[Bug c++/112658] New: ICE: finish_expr_stmt , at cp/semantics.cc:892

[Bug c++/112658] New: ICE: finish_expr_stmt , at cp/semantics.cc:892

[julia.desmazes at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

            Bug ID: 112658
           Summary: ICE: finish_expr_stmt , at cp/semantics.cc:892
           Product: gcc
           Version: 13.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: julia.desmazes at gmail dot com
  Target Milestone: ---

Created attachment 56664
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56664&action=edit
preprocessed file ( ii )

Hello,

I have come across an internal compiler error when using g++ 13.2.1.

The error occurs when casting a temporary array into a pointer and forwarding
the result to a constructor.

Code to reproduce : 
```
#include <stdint.h>
#include <iostream>
#include <cstring> 

#define DEFAULT_DST_MAC ((uint8_t[6]) { 0xFC, 0xFC, 0x48, 0, 0, 0})

class foo{
        public:
                foo(const uint8_t new_mac[6]){
                        std::cout << new_mac << std::endl;      
                        memcpy(&this->mac, new_mac, 6);
                }
        private:
                uint8_t mac[6];
};

int main(){
        foo f((uint8_t*)DEFAULT_DST_MAC);
        return 0;
}

```

Console log for `g++ -v -c main.cpp -freport-bug -save-temps` :

```
Using built-in specs.
COLLECT_GCC=g++
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure
--enable-languages=ada,c,c++,d,fortran,go,lto,objc,obj-c++ --enable-bootstrap
--prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/
--with-build-config=bootstrap-lto --with-linker-hash-style=gnu
--with-system-zlib --enable-__cxa_atexit --enable-cet=auto
--enable-checking=release --enable-clocale=gnu --enable-default-pie
--enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object
--enable-libstdcxx-backtrace --enable-link-serialization=1
--enable-linker-build-id --enable-lto --enable-multilib --enable-plugin
--enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-werror
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.2.1 20230801 (GCC)
COLLECT_GCC_OPTIONS='-v' '-c' '-freport-bug' '-save-temps' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
 /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/cc1plus -E -quiet -v -D_GNU_SOURCE
main.cpp -mtune=generic -march=x86-64 -freport-bug -fpch-preprocess -o main.ii
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/../../../../x86_64-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/../../../../include/c++/13.2.1

/usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/../../../../include/c++/13.2.1/x86_64-pc-linux-gnu

/usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/../../../../include/c++/13.2.1/backward
 /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/include
 /usr/local/include
 /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/include-fixed
 /usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-c' '-freport-bug' '-save-temps' '-shared-libgcc'
'-mtune=generic' '-march=x86-64'
 /usr/lib/gcc/x86_64-pc-linux-gnu/13.2.1/cc1plus -fpreprocessed main.ii -quiet
-dumpbase main.cpp -dumpbase-ext .cpp -mtune=generic -march=x86-64 -version
-freport-bug -o main.s
GNU C++17 (GCC) version 13.2.1 20230801 (x86_64-pc-linux-gnu)
        compiled by GNU C version 13.2.1 20230801, GMP version 6.3.0, MPFR
version 4.2.0-p12, MPC version 1.3.1, isl version isl-0.26-GMP

warning: MPFR header version 4.2.0-p12 differs from library version 4.2.1.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 5a490a353c29b926850bca65a518c219
main.cpp: In function ‘int main()’:
main.cpp:18:68: internal compiler error: in finish_expr_stmt, at
cp/semantics.cc:892
   18 |         foo f((uint8_t*)DEFAULT_DST_MAC);
      |                                                                    ^
0x1ad33c8 internal_error(char const*, ...)
        ???:0
0x6b7b63 fancy_abort(char const*, int, char const*)
        ???:0
0x76527f cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int)
        ???:0
0x9443d0 c_common_parse_file()
        ???:0
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <https://bugs.archlinux.org/> for instructions.
Preprocessed source stored into /tmp/ccJZigsM.out file, please attach this to
your bugreport.
make: *** [makefile:10: main.o] Error 1
```

If needed, the `ccJZigsM.out` file can be found in the following git :
https://github.com/Essenceia/gcc_bug 

I will be happy to provide any additional files if needed.

Regards,

Julia Desmazes

[Bug c++/112658] [12/13/14 Regression] ICE: finish_expr_stmt , at cp/semantics.cc:892

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
   Target Milestone|---                         |12.4
            Summary|ICE: finish_expr_stmt , at  |[12/13/14 Regression] ICE:
                   |cp/semantics.cc:892         |finish_expr_stmt , at
                   |                            |cp/semantics.cc:892
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2023-11-21
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Reduced testcase:
```
struct foo{
  foo(const int *new_mac);
};

void g(){
  foo f((int*)((int[1]){ 0xFC}));
}

```

[Bug c++/112658] [12/13/14 Regression] ICE: finish_expr_stmt with casting an temp array to pointer

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[12/13/14 Regression] ICE:  |[12/13/14 Regression] ICE:
                   |finish_expr_stmt , at       |finish_expr_stmt with
                   |cp/semantics.cc:892         |casting an temp array to
                   |                            |pointer

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is a better testcase:
```
struct foo{
  foo(const int *new_mac);
};

typedef int t[1];
void g(){
  foo f((int*)t{ 0xFC});
}
```

Which is definitely valid code.

