2016-02-02 15:46 GMT+03:00 H.J. Lu <hjl.to...@gmail.com>: > On Tue, Feb 2, 2016 at 4:30 AM, H.J. Lu <hjl.to...@gmail.com> wrote: >> On Tue, Feb 2, 2016 at 4:29 AM, Jakub Jelinek <ja...@redhat.com> wrote: >>> 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. >> >> This patch is WRONG. >> >> -- >> H.J. > > You will run into the same ICE with > > -mincoming-stack-boundary=2 -msse2 -O2 -m32 > > in a leaf function which needs DImode spill/fill.
Why would we need DImode spill/fill having no DImode registers? Thanks, Ilya > > > -- > H.J.