[Bug tree-optimization/103361] New: ICE in adjust_unroll_factor, at gimple-loop-jam.c:407

[Bug tree-optimization/103361] New: ICE in adjust_unroll_factor, at gimple-loop-jam.c:407

[vsevolod.livinskij at frtk dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

            Bug ID: 103361
           Summary: ICE in adjust_unroll_factor, at gimple-loop-jam.c:407
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vsevolod.livinskij at frtk dot ru
  Target Milestone: ---

Link to the Compiler Explorer: https://godbolt.org/z/jbKEn7Tdq

Reproducer:
char a, b;
extern unsigned short c[];
extern bool d[];
const unsigned short &e(const unsigned short &f, const unsigned short &g) {
  if (g < f)
    return g;
  return f;
}
void k() {
  for (int h = 0; b; h += 3)
    for (unsigned long i = 0; i < 11104842004558084287ULL;
         i += -11104842004558084300ULL)
      for (bool j(e(6, e(6, c[h + i]))); j < (bool)a; j = 7)
        d[7] = 0;
}

Error:
>$ g++ -O3 -c func.cpp
during GIMPLE pass: unrolljam
func.cpp: In function 'void k()':
func.cpp:9:6: internal compiler error: in adjust_unroll_factor, at
gimple-loop-jam.c:407
    9 | void k() {
      |      ^
0x93ebce adjust_unroll_factor
        /testing/gcc/gcc_src_master/gcc/gimple-loop-jam.c:407
0x93ebce tree_loop_unroll_and_jam
        /testing/gcc/gcc_src_master/gcc/gimple-loop-jam.c:551
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

gcc version 12.0.0 20211121 (8fef6f720a5a0a056abfa986ba870bb406ab4716) (GCC)

[Bug tree-optimization/103361] [12 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Target Milestone|---                         |12.0
            Summary|[12 Regression] ICE in      |[12 Regression] ICE in
                   |adjust_unroll_factor, at    |adjust_unroll_factor, at
                   |gimple-loop-jam.c:407       |gimple-loop-jam.c:407 since
                   |                            |r12-3677-gf92901a508305f29
      Known to fail|                            |12.0
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
   Last reconfirmed|                            |2021-11-22
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Martin Liška <marxin at gcc dot gnu.org> ---
Thanks for the report, started with r12-3677-gf92901a508305f29

[Bug tree-optimization/103361] [12 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.

[Bug tree-optimization/103361] [12 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, so I think this is an overflow somewhere in data dependence compute ...

Creating dr for MEM <short unsigned int[<unknown>]> [(const short unsigned int
&)&c][_2]
analyze_innermost: success.
        base_address: &c
        offset from base address: (ssizetype) ((sizetype) h_10 * 2)
        constant offset from base address: 0
        step: -3762939935406616984(OVF)
        base alignment: 2
        base misalignment: 0
        offset alignment: 2
        step alignment: 8
        base_object: MEM <short unsigned int[<unknown>]> [(const short unsigned
int &)&c]
        Access function 0: {{0, +, 3}_1, +, 7341902069151467316}_2
...
(Data Dep: 
#(Data Ref: 
#  bb: 4 
#  stmt: _25 = MEM <short unsigned int[<unknown>]> [(const short unsigned int
&)&c][_2];
#  ref: MEM <short unsigned int[<unknown>]> [(const short unsigned int
&)&c][_2];
#  base_object: MEM <short unsigned int[<unknown>]> [(const short unsigned int
&)&c];
#  Access function 0: {{0, +, 3}_1, +, 7341902069151467316}_2
#)
#(Data Ref: 
#  bb: 5 
#  stmt: pretmp_28 = MEM[(const short unsigned int &)_3];
#  ref: MEM[(const short unsigned int &)_3];
#  base_object: MEM[(const short unsigned int &)&c];
#  Access function 0: {{0B, +, 6}_1, +, 14683804138302934632}_2
#)
  access_fn_A: {{0B, +, 6}_1, +, 14683804138302934632}_2
  access_fn_B: {{0B, +, 6}_1, +, 14683804138302934632}_2

 (subscript 
  iterations_that_access_an_element_twice_in_A: [0]
  last_conflict: scev_not_known
  iterations_that_access_an_element_twice_in_B: [0]
  last_conflict: scev_not_known
  (Subscript distance: 0 ))
  loop nest: (1 2 )
  distance_vector:   0   0 
  distance_vector: -1736083252   3 
  direction_vector:     =    =
  direction_vector:     -    +
)

the accesses are equal so the distance vector should be 0 0 which it is
for the inner loop but not for the outer it seems(!?).  We run into

  if (same_access_functions (ddr))
    {
      /* Save the 0 vector.  */
      dist_v = lambda_vector_new (DDR_NB_LOOPS (ddr));
      save_dist_v (ddr, dist_v);

      if (invariant_access_functions (ddr, loop_nest->num))
        add_distance_for_zero_overlaps (ddr);

      if (DDR_NB_LOOPS (ddr) > 1)
        add_other_self_distances (ddr);

      return true;

where invariant_access_functions is false and we eventually run into
add_multivariate_self_dist.

