[Bug testsuite/102690] New: [12 regression] g++.dg/warn/Warray-bounds-16.C fails

[Bug testsuite/102690] New: [12 regression] g++.dg/warn/Warray-bounds-16.C fails

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

            Bug ID: 102690
           Summary: [12 regression] g++.dg/warn/Warray-bounds-16.C fails
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: testsuite
          Assignee: unassigned at gcc dot gnu.org
          Reporter: seurer at gcc dot gnu.org
  Target Milestone: ---

Somewhere in the range

177b800f5fc861af1bf8700f050de28dd47ee1aa, r12-4288 to
338725652f84793805c55f08a7607c2f45d5512b, r12-4320

these tests started failing.  For some reason git bisect isn't pointing me to
the right revision, though.

FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++14  scan-tree-dump-not
optimized "goto"
FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++14 (test for excess errors)
FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++17  scan-tree-dump-not
optimized "goto"
FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++17 (test for excess errors)
FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++2a  scan-tree-dump-not
optimized "goto"
FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++2a (test for excess errors)
FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++98  scan-tree-dump-not
optimized "goto"
FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++98 (test for excess errors)

[Bug tree-optimization/102690] [12 regression] g++.dg/warn/Warray-bounds-16.C fails

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|testsuite                   |tree-optimization
   Target Milestone|---                         |12.0
           Keywords|                            |diagnostic

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This was known to happen, see r12-4319 .

[Bug tree-optimization/102690] [12 regression] g++.dg/warn/Warray-bounds-16.C fails

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |msebor at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Yes, sorry for that.

[Bug tree-optimization/102690] [12 regression] g++.dg/warn/Warray-bounds-16.C fails

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-10-12
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Oh, I can probably fix the

FAIL: g++.dg/warn/Warray-bounds-16.C  -std=gnu++17  scan-tree-dump-not
optimized "goto"

since the expected optimization is not valid.  But the IMHO bogus excess error
remains, see PR101480 for an analysis.  Quote:

--
What we see is the global variable construction function which accesses
just 'a', and yes, the call to 'new' is considered clobbering global
variables (including 'a'):

  <bb 2> [local count: 1073741824]:
  MEM[(struct __as_base  &)&a] ={v} {CLOBBER};
  a.m = 0;
  _5 = operator new [] (0);
  a.p = _5;
  goto <bb 4>; [100.00%]

  <bb 3> [local count: 8687547547]:
  _7 = (long unsigned int) i_6;
  _8 = _7 * 4;
  _9 = _5 + _8;
  MEM[(int *)_9] = 0;
  i_10 = i_6 + 1;

  <bb 4> [local count: 9761289362]:
  # i_6 = PHI <0(2), i_10(3)>
  _11 = a.m;
  if (i_6 < _11)
    goto <bb 3>; [89.00%]
  else
    goto <bb 5>; [11.00%]

  <bb 5> [local count: 1073741824]:
  return;

I suppose implementing the global operator new as accessing a.m would
be valid as IIRC lifetime of a starts when the CTOR is invoked, not
when it finished (otherwise the CTOR could not access the variable itself).

We somehow conclude that

_9: void * [1B, +INF]  EQUIVALENCES: { } (0 elements)

possibly because it cannot be NULL (?):

extract_range_from_stmt visiting:
_5 = operator new [] (0);
Found new range for _5: void * [1B, +INF]
marking stmt to be not simulated again

(huh?)

and then the -Warray-bounds warning concludes the access is always outside
of the allocated area.

I suspect when we'd arrive at VARYING we'd not issue the warning even
when the access would always extend beyond a zero-sized allocation.
--

[Bug tree-optimization/102690] [12 regression] g++.dg/warn/Warray-bounds-16.C fails

[seurer at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

--- Comment #4 from seurer at gcc dot gnu.org ---
Was the change that caused this backported to gcc 11?  I am seeing the same
failures there now.

