[Bug tree-optimization/23603] New: VRP does not say range for a in a = b == c; is [0,1]

[Bug tree-optimization/23603] New: VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

Example:
int f(int i)
{
  int t = i == 1;
  int g = t == 2;
  int h = g == 3;
  return h;
}
We should convert this to return 0 on the tree level but currently we get:
return i == 1 == 2 == 3;
in final_cleanup

-- 
           Summary: VRP does not say range for a in a = b == c; is [0,1]
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P2
         Component: tree-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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-28 17:22 -------
The fix would be instead of setting the range to varrying in extract_range_from_comparison, set it to 
[0,1].

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-28 17:25 -------
I have a fix.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |pinskia at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-08-28 17:25:25
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |23604


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-29 00:49 -------
This really does depend on PR 23604 as it exposes that latent bug while bootstrapping.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[dnovillo at gcc dot gnu dot org]

-- 
Bug 23603 depends on bug 23604, which changed state.

Bug 23604 Summary: [4.1 Regression] wrong code due to VRP
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23604

           What    |Old Value                   |New Value
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Comment #5 from pinskia at gcc dot gnu dot org  2005-10-03 00:43 -------
I just tried to bootstrap the patch on x86_64-linux-gnu and I think I ran into
another VRP bug.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Comment #6 from pinskia at gcc dot gnu dot org  2005-10-03 02:39 -------
(In reply to comment #5)
> I just tried to bootstrap the patch on x86_64-linux-gnu and I think I ran into
> another VRP bug.
I could not find it in cc1files and there was only one extra "Folding
predicate" in the whole cc1files :(.
I know it is in the gnat1 front-end but I really don't want to do the dumps for
that :(.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Comment #7 from pinskia at gcc dot gnu dot org  2005-10-04 19:44 -------
(In reply to comment #6)
> I know it is in the gnat1 front-end but I really don't want to do the dumps for
> that :(.

I figured out how to fix the problem but to me it seems like a front-end bug in
that it does not set TREE_PRECISSION on its boolean type correctly.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Comment #8 from pinskia at gcc dot gnu dot org  2005-10-23 00:06 -------
The patch above is almost correct and I just lost the correct one as my laptop
is dead so I am no longer working on this.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|pinskia at gcc dot gnu dot  |unassigned at gcc dot gnu
                   |org                         |dot org
             Status|ASSIGNED                    |NEW


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[pinskia at gcc dot gnu dot org]

------- Comment #9 from pinskia at gcc dot gnu dot org  2006-08-21 06:11 -------
I am going to try to get this done for 4.3.0.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |pinskia at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[rguenth at gcc dot gnu dot org]

------- Comment #10 from rguenth at gcc dot gnu dot org  2007-01-07 17:44 -------
In extract_range_from_binary we have another case where we drop to varying:

  /* For integer ranges, apply the operation to each end of the
     range and see what we end up with.  */
  if (code == TRUTH_ANDIF_EXPR
      || code == TRUTH_ORIF_EXPR
      || code == TRUTH_AND_EXPR
      || code == TRUTH_OR_EXPR)
    {
...
      else
        {
          set_value_range_to_varying (vr);
          return;
        }
    }

But the latent problems seem to be fixed, the following (simple) patch
bootstrapped and regtested ok for me:

*************** extract_range_from_comparison (value_ran
*** 1920,1926 ****
        set_value_range (vr, VR_RANGE, val, val, vr->equiv);
      }
    else
!     set_value_range_to_varying (vr);
  }


--- 1925,1933 ----
        set_value_range (vr, VR_RANGE, val, val, vr->equiv);
      }
    else
!     /* The result of a comparison is always true or false.  */
!     set_value_range (vr, VR_RANGE, build_int_cst (TREE_TYPE (expr), 0),
!                    build_int_cst (TREE_TYPE (expr), 1), vr->equiv);
  }


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[rguenth at gcc dot gnu dot org]

------- Comment #11 from rguenth at gcc dot gnu dot org  2007-01-08 11:20 -------
Subject: Bug 23603

Author: rguenth
Date: Mon Jan  8 11:20:00 2007
New Revision: 120578

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=120578
Log:
2007-01-08  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/23603
        * tree-vrp.c (set_value_range_to_truthvalue): New function.
        (extract_range_from_binary): Fall back to truthvalue instead of
        varying for TRUTH_*_EXPR.
        (extract_range_from_comparison): Fall back to truthvalue instead of
        varying.
        (vrp_visit_phi_node): Don't adjust new range bounds to +INF/-INF
        if all visited PHI values were constant.

        * gcc.dg/tree-ssa/vrp31.c: New testcase.
        * gcc.dg/tree-ssa/vrp32.c: Likewise.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp31.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/vrp32.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vrp.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603

[Bug tree-optimization/23603] VRP does not say range for a in a = b == c; is [0,1]

[rguenth at gcc dot gnu dot org]

------- Comment #12 from rguenth at gcc dot gnu dot org  2007-01-08 11:21 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23603