[Bug c++/104583] New: [12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[Bug c++/104583] New: [12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[slyfox at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

            Bug ID: 104583
           Summary: [12 regression] ICE dolphin-emu at
                    cp/cp-gimplify.cc:746
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: slyfox at gcc dot gnu.org
  Target Milestone: ---

Noticed ICE today when was building dolpjin-emu with a weekly gcc snapshot and
current gcc master.

Minimal reproducer:

    // $ cat bug.cc
    struct TVec3 {
      TVec3();
      int data;
    };
    using Vec3 = TVec3;
    struct {
      Vec3 position{};
    } EmulatePoint_state;
    void EmulatePoint() { EmulatePoint_state = {}; }

/tmp/gcc/xg++ -B/tmp/gcc -c bug.cc -freport-bug
bug.cc: In function ‘void EmulatePoint()’:
bug.cc:9:42: internal compiler error: in cp_gimplify_expr, at
cp/cp-gimplify.cc:746
    9 | void EmulatePoint() { EmulatePoint_state = {}; }
      |                       ~~~~~~~~~~~~~~~~~~~^~~~
0x7a0fb2 cp_gimplify_expr(tree_node**, gimple**, gimple**)
        /home/slyfox/dev/git/gcc/gcc/cp/cp-gimplify.cc:746
0xd9fb80 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:14893
0xdab095 gimplify_init_ctor_preeval
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:4678
0xdab19d gimplify_init_ctor_preeval
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:4664
0xdac73d gimplify_init_constructor
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:5243
0xdacf76 gimplify_modify_expr_rhs
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:5560
0xdad79f gimplify_modify_expr
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:5926
0xd9b0b1 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:14984
0xda029d gimplify_stmt(tree_node**, gimple**)
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:7039
0xda18fc gimplify_cleanup_point_expr
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:6778
0xd9c491 gimplify_expr(tree_node**, gimple**, gimple**, bool (*)(tree_node*),
int)
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:15377
0xda029d gimplify_stmt(tree_node**, gimple**)
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:7039
0xda1e49 gimplify_body(tree_node*, bool)
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:16230
0xda2365 gimplify_function_tree(tree_node*)
        /home/slyfox/dev/git/gcc/gcc/gimplify.cc:16384
0xbaceda cgraph_node::analyze()
        /home/slyfox/dev/git/gcc/gcc/cgraphunit.cc:675
0xbaf6a5 analyze_functions
        /home/slyfox/dev/git/gcc/gcc/cgraphunit.cc:1240
0xbb0795 symbol_table::finalize_compilation_unit()
        /home/slyfox/dev/git/gcc/gcc/cgraphunit.cc:2500
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Preprocessed source stored into /tmp/ccpGKHxu.out file, please attach this to
your bugreport.

$ /tmp/gcc/xg++ -B/tmp/gcc -v
Reading specs from /tmp/gcc/specs
COLLECT_GCC=/tmp/gcc/xg++
COLLECT_LTO_WRAPPER=/tmp/gcc/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/slyfox/dev/git/gcc/configure --disable-multilib
--disable-bootstrap
--with-native-system-header-dir=/nix/store/vccvfa5bjb9dv4x6zq5gjf1yp58y4brg-glibc-2.33-108-dev/include
--prefix=/tmp/__td__ CFLAGS='-O1 -ggdb3' CXXFLAGS='-O1 -ggdb3' LDFLAGS='-O1
-ggdb3'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.1 20220217 (experimental) (GCC)

[Bug c++/104583] [10/11/12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
            Summary|[12 regression] ICE         |[10/11/12 regression] ICE
                   |dolphin-emu at              |dolphin-emu at
                   |cp/cp-gimplify.cc:746       |cp/cp-gimplify.cc:746
             Status|UNCONFIRMED                 |NEW
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |jason at gcc dot gnu.org
   Target Milestone|---                         |10.4
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-02-17

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r10-5822-g08f594eb399dab0637b57b0ca4b0a5ce912b8171

[Bug c++/104583] [10/11/12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-checking

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note I noticed it does not ICE with -std=c++11 . Nor with
--enable-checking=release

[Bug c++/104583] [10/11/12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

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

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
The attached 93280 test no longer ICEs but looks like it was never added to the
testsuite.  The 104583 test, modified so that it closely resembles 93280, still
ICEs.

The problem is that in 104583 we have a value-init from {}, so this code in
convert_like_internal
 7960         /* If we're initializing from {}, it's value-initialization.  */
 7961         if (BRACE_ENCLOSED_INITIALIZER_P (expr)
 7962             && CONSTRUCTOR_NELTS (expr) == 0
 7963             && TYPE_HAS_DEFAULT_CONSTRUCTOR (totype)
 7964             && !processing_template_decl)
 7965           {
 7966             bool direct = CONSTRUCTOR_IS_DIRECT_INIT (expr);
...
 7974                 TARGET_EXPR_DIRECT_INIT_P (expr) = direct;

sets TARGET_EXPR_DIRECT_INIT_P (line #1 in 104583).  This does not happen in
93280.

When gimplifying, the #2 line, we have

d = {.a=TARGET_EXPR <D.2474, <<< Unknown tree: aggr_init_expr
  4
  __ct_comp 
  D.2474
  (struct A *) <<< Unknown tree: void_cst >>> >>>>}

where the TARGET_EXPR is the one with TARGET_EXPR_DIRECT_INIT_P set.  In
gimplify_init_ctor_preeval we do

 4724       FOR_EACH_VEC_SAFE_ELT (v, ix, ce)
 4725         gimplify_init_ctor_preeval (&ce->value, pre_p, post_p, data);

so we gimplify the TARGET_EXPR, crashing at

 744     case TARGET_EXPR:
 745       /* A TARGET_EXPR that expresses direct-initialization should have
been
 746          elided by cp_gimplify_init_expr.  */
 747       gcc_checking_assert (!TARGET_EXPR_DIRECT_INIT_P (*expr_p));

but there is no INIT_EXPR so cp_gimplify_init_expr was never called!


