[Bug c++/27881] New: Memory exhausted with -finline-functions on testsuite file alias3.C

[Bug c++/27881] New: Memory exhausted with -finline-functions on testsuite file alias3.C

[flash at pobox dot com]

Compiling the GCC testsuite file alias3.C with -O1 -finline-functions exhausts
memory on checking=all or =yes builds of GCC 4.1.1, on Ubuntu 5.04 with virtual
memory limited to 500M.  Roughly similar behavior on Mac OSX 10.4.6 with a
checking=all build of GCC 4.1.0, though ulimit is broken on the Mac, so I had
to kill the process manually.  A checking=all build of GCC 4.0.2 compiles
without error.
    The symptoms are similar to my PR26774, but that's fixed in 4.1.1, and
didn't require optimization.
    Here's the Delta-reduced file:

namespace A{
  struct X{};
  void f(X&);
  namespace a_very_long_namespace_name{
  }
}
namespace B = A;
void B::f(A::X& x)
{
  B::f(x);
  f(x);
}


============
Here's the session; I'll attach the preprocessed file.

131> /opt/gcc411-chk-all/bin/gcc -v -save-temps -c -O1 -finline-functions  
../cpp/bugfiles/GCC_bugfiles/noerror/131415_alias3_min.cpp
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: /third-party_source/gcc-4.1.1/configure --enable-checking=all
--prefix=/opt/gcc411-chk-all/ --enable-languages=c,c++
--with-comment=PalmSource checking=all build by Flash Sheridan 5/31/06 on
Kondal
Thread model: posix
gcc version 4.1.1
 /home/opt/gcc411-chk-all/bin/../libexec/gcc/i686-pc-linux-gnu/4.1.1/cc1plus -E
-quiet -v -iprefix
/home/opt/gcc411-chk-all/bin/../lib/gcc/i686-pc-linux-gnu/4.1.1/ -D_GNU_SOURCE
../cpp/bugfiles/GCC_bugfiles/noerror/131415_alias3_min.cpp -mtune=pentiumpro
-finline-functions -O1 -fpch-preprocess -o 131415_alias3_min.ii
ignoring nonexistent directory
"/home/opt/gcc411-chk-all/bin/../lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../i686-pc-linux-gnu/include"
ignoring duplicate directory
"/opt/gcc411-chk-all//lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../include/c++/4.1.1"
ignoring duplicate directory
"/opt/gcc411-chk-all//lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../include/c++/4.1.1/i686-pc-linux-gnu"
ignoring duplicate directory
"/opt/gcc411-chk-all//lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../include/c++/4.1.1/backward"
ignoring duplicate directory
"/opt/gcc411-chk-all//lib/gcc/i686-pc-linux-gnu/4.1.1/include"
ignoring nonexistent directory
"/opt/gcc411-chk-all//lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:

/home/opt/gcc411-chk-all/bin/../lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../include/c++/4.1.1

/home/opt/gcc411-chk-all/bin/../lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../include/c++/4.1.1/i686-pc-linux-gnu

/home/opt/gcc411-chk-all/bin/../lib/gcc/i686-pc-linux-gnu/4.1.1/../../../../include/c++/4.1.1/backward
 /home/opt/gcc411-chk-all/bin/../lib/gcc/i686-pc-linux-gnu/4.1.1/include
 /usr/local/include
 /opt/gcc411-chk-all//include
 /usr/include
End of search list.
 /home/opt/gcc411-chk-all/bin/../libexec/gcc/i686-pc-linux-gnu/4.1.1/cc1plus
-fpreprocessed 131415_alias3_min.ii -quiet -dumpbase 131415_alias3_min.cpp
-mtune=pentiumpro -auxbase 131415_alias3_min -O1 -version -finline-functions -o
131415_alias3_min.s
GNU C++ version 4.1.1 (i686-pc-linux-gnu)
        compiled by GNU C version 3.3.5 (Debian 1:3.3.5-8ubuntu2).
GGC heuristics: --param ggc-min-expand=0 --param ggc-min-heapsize=0
Compiler executable checksum: 0017ab69adc149664c23a10e9b6eba83
virtual memory exhausted: Cannot allocate memory


