[Bug middle-end/120205] [15/16 regression] unifdef miscompiled

[sjames at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120205

--- Comment #2 from Sam James <sjames at gcc dot gnu.org> ---
In objsz1:
```
   <bb 4> [local count: 118111600]:
   __builtin_puts (&"foo"[0]);
-  parseline_len.1_4 = parseline_len;
-  parseline_len.2_5 = (sizetype) parseline_len.1_4;
-  _20 = MAX_EXPR <parseline_len.2_5, 4096>;
-  _19 = _20 - parseline_len.2_5;
-  _6 = &tline + parseline_len.2_5;
-  _13 = _19;
-  if (_13 == 18446744073709551615)
-    goto <bb 5>; [11.56%]
-  else
-    goto <bb 6>; [88.44%]
-
-  <bb 5> [local count: 13653701]:
-  _14 = __fgets_alias ();
-
-  <bb 6> [local count: 118111600]:
-  # _16 = PHI <_14(5), _18(D)(4)>
-  if (_16 == 0B)
-    goto <bb 7>; [0.00%]
+  if (_10(D) == 0B)
+    goto <bb 5>; [0.00%]
   else
-    goto <bb 8>; [100.00%]
+    goto <bb 6>; [100.00%]
```