roy rosen <roy.1ro...@gmail.com> writes: > 2011/3/24 Ian Lance Taylor <i...@google.com>: >> roy rosen <roy.1ro...@gmail.com> writes: >> >>>> You build a RECORD_TYPE holding the fields you want to return. You >>>> define the appropriate builtin functions to return that record type. >>> >>> How is that done? using define_insn? How do I tell it to return a struct? >>> Is there an example I can look at? >> >> A RECORD_TYPE is what gcc generates when you define a struct in your >> source code. For an example of a backend building a struct, see, e.g., >> ix86_build_builtin_va_list_abi. >> >> When you define your builtin functions in TARGET_INIT_BUILTINS you >> specify the argument types and the return type, typically by building a >> FUNCTION_TYPE and passing it to add_builtin_function. To define a >> builtin which returns a struct, just arrange for the return type of the >> FUNCTION_TYPE that you pass to add_builtin_function be the RECORD_TYPE >> that you built. > > I understood this part. > What I don't understand is: > In addition to adding the builtin function, in the md file I have a > define_insn for each built in, for example: > > (define_insn "A_ssodssxx2w" > [(set (match_operand:SI 0 "register_operand" "=d ") > (unspec:SI [(match_operand:SI 1 "register_operand" "d ") > (match_operand:SI 2 "register_operand" "d ")] > UNSPEC_A_SSODSSXX2W))] > "" > "ssodssxx.2w %2,%1,%0 %!" > ) > > How do I create something equivalent which would have an rtl set > expression to the structure.
At the RTL level the structure doesn't matter. Your instruction presumably sets some registers. A register is just a register, it doesn't have a type. In TARGET_EXPAND_BUILTIN you need to pick up the two registers and assemble them into a PARALLEL. You're going to build REGs to pass to the insn pattern. Then do something along the lines of: ret0 = gen_rtx_EXPR_LIST (VOIDmode, reg0, const0_rtx); ret1 = gen_rtx_EXPR_LIST (VOIDmode, reg1, const1_rtx); ret = gen_rtx_PARALLEL (??mode, gen_rtvec (2, reg0, reg1)); tree nt = build_qualified_type (struct_type, TYPE_QUAL_CONST); target = assign_temp (nt, 0, 0, 1); emit_group_store (target, ret, struct_type, ??); Ian
