[Bug c++/66590] switch statement: incorrect warning "reaches end of non-void function"

["pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66590

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This is what we have now:

;; Function f (_Z1fi, funcdef_no=0, decl_uid=2362, cgraph_uid=1,
symbol_order=0)

Removing basic block 6
Removing basic block 8
Merging blocks 3 and 4
Removing basic block 11
Merging blocks 12 and 14
Merging blocks 3 and 5
;; 1 loops found
;;
;; Loop 0
;;  header 0, latch 1
;;  depth 0, outer -1
;;  nodes: 0 1 2 3 4 5 6 7 8 9
;; 2 succs { 4 3 }
;; 3 succs { 5 }
;; 4 succs { 5 }
;; 5 succs { 8 6 }
;; 6 succs { 7 }
;; 7 succs { 1 }
;; 8 succs { 9 }
;; 9 succs { 1 }
int f (int x)
{
  int finally_tmp.0;
  struct A tmp;
  struct A a;
  int D.2384;

  <bb 2> :
  if (x == 1)
    goto <bb 3>; [INV]
  else
    goto <bb 4>; [INV]

  <bb 3> :
<L0>:
  D.2384 = 1;
  A::~A (&tmp);
  tmp = {CLOBBER};
  finally_tmp.0 = 0;
  goto <bb 5>; [INV]

  <bb 4> :
<L3>:
  D.2384 = 0;
  finally_tmp.0 = 0;

  <bb 5> :
  A::~A (&a);
  if (finally_tmp.0 == 1)
    goto <bb 6>; [INV]
  else
    goto <bb 8>; [INV]

  <bb 6> :
<L6>:

  <bb 7> :
  a = {CLOBBER};
  return;

  <bb 8> :
  a = {CLOBBER};

  <bb 9> :
<L11>:
  return D.2384;

}


Looks like there was a case where we thought finally_tmp.0 could be equal to 1.
 Note this is all internal.