[Bug ipa/120987] [13/14/15/16 regression] gdb build with lto triggers use after free since r12-5541-g2cadaa1f134bec

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120987

--- Comment #26 from Tom de Vries <vries at gcc dot gnu.org> ---
Eventually, a-test-2.c.121t.retslot has:
...
  <bb 9> [count: 0]:
<L0>:
  _3 = MEM[(struct __shared_count *)&file_exception + 8B]._M_pi;
  if (_3 != 0B)
...
and then the following a-test-2.c.122t.fre3 introduces the wrong code:
...
  <bb 7> [count: 0]:
<L0>:
  if (_15 != 0B)
...
where _15 is the initial nonnull value of
file_exception.message._M_refcount._M_pi, and we need the actual value as
updated by throw_exception, which is null.