On Tue, Oct 02, 2012 at 11:32:30AM -0700, Richard Henderson wrote:
> Like add2, do operand ordering, constant folding, and dead operand
> elimination. The latter happens about 15% of all mulu2 during an
> x86_64 bios boot.
>
> Signed-off-by: Richard Henderson <r...@twiddle.net>
> ---
> tcg/optimize.c | 26 ++++++++++++++++++++++++++
> tcg/tcg-op.h | 2 ++
> tcg/tcg.c | 19 +++++++++++++++++++
> 3 files changed, 47 insertions(+)
>
> diff --git a/tcg/optimize.c b/tcg/optimize.c
> index 05891ef..a06c8eb 100644
> --- a/tcg/optimize.c
> +++ b/tcg/optimize.c
> @@ -543,6 +543,9 @@ static TCGArg *tcg_constant_folding(TCGContext *s,
> uint16_t *tcg_opc_ptr,
> swap_commutative(args[0], &args[2], &args[4]);
> swap_commutative(args[1], &args[3], &args[5]);
> break;
> + case INDEX_op_mulu2_i32:
> + swap_commutative(args[0], &args[2], &args[3]);
> + break;
> case INDEX_op_brcond2_i32:
> if (swap_commutative2(&args[0], &args[2])) {
> args[4] = tcg_swap_cond(args[4]);
> @@ -831,6 +834,29 @@ static TCGArg *tcg_constant_folding(TCGContext *s,
> uint16_t *tcg_opc_ptr,
> }
> goto do_default;
>
> + case INDEX_op_mulu2_i32:
> + if (temps[args[2]].state == TCG_TEMP_CONST
> + && temps[args[3]].state == TCG_TEMP_CONST) {
> + uint32_t a = temps[args[2]].val;
> + uint32_t b = temps[args[3]].val;
> + uint64_t r = (uint64_t)a * b;
> + TCGArg rl, rh;
> +
> + /* We emit the extra nop when we emit the mulu2. */
> + assert(gen_opc_buf[op_index + 1] == INDEX_op_nop);
> +
> + rl = args[0];
> + rh = args[1];
> + gen_opc_buf[op_index] = INDEX_op_movi_i32;
> + gen_opc_buf[++op_index] = INDEX_op_movi_i32;
> + tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)r);
> + tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(r >> 32));
> + gen_args += 4;
> + args += 4;
> + break;
> + }
> + goto do_default;
> +
> case INDEX_op_brcond2_i32:
> tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]);
> if (tmp != 2) {
> diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
> index 1f5a021..044e648 100644
> --- a/tcg/tcg-op.h
> +++ b/tcg/tcg-op.h
> @@ -997,6 +997,8 @@ static inline void tcg_gen_mul_i64(TCGv_i64 ret, TCGv_i64
> arg1, TCGv_i64 arg2)
>
> tcg_gen_op4_i32(INDEX_op_mulu2_i32, TCGV_LOW(t0), TCGV_HIGH(t0),
> TCGV_LOW(arg1), TCGV_LOW(arg2));
> + /* Allow the optimizer room to replace mulu2 with two moves. */
> + tcg_gen_op0(INDEX_op_nop);
>
> tcg_gen_mul_i32(t1, TCGV_LOW(arg1), TCGV_HIGH(arg2));
> tcg_gen_add_i32(TCGV_HIGH(t0), TCGV_HIGH(t0), t1);
> diff --git a/tcg/tcg.c b/tcg/tcg.c
> index 21c1074..8280489 100644
> --- a/tcg/tcg.c
> +++ b/tcg/tcg.c
> @@ -1337,6 +1337,25 @@ static void tcg_liveness_analysis(TCGContext *s)
> }
> goto do_not_remove;
>
> + case INDEX_op_mulu2_i32:
> + args -= 4;
> + nb_iargs = 2;
> + nb_oargs = 2;
> + /* Likewise, test for the high part of the operation dead. */
> + if (dead_temps[args[1]]) {
> + if (dead_temps[args[0]]) {
> + goto do_remove;
> + }
> + gen_opc_buf[op_index] = op = INDEX_op_mul_i32;
Very minor nitpick: you probably don't need to set op there.
> + args[1] = args[2];
> + args[2] = args[3];
> + assert(gen_opc_buf[op_index + 1] == INDEX_op_nop);
> + tcg_set_nop(s, gen_opc_buf + op_index + 1, args + 3, 1);
> + /* Fall through and mark the single-word operation live. */
> + nb_oargs = 1;
> + }
> + goto do_not_remove;
> +
> default:
> /* XXX: optimize by hardcoding common cases (e.g. triadic ops) */
> args -= def->nb_args;
Reviewed-by: Aurelien Jarno <aurel...@aurel32.net>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurel...@aurel32.net http://www.aurel32.net
