[Bug rtl-optimization/104869] [12 Regression] Miscompilation of qt5-qtdeclarative since r12-6342-ge7a7dbb5ca5dd696

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104869

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2022-03-11
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Reduced self-contained testcase for the testsuite:

// PR rtl-optimization/104869
// { dg-do run }
// { dg-options "-O2 -fvisibility=hidden" }
// { dg-require-visibility "" }

struct QBasicAtomicInteger {
  [[gnu::noipa]] int loadRelaxed() { return 1; }
};
struct RefCount {
  bool deref() {
    int count = atomic.loadRelaxed();
    if (count)
      return false;
    return deref();
  }
  QBasicAtomicInteger atomic;
};
struct QArrayData {
  RefCount ref;
};
struct QString {
  ~QString();
  QArrayData d;
};
int ok;
QString::~QString() { d.ref.deref(); }
struct Label {
  bool isValid() { return generator; }
  int *generator;
  int index;
};
struct ControlFlow;
struct Codegen {
  [[gnu::noipa]] bool visit();
  ControlFlow *controlFlow;
};
struct ControlFlow {
  enum UnwindType { EE };
  struct UnwindTarget {
    Label linkLabel;
  };
  ControlFlow *parent;
  UnwindType unwindTarget_type;
  UnwindTarget unwindTarget() {
    QString label;
    ControlFlow *flow = this;
    while (flow) {
      Label l = getUnwindTarget(unwindTarget_type, label);
      if (l.isValid())
        return {l};
      flow = flow->parent;
    }
    return UnwindTarget();
  }
  [[gnu::noipa]] Label getUnwindTarget(UnwindType, QString &) {
    Label l = { &ok, 0 };
    return l;
  }
};
[[gnu::noipa]] void foo(int) {
  ok = 1;
}
[[gnu::noipa]] bool Codegen::visit() {
  if (!controlFlow)
    return false;
  ControlFlow::UnwindTarget target = controlFlow->unwindTarget();
  if (target.linkLabel.isValid())
    foo(2);
  return false;
}
int
main() {
  ControlFlow cf = { nullptr, ControlFlow::UnwindType::EE };
  Codegen c = { &cf };
  c.visit();
  if (!ok)
    __builtin_abort ();
}