Bug#757982: xserver segmentation fault

[repron <repron@o2.pl>]

(bug #757982):
I received also such informationon on the screen after Xserver freeze
-----------------------------------------------------------------------------------------
(EE)
(EE) Backtrace:
(EE) 0: /usr/bin/X  (xorg_backtrace+0x56)  [0x7f09e5f0d7a6]
(EE) 1: /usr/bin/X  (0x7f09e5d58000+0x1b99a9)  (0x7f09e5f119a9)
(EE) 2: /lib/x86_64-linux-gnu/libc.so.6 (0x7f09e3a68000+0x350f0) [0x7f09e3a9d0f0]
(EE) 3: /usr/lib/x86_64-linux-gnu/libLLVM-3.4.so.1 (0x7f09dcbb8000+0x660920) [0x7f09dd218920]
(EE) 4: /lib/x86_64-linux-gnu/libc.so.6 (0x7f09e3a68000+0x37b39) [0x7f09e3a9fb39]
(EE) 5: /lib/x86_64-linux-gnu/libc.so.6 (0x7f09e3a68000+0x37b85) [0x7f09e3a9fb85]
(EE) 6: /lib/x86_64-linux-gnu/libc.so.6 (__libc_start_main+0xfc) [0x7f09e3a89b4c]
(EE) 7: /usr/bin/X  (0x7f09e5d58000+0x4550e)  (0x7f09e5d9d50e)
(EE)
(EE) Illegal instruction at address 0x7f09dd218920
(EE)
Fatal server error:
(EE) Caught signal 4 (Illegal instruction). Server aborting
(EE)
(EE)
Please consult the The X.Org Foundation support
         at http://wiki.x.org
for help
(EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information
(EE)
(EE)
(EE) Backtrace:

with regards,
richi