[Bug lto/115890] New: ICE: verify_gimple failed with -flto

[iamanonymous.cs at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115890

            Bug ID: 115890
           Summary: ICE: verify_gimple failed with -flto
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: iamanonymous.cs at gmail dot com
  Target Milestone: ---

*******************************************************************************
OS and Platform:
$ uname -a:
Linux 65dac7c84719 4.15.0-213-generic #224-Ubuntu SMP Mon Jun 19 13:30:12 UTC
2023 x86_64 x86_64 x86_64 GNU/Linux
*******************************************************************************
gcc version:
Using built-in specs.
COLLECT_GCC=/home/software/gcc-trunk-3aa004f/bin/gcc
COLLECT_LTO_WRAPPER=/home/software/gcc-trunk-3aa004f/libexec/gcc/x86_64-pc-linux-gnu/15.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --disable-multilib --disable-bootstrap
--enable-languages=c,c++ --prefix=/home/software/gcc-trunk-3aa004f
--enable-coverage
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 15.0.0 20240630 (experimental) (GCC) 

*******************************************************************************
Program:
$ cat mutant.c
int b;
void c() {
  struct d {
    int a[b]
  } e() {
  }
  struct d f() { return e(); }
  f();
}

*******************************************************************************
Command Lines:
$ gcc -flto mutant.c
mutant.c: In function 'c':
mutant.c:5:3: warning: no semicolon at end of struct or union
    5 |   } e() {
      |   ^
mutant.c: In function 'f':
mutant.c:7:12: error: invalid conversion in gimple call
    7 |   struct d f() { return e(); }
      |            ^
struct d

struct d

# .MEM_14 = VDEF <.MEM_13(D)>
<retval> = e (); [static-chain: CHAIN.3_8(D)] [return slot optimization]
during GIMPLE pass: fixup_cfg
mutant.c:7:12: internal compiler error: verify_gimple failed
0x4ddb72b diagnostic_context::report_diagnostic(diagnostic_info*)
        ???:0
0x4ddbffd diagnostic_context::diagnostic_impl(rich_location*,
diagnostic_metadata const*, int, char const*, __va_list_tag (*) [1],
diagnostic_t)
        ???:0
0x4dfc327 internal_error(char const*, ...)
        ???:0
0x1cc84a5 verify_gimple_in_cfg(function*, bool, bool)
        ???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
lto-wrapper: fatal error: /home/software/gcc-trunk-3aa004f/bin/gcc returned 1
exit status
compilation terminated.
/usr/bin/ld: error: lto-wrapper failed
collect2: error: ld returned 1 exit status

Also ICE on trunk.
Compiler Explorer: https://godbolt.org/z/x8fPWKqs7