[PATCH] D62017: [CodeGen] Add lrint/llrint builtins

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added a comment.

In D62017#2180852 <https://reviews.llvm.org/D62017#2180852>, @craig.topper wrote:

> In D62017#2180847 <https://reviews.llvm.org/D62017#2180847>, @arsenm wrote:
>
>> What is the point of these intrinsics exactly? It seems like it's just copying the libm function names, despite them only differing in the return integer type. Why can't this be accomplished with adding type mangling to the regular rint intrinsic?
>
> I think the primary complication is that we need to know what libcall to emit if the target doesn't natively support them. The backend doesn't know how to map from IR type "long" or "long long" to generate the right libcall.

But does that matter? What does the right library call really mean? I don't think the purpose of the math intrinsics is to wrap libm. Intrinsics should provide functionality independently of whatever the platform libm does. The backend is responsible for figuring out how to codegen any intrinsics which may or may not involve a platform provided library call.


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  https://reviews.llvm.org/D62017/new/

https://reviews.llvm.org/D62017