[Bug tree-optimization/18650] New: Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[Bug tree-optimization/18650] New: Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[jgrimm2 at us dot ibm dot com]

I didn't find a bug report for this yet.

This regressoin roughly started happening Oct 26-27. as it shows up in
testresults from Janis Johson here.  (32-bit default32 compiler.  Regression
only at -m64)

http://gcc.gnu.org/ml/gcc-testresults/2004-10/msg01382.html

Interestingly, this also shows up in my 64-bit default64 compiler but at -m32:

http://gcc.gnu.org/ml/gcc-testresults/2004-10/msg01391.html

The check that is failing in the test case is:

  /* { dg-final { scan-tree-dump-times " \\* 17" 0 "vars" } } */
  /* { dg-final { scan-tree-dump-times " \\+ 17" 1 "vars" } } */

as 17 * iter is not getting reduced.


I played with the testcase a bit using a 32-bit biarch compiler w/ -m64 and
noticed a couple things.

1) Changing the iter var from 'int' to a 'long' seems to let the test pass again
.  The test case is tiny so I'll original code here:

struct bla
{
  char x[187];
  int y;
  char z[253];
} arr_base[100];

void xxx(void)
{
  int  iter;

  for (iter = 0; iter < 100; iter++)
    arr_base[iter].y = 17 * iter;
}



2) Dumps of t52.ivopts pass (from dump-tree-all-all), look funny:

(add_to_evolution
  (loop_nb = 1)
  (chrec_before = 100)
  (to_add = 1)
  (res = {100, +, 4294967295}_1))
  (evolution_function = {100, +, 4294967295}_1))
(set_scalar_evolution
  (scalar = ivtmp.1_5)
  (scalar_evolution = {100, +, 4294967295}_1))
)

,as 4294967295 looks quite peculiar.and would have expected 0 there.   

I'll attach the entire loop-2.c.t52.ivopts for 32 bit and for 64 bit, in case
someone wise in the ways of tree/loops/scalarev has interest.

-- 
           Summary: Failure in tree-ssa/loop-2.c with powerpc64 with biarch
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jgrimm2 at us dot ibm dot com
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[jgrimm2 at us dot ibm dot com]

------- Additional Comments From jgrimm2 at us dot ibm dot com  2004-11-24 16:14 -------
Created an attachment (id=7596)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7596&action=view)
ivopts dump at -m32   (when testcase passes)

ivopts dump at -m32   (when testcase passes)

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[jgrimm2 at us dot ibm dot com]

------- Additional Comments From jgrimm2 at us dot ibm dot com  2004-11-24 16:15 -------
Created an attachment (id=7597)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7597&action=view)
ivopts dump at -m64   (when testcase fails)

ivopts dump at -m64   (when testcase fails)

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
            Summary|Failure in tree-ssa/loop-2.c|Failure in tree-ssa/loop-2.c
                   |with powerpc64 with biarch  |with powerpc64 with biarch


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[jgrimm2 at us dot ibm dot com]

------- Additional Comments From jgrimm2 at us dot ibm dot com  2004-11-24 22:08 -------
Ugh. Ignore my comments on add_to_evolution comment, I was sleepy when I wrote
up notes.  The dumps still may be useful though. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[jgrimm2 at us dot ibm dot com]

------- Additional Comments From jgrimm2 at us dot ibm dot com  2004-11-24 22:59 -------
This set of changes seems to have caused the regression:
http://gcc.gnu.org/ml/gcc-cvs/2004-10/msg01561.html

Or more specifically
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-loop-ivopts.c.diff?cvsroot=gcc&r1=2.20&r2=2.21

If I re-enable walking all of the candidates (as opposed to just the "important"
ones" I get back the optimizations that were present before and this test case
will pass again. 



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] [4.0 Regression] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-11-24 23:01 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-11-24 23:01:11
               date|                            |
            Summary|Failure in tree-ssa/loop-2.c|[4.0 Regression] Failure in
                   |with powerpc64 with biarch  |tree-ssa/loop-2.c with
                   |                            |powerpc64 with biarch
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] [4.0 Regression] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[jgrimm2 at us dot ibm dot com]

------- Additional Comments From jgrimm2 at us dot ibm dot com  2004-11-29 19:02 -------
adding cc for awareness.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] [4.0 Regression] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[jgrimm2 at us dot ibm dot com]

------- Additional Comments From jgrimm2 at us dot ibm dot com  2005-01-06 23:22 -------
Seems fixed?

Last broken here:
http://gcc.gnu.org/ml/gcc-testresults/2004-12/msg00804.html

Not failing here:
http://gcc.gnu.org/ml/gcc-testresults/2004-12/msg00844.html

Maybe fixed by??:
http://gcc.gnu.org/ml/gcc-patches/2004-12/msg01554.html

Probably can close this out as WORKSFORME or something like that?? or dup to
19078 or if there is a PR + fix that this can concretely be attributed to. 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650

[Bug tree-optimization/18650] [4.0 Regression] Failure in tree-ssa/loop-2.c with powerpc64 with biarch

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-07 01:10 -------
So closing as fixed.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18650