> (insn 708 707 6 (unspec_volatile[ > (mem (mem:SI (plus:SI (reg:SI 272) > (const_int 8 [0x8])) 0) 0) > ] 4) -1 (nil) > (expr_list:REG_DEAD (reg:SI 272) > (nil)))
It's the textual form of Register Tranfer Language - the GCC intermediate representation - It's described in "Using and Porting GNU CC" - Richard M. Stallman. I've no idea where the cog is, but thinking to the old "X crashes with Netscape bug" due to kernel compilation problem, I would check the gcc/egcs version.

