Re: [PATCH v4 1/5] tcg/sparc: Add scratch argument to tcg_out_movi_int

[Peter Maydell]

On Fri, 4 Feb 2022 at 07:53, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> This will allow us to control exactly what scratch register is
> used for loading the constant.  Also, fix a theoretical problem
> in recursing through tcg_out_movi, which may provide a different
> value for in_prologue.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  tcg/sparc/tcg-target.c.inc | 20 ++++++++++++--------
>  1 file changed, 12 insertions(+), 8 deletions(-)

>  static void tcg_out_movi(TCGContext *s, TCGType type,
>                           TCGReg ret, tcg_target_long arg)
>  {
> -    tcg_out_movi_int(s, type, ret, arg, false);
> +    tcg_debug_assert(ret != TCG_REG_T2);
> +    tcg_out_movi_int(s, type, ret, arg, false, TCG_REG_T2);

Here we assert that 'ret' isn't TCG_REG_T2, but in
tcg_out_addsub2_i64() we do:

           tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_T2, bh);
and
           tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_T2, bh + (is_sub ? -1 : 1));

Otherwise looks OK.

thanks
-- PMM