[Bug tree-optimization/21218] New: [4.1 regression] ICE using -ftree-vectorize

[Bug tree-optimization/21218] New: [4.1 regression] ICE using -ftree-vectorize

[reichelt at gcc dot gnu dot org]

Compiling the following code snippet with
"-ftree-vectorize -O2 -march=pentium4" triggers an ICE on mainline
(the 4.0 branch is not affected):

============================================
struct A
{
    double d[2];
    double foo(int i) { return d[i]; }
};

struct B : public A {};

void bar(B& b)
{
    for (int i=0; i<2; ++i)
        b.d[i] = b.foo(i);
}
============================================

bug.cc: In function 'void bar(B&)':
bug.cc:9: error: Definition in block 1 does not dominate use in block 18
for SSA_NAME: this_5 in statement:
vect_p.20_56 = this_5 + base_off.19_55;
lall.cc:9: internal compiler error: verify_ssa failed.
Please submit a full bug report, [etc.]

-- 
           Summary: [4.1 regression] ICE using -ftree-vectorize
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code, monitored
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: reichelt at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-25 14:43 -------
Confirmed.

Failing since at least 20050421.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-04-25 14:43:35
               date|                            |
   Target Milestone|---                         |4.1.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[irar at il dot ibm dot com]

------- Additional Comments From irar at il dot ibm dot com  2005-04-26 10:04 -------
We get the following code for the loop:
  this_5 = &b_4->D.2068;
  D.2080_9 = this_5->d[i_18];
  b_4->D.2068.d[i_18] = D.2080_9;

In analysis of data-ref this_5->d[i_18] we don't check that the initial 
condition of access_fn of *this_5 is not loop invariant (we rely on evolution 
== NULL test, which is wrong). This is already fixed in autovect branch, and I 
am working on a patch to bring the changes in data-refs analysis to mainline.

Another issue here is that  this_5 = &b_4->D.2068; is loop invariant and can be 
hoist out of the loop. Maybe it will happen with structure-aliasing-branch?

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dberlin at gcc dot gnu dot
                   |                            |org
         AssignedTo|unassigned at gcc dot gnu   |irar at il dot ibm dot com
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2005-04-25 14:43:35         |2005-04-26 10:04:49
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-04-28 16:24 -------
(In reply to comment #2)
> Another issue here is that  this_5 = &b_4->D.2068; is loop invariant and can be 
> hoist out of the loop. Maybe it will happen with structure-aliasing-branch?

Well really we should prograte that statement into the next statement so we get something like:
  D.2080_9 = b_4->D.2068.d[i_18];

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2005-05-20 16:56 -------
The problem disappeared with Jan Hubicka's patch
http://gcc.gnu.org/ml/gcc-cvs/2005-05/msg00805.html

Is the patch a proper fix (i.e. can we close the PR)
or does it only paper over the problem?


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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[hubicka at ucw dot cz]

------- Additional Comments From hubicka at ucw dot cz  2005-05-20 17:22 -------
Subject: Re:  [4.1 regression] ICE using -ftree-vectorize

> 
> ------- Additional Comments From reichelt at gcc dot gnu dot org  2005-05-20 16:56 -------
> The problem disappeared with Jan Hubicka's patch
> http://gcc.gnu.org/ml/gcc-cvs/2005-05/msg00805.html
> 
> Is the patch a proper fix (i.e. can we close the PR)
> or does it only paper over the problem?

I would say that it just masks the problem somehow.  The non-dominated
use would be probably produced much later in optimization queue than my
patch affects.

Honza
> 
> 
> -- 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |hubicka at gcc dot gnu dot
>                    |                            |org
> 
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218
> 
> ------- You are receiving this mail because: -------
> You are on the CC list for the bug, or are watching someone who is.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2005-06-28 23:10 -------
Volker, your testcase does not fail anymore. Should we close this PR? I 
have other testcases that fail with the same error message and for which 
I will open another PR shortly... 
 
W. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[bangerth at dealii dot org]

------- Additional Comments From bangerth at dealii dot org  2005-06-28 23:23 -------
See PR 22228... 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218

[Bug tree-optimization/21218] [4.1 regression] ICE using -ftree-vectorize

[reichelt at gcc dot gnu dot org]

------- Additional Comments From reichelt at gcc dot gnu dot org  2005-06-29 13:37 -------
Closing as fixed as suggested by Wolfgang.


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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21218