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. -- H.J.
