[Bug bootstrap/48327] New: [4.7 Regression] Bootstrap comparison failure with ada since r171622

["jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48327

           Summary: [4.7 Regression] Bootstrap comparison failure with ada
                    since r171622
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jakub@gcc.gnu.org
                CC: law@gcc.gnu.org
            Target: x86_64-linux


../configure --enable-languages=all,obj-c++,ada,lto,go
--enable-checking=yes,rtl
configured gcc results in .bad_compare:
gcc/ada/exp_dist.o differs
r171621 works, r171622 fails.
Most likely stage2 tree-ssa-forwprop.o is miscompiled, doesn't seem to be
VTA related, as even when I compile exp_dist.adb with -g0 by both
stage1-gcc/gnat1 and prev-gcc/gnat1, it differs.  r171621 compiled exp_dist.s
is identical to what stage1-gcc/gnat1 in r171622 produces, differences start in
forwprop1 pass.