Here is the bug:

s_mov_b64 vcc, s[6:7]  ; Store pointer for s_load_dword* in vcc

<snip>

v_cmpx_le_f32_e32 vcc, 0, v6 ; Kill instructions
v_cmpx_le_f32_e32 vcc, 0, v6
v_cmpx_le_f32_e32 vcc, 0, v6
v_cmpx_le_f32_e32 vcc, 0, v6

<snip>

s_load_dwordx8 s[8:15], vcc, 0x48 ; vcc no longer contains a pointer.

The lowering of kill instructions needs to save and restore VCC if it is live.

As a work around, you can try this branch:
http://cgit.freedesktop.org/~tstellar/llvm/log/?h=sched-perf-Mar-27-2015
or take the top two commits and apply it to llvm master.  I think this will
avoid the bug.