On Thu, Oct 9, 2014 at 1:37 AM, Uros Bizjak <ubiz...@gmail.com> wrote: > On Thu, Oct 9, 2014 at 10:25 AM, Kirill Yukhin <kirill.yuk...@gmail.com> > wrote: >> On 08 Oct 23:02, Petr Murzin wrote: >>> Hi, >>> I have measured performance impact on Haswell platform according to this >>> input: >>> https://gcc.gnu.org/ml/gcc-patches/2014-06/msg00978.html
Kirill, please mention: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61296 in your ChangeLog. > What about older processors? Kirill, please collect data on Nehelam/Westmere, Sandybrigde/Ivybride and Silvermont. > The optimization was introduced well before Haswell for then current > processors, and it was based on the recommendation from Intel > optimization guide. If this optimization doesn't apply for new > processors, then tune option should be introduced and set accordingly. > I believe the original excessive alignment was introduced by cut/paste from https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=ed45e834f305d1f2709bf200a13d5beebc2fcfee to improve x86 FP performance, which might be partially copied from CONSTANT_ALIGNMENT: https://gcc.gnu.org/git/?p=gcc.git;a=patch;h=f7d6703c5d83fc9fb06246d6eb49e9b61098045c -- H.J.
