Redesign atomic store with hints intrinsics

[Lukacma]

This proposal is about redesigning atomic store with hint intrinsics, to make them more easily extensible.

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[CarolineConcatto]

What will be the behaviour if hint is not valid?

[Lukacma]

I guess that is undefined behaviour and will be implementation based. For LLVM we will throw error and reject.

[CarolineConcatto]

Should it throw an error or just ignore and still do the atomic store?

[Lukacma]

I would throw error. This seems like a user mistake and we shouldn't just let it silently pass imo.

[sallyarmneale]

Is it Hint or hint?

[CarolineConcatto]

What is the difference between Hint and hint besides the first letter being in capital or lower? Does it have different meaning for @sallyarmneale ?