[Bug rtl-optimization/83367] New: static global constructors stack memory clobbering

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83367

            Bug ID: 83367
           Summary: static global constructors stack memory clobbering
           Product: gcc
           Version: 7.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: weilercdale at gmail dot com
  Target Milestone: ---

Created attachment 42835
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42835&action=edit
I've combined three files here because Bugzilla does not support adding
multiple attachment files?

I spent several hours trying to reduce this to the most minimal test case I
could but the compiler is very picky about the static global constructors being
in their own translation unit to trigger the problems.

Test.cpp contains the core code for a "test" framework that accepts registering
tests and subtests through maintaining a static linked list as static global
constructors are invoked.

Test.h contains the definitions needed to define tests in a seperate
translation unit Tests.cpp (again because putting it inline the Test.cpp file
does not exibit the problem.)

Test.cpp contains a test + subtest that triggers the bug, however the
conditionally excluded equivlant example (avoiding cTestRegister) does not
exibit the problem either.

When you compile with -fsanitize=address asan reports stack memory corruption,
as does valgrind if you run it a couple times.

It should print "b\n\a\n", as it does with clang/msvc (at all optimization
levels) and gcc at -O0, any optimization level will lead to clobbering, garbage
output and in most cases Illegal instruction exceptions.