[PATCH] D75903: [AArch64][CodeGen] Fixing stack alignment of HFA arguments on AArch64 PCS

[Reid Kleckner via Phabricator via llvm-commits]

rnk added a comment.

In D75903#1914715 <https://reviews.llvm.org/D75903#1914715>, @ostannard wrote:

> This means that `stk1` should be passed as a copy with alignment 16 bytes, putting it at `sp+16`. GCC does this, clang without this patch passes it at `sp+8`, and clang with this patch passes it at `sp+32`.


MSVC puts it at `sp+8`: https://gcc.godbolt.org/z/aAku9j

They allegedly follow this same document. Either way, we need to remain compatible.

Given that neither GCC nor MSVC do things they way you are proposing, are you sure this is correct? What compiler does this change make us more compatible with?

I don't believe there is an issue from the user's standpoint, since Clang copies the entire argument into an appropriately aligned alloca. If it is address-taken and stored to, there will not be any faults.


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  https://reviews.llvm.org/D75903/new/

https://reviews.llvm.org/D75903