[Bug target/87253] New: Python test_ctypes fails when built with gcc 8.2

[kugan at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87253

            Bug ID: 87253
           Summary: Python test_ctypes fails when built with gcc 8.2
           Product: gcc
           Version: 8.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kugan at gcc dot gnu.org
  Target Milestone: ---

Python-2.7.15

Steps to reproduce error
In Python src directory:
./configure
make
./python Lib/test/regrtest.py -v test_ctypes

======================================================================
FAIL: test_struct_by_value (ctypes.test.test_win32.Structures)
----------------------------------------------------------------------
Traceback (most recent call last):
  File
"/home/kugan.vivekanandarajah/Python-2.7.15/Lib/ctypes/test/test_win32.py",
line 113, in test_struct_by_value
    self.assertEqual(ret.left, left.value)
AssertionError: -200 != 10



gdb ./python
b ReturnRect
r Lib/test/regrtest.py -v test_ctypesQuit

(gdb) p cp
$9 = {x = 15, y = 25}
(gdb) p fp
$10 = {x = 548534164448, y = 9890688}

cp and fp are the same as can  be seen from below:

vi /home/kugan.vivekanandarajah/Python-2.7.15/Lib/ctypes/test/test_win32.py
+112

pt = POINT(15, 25)
...
ReturnRect = dll.ReturnRect
ReturnRect.argtypes = [c_int, RECT, POINTER(RECT), POINT, RECT,
                      POINTER(RECT), POINT, RECT]
....

ret = ReturnRect(i, rect, pointer(rect), pt, rect,
                 byref(rect), pt, rect)


gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/home/kugan.vivekanandarajah/install/usr/local/bin/../libexec/gcc/aarch64-unknown-linux-gnu/8.2.1/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: ../gcc/configure --disable-bootstrap
Thread model: posix
gcc version 8.2.1 20180907 (GCC)