[Bug optimization/12472] [tree-ssa] miscompiles stage-2's gengtype

[Bug optimization/12472] [tree-ssa] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |tree-ssa

[Bug optimization/12472] New: [tree-ssa] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472

           Summary: [tree-ssa] miscompiles stage-2's gengtype
           Product: gcc
           Version: tree-ssa
            Status: UNCONFIRMED
          Keywords: wrong-code, build
          Severity: critical
          Priority: P1
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc-apple-darwin

Read <http://gcc.gnu.org/ml/gcc/2003-09/msg01190.html> and <http://gcc.gnu.org/ml/gcc/
2003-09/msg01206.html>.
Main just is that GCC miscompiles gengtype's update_lineno which cause a segfault.
The main difference between powerpc-apple-darwin and any other target is that it defines 
BOOL_TYPE_SIZE to be INT_TYPE_SIZE (so that _Bool is of size 4 instead of 1).
Even trying with commenting that line out, bootstrap does not pass.
Also note that the problem is not the trees that are causing the problem so it might be a problem 
on the mainline also.

[Bug optimization/12472] [tree-ssa] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dberlin at gcc dot gnu dot
                   |                            |org


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-06 20:45 -------
*** Bug 12528 has been marked as a duplicate of this bug. ***

[Bug optimization/12472] [tree-ssa] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2003-10-14 21:17:27
               date|                            |


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-14 21:17 -------
If I disable all the RTL optimizers by editing opts.c and #if 0 out the code to turn them on, I get 
passed this point.

[Bug optimization/12472] [tree-ssa] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-15 00:09 -------
This is caused by one of the following two options:
      flag_loop_optimize = 1;
      flag_crossjumping = 1;

Both are RTL based optimizers, if I have some more time to work on this I will.

[Bug optimization/12472] [tree-ssa] [loop-optimize] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[tree-ssa] miscompiles      |[tree-ssa] [loop-optimize]
                   |stage-2's gengtype          |miscompiles stage-2's
                   |                            |gengtype


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-15 01:29 -------
Okay I have narrowed it down to
      flag_loop_optimize = 1;

Now I need to find out what it is doing to cause the miscompile.

[Bug optimization/12472] [tree-ssa] [loop-optimize] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-15 02:33 -------
It is looking more like flag_branch_on_count_reg which is causing it.

[Bug optimization/12472] [tree-ssa] [doloop] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-15 03:32 -------
I have verified that it is flag_branch_on_count_reg which is causing it, I will look more at 
it tomorrow.

[Bug optimization/12472] [tree-ssa] [doloop] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-16 00:36 -------
This is another RTL optimization problem after the doloop optimization is fixed.
It is caused by one of following options:
      flag_optimize_sibling_calls = 1;
      flag_cse_follow_jumps = 1;
      flag_cse_skip_blocks = 1;
I am trying to narrow it down as I write this.

[Bug optimization/12472] [tree-ssa] [doloop] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-16 00:49 -------
Down to two:
      flag_optimize_sibling_calls = 1;
      flag_cse_skip_blocks = 1;

[Bug optimization/12472] [tree-ssa] [doloop] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472



------- Additional Comments From pinskia at gcc dot gnu dot org  2003-10-16 02:16 -------
So the final two options which are causing the miscompile on powerpc-darwin are:
      flag_optimize_sibling_calls = 1;  (-foptimize-sibling-calls)
flag_branch_on_count_reg (-fbranch-on-count-reg)
Both are enabled at -O2.

[Bug optimization/12472] [tree-ssa] [doloop] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2003-10-14 21:17:27         |2003-11-04 05:25:48
               date|                            |


------- Additional Comments From pinskia at gcc dot gnu dot org  2003-11-04 05:25 -------
One more thing, the tree-ssa adds 
	addi r4,r4,-1 to the asm for some reason, other than that it is identical to the mainline.

[Bug optimization/12472] [tree-ssa] [doloop] miscompiles stage-2's gengtype

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2003-11-18 22:53 -------
What is cool is this patch is no longer needed so closing as fixed because it passes the spot where 
the problem is.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12472