[Bug c++/15485] [tree-ssa] The C++ front-end generates a lot of (void) casts for statements (NVR)

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=15485

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P2                          |P4
                 CC|                            |msebor at gcc dot gnu.org
      Known to fail|                            |4.0.0, 4.8.3, 4.9.3, 5.3.0,
                   |                            |6.3.0, 7.0

--- Comment #12 from Martin Sebor <msebor at gcc dot gnu.org> ---
I have no idea how serious this is but with GCC 7.0 I still see some (void)
casts in the original dump for the test case from comment #1.  I'll lower the
Importance to P4 though due to the lack of activity or feedback.

$ cat t.C && gcc -S -Wformat -fdump-tree-original=/dev/stdout t.C
  struct _Refcount_Base
{
  volatile int _M_ref_count;
  void *_M_ref_count_lock;
  _Refcount_Base(int);
};
_Refcount_Base::_Refcount_Base (int __n): _M_ref_count(__n)
{
void *__tmp = 0;
_M_ref_count_lock = __tmp;
}

;; Function _Refcount_Base::_Refcount_Base(int) (null)
;; enabled by -tree-original


<<cleanup_point <<< Unknown tree: expr_stmt
  *(struct 
  {
    volatile int _M_ref_count;
    void * _M_ref_count_lock;
  } &) this = {CLOBBER} >>>>>;
{
  <<cleanup_point <<< Unknown tree: expr_stmt
  (void) (((struct _Refcount_Base *) this)->_M_ref_count = __n) >>>>>;
  {
    void * __tmp = 0B;

    <<cleanup_point     void * __tmp = 0B;>>;
    <<cleanup_point <<< Unknown tree: expr_stmt
  (void) (((struct _Refcount_Base *) this)->_M_ref_count_lock = __tmp) >>>>>;
  }
}