toolchain/46865: built-in memcpy() unaligned problem on the strict-align CPU

[msaitoh%five.execsw.org@localhost]

>Number:         46865
>Category:       toolchain
>Synopsis:       built-in memcpy() unaligned problem on the strict-align CPU
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Aug 27 09:25:00 +0000 2012
>Originator:     SAITOH Masanobu
>Release:        NetBSD 6.99.10
>Organization:
-----------------------------------------------
                SAITOH Masanobu (msaitoh%netbsd.org@localhost)
>Environment:
        netbsd-6 and -current that use gcc 4.5
Architecture: arm
Machine: evbarm
>Description:
        gcc 4.5.x has a bug that the optimizer makes unaligned builtin
        memcpy() code even if the target CPU is the strict-aligned CPU.

        see:
        http://mail-index.netbsd.org/current-users/2012/08/20/msg020951.html

        I got this problem on evbarm machines (both -current and netbsd-6).
        Other CPU may have the same problem(e.g. sparc).
        
>How-To-Repeat:
        Use test program that reported in:

        http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46483

>Fix:
        Make a patch or use gcc 4.6 or 4.7.