[Bug c++/112658] [12/13/14 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Hmm GCC rejects:
```
struct foo{
  foo(const int *new_mac);
};
typedef int t[1];

void g(){
  foo f(t{ 0xFC});
}
```
While clang, MSVC all accepts it ...

[Bug c++/112658] [12/13/14 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=94264

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #3)
> Hmm GCC rejects:
> ```
> struct foo{
>   foo(const int *new_mac);
> };
> typedef int t[1];
> 
> void g(){
>   foo f(t{ 0xFC});
> }
> ```
> While clang, MSVC all accepts it ...

Oh wait that is PR 94264.

[Bug c++/112658] [12/13/14 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |ppalka at gcc dot gnu.org
           Keywords|needs-bisection             |wrong-code
             Status|NEW                         |ASSIGNED
                 CC|                            |ppalka at gcc dot gnu.org

--- Comment #5 from Patrick Palka <ppalka at gcc dot gnu.org> ---
The ICE-on-valid started with r12-2233-gb9119edc09e466, but before that this
was wrong-code:

bool called;
struct foo{
  foo(const int *new_mac) { called = true; }
};

typedef int t[1];
int main() {
  foo f((int*)t{ 0xFC});
  if (!called) __builtin_abort();
}

If we do copy initialization instead of direct initialization then we ICE ever
since the sanity check assert was added in r6-6795-g0fd9d4921f7ba2

[Bug c++/112658] [12/13 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[12/13/14 Regression] ICE:  |[12/13 Regression] ICE:
                   |finish_expr_stmt with       |finish_expr_stmt with
                   |casting an temp array to    |casting an temp array to
                   |pointer and constructor     |pointer and constructor
                   |call                        |call

--- Comment #6 from Patrick Palka <ppalka at gcc dot gnu.org> ---
GCC trunk accepts (and correctly compiles) the testcase after the r14-5941 fix
for PR94264.

[Bug c++/112658] [12/13 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:5764825aed613f201a8bc47e5b239027a39691f0

commit r14-6342-g5764825aed613f201a8bc47e5b239027a39691f0
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri Dec 8 13:33:55 2023 -0500

    c++: undiagnosed error_mark_node from cp_build_c_cast [PR112658]

    When cp_build_c_cast commits to an erroneous const_cast, we neglect to
    replay errors from build_const_cast_1 which can lead to us incorrectly
    accepting (and "miscompiling") the cast, or triggering the assert in
    finish_expr_stmt.

    This patch fixes this oversight.  This was the original fix for the ICE
    in PR112658 before r14-5941-g305a2686c99bf9 made us accept the testcase
    there after all.  I wasn't able to come up with an alternate testcase for
    which this fix has an effect anymore, but below is a reduced version of
    the PR112658 testcase (accepted ever since r14-5941) for good measure.

            PR c++/112658
            PR c++/94264

    gcc/cp/ChangeLog:

            * typeck.cc (cp_build_c_cast): If we're committed to a const_cast
            and the result is erroneous, call build_const_cast_1 a second
            time to issue errors.  Use complain=tf_none instead of =false.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/initlist-array20.C: New test.

[Bug c++/112658] [12/13 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:0c018a74eb1affe2a1fa385cdddaa93979683420

commit r14-6343-g0c018a74eb1affe2a1fa385cdddaa93979683420
Author: Patrick Palka <ppalka@redhat.com>
Date:   Fri Dec 8 13:34:04 2023 -0500

    c++: guard more against undiagnosed error_mark_node [PR112658]

    This adds a sanity check to cp_parser_expression_statement similar to
    the one in finish_expr_stmt added by r6-6795-g0fd9d4921f7ba2, which
    effectively downgrades accepts-invalid/wrong-code bugs like this one
    into ice-on-invalid/ice-on-valid ones.

            PR c++/112658

    gcc/cp/ChangeLog:

            * parser.cc (cp_parser_expression_statement): If the statement
            is error_mark_node, make sure we've seen_error().

[Bug c++/112658] [12/13 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug c++/112658] [12/13 Regression] ICE: finish_expr_stmt with casting an temp array to pointer and constructor call

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112658

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
   Target Milestone|12.4                        |14.0
             Status|ASSIGNED                    |RESOLVED

--- Comment #9 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Not backporting any of these fixes since this never properly worked -- it was
either wrong-code, rejects-valid or (most recently) ice-on-valid -- and so not
really a regression.