[llvm-commits] Natural Stack Alignment - Prevent overly aggressive alignment promotion.

[Lang Hames]

Hi Anton,

That's my understanding too. In that case it's the ABI alignment which will force a dynamic stack realignment, and there's no way to avoid it. This patch is only to catch the case where the preferred alignment is higher than the ABI alignment, and a promotion to the preferred alignment would force a dynamic stack realignment.

Cheers,
Lang.

In cases like that a stack realignment will always be required.
On Oct 9, 2011, at 1:17 PM, Anton Korobeynikov wrote:

> Hi Lang,
> 
>> I don't think so. In the ARM bug I'm looking at i64's have a 64-bit preferred alignment, but the natural stack alignment is only 32-bits. I don't see anything
> inherently wrong with that, but it would force a dynamic stack
> realignment. This patch is designed to avoid such situations.
> iirc, i64 should be 64 bit aligned on some ARM ABIs, so, it will
> always require stack realignment
> 
> -- 
> With best regards, Anton Korobeynikov
> Faculty of Mathematics and Mechanics, Saint Petersburg State University