---
http://pobox.com/~flash
Quality Lead for Compilers and Debuggers
PalmSource, Inc. Tools Quality Assurance
PalmSource bug 131415


-- 
           Summary: Memory exhausted with -finline-functions on testsuite
                    file alias3.C
           Product: gcc
           Version: 4.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: flash at pobox dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug c++/27881] Memory exhausted with -finline-functions on testsuite file alias3.C

[flash at pobox dot com]

------- Comment #1 from flash at pobox dot com  2006-06-03 02:37 -------
Created an attachment (id=11583)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=11583&action=view)
Preprocessed Delta-reduced source file


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2006-06-03 20:32 -------
Confirmed.  Also fails for release checking.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |ice-on-valid-code
      Known to fail|                            |4.1.0 4.1.1
      Known to work|                            |4.2.0 4.0.3
   Last reconfirmed|0000-00-00 00:00:00         |2006-06-03 20:32:49
               date|                            |
            Summary|Memory exhausted with -     |[4.1 Regression] Memory
                   |finline-functions on        |exhausted with -finline-
                   |testsuite file alias3.C     |functions on testsuite file
                   |                            |alias3.C


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.1.2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2006-06-07 13:43 -------
Recursive inlining causes memory usage to grow exponentially.  The current
default limit is

DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
          "max-inline-recursive-depth-auto",
          "The maximum depth of recursive inlining for non-inline functions",
          8, 0, 0)

and for illustration, here's memory growth with changing this parameter:

1    3.2 MiB
2    3.2 MiB
3    5.5 MiB
4    killed after using 495 MiB

we simply create a lot of temporares and calls and basic blocks.  Which some
place of gcc doesn't very much like (t24.fixupcfg dump):

;; Function void A::f(A::X&) (_ZN1A1fERNS_1XE)

Removing basic block 27
Removing basic block 26
Removing basic block 20
Removing basic block 13
Removing basic block 12
Removing basic block 6
Merging blocks 0 and 1
Merging blocks 0 and 2
Merging blocks 0 and 3
Merging blocks 0 and 4
Merging blocks 0 and 5
Merging blocks 0 and 7
Merging blocks 0 and 8
Merging blocks 0 and 9
Merging blocks 0 and 10
Merging blocks 0 and 11
Merging blocks 0 and 14
Merging blocks 0 and 15
Merging blocks 0 and 16
Merging blocks 0 and 17
Merging blocks 0 and 18
Merging blocks 0 and 19
Merging blocks 0 and 21
Merging blocks 0 and 22
Merging blocks 0 and 23
Merging blocks 0 and 24
Merging blocks 0 and 25
Merging blocks 0 and 28
void A::f(A::X&) (x)
{
  struct X & x;
<repeat that line 16382(!!) times>

<bb 0>:
  x = x;
  x = x;
  x = x;
  f (x);
  f (x);
  x = x;
  f (x);
  f (x);
  x = x;
  x = x;
  f (x);
  f (x);
  x = x;
  f (x);
  f (x);
  x = x;
  x = x;
  x = x;
  f (x);
  f (x);
  x = x;
  f (x);
  f (x);
  x = x;
  x = x;
  f (x);
  f (x);
  x = x;
  f (x);
  f (x);
  return;

}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2006-06-07 13:49 -------
That was with recursion depth 3.  With depth 2 we have 63 temporaries, with
depth 1 there are 3.  Now guess what would be the number for a depth of 4.

