[04/10] tcg: Use common code when failing to optimize

This saves a whole lot of repetitive code sequences.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 tcg/optimize.c | 91 +++++++++++++++++++++-------------------------------------
 1 file changed, 32 insertions(+), 59 deletions(-)

On Tue, Oct 02, 2012 at 11:32:24AM -0700, Richard Henderson wrote:
> This saves a whole lot of repetitive code sequences.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/optimize.c | 91 +++++++++++++++++++++-------------------------------------
>  1 file changed, 32 insertions(+), 59 deletions(-)
> 
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index a713513..592d166 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -639,6 +639,7 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>              gen_args += 2;
>              args += 2;
>              break;
> +

Why this new line?

>          CASE_OP_32_64(not):
>          CASE_OP_32_64(neg):
>          CASE_OP_32_64(ext8s):
> @@ -651,14 +652,12 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                  gen_opc_buf[op_index] = op_to_movi(op);
>                  tmp = do_constant_folding(op, temps[args[1]].val, 0);
>                  tcg_opt_gen_movi(gen_args, args[0], tmp);
> -            } else {
> -                reset_temp(args[0]);
> -                gen_args[0] = args[0];
> -                gen_args[1] = args[1];
> +                gen_args += 2;
> +                args += 2;
> +                break;
>              }
> -            gen_args += 2;
> -            args += 2;
> -            break;
> +            goto do_default;
> +
>          CASE_OP_32_64(add):
>          CASE_OP_32_64(sub):
>          CASE_OP_32_64(mul):
> @@ -682,15 +681,11 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                                            temps[args[2]].val);
>                  tcg_opt_gen_movi(gen_args, args[0], tmp);
>                  gen_args += 2;
> -            } else {
> -                reset_temp(args[0]);
> -                gen_args[0] = args[0];
> -                gen_args[1] = args[1];
> -                gen_args[2] = args[2];
> -                gen_args += 3;
> +                args += 3;
> +                break;
>              }
> -            args += 3;
> -            break;
> +            goto do_default;
> +
>          CASE_OP_32_64(deposit):
>              if (temps[args[1]].state == TCG_TEMP_CONST
>                  && temps[args[2]].state == TCG_TEMP_CONST) {
> @@ -700,33 +695,22 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                        | ((temps[args[2]].val & tmp) << args[3]);
>                  tcg_opt_gen_movi(gen_args, args[0], tmp);
>                  gen_args += 2;
> -            } else {
> -                reset_temp(args[0]);
> -                gen_args[0] = args[0];
> -                gen_args[1] = args[1];
> -                gen_args[2] = args[2];
> -                gen_args[3] = args[3];
> -                gen_args[4] = args[4];
> -                gen_args += 5;
> +                args += 5;
> +                break;
>              }
> -            args += 5;
> -            break;
> +            goto do_default;
> +
>          CASE_OP_32_64(setcond):
>              tmp = do_constant_folding_cond(op, args[1], args[2], args[3]);
>              if (tmp != 2) {
>                  gen_opc_buf[op_index] = op_to_movi(op);
>                  tcg_opt_gen_movi(gen_args, args[0], tmp);
>                  gen_args += 2;
> -            } else {
> -                reset_temp(args[0]);
> -                gen_args[0] = args[0];
> -                gen_args[1] = args[1];
> -                gen_args[2] = args[2];
> -                gen_args[3] = args[3];
> -                gen_args += 4;
> +                args += 4;
> +                break;
>              }
> -            args += 4;
> -            break;
> +            goto do_default;
> +
>          CASE_OP_32_64(brcond):
>              tmp = do_constant_folding_cond(op, args[0], args[1], args[2]);
>              if (tmp != 2) {
> @@ -738,17 +722,11 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                  } else {
>                      gen_opc_buf[op_index] = INDEX_op_nop;
>                  }
> -            } else {
> -                memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
> -                reset_temp(args[0]);
> -                gen_args[0] = args[0];
> -                gen_args[1] = args[1];
> -                gen_args[2] = args[2];
> -                gen_args[3] = args[3];
> -                gen_args += 4;
> +                args += 4;
> +                break;
>              }
> -            args += 4;
> -            break;
> +            goto do_default;
> +
>          CASE_OP_32_64(movcond):
>              tmp = do_constant_folding_cond(op, args[1], args[2], args[5]);
>              if (tmp != 2) {
> @@ -763,18 +741,11 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                      tcg_opt_gen_mov(s, gen_args, args[0], args[4-tmp]);
>                      gen_args += 2;
>                  }
> -            } else {
> -                reset_temp(args[0]);
> -                gen_args[0] = args[0];
> -                gen_args[1] = args[1];
> -                gen_args[2] = args[2];
> -                gen_args[3] = args[3];
> -                gen_args[4] = args[4];
> -                gen_args[5] = args[5];
> -                gen_args += 6;
> +                args += 6;
> +                break;
>              }
> -            args += 6;
> -            break;
> +            goto do_default;
> +
>          case INDEX_op_call:
>              nb_call_args = (args[0] >> 16) + (args[0] & 0xffff);
>              if (!(args[nb_call_args + 1] & (TCG_CALL_CONST | TCG_CALL_PURE))) {
> @@ -793,11 +764,13 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                  i--;
>              }
>              break;
> +
>          default:
> -            /* Default case: we do know nothing about operation so no
> -               propagation is done.  We trash everything if the operation
> -               is the end of a basic block, otherwise we only trash the
> -               output args.  */
> +        do_default:
> +            /* Default case: we know nothing about operation (or were unable
> +               to compute the operation result) so no propagation is done.
> +               We trash everything if the operation is the end of a basic
> +               block, otherwise we only trash the output args.  */
>              if (def->flags & TCG_OPF_BB_END) {
>                  memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
>              } else {

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>

On 10/09/2012 08:25 AM, Aurelien Jarno wrote:
>> > @@ -639,6 +639,7 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>> >              gen_args += 2;
>> >              args += 2;
>> >              break;
>> > +
> Why this new line?
> 

After the patch, all of the CASE blocks have a separator line.
It looked weird to have that be true of all but one case block
within that switch.


r~