Re: [Qemu-devel] [PATCH 6/8] tcg/optimize: Simply some logical ops to NOT

[Aurelien Jarno <aurelien@aurel32.net>]

On Fri, Jan 31, 2014 at 08:47:01AM -0600, Richard Henderson wrote:
> Given, of course, an appropriate constant.  These could be generated
> from the "canonical" operation for inversion on the guest, or via
> other optimizations.
> 
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> ---
>  tcg/optimize.c | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
> 
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index 3291a08..cdfc746 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -655,6 +655,63 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
>                  }
>              }
>              break;
> +        CASE_OP_32_64(xor):
> +        CASE_OP_32_64(nand):
> +            if (temps[args[1]].state != TCG_TEMP_CONST
> +                && temps[args[2]].state == TCG_TEMP_CONST
> +                && temps[args[2]].val == -1) {
> +                i = 1;
> +                goto try_not;
> +            }
> +            break;
> +        CASE_OP_32_64(nor):
> +            if (temps[args[1]].state != TCG_TEMP_CONST
> +                && temps[args[2]].state == TCG_TEMP_CONST
> +                && temps[args[2]].val == 0) {
> +                i = 1;
> +                goto try_not;
> +            }
> +            break;
> +        CASE_OP_32_64(andc):
> +            if (temps[args[2]].state != TCG_TEMP_CONST
> +                && temps[args[1]].state == TCG_TEMP_CONST
> +                && temps[args[1]].val == -1) {
> +                i = 2;
> +                goto try_not;
> +            }
> +            break;
> +        CASE_OP_32_64(orc):
> +        CASE_OP_32_64(eqv):
> +            if (temps[args[2]].state != TCG_TEMP_CONST
> +                && temps[args[1]].state == TCG_TEMP_CONST
> +                && temps[args[1]].val == 0) {
> +                i = 2;
> +                goto try_not;
> +            }
> +            break;
> +        try_not:
> +            {
> +                TCGOpcode not_op;
> +                bool have_not;
> +
> +                if (def->flags & TCG_OPF_64BIT) {
> +                    not_op = INDEX_op_not_i64;
> +                    have_not = TCG_TARGET_HAS_not_i64;
> +                } else {
> +                    not_op = INDEX_op_not_i32;
> +                    have_not = TCG_TARGET_HAS_not_i32;
> +                }
> +                if (!have_not) {
> +                    break;
> +                }
> +                s->gen_opc_buf[op_index] = not_op;
> +                reset_temp(args[0]);
> +                gen_args[0] = args[0];
> +                gen_args[1] = args[i];
> +                args += 3;
> +                gen_args += 2;
> +                continue;
> +            }
>          default:
>              break;
>          }

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

-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net