[Bug c/65244] Bogus -Wmaybe-uninitialized warning with posix_memalign() and -Og

[ulfalizer at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65244

--- Comment #9 from Ulf Magnusson <ulfalizer at gmail dot com> ---
Created attachment 34897
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34897&action=edit
Reduce testcase using __builtin_posix_memalign().

The warning goes away with -fno-builtin. I didn't realize posix_memalign()
existed as a builtin (documentation bug?).

Attaching a further reduced testcase.