Status of conflicting inline IR attributes on declaration vs call

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1

Hello,

I’d like to clarify the behavior of LLVM in presence of inline-related attribute annotation on both declaration and the function call, specifically if it differs.

Currently, it looks like LLVM would always inline the function if it sees ‘alwaysinline’ attribute on either the call or the declaration, ignoring the ‘noinline’:

https://godbolt.org/z/r4e837dj5

https://godbolt.org/z/4xnoKz978

However, this seems purely accidental (related to how hasFnAttr works), so I wonder if the IR such as in above cases is considered correct.

I can see it being useful for something like https://lists.llvm.org/pipermail/cfe-dev/2018-September/059232.html , but at the moment the inliner behavior appears inconsistent.

So, what are the IR guarantees regarding the (no|always)inline attributes? If the programs linked above are incorrect, should there be a verifier check to guard against such IR?

2

I would allow it and give call sites precedence. That will require to modify a little bit of code
but we already have getters for call site attributes that work differently (maybe accidentally but anyway).

~ Johannes