[Bug debug/105415] [9/10/11/12/13 Regression] '-fcompare-debug' failure w/ -O2 -ftree-parallelize-loops=2 since r7-4900-g59ec925b1199f9

[asolokha at gmx dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105415

Arseny Solokha <asolokha at gmx dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[9/10/11/12 Regression]     |[9/10/11/12/13 Regression]
                   |'-fcompare-debug' failure   |'-fcompare-debug' failure
                   |w/ -O2                      |w/ -O2
                   |-ftree-parallelize-loops=2  |-ftree-parallelize-loops=2
                   |since                       |since
                   |r7-4900-g59ec925b1199f9     |r7-4900-g59ec925b1199f9

--- Comment #8 from Arseny Solokha <asolokha at gmx dot com> ---
I still get a similar failure w/ gcc 13.0.0 20220515 snapshot:

@@ -360,7 +360,7 @@
 1:   int i;
 2:   signed int D.xxxx;

-;; Function bar._loopfn.0 (bar._loopfn.0, funcdef_no=2, cgraph_uid=3,
symbol_order=5)
+;; Function bar._loopfn.0 (bar._loopfn.0, funcdef_no=2, cgraph_uid=3,
symbol_order=6)

 (note # 0 0 NOTE_INSN_DELETED)
 (note # 0 0 [bb 2] NOTE_INSN_BASIC_BLOCK)

upon the following change to the original testcase:

@@ -4,13 +4,10 @@ static int n;
 void
 foo (void)
 {
-  int s = 0;
+  int *arr[] = { &n, &n, &n };
+  int unused = n;

-  while (m < 1)
-    {
-      s += n;
-      ++m;
-    }
+  m = 0;
 }

 void

Do you want me to open a separate PR for that?