[PATCH] x86-64: Align the stack in __tls_get_addr [BZ #21609]

[Florian Weimer]

On 07/03/2017 10:25 PM, H.J. Lu wrote:
> I prefer to let GCC realign the stack for us.  What do you think?

I tried that first, but it does not work with all the GCC versions we
support.  We would have to add a configure check and hope that older GCC
versions never generate code which needs an aligned stack.

Furthermore, the code GCC generates for stack realignment is really bad,
and __tls_get_addr appears to be quite performance-critical because not
all callers cache the result.

Thanks,
Florian