Comment # 4 on bug 72680 from Vadim Girlin

That assert in sb_bc_parser means that it can't find corresponding instruction
in the previous group for PV/PS. E.g.:

 0648  801fa00b 61007210    78      t: LSHL_INT           R8.w,  R11.x,
[0x0000001f 0].x
 0650  0000001f 
 0652  801facfe 61007010    79      t: ASHR_INT           R8.w,  PV.w,
[0x0000001f 0].x
 0654  0000001f 

Group 79 uses PV.w, but group 78 has nothing in W slot. LLVM backend produces
incorrect code in this case.