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

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

[jakub at gcc dot gnu.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.

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

[ebotcazou at gcc dot gnu.org]

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

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|x86_64-linux                |x86_64-linux x86-linux
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011.03.29 07:49:51
                 CC|                            |ebotcazou at gcc dot
                   |                            |gnu.org
            Version|4.6.0                       |4.7.0
     Ever Confirmed|0                           |1

--- Comment #1 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2011-03-29 07:49:51 UTC ---
Confirmed.  Same error on x86.

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

[rguenth at gcc dot gnu.org]

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

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.7.0

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

[jakub at gcc dot gnu.org]

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

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-03-29 10:56:50 UTC ---
Binary search revealed it is actually gimple.o that got miscompiled by
stage1-gcc/cc1.  Ignoring .LXXXX number differences, only is_gimple_val
and canonicalize_cond_expr_cond functions are different.

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

[law at redhat dot com]

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

--- Comment #3 from Jeffrey A. Law <law at redhat dot com> 2011-03-29 15:59:11 UTC ---
It's a problem with updating the SSA graph in a relatively uncommon case. 
We're failing to update a PHI argument correctly.  I'm still thinking about how
best to address the problem.

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

[law at gcc dot gnu.org]

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

--- Comment #4 from Jeffrey A. Law <law at gcc dot gnu.org> 2011-03-29 22:49:07 UTC ---
Author: law
Date: Tue Mar 29 22:49:00 2011
New Revision: 171703

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=171703
Log:
    PR bootstrap/48327
    * tree-ssa-threadupdate.c (struct redirection_data): Remove
    do_not_duplicate field.
    (lookup_redirection_data): Corresponding changes.
    (create_duplicates): Always create a template block.
    (redirect_edges): Remove code which reused the original block
    when it was going to become unreachable code.
    (thread_block): Don't set do_not_duplicate field.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-threadupdate.c

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

[law at redhat dot com]

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

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #5 from Jeffrey A. Law <law at redhat dot com> 2011-03-29 22:56:12 UTC ---
Fixed by tree-ssa-threadupdate patch.