[Bug tree-optimization/17400] New: out of SSA corruption

[Bug tree-optimization/17400] New: out of SSA corruption

[steven at gcc dot gnu dot org]

I'm seeing this ICE on ia64 and amd64 at least. 
 
$ g++ --version 
g++ (GCC) 3.5.0 20040909 (experimental) 
Copyright (C) 2004 Free Software Foundation, Inc. 
This is free software; see the source for copying conditions.  There is NO 
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 
$ g++ -O3 -c t.ii 
 
Different root vars: <D17229> and <D17231> across an abnormal edge from 
BB446->BB564 
t.ii: In member function `void COWIntrusiveReferenceTestCases::n_swap()': 
t.ii:18074: internal compiler error: SSA corruption 
 
 
If anyone can reduce this to a manageable test case, would be 
much appreciated.  *sigh*  That is so hard to do for C++ :-(

-- 
           Summary: out of SSA corruption
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: steven at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400

[Bug tree-optimization/17400] out of SSA corruption

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2004-09-10 15:39 -------
Created an attachment (id=7086)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7086&action=view)
Test case for this bug

test case

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400

[Bug tree-optimization/17400] out of SSA corruption

[amacleod at redhat dot com]

------- Additional Comments From amacleod at redhat dot com  2004-09-10 18:11 -------
copyrename is making no attempt to prevent coalescing across abnormal edges.
 
There are a couple of issues to be resolved.
1 - abormal phi usage should be propagated to partitions when variables are merged
2 - dont coalesce partitions which are used in abnormnal phis,
3 - unless we are sure its safe to coalesce. Which we can be sure of in some
circumstances. (for instance, a single SSA_NAME occurence of a root variable)
 
3) May turn out to be an enhancement for 4.1


I'll provide a patch in a bit when I've thought about 3) a tiny bit more.



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400

[Bug tree-optimization/17400] [4.0 Regression] out of SSA corruption

[belyshev at lubercy dot com]

------- Additional Comments From belyshev at lubercy dot com  2004-09-10 18:19 -------
// small testcase, use '-O1':

void inc (int &);
bool dec_test (int &);

struct A
{
  int c;
  
  friend void AddRef (A * p)
  {
    inc (p->c);
  }
  
  friend void Release (A * p)
  {
    if(dec_test (p->c))
      delete p;
  }
};

struct B
{
  B (A *p) : obj(p)
  {
    AddRef (obj);
  }
  
  ~B()
  {
    Release (obj);
  }
  
  void swap (B &rhs)
  {
    A * tmp = obj;
    obj = rhs.obj;
    rhs.obj = tmp;
  }
  
  A *obj;
};

void bar (A *p1, A* p2)
{
    B px (p1);
    B px2 (p2);
    px.swap (px2);
}


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2004-09-10 18:19:19
               date|                            |
            Summary|out of SSA corruption       |[4.0 Regression] out of SSA
                   |                            |corruption
   Target Milestone|---                         |4.0.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400

[Bug tree-optimization/17400] [4.0 Regression] out of SSA corruption

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-09-10 22:26 -------
: Search converges between 2004-08-18-trunk (#517) and 2004-08-19-trunk (#518).

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400

[Bug tree-optimization/17400] [4.0 Regression] out of SSA corruption

[steven at gcc dot gnu dot org]

------- Additional Comments From steven at gcc dot gnu dot org  2004-09-13 10:03 -------
Andrew said he would provide a patch. 
 
This bug shows up in a very large number of larger C++ applications 
that I have tried to compile. 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |amacleod at redhat dot com
                   |dot org                     |
             Status|NEW                         |ASSIGNED
           Priority|P2                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400

[Bug tree-optimization/17400] [4.0 Regression] out of SSA corruption

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-09-13 19:12 -------
Subject: Bug 17400

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	amacleod@gcc.gnu.org	2004-09-13 19:12:15

Modified files:
	gcc            : ChangeLog tree-ssa-copyrename.c 

Log message:
	2004-09-13  Andrew MacLeod  <amacleod@redhat.com>
	
	PR tree-optimization/17400
	* tree-ssa-copyrename.c (copy_rename_partition_coalesce): Don't
	coalesce partitions when one occurs in an abnormal PHI.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.5421&r2=2.5422
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/tree-ssa-copyrename.c.diff?cvsroot=gcc&r1=2.14&r2=2.15



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400

[Bug tree-optimization/17400] [4.0 Regression] out of SSA corruption

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-09-13 20:44 -------
Fixed.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17400