Ah, so the issue is lambda vector dumping is broken (truncates to int) and
unroll-and-jam also fails to use lambda_int ...

[Bug tree-optimization/103361] [9/10/11/12 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|12.0                        |9.5
            Summary|[12 Regression] ICE in      |[9/10/11/12 Regression] ICE
                   |adjust_unroll_factor, at    |in adjust_unroll_factor, at
                   |gimple-loop-jam.c:407 since |gimple-loop-jam.c:407 since
                   |r12-3677-gf92901a508305f29  |r12-3677-gf92901a508305f29
           Priority|P3                          |P2

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is latent since lambda_int became HOST_WIDE_INT which happened in GCC
9.

[Bug tree-optimization/103361] [9/10/11/12 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

--- Comment #5 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:6cd440670078af89d82cbb67e01a5ecec8eec238

commit r12-5468-g6cd440670078af89d82cbb67e01a5ecec8eec238
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Nov 23 10:11:41 2021 +0100

    tree-optimization/103361 - fix unroll-and-jam direction vector handling

    This properly uses lambda_int instead of truncating the direction
    vector to int which leads to false unexpected negative values.

    2021-11-23  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/103361
            * gimple-loop-jam.c (adjust_unroll_factor): Use lambda_int
            for the dependence distance.
            * tree-data-ref.c (print_lambda_vector): Properly print a
lambda_int.

            * g++.dg/torture/pr103361.C: New testcase.

[Bug tree-optimization/103361] [9/10/11 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[9/10/11/12 Regression] ICE |[9/10/11 Regression] ICE in
                   |in adjust_unroll_factor, at |adjust_unroll_factor, at
                   |gimple-loop-jam.c:407 since |gimple-loop-jam.c:407 since
                   |r12-3677-gf92901a508305f29  |r12-3677-gf92901a508305f29
      Known to work|                            |12.0
      Known to fail|12.0                        |

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed on trunk sofar, queued for backporting.

[Bug tree-optimization/103361] [9/10/11 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

--- Comment #7 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:d2f4753d4ff0edf944281cc2e4d5b5b91a9f14c9

commit r11-9583-gd2f4753d4ff0edf944281cc2e4d5b5b91a9f14c9
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Nov 23 10:11:41 2021 +0100

    tree-optimization/103361 - fix unroll-and-jam direction vector handling

    This properly uses lambda_int instead of truncating the direction
    vector to int which leads to false unexpected negative values.

    2021-11-23  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/103361
            * gimple-loop-jam.c (adjust_unroll_factor): Use lambda_int
            for the dependence distance.
            * tree-data-ref.c (print_lambda_vector): Properly print a
lambda_int.

            * g++.dg/torture/pr103361.C: New testcase.

    (cherry picked from commit 6cd440670078af89d82cbb67e01a5ecec8eec238)

[Bug tree-optimization/103361] [9/10 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Richard Biener
<rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:4ed8728e2646897c98826cf43be2e4682d04fc2c

commit r10-10548-g4ed8728e2646897c98826cf43be2e4682d04fc2c
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Nov 23 10:11:41 2021 +0100

    tree-optimization/103361 - fix unroll-and-jam direction vector handling

    This properly uses lambda_int instead of truncating the direction
    vector to int which leads to false unexpected negative values.

    2021-11-23  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/103361
            * gimple-loop-jam.c (adjust_unroll_factor): Use lambda_int
            for the dependence distance.
            * tree-data-ref.c (print_lambda_vector): Properly print a
lambda_int.

            * g++.dg/torture/pr103361.C: New testcase.

    (cherry picked from commit 6cd440670078af89d82cbb67e01a5ecec8eec238)

[Bug tree-optimization/103361] [9 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

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

https://gcc.gnu.org/g:d55db847de865ec3a4d7a89c30295924508e1833

commit r9-10042-gd55db847de865ec3a4d7a89c30295924508e1833
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Nov 23 10:11:41 2021 +0100

    tree-optimization/103361 - fix unroll-and-jam direction vector handling

    This properly uses lambda_int instead of truncating the direction
    vector to int which leads to false unexpected negative values.

    2021-11-23  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/103361
            * gimple-loop-jam.c (adjust_unroll_factor): Use lambda_int
            for the dependence distance.
            * tree-data-ref.c (print_lambda_vector): Properly print a
lambda_int.

            * g++.dg/torture/pr103361.C: New testcase.

    (cherry picked from commit 6cd440670078af89d82cbb67e01a5ecec8eec238)

[Bug tree-optimization/103361] [9 Regression] ICE in adjust_unroll_factor, at gimple-loop-jam.c:407 since r12-3677-gf92901a508305f29

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103361

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
      Known to work|                            |9.4.1
         Resolution|---                         |FIXED
      Known to fail|                            |9.4.0

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.