Re: [Qemu-devel] [PATCH v3 3/8] target-sh4: optimize addc using add2

[Richard Henderson <rth@twiddle.net>]

On 05/24/2015 04:37 PM, Aurelien Jarno wrote:
> -            TCGv t0, t1;
> -            t0 = tcg_temp_new();
> +            TCGv t0, t1, t2;
> +            t0 = tcg_const_tl(0);
>               t1 = tcg_temp_new();
> -            tcg_gen_add_i32(t0, REG(B7_4), REG(B11_8));
> -            tcg_gen_add_i32(t1, cpu_sr_t, t0);
> -            tcg_gen_setcond_i32(TCG_COND_GTU, cpu_sr_t, REG(B11_8), t0);
> -            tcg_gen_setcond_i32(TCG_COND_GTU, t0, t0, t1);
> -            tcg_gen_or_i32(cpu_sr_t, cpu_sr_t, t0);
> +            t2 = tcg_temp_new();
> +            tcg_gen_add2_i32(t1, t2, REG(B11_8), t0, REG(B7_4), t0);
> +            tcg_gen_add2_i32(REG(B11_8), cpu_sr_t, t1, t2, cpu_sr_t, t0);

Swap these two adds and you don't need t2.  You can consume sr_t immediately 
and start producing it in the same go.


r~