When running callgrind on a program that I am currently developing, it crashes with the following error:

vex amd64->IR: unhandled instruction bytes: 0xC5 0xF8 0x57 0xC0 0x48 0xC7 0x43 0x58
==16926== valgrind: Unrecognised instruction at address 0x4c399a0.

The program executes normally without issues.

Some system info:

 % cat /proc/cpuinfo
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 42
model name	: Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz
stepping	: 7
microcode	: 0x18
cpu MHz		: 3502.659
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 0
cpu cores	: 4
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 13
wp		: yes
flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 popcnt tsc_deadline_timer aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid
bogomips	: 7008.20
clflush size	: 64
cache_alignment	: 64
address sizes	: 36 bits physical, 48 bits virtual
power management:


 % uname -a
Linux asterix-arch 3.3.1-1-ARCH #1 SMP PREEMPT Tue Apr 3 06:46:17 UTC 2012 x86_64 Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz GenuineIntel GNU/Linux