PowerPC64 alignment of double in structs

Benjamin Herrenschmidt benh at kernel.crashing.org
Thu Sep 18 07:26:14 EST 2003

On Wed, 2003-09-17 at 18:11, Alan Modra wrote:
> http://gcc.gnu.org/ml/gcc-patches/2003-09/msg01003.html is a proposal
> for fixing struct layout rules on powerpc64-linux-gcc to comply with
> the PowerPC64 Linux ABI.  The ABI specifies 4 byte alignment for
> doubles, which is a little surprising for someone without an AIX
> background, and isn't ideal for speed.  An alternative would be to
> change the ABI and gcc (and presumably xlc) to natural alignment.
> I'm interested in opinions..

For what it's worth on ABI matters, my opinion is too enforce strict
alignement (same goes for Altivec). I'd go further saying that not
enforcing alignement by default is completely insane.


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