[Bug c++/94955] New: ICE in to_wide

[Bug c++/94955] New: ICE in to_wide

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

            Bug ID: 94955
           Summary: ICE in to_wide
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hubicka at gcc dot gnu.org
  Target Milestone: ---

Created attachment 48454
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48454&action=edit
proposed patch

This was reported to me by Mark Williams (who also did the testcase and
proposed patch)

% g++ -std=gnu++17 bug.ii -S -o bug.s
bug.ii: In function �void d()�:
bug.ii:6:32: internal compiler error: in sign_mask, at wide-int.h:855
    6 | void d() { short e = e >> b::c(); }
      |                                ^
0xa56be2 generic_wide_int<wide_int_ref_storage<false, false> >::sign_mask()
const
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/wide-int.h:855
0xa56be2 bool wi::neg_p<generic_wide_int<wide_int_ref_storage<false, false> >
>(generic_wide_int<wide_int_ref_storage<false, false> > const&, signop)
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/wide-int.h:1836
0xa56be2 tree_int_cst_sgn(tree_node const*)
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/tree.c:7386
0x1065e85 cp_build_binary_op(op_location_t const&, tree_code, tree_node*,
tree_node*, int)
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/typeck.c:5613
0xfa9629 build_new_op_1
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/call.c:6501
0xfa931d build_new_op(op_location_t const&, tree_code, int, tree_node*,
tree_node*, tree_node*, tree_node**, int)
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/call.c:6547
0x106267f build_x_binary_op(op_location_t const&, tree_code, tree_node*,
tree_code, tree_node*, tree_code, tree_node**, int)
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/typeck.c:4248
0x10162f0 cp_parser_binary_expression
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:9684
0x10157a4 cp_parser_assignment_expression
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:9824
0x1015380 cp_parser_constant_expression
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:10118
0x1015380 cp_parser_initializer_clause
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:23148
0x1015380 cp_parser_initializer
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:23086
0x1008ab0 cp_parser_init_declarator
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:20780
0x1006144 cp_parser_simple_declaration
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:13689
0x101df42 cp_parser_declaration_statement
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:13121
0x101a67c cp_parser_statement
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:11434
0x101a38a cp_parser_statement_seq_opt
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:11800
0x101a38a cp_parser_compound_statement
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:11750
0x101a0f9 cp_parser_function_body
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:22992
0x101a0f9 cp_parser_ctor_initializer_opt_and_function_body
        /home/engshare/third-party2/gcc/9.x/src/gcc-10.x/gcc/cp/parser.c:23043

The problem was that it had previously used fold_for_warn to find an
INTEGER_CST, and assumed the cp_fold_rvalue would too. But fold_for_warn
handles some edge cases that cp_fold_rvalue does not, and in this case we end
up with a NOP_EXPR instead of the INTEGER_CST

[Bug c++/94955] [10 regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

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

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Can you provide the .ii file too?

[Bug c++/94955] [10 regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-05-05
             Status|UNCONFIRMED                 |WAITING
     Ever confirmed|0                           |1

[Bug c++/94955] [10 regression] ICE in to_wide

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

--- Comment #2 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Created attachment 48455
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48455&action=edit
testcase

[Bug c++/94955] [10 regression] ICE in to_wide

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Jan Hubicka <hubicka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW

[Bug c++/94955] [10/11 Regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |10.2
            Summary|[10 regression] ICE in      |[10/11 Regression] ICE in
                   |to_wide                     |to_wide

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r10-6527-gaaa26bf496a646778ac861aed124d960b5bf549f.  I can take a
look.

I've set the target to 10.2, but someone might disagree.

[Bug c++/94955] [10/11 Regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

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

[Bug c++/94955] [10/11 Regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |john at mcfarlane dot name

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
*** Bug 95022 has been marked as a duplicate of this bug. ***

[Bug c++/94955] [10/11 Regression] ICE in to_wide

[john at mcfarlane dot name]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

--- Comment #5 from John McFarlane <john at mcfarlane dot name> ---
I have applied a workaround and am not blocked:
https://github.com/johnmcfarlane/cnl/pull/589/commits/ca3478ed0002e5834227d7b6fa0010910aabc875

[Bug c++/94955] [10/11 Regression] ICE in to_wide

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:2d4e1e144c25e526e4f668be5a0bc10d0c1c738c

commit r11-474-g2d4e1e144c25e526e4f668be5a0bc10d0c1c738c
Author: Marek Polacek <polacek@redhat.com>
Date:   Wed May 6 15:53:33 2020 -0400

    c++: ICE when shortening right shift [PR94955]

    Since r10-6527 fold_for_warn calls maybe_constant_value, which means it
    can fold more than it previously could.  In this testcase it means that
    cp_build_binary_op/RSHIFT_EXPR set short_shift because now we were able
    to fold op1 to an INTEGER_CST.  But then when actually performing the
    shortening we crashed because cp_fold_rvalue wasn't able to fold as much
    as f_f_w and so tree_int_cst_sgn crashed on a NOP_EXPR.  Therefore the
    calls should probably match.

            PR c++/94955
            * typeck.c (cp_build_binary_op): Use fold_for_warn instead of
            cp_fold_rvalue.

            * g++.dg/cpp0x/constexpr-shift2.C: New test.

[Bug c++/94955] [10 Regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[10/11 Regression] ICE in   |[10 Regression] ICE in
                   |to_wide                     |to_wide

--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed on trunk so far.

[Bug c++/94955] [10 Regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |danny.schneider at posteo dot de

--- Comment #8 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
*** Bug 95206 has been marked as a duplicate of this bug. ***

[Bug c++/94955] [10 Regression] ICE in to_wide

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nmmm at nmmm dot nu

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
*** Bug 95579 has been marked as a duplicate of this bug. ***

[Bug c++/94955] [10 Regression] ICE in to_wide

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Marek Polacek
<mpolacek@gcc.gnu.org>:

https://gcc.gnu.org/g:18436d87ff85282b200579cb8da496659632ad6b

commit r10-8277-g18436d87ff85282b200579cb8da496659632ad6b
Author: Marek Polacek <polacek@redhat.com>
Date:   Thu Jun 11 16:26:41 2020 -0400

    c++: ICE when shortening right shift [PR94955]

    Since r10-6527 fold_for_warn calls maybe_constant_value, which means it
    can fold more than it previously could.  In this testcase it means that
    cp_build_binary_op/RSHIFT_EXPR set short_shift because now we were able
    to fold op1 to an INTEGER_CST.  But then when actually performing the
    shortening we crashed because cp_fold_rvalue wasn't able to fold as much
    as f_f_w and so tree_int_cst_sgn crashed on a NOP_EXPR.  Therefore the
    calls should probably match.

            PR c++/94955
            * typeck.c (cp_build_binary_op): Use fold_for_warn instead of
            cp_fold_rvalue.

            * g++.dg/cpp0x/constexpr-shift2.C: New test.

[Bug c++/94955] [10 Regression] ICE in to_wide

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94955

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

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

--- Comment #11 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed.