[Bug c++/105577] New: [12 Regression] ICE in delete_unmarked_insns, at dce.cc:653

[curdeius at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105577

            Bug ID: 105577
           Summary: [12 Regression] ICE in delete_unmarked_insns, at
                    dce.cc:653
           Product: gcc
           Version: 12.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: curdeius at gmail dot com
  Target Milestone: ---

Similar to bug https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90082.

GCC 12.1.0 ICEs when compiling this code with:
```
g++ -DROCKSDB_PLATFORM_POSIX -isystem rocksdb-cloud -isystem
rocksdb-cloud/include -O3 -march=haswell -fnon-call-exceptions -c
rocksdb-cloud/db/db_impl/db_impl_compaction_flush.cc
```
All the three flags are important, as the ICE doesn't happen with -O2, nor
without -march, nor with -march=skylake, but it does happen with microarchs
older than haswell.
ICE doesn't happen without -fnon-call-exceptions either.

Version:
```
$ g++ --version
g++ (GCC) 12.1.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
```

The minimized repro (couldn't do better for the moment, preprocessed source
attached of both minimal repro and the full file attached):
```
#include "db/db_impl/db_impl.h"

namespace ROCKSDB_NAMESPACE {

void DBImpl::InstallSuperVersionAndScheduleWork(
    ColumnFamilyData* cfd, SuperVersionContext* sv_context,
    const MutableCFOptions& mutable_cf_options) {
  if (UNLIKELY(sv_context->new_superversion == nullptr)) {
    sv_context->NewSuperVersion();
  }

  bottommost_files_mark_threshold_ = kMaxSequenceNumber;
  for (auto* my_cfd : *versions_->GetColumnFamilySet()) {
    bottommost_files_mark_threshold_ = std::min(
        bottommost_files_mark_threshold_,
        my_cfd->current()->storage_info()->bottommost_files_mark_threshold());
  }
}

}  // namespace ROCKSDB_NAMESPACE
```