// 93280.C
struct A {
  template <typename T> A(T);
  int c;
};
struct D {
  A a{0};
};
void f() {
  D d;
  d = {};
}

// 104583.C
struct A {
  A();
  int c;
};

struct D {
  A a{}; // #1
};

void g()
{
  D d;
  d = {}; // #2
}

[Bug c++/104583] [10/11/12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Candidate fix:

--- a/gcc/cp/init.cc
+++ b/gcc/cp/init.cc
@@ -679,10 +679,10 @@ get_nsdmi (tree member, bool in_ctor, tsubst_flags_t
complain)
   if (simple_target)
     init = TARGET_EXPR_INITIAL (init);
   init = break_out_target_exprs (init, /*loc*/true);
-  if (in_ctor && init && TREE_CODE (init) == TARGET_EXPR)
-    /* This expresses the full initialization, prevent perform_member_init
from
-       calling another constructor (58162).  */
-    TARGET_EXPR_DIRECT_INIT_P (init) = true;
+  if (init && TREE_CODE (init) == TARGET_EXPR)
+    /* If this expresses the full initialization, prevent perform_member_init
+       from calling another constructor (58162).  */
+    TARGET_EXPR_DIRECT_INIT_P (init) = in_ctor;
   if (simple_target && TREE_CODE (init) != CONSTRUCTOR)
     /* Now put it back so C++17 copy elision works.  */
     init = get_target_expr (init);

[Bug c++/104583] [10/11/12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

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

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Patch posted.

[Bug c++/104583] [10/11/12 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

https://gcc.gnu.org/g:f8c1f29a0b47b4b4a3c1506678f7ca2ce4b7ffbb

commit r12-7919-gf8c1f29a0b47b4b4a3c1506678f7ca2ce4b7ffbb
Author: Marek Polacek <polacek@redhat.com>
Date:   Fri Mar 25 17:46:07 2022 -0400

    c++: ICE with aggregate assignment and DMI [PR104583]

    The attached 93280 test no longer ICEs but looks like it was never added to
the
    testsuite.  The 104583 test, modified so that it closely resembles 93280,
still
    ICEs.

    The problem is that in 104583 we have a value-init from {} (the line A
a{};),
    so this code in convert_like_internal

     7960         /* If we're initializing from {}, it's value-initialization. 
*/
     7961         if (BRACE_ENCLOSED_INITIALIZER_P (expr)
     7962             && CONSTRUCTOR_NELTS (expr) == 0
     7963             && TYPE_HAS_DEFAULT_CONSTRUCTOR (totype)
     7964             && !processing_template_decl)
     7965           {
     7966             bool direct = CONSTRUCTOR_IS_DIRECT_INIT (expr);
    ...
     7974                 TARGET_EXPR_DIRECT_INIT_P (expr) = direct;

    sets TARGET_EXPR_DIRECT_INIT_P.  This does not happen in 93280 where we
    initialize from {0}.

    In 104583, when gimplifying, the d = {}; line, we have

    d = {.a=TARGET_EXPR <D.2474, <<< Unknown tree: aggr_init_expr
      4
      __ct_comp
      D.2474
      (struct A *) <<< Unknown tree: void_cst >>> >>>>}

    where the TARGET_EXPR is the one with TARGET_EXPR_DIRECT_INIT_P set.  In
    gimplify_init_ctor_preeval we do

     4724       FOR_EACH_VEC_SAFE_ELT (v, ix, ce)
     4725         gimplify_init_ctor_preeval (&ce->value, pre_p, post_p, data);

    so we gimplify the TARGET_EXPR, crashing at

     744     case TARGET_EXPR:
     745       /* A TARGET_EXPR that expresses direct-initialization should
have
    been
     746          elided by cp_gimplify_init_expr.  */
     747       gcc_checking_assert (!TARGET_EXPR_DIRECT_INIT_P (*expr_p));

    but there is no INIT_EXPR so cp_gimplify_init_expr was never called!

    Now, the fix for c++/93280
    <https://gcc.gnu.org/pipermail/gcc-patches/2020-January/538414.html>
    says "let's only set TARGET_EXPR_DIRECT_INIT_P when we're using the DMI in
    a constructor." and the comment talks about the full initialization.  Is
    is accurate to say that our TARGET_EXPR does not represent the full
    initialization, because it only initializes the 'a' subobject?  If so,
    then maybe get_nsdmi should clear TARGET_EXPR_DIRECT_INIT_P when in_ctor
    is false.

    I've compared the 93280.s and 104583.s files, they differ only in one
    movl $0, so there are no extra calls and similar.

            PR c++/93280
            PR c++/104583

    gcc/cp/ChangeLog:

            * init.cc (get_nsdmi): Set TARGET_EXPR_DIRECT_INIT_P to in_ctor.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/nsdmi-list7.C: New test.
            * g++.dg/cpp0x/nsdmi-list8.C: New test.

[Bug c++/104583] [10/11 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[10/11/12 regression] ICE   |[10/11 regression] ICE
                   |dolphin-emu at              |dolphin-emu at
                   |cp/cp-gimplify.cc:746       |cp/cp-gimplify.cc:746

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

[Bug c++/104583] [10/11 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.4                        |10.5

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.4 is being released, retargeting bugs to GCC 10.5.

[Bug c++/104583] [11 regression] ICE dolphin-emu at cp/cp-gimplify.cc:746

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104583

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.5                        |11.5

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 10 branch is being closed.