craig.topper added a comment.
In D86310#2231136 <https://reviews.llvm.org/D86310#2231136>, @efriedma wrote:
> I'm afraid the AutoUpgrade component of this isn't compatible with existing
> IR without some additional work. I'm most concerned about cases like the
> following:
>
> #pragma pack(8)
> struct X { __int128 x; }; // Not a packed struct in IR because the native
> alignment is 8
> struct Y { long long x; struct X y; }; // 24 bytes before autoupgrade, 32
> bytes after
> struct Y x;
>
>
>
> ------
>
> On a related note, we need to add "Fn8" to the x86 datalayout at some point.
I kind of feared that old IR was going to be a problem. Any thoughts on how to
fix it? Do we need to visit every alloca/load/store/etc that don't have
explicit alignment and force them to the old alignment? Alternatively, could
we skip the autoupgrade and weaken the compatible layout check somehow?
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D86310/new/
https://reviews.llvm.org/D86310
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