Note this problem is fixed in 4.2.  Anyone remembers which patch could have
done that?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2006-06-07 14:01 -------
I'm checking if it was fixed by

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=109379
Log:
2006-01-05  Richard Guenther  <rguenther@suse.de>
            Diego Novillo  <dnovillo@redhat.com>

        * tree-pass.h (TODO_remove_unused_locals): Define.
        * gimple-low.c (expand_var_p, remove_useless_vars,
        pass_remove_useless_vars): Remove.  Update all users.
        * tree-ssa-live.c (mark_all_vars_used_1): Handle SSA names.
        (remove_unused_locals): New function.
        * tree-flow.h (remove_unused_locals): Declare.
        * passes.c (execute_todo): Call remove_unused_locals if
        TODO_remove_unused_locals is set.
        * tree-into-ssa.c (pass_build_ssa): Add TODO_remove_unused_locals.
        * tree-ssa-dce.c (pass_dce): Likewise.
        * tree-outof-ssa.c (pass_del_ssa): Likewise.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2006-06-07 14:23 -------
No, it wasn't.  Janis, can you hunt this?


-- 

rguenth at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[janis at gcc dot gnu dot org]

------- Comment #7 from janis at gcc dot gnu dot org  2006-06-07 22:44 -------
A regression hunt on powerpc-linux using the testcase in the description with
"ulimit -v 500000" identified this patch as the start of the failures:

    http://gcc.gnu.org/viewcvs?view=rev&rev=102521

    r102521 | hubicka | 2005-07-28 21:45:27 +0000 (Thu, 28 Jul 2005)

The test still fails on mainline with r109576 and passes with r109587, so
something on 2006-01-11 in between those revisions fixes it.  Builds are broken
in that range, but I'm adapting my reghunt setup to handle that so I might come
up with an answer.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[janis at gcc dot gnu dot org]

------- Comment #8 from janis at gcc dot gnu dot org  2006-06-07 23:19 -------
The failures stop on mainline with this patch:

    http://gcc.gnu.org/viewcvs?view=rev&rev=109580

    r109580 | hubicka | 2006-01-11 13:13:37 +0000 (Wed, 11 Jan 2006)


-- 

janis at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[mmitchel at gcc dot gnu dot org]

------- Comment #9 from mmitchel at gcc dot gnu dot org  2006-11-14 17:25 -------
The following simpler test case is sufficient to show the same behavior:

struct X{};
void f(X& x)
{
  f(x);
  f(x);
}

Also, it is indeed true that --param max-inline-recursive-depth-auto=3 makes
this compile instantaneously, but a value of 4 makes it go for a long time.  I
understand expoentials, but 2^4 isn't that big a number, so I wonder if we're
hitting something else super-linear in here -- perhaps something that still in
later releases as well?

I am going to downgrade this to P2, as normally -finline-functions is only used
with -O3, and as the --param option provides a work-around.


-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P1                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[rguenth at gcc dot gnu dot org]

------- Comment #10 from rguenth at gcc dot gnu dot org  2006-11-14 17:42 -------
It's true that the number of created calls is 2^N, but unfortunately the number
of created temporaries grows super-exponential:

 --param max-inline-recursive-depth-auto      grep 'struct X' t.C.t24.fixupcfg 
| wc -l
   1       3
   2      63
   3   16383 (!)

So it grows like n_i = (2*(n_{i-1}+1))**2 - 1 with n_1 = 3.
For 4 we would have 1073741823, for 5 we get 4611686018427387904 number
of temporaries ;)

Honza's patch (comment #8) fixes this on the mainline, but I guess porting that
back is not really an option.  We might instead lower the default value of
max-inline-recursive-depth[-auto], which is currently 8.

>From the above numbers a limit of 2 should be appropriate.  Or we can make
it count the number of functions inlined, not the depth, to avoid exponential
behavior with multiple calls to self.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.1.2                       |4.1.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881

[Bug middle-end/27881] [4.1 Regression] Memory exhausted with -finline-functions on testsuite file alias3.C

[jsm28 at gcc dot gnu dot org]

------- Comment #11 from jsm28 at gcc dot gnu dot org  2008-07-04 15:33 -------
Closing 4.1 branch.


-- 

jsm28 at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
      Known to fail|4.1.0 4.1.1                 |4.1.0 4.1.1 4.1.3
         Resolution|                            |FIXED
   Target Milestone|4.1.3                       |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27881