[Bug c/101172] New: [12 regression] ICE Segmentation fault

[Bug c/101172] New: [12 regression] ICE Segmentation fault

[anbu1024.me at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

            Bug ID: 101172
           Summary: [12 regression] ICE Segmentation fault
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: anbu1024.me at gmail dot com
  Target Milestone: ---

$ cat 36.c 

union U
{
  int a[3];
  struct
  {
    int a : 3;
    struct this_struct var;
  } b;
};

const union U hello = {.a = {1, 2, 3}};


void foo()
{
  int x = hello.b.a;
}

-------------------------------------------------------------------------------

$ gcc-sp12 --version
gcc (GCC) 12.0.0 20210620 (experimental)
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

-------------------------------------------------------------------------------

$ gcc-sp12 36.c 
36.c:8:24: error: field ‘var’ has incomplete type
    8 |     struct this_struct var;
      |                        ^~~
36.c: In function ‘foo’:
36.c:17:18: internal compiler error: Segmentation fault
   17 |   int x = hello.b.a;
      |           ~~~~~~~^~
0xe600af crash_signal
        ../../gcc-12-20210620/gcc/toplev.c:327
0xb85ab1 fold_const_aggregate_ref_1(tree_node*, tree_node* (*)(tree_node*))
        ../../gcc-12-20210620/gcc/gimple-fold.c:8184
0xb86e49 fold_const_aggregate_ref(tree_node*)
        ../../gcc-12-20210620/gcc/gimple-fold.c:8250
0xb86e49 maybe_fold_reference
        ../../gcc-12-20210620/gcc/gimple-fold.c:333
0xb8bc86 fold_gimple_assign
        ../../gcc-12-20210620/gcc/gimple-fold.c:483
0xb8bc86 fold_stmt_1
        ../../gcc-12-20210620/gcc/gimple-fold.c:6250
0xbd1071 gimplify_modify_expr
        ../../gcc-12-20210620/gcc/gimplify.c:5982
0xbb909f gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc-12-20210620/gcc/gimplify.c:14094
0xbbc9f6 gimplify_stmt(tree_node**, gimple**)
        ../../gcc-12-20210620/gcc/gimplify.c:6865
0xbbe8d6 gimplify_and_add(tree_node*, gimple**)
        ../../gcc-12-20210620/gcc/gimplify.c:494
0xbbe8d6 internal_get_tmp_var
        ../../gcc-12-20210620/gcc/gimplify.c:647
0xbb887e get_formal_tmp_var(tree_node*, gimple**)
        ../../gcc-12-20210620/gcc/gimplify.c:668
0xbb887e gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc-12-20210620/gcc/gimplify.c:15083
0xbb9363 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc-12-20210620/gcc/gimplify.c:14399
0xbd0dff gimplify_modify_expr
        ../../gcc-12-20210620/gcc/gimplify.c:5806
0xbb909f gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc-12-20210620/gcc/gimplify.c:14094
0xbbc9f6 gimplify_stmt(tree_node**, gimple**)
        ../../gcc-12-20210620/gcc/gimplify.c:6865
0xbc3c9d gimplify_and_add(tree_node*, gimple**)
        ../../gcc-12-20210620/gcc/gimplify.c:494
0xbc3c9d gimplify_decl_expr
        ../../gcc-12-20210620/gcc/gimplify.c:1831
0xbb939a gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        ../../gcc-12-20210620/gcc/gimplify.c:14291
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-sp11 --version
gcc (GCC) 11.1.1 20210619
Copyright (C) 2021 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

-------------------------------------------------------------------------------

$ gcc-sp11 36.c 
36.c:8:24: error: field ‘var’ has incomplete type
    8 |     struct this_struct var;
      |                        ^~~
36.c:17: confused by earlier errors, bailing out

[Bug c/101172] [12 regression] ICE Segmentation fault

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-06-23
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
           Keywords|                            |error-recovery,
                   |                            |ice-on-invalid-code

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  The DECL_BIT_FIELD_REPRESENTATIVE of the field not NULL but its
type is.

[Bug c/101172] ICE Segmentation fault

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[12 regression] ICE         |ICE Segmentation fault
                   |Segmentation fault          |

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

36.c:17: confused by earlier errors, bailing out

is what we print for an internal compiler error that happens after an error was
reported for release builds.

