by a lot, so I don't think it's worth the complexity to try to produce one.  (And this way lets the user provide their own implementation if they want to.)

That sounds good, still a lot better than runtime computation errors

> My primary concern here is the effect on non-x86 targets.  For targets where "long double" is f128, lowering "llvm.sin.f128" to "sinl" is fine, and messing with the name could break previously working code.  So maybe instead of messing with RuntimeLibcalls.def directly, we should make the backend fix the names (call setLibcallName() in X86ISelLowering.cpp).

Thank you for the direction - is there a place to do this in a more platform-generic way based on the layout of `long double`? I think there quite a few targets where `long double != f128` especially non-64-bit.


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https://reviews.llvm.org/D157836