I can't reproduce it. Please provide a script without external data (arg).

backtrace:

#0  0x00000000008d69e5 in zend_fetch_dimension_address_read (result=0x2a95dac1d0, container_ptr=0x0, 
dim=0x2a95de57f8, dim_type=1, type=0)
    at /home/huixc/opensource/php-src/trunk/Zend/zend_execute.c:1244
1244		zval *container = *container_ptr;
(gdb) bt
#0  0x00000000008d69e5 in zend_fetch_dimension_address_read (result=0x2a95dac1d0, container_ptr=0x0, 
dim=0x2a95de57f8, dim_type=1, type=0)
    at /home/huixc/opensource/php-src/trunk/Zend/zend_execute.c:1244
#1  0x000000000091630d in ZEND_FETCH_DIM_R_SPEC_VAR_CONST_HANDLER (execute_data=0x2a95dac0e8)
    at /home/huixc/opensource/php-src/trunk/Zend/zend_vm_execute.h:12694
#2  0x00000000008d79ae in execute (op_array=0x2a95de36e8) at /home/huixc/opensource/php-
src/trunk/Zend/zend_vm_execute.h:410
#3  0x00000000008a0063 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at 
/home/huixc/opensource/php-src/trunk/Zend/zend.c:1272
#4  0x0000000000820850 in php_execute_script (primary_file=0x7fbffff2a0) at /home/huixc/opensource/php-
src/trunk/main/main.c:2414
#5  0x00000000009c12dd in do_cli (argc=2, argv=0x7fbffff588) at /home/huixc/opensource/php-
src/trunk/sapi/cli/php_cli.c:983
#6  0x00000000009c217e in main (argc=2, argv=0x7fbffff588) at /home/huixc/opensource/php-
src/trunk/sapi/cli/php_cli.c:1356

I can reproduce this on linux with a more simple script:
<?php
$arr  = array("test");
list($a)= is_array($arr)? $arr : $arr;
?>

and I have pasted the bt above~

Arnaud, could you try to give a look please? Happens only in 5.4, the recent 
optimization in this area could be the cause.

there is also segfault in (***)?:value notation.
like:
   <?php
     $str = array('test');
     list($a, $b) = is_array($str)?:$str;

and this make *the patch doesn't work* (a memory leak)

I have submitted a new patch. lbarnaud, plz review it , thanks

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.