From 2552d60ebd6c519027d74bd452db7580b90e5cbd Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 14 Sep 2020 19:25:58 -0700 Subject: [PATCH] tcg: Expand usadd/ussub with umin/umax For usadd, we only have to consider overflow. Since ~B + B == -1, the maximum value for A that saturates is ~B. For ussub, we only have to consider underflow. The minimum value that saturates to 0 from A - B is B. Signed-off-by: Richard Henderson --- tcg/tcg-op-vec.c | 37 +++++++++++++++++++++++++++++++++++-- 1 file changed, 35 insertions(+), 2 deletions(-) diff --git a/tcg/tcg-op-vec.c b/tcg/tcg-op-vec.c index 15e026ae49..faf30f9cdd 100644 --- a/tcg/tcg-op-vec.c +++ b/tcg/tcg-op-vec.c @@ -119,6 +119,18 @@ bool tcg_can_emit_vecop_list(const TCGOpcode *list, continue; } break; + case INDEX_op_usadd_vec: + if (tcg_can_emit_vec_op(INDEX_op_umin_vec, type, vece) || + tcg_can_emit_vec_op(INDEX_op_cmp_vec, type, vece)) { + continue; + } + break; + case INDEX_op_ussub_vec: + if (tcg_can_emit_vec_op(INDEX_op_umax_vec, type, vece) || + tcg_can_emit_vec_op(INDEX_op_cmp_vec, type, vece)) { + continue; + } + break; case INDEX_op_cmpsel_vec: case INDEX_op_smin_vec: case INDEX_op_smax_vec: @@ -603,7 +615,18 @@ void tcg_gen_ssadd_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b) void tcg_gen_usadd_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b) { - do_op3_nofail(vece, r, a, b, INDEX_op_usadd_vec); + if (!do_op3(vece, r, a, b, INDEX_op_usadd_vec)) { + const TCGOpcode *hold_list = tcg_swap_vecop_list(NULL); + TCGv_vec t = tcg_temp_new_vec_matching(r); + + /* usadd(a, b) = min(a, ~b) + b */ + tcg_gen_not_vec(vece, t, b); + tcg_gen_umin_vec(vece, t, t, a); + tcg_gen_add_vec(vece, r, t, b); + + tcg_temp_free_vec(t); + tcg_swap_vecop_list(hold_list); + } } void tcg_gen_sssub_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b) @@ -613,7 +636,17 @@ void tcg_gen_sssub_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b) void tcg_gen_ussub_vec(unsigned vece, TCGv_vec r, TCGv_vec a, TCGv_vec b) { - do_op3_nofail(vece, r, a, b, INDEX_op_ussub_vec); + if (!do_op3(vece, r, a, b, INDEX_op_ussub_vec)) { + const TCGOpcode *hold_list = tcg_swap_vecop_list(NULL); + TCGv_vec t = tcg_temp_new_vec_matching(r); + + /* ussub(a, b) = max(a, b) - b */ + tcg_gen_umax_vec(vece, t, a, b); + tcg_gen_sub_vec(vece, r, t, b); + + tcg_temp_free_vec(t); + tcg_swap_vecop_list(hold_list); + } } static void do_minmax(unsigned vece, TCGv_vec r, TCGv_vec a,