[Bug tree-optimization/79671] [7 Regression] mapnik miscompilation on armv7hl since r235622

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79671

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
E.g. on 122 valgrind says:
==21905== Invalid free() / delete / delete[] / realloc()
==21905==    at 0x484B224: operator delete(void*) (vg_replace_malloc.c:576)
==21905==    by 0x11BB3:
path_expression_grammar<__gnu_cxx::__normal_iterator<char const*,
std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >
> >::path_expression_grammar() (in /tmp/rh1422456.122)
==21905==  Address 0xbd8fd048 is on thread 1's stack

Looking at tree dumps from PTRS_COMPARE_UNEQUAL=10000 (works) and
PTRS_COMPARE_UNEQUAL=122 (calls free on invalid arg), I see the first change in
*.fre1 in path_expression_grammar<Iterator>::path_expression_grammar()
function,
   MEM[(struct  &)this_10(D) + 56] ={v} {CLOBBER};
   MEM[(struct function_base *)this_10(D) + 56B].vtable = 0B;
   _122 = MEM[(char * *)&D.552047];
-  if (&D.552047.D.20672._M_local_buf != _122)
-    goto <bb 9>;
-  else
-    goto <bb 10>;
-
-  <bb 9>:
   operator delete (_122);
-
-  <bb 10>:
   MEM[(struct  &)&D.552047] ={v} {CLOBBER};
   D.552047 ={v} {CLOBBER};
   D.552048 ={v} {CLOBBER};
   _29 = &this_10(D)->attr;
and
@@ -12334,15 +12330,7 @@ path_expression_grammar<Iterator>::path_

 <L4>:
   _140 = MEM[(char * *)&D.552047];
-  if (&D.552047.D.20672._M_local_buf != _140)
-    goto <bb 27>;
-  else
-    goto <bb 28>;
-
-  <bb 27>:
   operator delete (_140);
-
-  <bb 28>:
   MEM[(struct  &)&D.552047] ={v} {CLOBBER};
   D.552047 ={v} {CLOBBER};
   resx 7

(all other changes are just in bb numbers, as some bbs have been removed in the
latter case).
No idea what to figure out from this though, it just removes some operator
delete calls (free), but that shouldn't cause free being called on invalid,
worst case just memory leak.