[Bug tree-optimization/93258] [10 regression] Missed constant folding from constructor

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93258

--- Comment #5 from Martin Liška <marxin at gcc dot gnu.org> ---
Fixed on trunk with g:r10-5888-ge0804c9b5efdf17bbfb692a787df36b86f71af8d.

Bisecting latest revisions
  e0804c9b5efdf17b(10 Jan 2020 13:47)(jason@redhat.com): [took: 4.921s] result:
OK

;; Function fn1 (_Z3fn1v, funcdef_no=9, decl_uid=2587, cgraph_uid=8,
symbol_order=8) (executed once)

fn1 ()
{
  struct o D.2606;

  <bb 2> [local count: 1073741824]:
  D.2606 = bw::ci::cj (0B, 6); [return slot optimization]
  D.2606 ={v} {CLOBBER};
  __builtin_unreachable ();

}


  640b23d7ff5f3fad(10 Jan 2020 13:46)(jason@redhat.com): [took: 5.350s] result:
OK

;; Function fn1 (_Z3fn1v, funcdef_no=9, decl_uid=2587, cgraph_uid=8,
symbol_order=8) (executed once)

fn1 ()
{
  const char * p$cd;
  struct o D.2606;
  long int _6;

  <bb 2> [local count: 1073741824]:
  p$cd_5 = ck.cd;
  _6 = p$cd_5 - "";
  D.2606 = bw::ci::cj (0B, _6); [return slot optimization]
  D.2606 ={v} {CLOBBER};
  __builtin_unreachable ();

}