On Tue, Feb 02, 2016 at 01:24:26PM +0100, Uros Bizjak wrote: > On Tue, Feb 2, 2016 at 12:53 PM, Jakub Jelinek <ja...@redhat.com> wrote: > > >> The bottom line is ix86_minimum_alignment must return the correct > >> number for DImode or you can just turn off STV. My suggestion is > >> to use my patch. > > > > Uros, any preferences here? I mean, it is possible to use > > e.g. the ix86_option_override_internal and have H.J's ix86_minimum_alignment > > change as a safety net, in the usual case for -mpreferred-stack-boundary=2 > > we'll just disable TARGET_STV and ix86_minimum_alignment change won't do > > anything, as TARGET_STV will be false, and if for whatever case it gets > > through (target attribute, -mincoming-stack-boundary=, ...) > > ix86_minimum_alignment will be there to ensure enough stack alignment. > > Most of the smaller -mpreferred-stack-boundary= uses are -mno-sse anyway, > > and that is something we don't want to affect. > > IMO, we should disable STV when -mpreferred-stack-boundary < 3, as STV > is only an optimization. Perhaps we can also emit a "sorry" for > explicit -mstv in case stack boundary requirement is not satisfied. > *If* there is a need for -mstv with smaller stack boundary, we can > revisit this decision for later gcc versions. > > I think disabling STV is less surprising option than increasing stack > boundary behind the user's back.
So, is http://gcc.gnu.org/ml/gcc-patches/2016-01/msg02129.html ok for trunk then (alone or with additional sorry, incremental or not?)? I believe it does just that. Jakub