[Bug tree-optimization/109689] New: ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645

[Bug tree-optimization/109689] New: ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645

[zhendong.su at inf dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

            Bug ID: 109689
           Summary: ICE at -O1 with "-ftree-vectorize": in
                    check_loop_closed_ssa_def, at
                    tree-ssa-loop-manip.cc:645
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zhendong.su at inf dot ethz.ch
  Target Milestone: ---

This appears to be a very recent regression.

Compiler Explorer: https://godbolt.org/z/nv9dPa1Y7

[629] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++
--disable-werror --disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230501 (experimental) (GCC)
[630] %
[630] % gcctk -O1 -ftree-vectorize small.c
during GIMPLE pass: ch_vect
small.c: In function ‘main’:
small.c:2:5: internal compiler error: in check_loop_closed_ssa_def, at
tree-ssa-loop-manip.cc:645
    2 | int main() {
      |     ^~~~
0x822c59 check_loop_closed_ssa_def
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:645
0x11cfc34 check_loop_closed_ssa_bb
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:659
0x11d18be verify_loop_closed_ssa(bool, loop*)
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:695
0x11d18be verify_loop_closed_ssa(bool, loop*)
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:679
0xf243f9 execute_function_todo
        ../../gcc-trunk/gcc/passes.cc:2116
0xf24bfe execute_todo
        ../../gcc-trunk/gcc/passes.cc:2152
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
[631] %
[631] % cat small.c
int a, b, c, d, e;
int main() {
  char f;
  while (a) {
    int g, h = 3;
    if (b)
    i:
      if (d)
        goto j;
  k:
    if (a) {
    j:
      if (!g)
        goto k;
      if (e) {
        while (e)
          e = f;
        h = 0;
        goto i;
      }
      if (!h)
        for (; g < 1; g++)
          ;
      g = ~((~c & h & c) ^ ~g);
      if (!g)
        for (; a < 1; a++)
          f++;
    }
  }
  return 0;
}

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ICE at -O1 with             |[14 Regression] ICE at -O1
                   |"-ftree-vectorize": in      |with "-ftree-vectorize": in
                   |check_loop_closed_ssa_def,  |check_loop_closed_ssa_def,
                   |at                          |at
                   |tree-ssa-loop-manip.cc:645  |tree-ssa-loop-manip.cc:645
   Target Milestone|---                         |14.0
           Keywords|                            |ice-on-valid-code,
                   |                            |needs-bisection

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Maybe r14-301-gf2d6beb7a4ddf18dd or r14-145-g2f4e45101dd812a6f (or
r14-150-gf7b9258e0d4127c1f4 ).

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
            Version|unknown                     |14.0
                 CC|                            |hubicka at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
   Last reconfirmed|                            |2023-05-02
             Status|UNCONFIRMED                 |NEW
           Priority|P3                          |P1

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
LC SSA is broken by unloop_loops ().  That introduces BB 19 which is

<bb 19> [count: 0]:
f.8_13 = (unsigned char) f_19;
_14 = f.8_13 + 1;
f_38 = (char) _14;
_16 = a_lsm.17_51 + 1;
__builtin_unreachable ();

but that's an exit from the loop and is missing LC PHI nodes for all of the
SSA names used.

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[14 Regression] ICE at -O1  |[14 Regression] ICE at -O1
                   |with "-ftree-vectorize": in |with "-ftree-vectorize": in
                   |check_loop_closed_ssa_def,  |check_loop_closed_ssa_def,
                   |at                          |at
                   |tree-ssa-loop-manip.cc:645  |tree-ssa-loop-manip.cc:645
                   |                            |since
                   |                            |r14-301-gf2d6beb7a4ddf1
                 CC|                            |marxin at gcc dot gnu.org

--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r14-301-gf2d6beb7a4ddf1.

