[Bug d/94970] d: internal compiler error: in verify_gimple_stmt, at tree-cfg.c:4959

[ibuclaw at gdcproject dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94970

--- Comment #2 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
Because RegexMatch needs destruction, a temporary is created that requires
scope destruction.  The temporary is wrapped in a TARGET_EXPR, and dtor call
set in TARGET_EXPR_CLEANUP.

  TARGET_EXPR <D.4046, tmp = m () [return slot optimization], __dtor(&tmp)>


A clean-up point is then created around the initialization of 'a'.

  <<cleanup_point a = ... >>


The problem is that for the array concat expression on the RHS, a BIND_EXPR is
set-up for a temporary created for the character literal (its address needs to
be taken).

The routine gimplify_cleanup_point_expr does not look any lower than the first
level of sequences in the body, so it completely misses the
GIMPLE_WITH_CLEANUP_EXPRs in the following:

{
  const char D.4043;

  try 
    { 
      D.4043 = 32;
      D.4110.length = 1;
      D.4110.ptr = &D.4043;
      __tmpfordtor57 = m (); [return slot optimization]
      <<< Unknown GIMPLE statement: gimple_with_cleanup_expr >>>

      <<< Unknown GIMPLE statement: gimple_with_cleanup_expr >>>

      D.4111 = index (&__tmpfordtor57);
      D.4112 = _d_arraycatT (&_D12TypeInfo_Aya6__initZ, D.4111, D.4110);
      retval.0 = VIEW_CONVERT_EXPR<struct >(D.4112);
    } 
  finally
    {
      D.4043 = {CLOBBER};
    }
}
retval.1 = retval.0;
a = retval.1;



There is a note above gimplify_cleanup_point_expr:

FIXME should we complexify the prequeue handling instead?  Or use flags
for all the cleanups and let the optimizer tighten them up?  The current
code seems pretty fragile; it will break on a cleanup within any
non-conditional nesting.  But any such nesting would be broken, anyway;
we can't write a TRY_FINALLY_EXPR that starts inside a nesting construct
and continues out of it.  We can do that at the RTL level, though, so
having an optimizer to tighten up try/finally regions would be a Good
Thing.