Re: how to use emit_clobber () ?

[William Tambe <tambewilliam@gmail.com>]

Correcting typo in my previous email.

On Sat, Apr 25, 2020 at 3:21 PM William Tambe <tambewilliam@gmail.com> wrote:
>
> The following define_expand is used to generate a call to
> __tls_get_addr() when the first operand of movsi is detected as a TLS
> symbol by tls_symbol_operand().
>
> I am trying to accomplish generating a call to __tls_get_addr()
> passing two arguments in two registers where I would like to clobber
> the first register argument.
>
> However the use of emit_clobber() has no effect.
>
> Any idea, how emit_clobber should be used below ?
>
> (define_expand "movsi"
>  [(set (match_operand:SI 0 "nonimmediate_operand" "")
>        (match_operand:SI 1 "general_operand"      ""))]
>  ""
>  {
>    rtx op0 = operands[0];
>    rtx op1 = operands[1];
>    if (tls_symbolic_operand (op0, VOIDmode)) {
>      rtx arg0 = gen_rtx_REG (SImode, ARCH_FIRST_ARG_REGNUM);
>      rtx arg1 = gen_rtx_REG (SImode, ARCH_FIRST_ARG_REGNUM+1);
>      emit_insn (arg1);
>      emit_clobber (gen__movsi (arg0, op0));

Above is incorrect; what I am using is below:
     emit_clobber (arg1);
     emit_insn (gen__movsi (arg0, op0));

Question remain the same; any idea how emit_clobber should be used in
order to have an effect ?

>      rtx fn = gen_rtx_MEM (FUNCTION_MODE, gen_arch_tga());
>      rtx_insn *insn = emit_call_insn (gen_call_value (arg0, fn, const0_rtx));
>      RTL_CONST_CALL_P (insn) = 1;
>      use_reg (&CALL_INSN_FUNCTION_USAGE (insn), arg0);
>      use_reg (&CALL_INSN_FUNCTION_USAGE (insn), arg1);
>      if (GET_CODE (op0) == MEM)
>        arg0 = gen_rtx_MEM (SImode, arg0);
>      operands[0] = arg0;
>    }
>    emit_insn (gen__movsi (operands[0], operands[1]));
>    DONE;
>  })