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tcg: Do constant folding on double-word comparisons 

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
master
Richard Henderson 2012-10-02 11:32:27 -07:00 committed by Aurelien Jarno
parent 9519da7e39
commit 6c4382f8f4
1 changed files with 72 additions and 21 deletions
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93
tcg/optimize.c
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@ -398,6 +398,40 @@ static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
}
}
/* Return 2 if the condition can't be simplified, and the result
of the condition (0 or 1) if it can */
static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c)
{
TCGArg al = p1[0], ah = p1[1];
TCGArg bl = p2[0], bh = p2[1];
if (temps[bl].state == TCG_TEMP_CONST
&& temps[bh].state == TCG_TEMP_CONST) {
uint64_t b = ((uint64_t)temps[bh].val << 32) | (uint32_t)temps[bl].val;
if (temps[al].state == TCG_TEMP_CONST
&& temps[ah].state == TCG_TEMP_CONST) {
uint64_t a;
a = ((uint64_t)temps[ah].val << 32) | (uint32_t)temps[al].val;
return do_constant_folding_cond_64(a, b, c);
}
if (b == 0) {
switch (c) {
case TCG_COND_LTU:
return 0;
case TCG_COND_GEU:
return 1;
default:
break;
}
}
}
if (temps_are_copies(al, bl) && temps_are_copies(ah, bh)) {
return do_constant_folding_cond_eq(c);
}
return 2;
}
static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
{
TCGArg a1 = *p1, a2 = *p2;
@ -763,43 +797,60 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
goto do_default;
case INDEX_op_brcond2_i32:
/* Simplify LT/GE comparisons vs zero to a single compare
vs the high word of the input. */
if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE)
&& temps[args[2]].state == TCG_TEMP_CONST
&& temps[args[3]].state == TCG_TEMP_CONST
&& temps[args[2]].val == 0
&& temps[args[3]].val == 0) {
tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]);
if (tmp != 2) {
if (tmp) {
memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
gen_opc_buf[op_index] = INDEX_op_br;
gen_args[0] = args[5];
gen_args += 1;
} else {
gen_opc_buf[op_index] = INDEX_op_nop;
}
} else if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE)
&& temps[args[2]].state == TCG_TEMP_CONST
&& temps[args[3]].state == TCG_TEMP_CONST
&& temps[args[2]].val == 0
&& temps[args[3]].val == 0) {
/* Simplify LT/GE comparisons vs zero to a single compare
vs the high word of the input. */
memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
gen_opc_buf[op_index] = INDEX_op_brcond_i32;
gen_args[0] = args[1];
gen_args[1] = args[3];
gen_args[2] = args[4];
gen_args[3] = args[5];
gen_args += 4;
args += 6;
memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
break;
} else {
goto do_default;
}
goto do_default;
args += 6;
break;
case INDEX_op_setcond2_i32:
/* Simplify LT/GE comparisons vs zero to a single compare
vs the high word of the input. */
if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE)
&& temps[args[3]].state == TCG_TEMP_CONST
&& temps[args[4]].state == TCG_TEMP_CONST
&& temps[args[3]].val == 0
&& temps[args[4]].val == 0) {
tmp = do_constant_folding_cond2(&args[1], &args[3], args[5]);
if (tmp != 2) {
gen_opc_buf[op_index] = INDEX_op_movi_i32;
tcg_opt_gen_movi(gen_args, args[0], tmp);
gen_args += 2;
} else if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE)
&& temps[args[3]].state == TCG_TEMP_CONST
&& temps[args[4]].state == TCG_TEMP_CONST
&& temps[args[3]].val == 0
&& temps[args[4]].val == 0) {
/* Simplify LT/GE comparisons vs zero to a single compare
vs the high word of the input. */
gen_opc_buf[op_index] = INDEX_op_setcond_i32;
gen_args[0] = args[0];
gen_args[1] = args[2];
gen_args[2] = args[4];
gen_args[3] = args[5];
gen_args += 4;
args += 6;
break;
} else {
goto do_default;
}
goto do_default;
args += 6;
break;
case INDEX_op_call:
nb_call_args = (args[0] >> 16) + (args[0] & 0xffff);