Verified with a fresh checkout. Assigning to Derick. 

david@beirut:~/php/5_3$ sapi/cli/php -v
PHP 5.3.3-dev (cli) (built: Jun 17 2010 19:42:56) 
Copyright (c) 1997-2010 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies


(gdb) r -ddate.timezone="America/Chicago" /home/david/test.php
Starting program: /home/david/php/5_3/sapi/cli/php -
ddate.timezone="America/Chicago" /home/david/test.php
[Thread debugging using libthread_db enabled]

Program received signal SIGSEGV, Segmentation fault.
timelib_rel_time_clone (rel=0x0) at /usr/include/bits/string3.h:52
52	  return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
(gdb) bt
#0  timelib_rel_time_clone (rel=0x0) at /usr/include/bits/string3.h:52
#1  0x0000000000421728 in zim_DatePeriod___construct (ht=<value optimized out>, 
return_value=<value optimized out>, return_value_ptr=<value optimized out>, 
this_ptr=0xde26c8, 
    return_value_used=<value optimized out>) at 
/home/david/php/5_3/ext/date/php_date.c:3752
#2  0x00000000006afd36 in zend_do_fcall_common_helper_SPEC 
(execute_data=0x7ffff7e7f050) at /home/david/php/5_3/Zend/zend_vm_execute.h:316
#3  0x00000000006a9e58 in execute (op_array=0xddd8f8) at 
/home/david/php/5_3/Zend/zend_vm_execute.h:107
#4  0x00000000006855da in zend_execute_scripts (type=8, retval=<value optimized 
out>, file_count=3) at /home/david/php/5_3/Zend/zend.c:1194
#5  0x00000000006352ed in php_execute_script (primary_file=<value optimized 
out>) at /home/david/php/5_3/main/main.c:2260
#6  0x000000000070bad0 in main (argc=<value optimized out>, argv=<value 
optimized out>) at /home/david/php/5_3/sapi/cli/php_cli.c:1192

DatePeriod, as most others Date* objects, does not have proper serialization 
handler, this is the cause of the segfault.

I meant DateInterval, but true for DatePeriod too.

Another way to have a related crash:

<?php
class dummy extends DateInterval {
        public function __construct() {
        }
}
$x = new dummy;
$x->y = 1;


0x0000000000447349 in date_interval_write_property (object=0x7ffff7fcb200, member=0x7ffff7fcd708, value=0x7ffff7fcb180, key=0x7ffff7fcd708, tsrm_ls=0x13ae0c0) at /home/felipe/dev/phptrunk/ext/date/php_date.c:3496
3496			SET_VALUE_FROM_STRUCT(y, "y");
gdb$ bt
#0  0x0000000000447349 in date_interval_write_property (object=0x7ffff7fcb200, member=0x7ffff7fcd708, value=0x7ffff7fcb180, key=0x7ffff7fcd708, tsrm_ls=0x13ae0c0) at /home/felipe/dev/phptrunk/ext/date/php_date.c:3496
#1  0x0000000000af9683 in zend_assign_to_object (retval=0x0, object_ptr=0x7ffff7fcf8f0, property_name=0x7ffff7fcd708, value_type=0x1, value_op=0x7ffff7fcc7a0, Ts=0x7ffff7f95190, opcode=0x88, key=0x7ffff7fcd708, tsrm_ls=0x13ae0c0) at /home/felipe/dev/phptrunk/Zend/zend_execute.c:738
#2  0x0000000000bfe0b1 in ZEND_ASSIGN_OBJ_SPEC_CV_CONST_HANDLER (execute_data=0x7ffff7f950f8, tsrm_ls=0x13ae0c0) at /home/felipe/dev/phptrunk/Zend/zend_vm_execute.h:28753
#3  0x0000000000afdab1 in execute (op_array=0x7ffff7fcec00, tsrm_ls=0x13ae0c0) at /home/felipe/dev/phptrunk/Zend/zend_vm_execute.h:410
#4  0x0000000000ab5029 in zend_execute_scripts (type=0x8, tsrm_ls=0x13ae0c0, retval=0x0, file_count=0x3) at /home/felipe/dev/phptrunk/Zend/zend.c:1272
#5  0x00000000009fa7a5 in php_execute_script (primary_file=0x7fffffffe180, tsrm_ls=0x13ae0c0) at /home/felipe/dev/phptrunk/main/main.c:2414
#6  0x0000000000c3d2ce in do_cli (argc=0x2, argv=0x7fffffffe538, tsrm_ls=0x13ae0c0) at /home/felipe/dev/phptrunk/sapi/cli/php_cli.c:983
#7  0x0000000000c3e519 in main (argc=0x2, argv=0x7fffffffe538) at /home/felipe/dev/phptrunk/sapi/cli/php_cli.c:1356

This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.