Commit ebcfb91a authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg/i386: Use umin/umax in expanding unsigned compare 



Using umin(a, b) == a as an expansion for TCG_COND_LEU is a
better alternative to (a - INT_MIN) <= (b - INT_MIN).

Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
parent 3ec3538a

tcg/i386/tcg-target.inc.c

+61 −19
Original line number Diff line number Diff line
@@ -3468,28 +3468,61 @@ static bool expand_vec_cmp_noinv(TCGType type, unsigned vece, TCGv_vec v0, 
                                 TCGv_vec v1, TCGv_vec v2, TCGCond cond)

{

    enum {

        NEED_SWAP = 1,

        NEED_INV  = 2,

        NEED_BIAS = 4

    };

    static const uint8_t fixups[16] = {

        [0 ... 15] = -1,

        [TCG_COND_EQ] = 0,

        [TCG_COND_NE] = NEED_INV,

        [TCG_COND_GT] = 0,

        [TCG_COND_LT] = NEED_SWAP,

        [TCG_COND_LE] = NEED_INV,

        [TCG_COND_GE] = NEED_SWAP | NEED_INV,

        [TCG_COND_GTU] = NEED_BIAS,

        [TCG_COND_LTU] = NEED_BIAS | NEED_SWAP,

        [TCG_COND_LEU] = NEED_BIAS | NEED_INV,

        [TCG_COND_GEU] = NEED_BIAS | NEED_SWAP | NEED_INV,

        NEED_INV  = 1,

        NEED_SWAP = 2,

        NEED_BIAS = 4,

        NEED_UMIN = 8,

        NEED_UMAX = 16,

    };

    TCGv_vec t1, t2;

    uint8_t fixup;



    fixup = fixups[cond & 15];

    tcg_debug_assert(fixup != 0xff);

    switch (cond) {

    case TCG_COND_EQ:

    case TCG_COND_GT:

        fixup = 0;

        break;

    case TCG_COND_NE:

    case TCG_COND_LE:

        fixup = NEED_INV;

        break;

    case TCG_COND_LT:

        fixup = NEED_SWAP;

        break;

    case TCG_COND_GE:

        fixup = NEED_SWAP | NEED_INV;

        break;

    case TCG_COND_LEU:

        if (vece <= MO_32) {

            fixup = NEED_UMIN;

        } else {

            fixup = NEED_BIAS | NEED_INV;

        }

        break;

    case TCG_COND_GTU:

        if (vece <= MO_32) {

            fixup = NEED_UMIN | NEED_INV;

        } else {

            fixup = NEED_BIAS;

        }

        break;

    case TCG_COND_GEU:

        if (vece <= MO_32) {

            fixup = NEED_UMAX;

        } else {

            fixup = NEED_BIAS | NEED_SWAP | NEED_INV;

        }

        break;

    case TCG_COND_LTU:

        if (vece <= MO_32) {

            fixup = NEED_UMAX | NEED_INV;

        } else {

            fixup = NEED_BIAS | NEED_SWAP;

        }

        break;

    default:

        g_assert_not_reached();

    }



    if (fixup & NEED_INV) {

        cond = tcg_invert_cond(cond);
@@ -3500,7 +3533,16 @@ static bool expand_vec_cmp_noinv(TCGType type, unsigned vece, TCGv_vec v0, 
    }



    t1 = t2 = NULL;

    if (fixup & NEED_BIAS) {

    if (fixup & (NEED_UMIN | NEED_UMAX)) {

        t1 = tcg_temp_new_vec(type);

        if (fixup & NEED_UMIN) {

            tcg_gen_umin_vec(vece, t1, v1, v2);

        } else {

            tcg_gen_umax_vec(vece, t1, v1, v2);

        }

        v2 = t1;

        cond = TCG_COND_EQ;

    } else if (fixup & NEED_BIAS) {

        t1 = tcg_temp_new_vec(type);

        t2 = tcg_temp_new_vec(type);

        tcg_gen_dupi_vec(vece, t2, 1ull << ((8 << vece) - 1));