[Bug lto/88677] New: Divergence in -O2 and -O2 -flto early opts

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88677

            Bug ID: 88677
           Summary: Divergence in -O2 and -O2 -flto early opts
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hubicka at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

Created attachment 45325
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45325&action=edit
testcase

This causes profile data loss for Firefox.
There is one PHI different in function obj_seal in fre1 dump when built with:

g++ test2.ii -O3 -fomit-frame-pointer -funwind-tables -fno-strict-aliasing
-fno-rtti -fno-exceptions -fno-math-errno test2.ii  -fdump-tree-fre1 -flto

and 

g++ test2.ii -O3 -fomit-frame-pointer -funwind-tables -fno-strict-aliasing
-fno-rtti -fno-exceptions -fno-math-errno test2.ii  -fdump-tree-fre1