Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

[bangerth]

Synopsis: [tree-ssa] Segfault for (essentially) empty function

Responsible-Changed-From-To: unassigned->law
Responsible-Changed-By: bangerth
Responsible-Changed-When: Mon May 19 14:51:18 2003
Responsible-Changed-Why:
    Jeff, you had been doing the tree-ssa C++ stuff, right? Or
    is there someone else whom I could bother?
    
    Besides, apart from this one and 10863 (which triggers 
    _really_ frequent on my code), the tree-ssa branch seems
    to be in pretty good shape -- thanks!
    
    W.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10862

Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

[bangerth]

Synopsis: [tree-ssa] Segfault for (essentially) empty function

State-Changed-From-To: open->closed
State-Changed-By: bangerth
State-Changed-When: Mon May 19 22:06:49 2003
State-Changed-Why:
    Jeff already fixed it. Thanks a lot!
    W.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10862

Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

[Wolfgang Bangerth]

The following reply was made to PR optimization/10862; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ices.utexas.edu>
To: law@redhat.com
Cc: gcc-gnats@gcc.gnu.org, <gcc-patches@gcc.gnu.org>
Subject: Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty
  function
Date: Mon, 19 May 2003 17:05:02 -0500 (CDT)

 > This patch ought to fix this problem.
 
 Yes, it does. Thanks!
   W.
 
 -------------------------------------------------------------------------
 Wolfgang Bangerth              email:            bangerth@ices.utexas.edu
                                www: http://www.ices.utexas.edu/~bangerth/
 
 

Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

[law]

The following reply was made to PR optimization/10862; it has been noted by GNATS.

From: law@redhat.com
To: bangerth@dealii.org
Cc: gcc-gnats@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty 
 function
Date: Mon, 19 May 2003 12:12:35 -0600

 In message <20030519144341.25098.qmail@sources.redhat.com>, bangerth@dealii.org
  writes:
  >
  >>Number:         10862
  >>Category:       optimization
  >>Synopsis:       [tree-ssa] Segfault for (essentially) empty function
  >>Confidential:   no
  >>Severity:       serious
  >>Priority:       medium
  >>Responsible:    unassigned
  >>State:          open
  >>Class:          sw-bug
  >>Submitter-Id:   net
  >>Arrival-Date:   Mon May 19 14:46:01 UTC 2003
  >>Closed-Date:
  >>Last-Modified:
  >>Originator:     Wolfgang Bangerth
  >>Release:        unknown-1.0
  >>Organization:
  >>Environment:
  >
  >>Description:
  >This one's rather funny (and was much simpler to reduce).
  >We ICE on a function that's essentially empty:
  >---------------------------------------template <int N> void foo () {
  >  int i;
  >  switch (i) {
  >    case 1:
  >          switch (N) {}
  >    default: ;
  >  }
  >}
  >
  >template void foo<1> ();
  >---------------------------
  >
  >g/x> /home/bangerth/bin/gcc-3.4-tree-ssa/bin/c++ -O2 -c a.cc
  >a.cc: In function `void foo() [with int N = 1]':
  >a.cc:10:   instantiated from here
  >a.cc:6: internal compiler error: Segmentation fault
  >Please submit a full bug report,
  >with preprocessed source if appropriate.
  >See <URL:http://gcc.gnu.org/bugs.html> for instructions.
 This patch ought to fix this problem.
 
 	* tree-ssa-dce.c (remove_conditional): If the conditional's block
 	has no post dominator in the CFG, then wire it to the exit node.
 	Avoid unnecessary check of bb->succ.
 
 Index: tree-ssa-dce.c
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/Attic/tree-ssa-dce.c,v
 retrieving revision 1.1.2.37
 diff -c -3 -p -r1.1.2.37 tree-ssa-dce.c
 *** tree-ssa-dce.c	16 May 2003 18:09:19 -0000	1.1.2.37
 --- tree-ssa-dce.c	19 May 2003 16:50:25 -0000
 *************** remove_conditional (basic_block bb)
 *** 627,632 ****
 --- 627,637 ----
     if (bb->succ)
       return;
   
 +   /* If there is no post dominator, then this block is going to the
 +      exit node.  */
 +   if (pdom_bb == NULL)
 +     pdom_bb = EXIT_BLOCK_PTR;
 + 
     /* If the post dominator has any PHI nodes in it at all, the 
        conditional has been marked as necessary. This means no PHI
        node updating is required. If there are any PHI nodes, its a bug
 *************** remove_conditional (basic_block bb)
 *** 642,647 ****
   #endif
   
     /* Add an edge to BB's post dominator.  */
 !   if (bb->succ == NULL)
 !     make_edge (bb, pdom_bb,  EDGE_FALLTHRU);
   }
 --- 647,651 ----
   #endif
   
     /* Add an edge to BB's post dominator.  */
 !   make_edge (bb, pdom_bb,  EDGE_FALLTHRU);
   }
 
 

Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

[Diego Novillo]

The following reply was made to PR optimization/10862; it has been noted by GNATS.

