[PATCH] D74651: Add IR constructs for inalloca replacement preallocated call setup

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added a comment.

In D74651#2005985 <https://reviews.llvm.org/D74651#2005985>, @efriedma wrote:

> > What about if we directly replace the llvm.call.preallocated.arg() with an alloca (as opposed to an alloca in the entry block)?
>
> There can be more than one llvm.call.preallocated.arg referring to the same argument, so probably you'd want to insert the alloca at the point of the llvm.call.preallocated.setup.  But yes, that should work.


We could go down the route of doing something similar to inalloca where the `llvm.call.preallocated.setup` becomes an `alloca` of a structure containing all the arguments, and the `llvm.call.preallocated.arg` becomes a gep of the `alloca`. I've changed the LangRef to say that. I'm not sure if I'm overspecifying in the LangRef though, maybe that should be an implementation detail?


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https://reviews.llvm.org/D74651