[Bug tree-optimization/27056] New: ICE in loop_depth_of_name

[Bug tree-optimization/27056] New: ICE in loop_depth_of_name

[jakub at gcc dot gnu dot org]

On the attached testcase with today's gcc-4_1-branch
-m32 -g -O2 I get ICE during copy propagation.  Unfortunately, even doing minor
changes in different routines makes the problem go away.
What I see in the dumps is:
1) at *t26.ssa, in draw_digit, there are two SSA_NAMEs with version 2:
...
  D.52296_2 = dD.52286_1 * 2;
  #   VUSE <digit_texture_coordsD.52285_3>;
  x1D.52291_4 = digit_texture_coordsD.52285[D.52296_2];
  D.52296_5 = dD.52286_1 * 2;
  D.52297_6 = D.52296_5 + 1;
  #   VUSE <digit_texture_coordsD.52285_3>;
  y1D.52292_7 = digit_texture_coordsD.52285[D.52297_6];
  x2D.52293_8 = x1D.52291_4 + 2.5e-1;
  y2D.52294_9 = y1D.52292_7 + 2.5e-1;
  #   VUSE <cfgD.24335_2>;
...
2) when DCE is run, it first sees cfgD.24335_2 and sets bit 2 in processed
bitmap
in mark_operand_necessary, later on thus removes the D.52296_2 = dD.52286_1 *
2;
statement as dead, eventhough it is not dead, yet keeps the other 2 uses of
D.52296_2 around
3) in copyprop, we look at D.52296_2 which is on the free list in the mean time
and crash because it's SSA_NAME_DEF_STMT is NULL in bb_for_stmt called from
loop_depth_of_name.  Is already 1) a bug?

BTW, in *t26.ssa I see cfgD.24335_2 being used in 2 different functions,
load_background_image and draw_digit, in both cases only in VUSE<>.
Maybe some tree sharing issue?


-- 
           Summary: ICE in loop_depth_of_name
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org
GCC target triplet: x86_64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27056

[Bug tree-optimization/27056] ICE in loop_depth_of_name

[jakub at gcc dot gnu dot org]

------- Comment #1 from jakub at gcc dot gnu dot org  2006-04-06 11:51 -------
Created an attachment (id=11216)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11216&action=view)
188125.ii.bz2


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27056

[Bug tree-optimization/27056] ICE in loop_depth_of_name

[bonzini at gnu dot org]

------- Comment #2 from bonzini at gnu dot org  2006-04-06 13:53 -------
The ICE was probably exposed by my changes for PR26830, but if I understand
right it was causing a wrong code before that?


-- 

bonzini at gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bonzini at gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27056

[Bug tree-optimization/27056] ICE in loop_depth_of_name

[jakub at gcc dot gnu dot org]

------- Comment #3 from jakub at gcc dot gnu dot org  2006-04-06 13:59 -------
I get the same ICE also with
gcc version 4.1.0 20060304 (Red Hat 4.1.0-3)
which is much older than your PR26830 fix.
So those 2 seem to be unrelated.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27056

[Bug tree-optimization/27056] ICE in loop_depth_of_name

[reichelt at gcc dot gnu dot org]

------- Comment #4 from reichelt at gcc dot gnu dot org  2006-04-06 16:13 -------


*** This bug has been marked as a duplicate of 26757 ***


-- 

reichelt at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27056

[Bug tree-optimization/27056] ICE in loop_depth_of_name

[dberlin at dberlin dot org]

------- Comment #5 from dberlin at gcc dot gnu dot org  2006-04-06 16:15 -------
Subject: Re:   New: ICE in loop_depth_of_name

On Thu, 2006-04-06 at 11:49 +0000, jakub at gcc dot gnu dot org wrote:
> On the attached testcase with today's gcc-4_1-branch
> -m32 -g -O2 I get ICE during copy propagation.  Unfortunately, even doing minor
> changes in different routines makes the problem go away.
> What I see in the dumps is:
> 1) at *t26.ssa, in draw_digit, there are two SSA_NAMEs with version 2:

This is already wrong :)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27056

Re: [Bug tree-optimization/27056] New: ICE in loop_depth_of_name

[Daniel Berlin]

On Thu, 2006-04-06 at 11:49 +0000, jakub at gcc dot gnu dot org wrote:
> On the attached testcase with today's gcc-4_1-branch
> -m32 -g -O2 I get ICE during copy propagation.  Unfortunately, even doing minor
> changes in different routines makes the problem go away.
> What I see in the dumps is:
> 1) at *t26.ssa, in draw_digit, there are two SSA_NAMEs with version 2:

This is already wrong :)