rtx的指令：参看rtl.def
DEF_RTL_EXPR(UNKNOWN, "UnKnown", "*", RTX_EXTRA)
DEF_RTL_EXPR(VALUE, "value", "0", RTX_OBJ)
DEF_RTL_EXPR(DEBUG_EXPR, "debug_expr", "0", RTX_OBJ)
DEF_RTL_EXPR(EXPR_LIST, "expr_list", "ee", RTX_EXTRA)
DEF_RTL_EXPR(INSN_LIST, "insn_list", "ue", RTX_EXTRA)
DEF_RTL_EXPR(INT_LIST, "int_list", "ie", RTX_EXTRA)
DEF_RTL_EXPR(SEQUENCE, "sequence", "E", RTX_EXTRA)
DEF_RTL_EXPR(ADDRESS, "address", "i", RTX_EXTRA)
DEF_RTL_EXPR(DEBUG_INSN, "debug_insn", "uuBeLie", RTX_INSN)
DEF_RTL_EXPR(INSN, "insn", "uuBeLie", RTX_INSN)
DEF_RTL_EXPR(JUMP_INSN, "jump_insn", "uuBeLie0", RTX_INSN)
DEF_RTL_EXPR(CALL_INSN, "call_insn", "uuBeLiee", RTX_INSN)
DEF_RTL_EXPR(JUMP_TABLE_DATA, "jump_table_data", "uuBe0000", RTX_INSN)
DEF_RTL_EXPR(BARRIER, "barrier", "uu00000", RTX_EXTRA)
DEF_RTL_EXPR(CODE_LABEL, "code_label", "uuB00is", RTX_EXTRA)
DEF_RTL_EXPR(NOTE, "note", "uuB0ni", RTX_EXTRA)
DEF_RTL_EXPR(COND_EXEC, "cond_exec", "ee", RTX_EXTRA)
DEF_RTL_EXPR(PARALLEL, "parallel", "E", RTX_EXTRA)
DEF_RTL_EXPR(ASM_INPUT, "asm_input", "sL", RTX_EXTRA)
DEF_RTL_EXPR(ASM_OPERANDS, "asm_operands", "ssiEEEL", RTX_EXTRA)
DEF_RTL_EXPR(UNSPEC, "unspec", "Ei", RTX_EXTRA)
DEF_RTL_EXPR(UNSPEC_VOLATILE, "unspec_volatile", "Ei", RTX_EXTRA)
DEF_RTL_EXPR(ADDR_VEC, "addr_vec", "E", RTX_EXTRA)
DEF_RTL_EXPR(ADDR_DIFF_VEC, "addr_diff_vec", "eEee0", RTX_EXTRA)
DEF_RTL_EXPR(PREFETCH, "prefetch", "eee", RTX_EXTRA)
DEF_RTL_EXPR(SET, "set", "ee", RTX_EXTRA)
DEF_RTL_EXPR(USE, "use", "e", RTX_EXTRA)
DEF_RTL_EXPR(CLOBBER, "clobber", "e", RTX_EXTRA)
DEF_RTL_EXPR(CALL, "call", "ee", RTX_EXTRA)
DEF_RTL_EXPR(RETURN, "return", "", RTX_EXTRA)
DEF_RTL_EXPR(SIMPLE_RETURN, "simple_return", "", RTX_EXTRA)
DEF_RTL_EXPR(EH_RETURN, "eh_return", "", RTX_EXTRA)
DEF_RTL_EXPR(TRAP_IF, "trap_if", "ee", RTX_EXTRA)
DEF_RTL_EXPR(CONST_INT, "const_int", "w", RTX_CONST_OBJ)
DEF_RTL_EXPR(CONST_WIDE_INT, "const_wide_int", "", RTX_CONST_OBJ)
DEF_RTL_EXPR(CONST_POLY_INT, "const_poly_int", "", RTX_CONST_OBJ)
DEF_RTL_EXPR(CONST_FIXED, "const_fixed", "www", RTX_CONST_OBJ)
DEF_RTL_EXPR(CONST_DOUBLE, "const_double", CONST_DOUBLE_FORMAT, RTX_CONST_OBJ)
DEF_RTL_EXPR(CONST_VECTOR, "const_vector", "E", RTX_CONST_OBJ)
DEF_RTL_EXPR(CONST_STRING, "const_string", "s", RTX_OBJ)
DEF_RTL_EXPR(CONST, "const", "e", RTX_CONST_OBJ)
DEF_RTL_EXPR(PC, "pc", "", RTX_OBJ)
DEF_RTL_EXPR(REG, "reg", "r", RTX_OBJ)
DEF_RTL_EXPR(SCRATCH, "scratch", "", RTX_OBJ)
DEF_RTL_EXPR(SUBREG, "subreg", "ep", RTX_EXTRA)
DEF_RTL_EXPR(STRICT_LOW_PART, "strict_low_part", "e", RTX_EXTRA)
DEF_RTL_EXPR(CONCAT, "concat", "ee", RTX_OBJ)
DEF_RTL_EXPR(CONCATN, "concatn", "E", RTX_OBJ)
DEF_RTL_EXPR(MEM, "mem", "e0", RTX_OBJ)
DEF_RTL_EXPR(LABEL_REF, "label_ref", "u", RTX_CONST_OBJ)
DEF_RTL_EXPR(SYMBOL_REF, "symbol_ref", "s0", RTX_CONST_OBJ)
DEF_RTL_EXPR(IF_THEN_ELSE, "if_then_else", "eee", RTX_TERNARY)
DEF_RTL_EXPR(COMPARE, "compare", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(PLUS, "plus", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(MINUS, "minus", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(NEG, "neg", "e", RTX_UNARY)
DEF_RTL_EXPR(MULT, "mult", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(SS_MULT, "ss_mult", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(US_MULT, "us_mult", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(SMUL_HIGHPART, "smul_highpart", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(UMUL_HIGHPART, "umul_highpart", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(DIV, "div", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(SS_DIV, "ss_div", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(US_DIV, "us_div", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(MOD, "mod", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(UDIV, "udiv", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(UMOD, "umod", "ee", RTX_BIN_ARITH)
DEF_RTL_EXPR(AND, "and", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(IOR, "ior", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(XOR, "xor", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(NOT, "not", "e", RTX_UNARY)
DEF_RTL_EXPR(ASHIFT, "ashift", "ee", RTX_BIN_ARITH) /* shift left */
DEF_RTL_EXPR(ROTATE, "rotate", "ee", RTX_BIN_ARITH) /* rotate left */
DEF_RTL_EXPR(ASHIFTRT, "ashiftrt", "ee", RTX_BIN_ARITH) /* arithmetic shift right */
DEF_RTL_EXPR(LSHIFTRT, "lshiftrt", "ee", RTX_BIN_ARITH) /* logical shift right */
DEF_RTL_EXPR(ROTATERT, "rotatert", "ee", RTX_BIN_ARITH) /* rotate right */
DEF_RTL_EXPR(SMIN, "smin", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(SMAX, "smax", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(UMIN, "umin", "ee", RTX_COMM_ARITH)