[Bug rtl-optimization/70461] New: [6 Regression] Performance regression after r234527

[afomin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70461

            Bug ID: 70461
           Summary: [6 Regression] Performance regression after r234527
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: afomin at gcc dot gnu.org
                CC: izamyatin at gmail dot com, vmakarov at redhat dot com
  Target Milestone: ---
            Target: i686-*-*

Created attachment 38134
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38134&action=edit
A reproducer

When trying to compile the attached reproducer with -m32 -O2 -march=core-avx2
we generate 12 extra instructions (namely spills & fills) for the hot loop
since r234527.