Bug #46311 [Asn]: Pointer aliasing issue results in miscompile on gcc4.4

Edit report at https://bugs.php.net/bug.php?id=46311&edit=1 ID: 46311 Updated by: dmitry@php.net Reported by: anton at samba dot org Summary: Pointer aliasing issue results in miscompile on gcc4.4 Status: Assigned Type: Bug Package: Compile Failure Operating System: RHEL5.2 / PowerPC64 PHP Version: 5.2.9 Assigned To: dmitry Block user comment: N Private report: N New Comment: This is not a PHP problem. The C code is absolutely legal and wrong compilation caused by a bug in GCC or too aggressive optimization options that make wrong assumptions. Previous Comments: ------------------------------------------------------------------------ [2013-03-19 18:51:42] olemarkus@php.net The Gentoo patchset has been running with this for years now. Any reason why this has not been resolved yet? ------------------------------------------------------------------------ [2010-07-25 02:17:06] mabi at gentoo dot org There are Gentoo downstream bugs related to this issue: https://bugs.gentoo.org/show_bug.cgi?id=295682 https://bugs.gentoo.org/show_bug.cgi?id=329753 I'd love to see this fixed upstream, but will ship a custom patch to get this more testing shortly. ------------------------------------------------------------------------ [2008-10-16 09:35:17] johannes@php.net Dmitry, can you check this? ------------------------------------------------------------------------ [2008-10-16 05:54:12] anton at samba dot org To clarify... the Zend code reads via zval *, not long *. The cut down test case I submitted was simplified to use a long *. ------------------------------------------------------------------------ [2008-10-16 03:20:35] anton at samba dot org I can't work out how to attach things in this tool. Here is a copy and paste of it and a non whitespace damaged version can be found at: http://ozlabs.org/~anton/junkcode/php_fix_aliasing.patch Index: php-5.2.6/Zend/zend_execute.h =================================================================== --- php-5.2.6.orig/Zend/zend_execute.h 2007-12-31 02:20:02.000000000 -0500 +++ php-5.2.6/Zend/zend_execute.h 2008-10-15 23:03:01.000000000 -0400 @@ -150,7 +150,7 @@ EG(argument_stack).top -= (delete_count+2); while (--delete_count>=0) { - zval *q = *(zval **)(--p); + zval *q = *(--p); *p = NULL; zval_ptr_dtor(&q); } ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=46311 -- Edit this bug report at https://bugs.php.net/bug.php?id=46311&edit=1