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |19373742 at buaa dot edu.cn

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 110123 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 110135 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[zhendong.su at inf dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #7 from Zhendong Su <zhendong.su at inf dot ethz.ch> ---
Another related and smaller reproducer:

[514] % gcctk -O3 -fno-tree-loop-ivcanon small.c
during GIMPLE pass: ch_vect
small.c: In function ‘main’:
small.c:3:5: internal compiler error: in check_loop_closed_ssa_def, at
tree-ssa-loop-manip.cc:647
    3 | int main() {
      |     ^~~~
0x81089b check_loop_closed_ssa_def
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:647
0x1137d37 check_loop_closed_ssa_bb
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:672
0x1138116 verify_loop_closed_ssa(bool, loop*)
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:697
0x1138116 verify_loop_closed_ssa(bool, loop*)
        ../../gcc-trunk/gcc/tree-ssa-loop-manip.cc:681
0xe9ff39 execute_function_todo
        ../../gcc-trunk/gcc/passes.cc:2116
0xea032b execute_todo
        ../../gcc-trunk/gcc/passes.cc:2152
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
[515] % 
[515] % cat small.c
int a;
unsigned c;
int main() {
 L:
  if (c)
    for (; c < 2;) {
      int e;
      for (a = 0; a < 2; a++) {
        c++;
        while (e)
          goto L;
      }
    }
  return 0;
}

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #8 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
An easy way would be to avoid unlooping if tree_ssa_loop_ch is executed in loop
closed ssa (which happens from ch_vect pass).

I wonder how hard would be however to get this right?
I think this means to take the basic block we turn into unreachable and look on
its predecessors that are in loop introducing new PHIs and renaming.  This is
bit involved to do by hand.

So perhaps simply:
  rewrite_into_loop_closed_ssa (NULL, 0);
in case we unlooped in loop closed ssa form (which is not that common). Would
that be acceptable?

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jan Hubicka from comment #8)
> An easy way would be to avoid unlooping if tree_ssa_loop_ch is executed in
> loop closed ssa (which happens from ch_vect pass).
> 
> I wonder how hard would be however to get this right?
> I think this means to take the basic block we turn into unreachable and look
> on its predecessors that are in loop introducing new PHIs and renaming. 
> This is bit involved to do by hand.
> 
> So perhaps simply:
>   rewrite_into_loop_closed_ssa (NULL, 0);
> in case we unlooped in loop closed ssa form (which is not that common).
> Would that be acceptable?

Yes, we do that in other places as well.

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[hubicka at ucw dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #10 from Jan Hubicka <hubicka at ucw dot cz> ---
> > So perhaps simply:
> >   rewrite_into_loop_closed_ssa (NULL, 0);
> > in case we unlooped in loop closed ssa form (which is not that common).
> > Would that be acceptable?
> 
> Yes, we do that in other places as well.
OK, I will test the fix.

Thanks
Honza

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |shaohua.li at inf dot ethz.ch

--- Comment #11 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 111389 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |141242068 at smail dot nju.edu.cn

--- Comment #12 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 112489 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #13 from Sam James <sjames at gcc dot gnu.org> ---
*** Bug 111678 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

--- Comment #14 from GCC 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:8ff02df62935429d8956361cfdb897122492523d

commit r14-6181-g8ff02df62935429d8956361cfdb897122492523d
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Dec 5 08:50:57 2023 +0100

    tree-optimization/112856 - fix LC SSA after loop header copying

    When loop header copying unloops loops we have to possibly fixup
    LC SSA.  I've take the opportunity to streamline the unloop_loops
    API, removing the use of a ivcanon local global variable.

            PR tree-optimization/109689
            PR tree-optimization/112856
            * cfgloopmanip.h (unloop_loops): Adjust API.
            * tree-ssa-loop-ivcanon.cc (unloop_loops): Take edges_to_remove
            as parameter.
            (canonicalize_induction_variables): Adjust.
            (tree_unroll_loops_completely): Likewise.
            * tree-ssa-loop-ch.cc (ch_base::copy_headers): Rewrite into
            LC SSA if we unlooped some loops and we are in LC SSA.

            * gcc.dg/torture/pr109689.c: New testcase.
            * gcc.dg/torture/pr112856.c: Likewise.

[Bug tree-optimization/109689] [14 Regression] ICE at -O1 with "-ftree-vectorize": in check_loop_closed_ssa_def, at tree-ssa-loop-manip.cc:645 since r14-301-gf2d6beb7a4ddf1

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109689

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

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

--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.