[Bug tree-optimization/102690] [12 regression] g++.dg/warn/Warray-bounds-16.C fails

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

--- Comment #5 from Martin Sebor <msebor at gcc dot gnu.org> ---
It was backported here: g:19dcea67ac40cfdeb396fa264ebbe04fbe61fdc0

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|12.0                        |11.3
            Summary|[12 regression]             |[11/12 regression]
                   |g++.dg/warn/Warray-bounds-1 |g++.dg/warn/Warray-bounds-1
                   |6.C fails                   |6.C fails
          Component|tree-optimization           |testsuite
           Priority|P3                          |P1

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Yes.  Whatever solution we find for the testcase needs to be backported as
well.

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ebotcazou at gcc dot gnu.org

--- Comment #7 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
So can we XFAIL it in the meantime, especially on the 11 branch?

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Eric Botcazou from comment #7)
> So can we XFAIL it in the meantime, especially on the 11 branch?

Let me do that.

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:b2cd32b743ba440e75505ce30c6b5c592ed144ea

commit r12-5107-gb2cd32b743ba440e75505ce30c6b5c592ed144ea
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Nov 10 11:08:03 2021 +0100

    testsuite/102690 - XFAIL g++.dg/warn/Warray-bounds-16.C

    This XFAILs the bogus diagnostic test and rectifies the expectation
    on the optimization.

    2021-11-10  Richard Biener  <rguenther@suse.de>

            PR testsuite/102690
            * g++.dg/warn/Warray-bounds-16.C: XFAIL diagnostic part
            and optimization.

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:3dea90505df136a4b361665772ef8e62306cfcdb

commit r11-9233-g3dea90505df136a4b361665772ef8e62306cfcdb
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Nov 10 11:08:03 2021 +0100

    testsuite/102690 - XFAIL g++.dg/warn/Warray-bounds-16.C

    This XFAILs the bogus diagnostic test and rectifies the expectation
    on the optimization.

    2021-11-10  Richard Biener  <rguenther@suse.de>

            PR testsuite/102690
            * g++.dg/warn/Warray-bounds-16.C: XFAIL diagnostic part
            and optimization.

    (cherry picked from commit b2cd32b743ba440e75505ce30c6b5c592ed144ea)

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Richard Biener <rguenth at gcc dot gnu.org> changed:

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

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
XFAILed.  I still think the diagnostic should be fixed.

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

--- Comment #12 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> XFAILed.  I still think the diagnostic should be fixed.

This works fine on the 11 branch, thanks!

[Bug testsuite/102690] [11/12 regression] g++.dg/warn/Warray-bounds-16.C fails

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.3                        |11.4

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 11.3 is being released, retargeting bugs to GCC 11.4.

[Bug testsuite/102690] [11/12/13 regression] g++.dg/warn/Warray-bounds-16.C fails

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

--- Comment #14 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Kito Cheng <kito@gcc.gnu.org>:

https://gcc.gnu.org/g:0f6eef398045deb2a62d18b526831719c7c20c8a

commit r13-1357-g0f6eef398045deb2a62d18b526831719c7c20c8a
Author: Kito Cheng <kito.cheng@sifive.com>
Date:   Tue Jun 28 18:43:42 2022 +0800

    testsuite/102690: Only check warning for lp64 in Warray-bounds-16.C

    That warning won't happen on ilp32 targets, seems like Andrew Pinski
    already mention that[1] before.

    Verified on riscv32-unknown-elf and riscv64-unknown-elf.

    [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92879#c1

    gcc/testsuite/ChangeLog:

            PR testsuite/102690
            * g++.dg/warn/Warray-bounds-16.C: XFAIL only on lp64 for the
            warning.

[Bug testsuite/102690] [11/12/13/14 regression] g++.dg/warn/Warray-bounds-16.C fails

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102690

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|11.4                        |11.5

--- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 11.4 is being released, retargeting bugs to GCC 11.5.