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

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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: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2019-04-30 20:45:16 -07:00
parent 3ec3538a45
commit ebcfb91abe
1 changed files with 61 additions and 19 deletions
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80
tcg/i386/tcg-target.inc.c
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@ -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));