Re: [PATCH v2 17/36] tcg/optimize: Adjust TempOptInfo allocation

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> Do not allocate a large block for indexing.  Instead, allocate
> for each temporary as they are seen.
>
> In general, this will use less memory, if we consider that most
> TBs do not touch every target register.  This also allows us to
> allocate TempOptInfo for new temps created during optimization.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  tcg/optimize.c | 60 ++++++++++++++++++++++++++++----------------------
>  1 file changed, 34 insertions(+), 26 deletions(-)
>
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index b86bf3d707..d36d7e1d7f 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -89,35 +89,41 @@ static void reset_temp(TCGArg arg)
>  }
>  
>  /* Initialize and activate a temporary.  */
> -static void init_ts_info(TempOptInfo *infos,
> -                         TCGTempSet *temps_used, TCGTemp *ts)
> +static void init_ts_info(TCGTempSet *temps_used, TCGTemp *ts)
>  {
>      size_t idx = temp_idx(ts);
> -    if (!test_bit(idx, temps_used->l)) {
> -        TempOptInfo *ti = &infos[idx];
> +    TempOptInfo *ti;
>  
> +    if (test_bit(idx, temps_used->l)) {
> +        return;
> +    }
> +    set_bit(idx, temps_used->l);
> +
> +    ti = ts->state_ptr;
> +    if (ti == NULL) {
> +        ti = tcg_malloc(sizeof(TempOptInfo));
>          ts->state_ptr = ti;
> -        ti->next_copy = ts;
> -        ti->prev_copy = ts;
> -        if (ts->kind == TEMP_CONST) {
> -            ti->is_const = true;
> -            ti->val = ti->mask = ts->val;
> -            if (TCG_TARGET_REG_BITS > 32 && ts->type == TCG_TYPE_I32) {
> -                /* High bits of a 32-bit quantity are garbage.  */
> -                ti->mask |= ~0xffffffffull;
> -            }
> -        } else {
> -            ti->is_const = false;
> -            ti->mask = -1;
> +    }
> +
> +    ti->next_copy = ts;
> +    ti->prev_copy = ts;
> +    if (ts->kind == TEMP_CONST) {
> +        ti->is_const = true;
> +        ti->val = ts->val;
> +        ti->mask = ts->val;
> +        if (TCG_TARGET_REG_BITS > 32 && ts->type == TCG_TYPE_I32) {
> +            /* High bits of a 32-bit quantity are garbage.  */
> +            ti->mask |= ~0xffffffffull;
>          }
> -        set_bit(idx, temps_used->l);
> +    } else {
> +        ti->is_const = false;
> +        ti->mask = -1;
>      }
>  }
>  
> -static void init_arg_info(TempOptInfo *infos,
> -                          TCGTempSet *temps_used, TCGArg arg)
> +static void init_arg_info(TCGTempSet *temps_used, TCGArg arg)
>  {
> -    init_ts_info(infos, temps_used, arg_temp(arg));
> +    init_ts_info(temps_used, arg_temp(arg));
>  }
>  
>  static TCGTemp *find_better_copy(TCGContext *s, TCGTemp *ts)
> @@ -603,9 +609,8 @@ static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
>  /* Propagate constants and copies, fold constant expressions. */
>  void tcg_optimize(TCGContext *s)
>  {
> -    int nb_temps, nb_globals;
> +    int nb_temps, nb_globals, i;
>      TCGOp *op, *op_next, *prev_mb = NULL;
> -    TempOptInfo *infos;
>      TCGTempSet temps_used;
>  
>      /* Array VALS has an element for each temp.
> @@ -615,12 +620,15 @@ void tcg_optimize(TCGContext *s)
>  
>      nb_temps = s->nb_temps;
>      nb_globals = s->nb_globals;
> +
>      bitmap_zero(temps_used.l, nb_temps);
> -    infos = tcg_malloc(sizeof(TempOptInfo) * nb_temps);
> +    for (i = 0; i < nb_temps; ++i) {
> +        s->temps[i].state_ptr = NULL;
> +    }
>  
>      QTAILQ_FOREACH_SAFE(op, &s->ops, link, op_next) {
>          tcg_target_ulong mask, partmask, affected;
> -        int nb_oargs, nb_iargs, i;
> +        int nb_oargs, nb_iargs;
>          TCGArg tmp;
>          TCGOpcode opc = op->opc;
>          const TCGOpDef *def = &tcg_op_defs[opc];
> @@ -633,14 +641,14 @@ void tcg_optimize(TCGContext *s)
>              for (i = 0; i < nb_oargs + nb_iargs; i++) {
>                  TCGTemp *ts = arg_temp(op->args[i]);
>                  if (ts) {
> -                    init_ts_info(infos, &temps_used, ts);
> +                    init_ts_info(&temps_used, ts);
>                  }
>              }
>          } else {
>              nb_oargs = def->nb_oargs;
>              nb_iargs = def->nb_iargs;
>              for (i = 0; i < nb_oargs + nb_iargs; i++) {
> -                init_arg_info(infos, &temps_used, op->args[i]);
> +                init_arg_info(&temps_used, op->args[i]);
>              }
>          }


-- 
Alex Bennée