[PATCH] D79636: [LangRef] Clarify the semantics of the `byval` attribute

[Eli Friedman via Phabricator via cfe-commits]

efriedma added a comment.

Sure, I'm happy with the second option.

> Alignment at the call site might be higher than of the copy, breaking with the idea that the call site and callee "properties" match. Though, the attributes can probably be kept in sync if we teach the relevant parts.

The meaning of the "align" attribute with byval is weird from any perspective: it specifies both the alignment of the allocation, and the required alignment of the input.  It would be nice to separate those at some point.  (That would probably mean something like `byval(<ty>, <align>)` to specify the alignment of the copied memory, and then the `align` attribute would just specify the alignment of the input, like it does for other calls.)


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  https://reviews.llvm.org/D79636/new/

https://reviews.llvm.org/D79636