[Bug c/101172] ICE Segmentation fault

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |marxin at gcc dot gnu.org

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
Btw. started with r11-2225-ge4f1cbc35b1e823a.

[Bug c/101172] [11/12 Regression] ICE Segmentation fault

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |minor
   Target Milestone|---                         |11.2
            Summary|ICE Segmentation fault      |[11/12 Regression] ICE
                   |                            |Segmentation fault

[Bug middle-end/101172] [11/12 Regression] ICE Segmentation fault

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |middle-end
             Status|NEW                         |ASSIGNED

[Bug middle-end/101172] [11/12 Regression] ICE Segmentation fault

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 51054
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51054&action=edit
gcc12-pr101172.patch

Untested fix.

[Bug middle-end/101172] [11/12 Regression] ICE Segmentation fault

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:65371066d8967560e3508af4a804e0ddb90acee7

commit r12-1771-g65371066d8967560e3508af4a804e0ddb90acee7
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Jun 24 12:22:14 2021 +0200

    stor-layout: Avoid DECL_BIT_FIELD_REPRESENTATIVE with NULL TREE_TYPE
[PR101172]

    finish_bitfield_representative has an early out if the field after a
    bitfield has error_mark_node type, but that early out leads to TREE_TYPE
    of the DECL_BIT_FIELD_REPRESENTATIVE being NULL, which breaks assumptions
    on code that uses the DECL_BIT_FIELD_REPRESENTATIVE during error-recovery.

    The following patch instead sets TREE_TYPE of the representative to
    error_mark_node, something the users can deal with better.  At this point
    the representative can be set as DECL_BIT_FIELD_REPRESENTATIVE for multiple
    bitfields, so making sure that we clear the DECL_BIT_FIELD_REPRESENTATIVE
    instead would be harder (but doable, e.g. with the error_mark_node
TREE_TYPE
    set by this patch set some flag in the caller and if the flag is there,
walk
    all the fields once again and clear all DECL_BIT_FIELD_REPRESENTATIVE that
    have error_mark_node TREE_TYPE).

    2021-06-24  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/101172
            * stor-layout.c (finish_bitfield_representative): If nextf has
            error_mark_node type, set repr type to error_mark_node too.

            * gcc.dg/pr101172.c: New test.

[Bug middle-end/101172] [11 Regression] ICE Segmentation fault

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[11/12 Regression] ICE      |[11 Regression] ICE
                   |Segmentation fault          |Segmentation fault

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed on the trunk so far.

[Bug middle-end/101172] [11 Regression] ICE Segmentation fault

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4

[Bug middle-end/101172] [11 Regression] ICE Segmentation fault

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:2b99794806d83e47249fd7c05bf521caee1fdcd4

commit r11-8765-g2b99794806d83e47249fd7c05bf521caee1fdcd4
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Jun 24 12:22:14 2021 +0200

    stor-layout: Avoid DECL_BIT_FIELD_REPRESENTATIVE with NULL TREE_TYPE
[PR101172]

    finish_bitfield_representative has an early out if the field after a
    bitfield has error_mark_node type, but that early out leads to TREE_TYPE
    of the DECL_BIT_FIELD_REPRESENTATIVE being NULL, which breaks assumptions
    on code that uses the DECL_BIT_FIELD_REPRESENTATIVE during error-recovery.

    The following patch instead sets TREE_TYPE of the representative to
    error_mark_node, something the users can deal with better.  At this point
    the representative can be set as DECL_BIT_FIELD_REPRESENTATIVE for multiple
    bitfields, so making sure that we clear the DECL_BIT_FIELD_REPRESENTATIVE
    instead would be harder (but doable, e.g. with the error_mark_node
TREE_TYPE
    set by this patch set some flag in the caller and if the flag is there,
walk
    all the fields once again and clear all DECL_BIT_FIELD_REPRESENTATIVE that
    have error_mark_node TREE_TYPE).

    2021-06-24  Jakub Jelinek  <jakub@redhat.com>

            PR middle-end/101172
            * stor-layout.c (finish_bitfield_representative): If nextf has
            error_mark_node type, set repr type to error_mark_node too.

            * gcc.dg/pr101172.c: New test.

    (cherry picked from commit 65371066d8967560e3508af4a804e0ddb90acee7)

[Bug middle-end/101172] [11 Regression] ICE Segmentation fault

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101172

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

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

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed for 11.2 too.