[Bug c++/103468] New: [modules] ICE Segmentation fault during GIMPLE pass walloca

[johelegp at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103468

            Bug ID: 103468
           Summary: [modules] ICE Segmentation fault during GIMPLE pass
                    walloca
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: johelegp at gmail dot com
                CC: johelegp at gmail dot com
  Target Milestone: ---

my.std.headers.hpp:
```c++
#include <algorithm>
#include <cstddef>
```

my.std.cpp:
```C++
export module my.std;

export import "my.std.headers.hpp";
```

test.cpp:
```C++
import my.std;

int main() {
  std::byte *b{};
  std::copy(b, b, b);
}
```

Compile commands:
```
g++ -pedantic -Wall -Wextra -Wconversion -g -fmodules-ts -std=c++23 -x
c++-header -c my.std.headers.hpp
g++ -pedantic -Wall -Wextra -Wconversion -g -fmodules-ts -std=c++23 -c
my.std.cpp
g++ -pedantic -Wall -Wextra -Wconversion -g -fmodules-ts -std=c++23 -c test.cpp
```

Output:
```
during GIMPLE pass: walloca
In file included from /home/johel/root/gcc/include/c++/12.0.0/algorithm:60,
                 from my.std.headers.hpp:1,
of module ./my.std.headers.hpp, imported at my.std.cpp:3,
of module my.std, imported at test.cpp:1:
/home/johel/root/gcc/include/c++/12.0.0/bits/stl_algobase.h: In static member
function ‘static constexpr _OI std::__copy_move<false, false,
std::random_access_iterator_tag>::__copy_m(_II, _II, _OI) [with _II =
std::byte*; _OI = std::byte*]’:
/home/johel/root/gcc/include/c++/12.0.0/bits/stl_algobase.h:380:9: internal
compiler error: Segmentation fault
  380 |         __copy_m(_II __first, _II __last, _OI __result)
      |         ^~~~~~~~
0x2140f6d internal_error(char const*, ...)
        ???:0
0xed8190 irange::set_varying(tree_node*)
        ???:0
0x14f2d91 gimple_range_global(tree_node*)
        ???:0
0x1f21f7b ranger_cache::get_global_range(irange&, tree_node*) const
        ???:0
0x1f1ecdb gimple_ranger::export_global_ranges()
        ???:0
0x1f5de40 pass_walloca::execute(function*)
        ???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://bugs.archlinux.org/> for instructions.
```