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Re: [s390] increase stack alignment
On Wed, Oct 8, 2008 at 1:55 PM, DJ Delorie <email@example.com> wrote:
>> So could you please elaborate why you think this is necessary.
> The CDSG opcode needs 16 byte alignment when accessing stack
> variables, currently it doesn't get it, I'm not really picky about how
> it gets fixed ;-)
> In the test case I have (from a customer), the cdsg opcode is in an
> inline asm, so gcc can't know that that stack is "special". However,
> the variables on stack are tagged for 32-byte alignment, and only get
> 8-byte alignment. Perhaps something in gcc could note when stack
> variables need greater alignment than the stack normally provides, and
> adjust the stack at runtime accordingly?
See http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16660. I had posted a
patch which realigned the stack variables if needed but it was not
commented on except by HJL. Intel implemented something different for
x86 where they realign the whole stack.