[Bug tree-optimization/79345] [6/7 Regression] passing yet-uninitialized member as argument to base class constructor should warn (-Wunitialized)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79345

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
Created attachment 40857
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40857&action=edit
unreduced testcase for false positive

Bootstrap issue #1 (I posted a reasonable workaround):

> ./cc1plus  -quiet -O2 -Wuninitialized -o /dev/null ~/fixed-value.ii 
In file included from /space/rguenther/src/svn/trunk/gcc/coretypes.h:365:0,
                 from /space/rguenther/src/svn/trunk/gcc/fixed-value.c:22:
/space/rguenther/src/svn/trunk/gcc/wide-int.h: In function ‘void
fixed_from_string(fixed_value*, const char*, machine_mode)’:
/space/rguenther/src/svn/trunk/gcc/wide-int.h:818:40: warning: ‘*((void*)& w
+34359738360)’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
   unsigned HOST_WIDE_INT high = this->get_val ()[len - 1];
                        ~~~~~~~~~~~~~~~~^
/space/rguenther/src/svn/trunk/gcc/wide-int.h: In function ‘bool
fixed_convert_from_real(fixed_value*, machine_mode, const real_value*, bool)’:
/space/rguenther/src/svn/trunk/gcc/wide-int.h:818:40: warning: ‘*((void*)& w
+34359738360)’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
   unsigned HOST_WIDE_INT high = this->get_val ()[len - 1];
                        ~~~~~~~~~~~~~~~~^