[Bug lto/88677] [9 Regression] Divergence in -O2 and -O2 -flto early opts

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88677

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-reduction             |

--- Comment #6 from Martin Liška <marxin at gcc dot gnu.org> ---
Reduced test-case:

$ cat test2.ii
template <typename> class c;
template <typename b> class D : public c<b> {
public:
  static D d() { return D(0, e, f); }
  enum g { e };
  enum h { f };
  D(b *, g, h) : i() {}
  b i;
};
struct j {
  int k;
};
template <> class c<j> {
public:
  void l();
};
extern const D<j> m;
class n {
  unsigned o;

public:
  D<j> p() { return o ? D<j>::d() : m; }
};
void fn1() {
  n a;
  a.p().l();
  a.p();
}

Minimal options: -O2

Difference for -fdump-tree-fre1:

$ diff -u 2 1
--- 2   2019-01-04 09:13:20.637935502 +0100
+++ 1   2019-01-04 09:13:17.961848506 +0100
@@ -57,7 +57,7 @@
 n::p (struct n * const this)
 {
   int SR.3;
-  struct D D.2531;
+  struct D D.2527;
   struct D D.2507;
   unsigned int _1;

@@ -108,9 +108,9 @@
   int SR.8;
   int SR.7;
   unsigned int a;
-  struct D D.2547;
-  struct D D.2545;
-  struct D D.2544;
+  struct D D.2543;
+  struct D D.2541;
+  struct D D.2540;
   struct n a;
   struct D D.2498;
   struct D D.2497;
@@ -140,7 +140,8 @@
   SR.9_27 = MEM[(struct D *)&m];

   <bb 7> :
-  MEM[(struct D *)&D.2498] = SR.8_11;
+  # SR.9_12 = PHI <0(5), SR.9_27(6)>
+  MEM[(struct D *)&D.2498] = SR.9_12;
   return;

   <bb 8> :