[Bug c++/70558] New: POD datatype array crash in initialization when using optimization

["hlprasu at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70558

            Bug ID: 70558
           Summary: POD datatype array crash in initialization when using
                    optimization
           Product: gcc
           Version: 5.2.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hlprasu at gmail dot com
  Target Milestone: ---

Created attachment 38197
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=38197&action=edit
Contains example code to reproduce this problem

I have created a simple POD class named Double, which encapsulates 'double'
type so that comparison operators can be handled in a numerically correct
fashion. This is in the attached .tar.gz file.

My problem is that if a create a fixed array with it and try to initialize all
elements in a single statement then it crashes only when optimization is
enabled.

E.g.:

Double v[3];

v[0] = v[1] = v[2] = 0.0; // <- crash here with -O or -O2 or -O3

Funnily enough, this does not crash if you do
v[0] = 0.0;
v[1] = 0.0;
v[2] = 0.0;


To reproduce this error,
1. Untar the attached file and go to the directory

   tar -xvzf double-pod-crash.tar.gz
   cd double-pod-crash/

2. Run 'make' and execute the test file.

   make
   ./test # <- This segfaults at the above statement

I saw the crash to be at the above statement by using gdb after recompiling
with -g option.

Please let me know a solution to this problem.