http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59968
--- Comment #16 from H.J. Lu <hjl.tools at gmail dot com> --- I couldn't get GCC to use those BT patterns: (define_insn "*btsq" [(set (zero_extract:DI (match_operand:DI 0 "register_operand" "+r") (const_int 1) (match_operand:DI 1 "const_0_to_63_operand")) (const_int 1)) (clobber (reg:CC FLAGS_REG))] "TARGET_64BIT && (TARGET_USE_BT || reload_completed)" "bts{q}\t{%1, %0|%0, %1}" [(set_attr "type" "alu1") (set_attr "prefix_0f" "1") (set_attr "mode" "DI")]) (define_insn "*btrq" [(set (zero_extract:DI (match_operand:DI 0 "register_operand" "+r") (const_int 1) (match_operand:DI 1 "const_0_to_63_operand")) (const_int 0)) (clobber (reg:CC FLAGS_REG))] "TARGET_64BIT && (TARGET_USE_BT || reload_completed)" "btr{q}\t{%1, %0|%0, %1}" [(set_attr "type" "alu1") (set_attr "prefix_0f" "1") (set_attr "mode" "DI")]) (define_insn "*btcq" [(set (zero_extract:DI (match_operand:DI 0 "register_operand" "+r") (const_int 1) (match_operand:DI 1 "const_0_to_63_operand")) (not:DI (zero_extract:DI (match_dup 0) (const_int 1) (match_dup 1)))) (clobber (reg:CC FLAGS_REG))] "TARGET_64BIT && (TARGET_USE_BT || reload_completed)" "btc{q}\t{%1, %0|%0, %1}" [(set_attr "type" "alu1") (set_attr "prefix_0f" "1") (set_attr "mode" "DI")])