From: Diego Novillo <dnovillo@redhat.com>
To: bangerth@dealii.org, bangerth@dealii.org, gcc-bugs@gcc.gnu.org,
	gcc-prs@gcc.gnu.org, law@gcc.gnu.org, nobody@gcc.gnu.org,
	"gcc-gnats@gcc.gnu.org" <gcc-gnats@gcc.gnu.org>
Cc:  
Subject: Re: optimization/10862: [tree-ssa] Segfault for (essentially)
	empty function
Date: 19 May 2003 11:27:21 -0400

 On Mon, 2003-05-19 at 10:51, bangerth@dealii.org wrote:
 > Synopsis: [tree-ssa] Segfault for (essentially) empty function
 > 
 > Responsible-Changed-From-To: unassigned->law
 > Responsible-Changed-By: bangerth
 > Responsible-Changed-When: Mon May 19 14:51:18 2003
 > Responsible-Changed-Why:
 >     Jeff, you had been doing the tree-ssa C++ stuff, right? Or
 >     is there someone else whom I could bother?
 >
 It's not actually a C++ problem.  It was a bug in DCE when removing a
 conditional that had no basic blocks after it.
 
 >     Besides, apart from this one and 10863 (which triggers 
 >     _really_ frequent on my code), the tree-ssa branch seems
 >     to be in pretty good shape -- thanks!
 >
 I'm glad to hear that.  Thanks for testing!
 
 
 Diego.
 

Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function

[Diego Novillo]

The following reply was made to PR optimization/10862; it has been noted by GNATS.

From: Diego Novillo <dnovillo@redhat.com>
To: bangerth@dealii.org
Cc: gcc-gnats@gcc.gnu.org
Subject: Re: optimization/10862: [tree-ssa] Segfault for (essentially) empty function
Date: Mon, 19 May 2003 11:14:47 -0400

 On Mon, May 19, 2003 at 02:43:41PM -0000, bangerth@dealii.org wrote:
 > 
 > >Number:         10862
 > >Category:       optimization
 > >Synopsis:       [tree-ssa] Segfault for (essentially) empty function
 > >Confidential:   no
 > >Severity:       serious
 > >Priority:       medium
 > >Responsible:    unassigned
 > >State:          open
 > >Class:          sw-bug
 > >Submitter-Id:   net
 > >Arrival-Date:   Mon May 19 14:46:01 UTC 2003
 > >Closed-Date:
 > >Last-Modified:
 > >Originator:     Wolfgang Bangerth
 > >Release:        unknown-1.0
 > >Organization:
 > >Environment:
 > 
 > >Description:
 > This one's rather funny (and was much simpler to reduce).
 > We ICE on a function that's essentially empty:
 > ---------------------------------------template <int N> void foo () {
 >   int i;
 >   switch (i) {
 >     case 1:
 >           switch (N) {}
 >     default: ;
 >   }
 > }
 > 
 > template void foo<1> ();
 > ---------------------------
 > 
 When removing blocks with empty conditionals, we should not
 assume that the block has a post dominator.  I'm testing this
 patch.
 
 
 Diego.
 
 
 
 	* tree-ssa-dce.c (remove_conditional): Don't assume that the block
 	to remove has a post-dominator.
 
 Index: tree-ssa-dce.c
 ===================================================================
 RCS file: /cvs/gcc/gcc/gcc/Attic/tree-ssa-dce.c,v
 retrieving revision 1.1.2.37
 diff -d -u -p -r1.1.2.37 tree-ssa-dce.c
 --- tree-ssa-dce.c	16 May 2003 18:09:19 -0000	1.1.2.37
 +++ tree-ssa-dce.c	19 May 2003 15:11:18 -0000
 @@ -633,15 +633,16 @@ remove_conditional (basic_block bb)
       in DCE.  */
  
  #ifdef ENABLE_CHECKING
 -  {
 -    tree phi;
 -    for (phi = phi_nodes (pdom_bb); phi; phi = TREE_CHAIN (phi))
 -      if (necessary_p (phi))
 -        abort ();
 -  }
 +  if (pdom_bb)
 +    {
 +      tree phi;
 +      for (phi = phi_nodes (pdom_bb); phi; phi = TREE_CHAIN (phi))
 +	if (necessary_p (phi))
 +	  abort ();
 +    }
  #endif
  
    /* Add an edge to BB's post dominator.  */
    if (bb->succ == NULL)
 -    make_edge (bb, pdom_bb,  EDGE_FALLTHRU);
 +    make_edge (bb, pdom_bb ? pdom_bb : EXIT_BLOCK_PTR,  EDGE_FALLTHRU);
  }

optimization/10862: [tree-ssa] Segfault for (essentially) empty function

[bangerth]

>Number:         10862
>Category:       optimization
>Synopsis:       [tree-ssa] Segfault for (essentially) empty function
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 19 14:46:01 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Wolfgang Bangerth
>Release:        unknown-1.0
>Organization:
>Environment:

>Description:
This one's rather funny (and was much simpler to reduce).
We ICE on a function that's essentially empty:
---------------------------------------template <int N> void foo () {
  int i;
  switch (i) {
    case 1:
          switch (N) {}
    default: ;
  }
}

template void foo<1> ();
---------------------------

g/x> /home/bangerth/bin/gcc-3.4-tree-ssa/bin/c++ -O2 -c a.cc
a.cc: In function `void foo() [with int N = 1]':
a.cc:10:   instantiated from here
a.cc:6: internal compiler error: Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.

g/x> /home/bangerth/bin/gcc-3.4-tree-ssa/bin/c++ -v
Reading specs from /home/bangerth/bin/gcc-3.4-tree-ssa/lib/gcc-lib/i686-pc-linux-gnu/3.5-tree-ssa/specs
Configured with: ../gcc-3.4-CVS-tree-ssa/configure --enable-checking --enable-languages=c,c++,f77 --prefix=/home/bangerth/bin/gcc-3.4-tree-ssa
Thread model: posix
gcc version 3.5-tree-ssa 20030516 (merged 20030511)
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: