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tcg/i386: generates dec/inc instead of sub/add when possible

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We must take care that dec/inc do not compute CF, which is needed by
add2/sub2.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Aurelien Jarno 2009-09-27 19:57:43 +02:00
parent b70650cbfe
commit 17cf428f2e
1 changed files with 15 additions and 9 deletions
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24
tcg/i386/tcg-target.c
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@ -276,9 +276,15 @@ static inline void tcg_out_st(TCGContext *s, TCGType type, int arg,
tcg_out_modrm_offset(s, 0x89, arg, arg1, arg2);
}
static inline void tgen_arithi(TCGContext *s, int c, int r0, int32_t val)
static inline void tgen_arithi(TCGContext *s, int c, int r0, int32_t val, int cf)
{
if (val == (int8_t)val) {
if (!cf && ((c == ARITH_ADD && val == 1) || (c == ARITH_SUB && val == -1))) {
/* inc */
tcg_out_opc(s, 0x40 + r0);
} else if (!cf && ((c == ARITH_ADD && val == -1) || (c == ARITH_SUB && val == 1))) {
/* dec */
tcg_out_opc(s, 0x48 + r0);
} else if (val == (int8_t)val) {
tcg_out_modrm(s, 0x83, c, r0);
tcg_out8(s, val);
} else if (c == ARITH_AND && val == 0xffu && r0 < 4) {
@ -296,7 +302,7 @@ static inline void tgen_arithi(TCGContext *s, int c, int r0, int32_t val)
static void tcg_out_addi(TCGContext *s, int reg, tcg_target_long val)
{
if (val != 0)
tgen_arithi(s, ARITH_ADD, reg, val);
tgen_arithi(s, ARITH_ADD, reg, val, 0);
}
static void tcg_out_jxx(TCGContext *s, int opc, int label_index)
@ -344,7 +350,7 @@ static void tcg_out_brcond(TCGContext *s, int cond,
/* test r, r */
tcg_out_modrm(s, 0x85, arg1, arg1);
} else {
tgen_arithi(s, ARITH_CMP, arg1, arg2);
tgen_arithi(s, ARITH_CMP, arg1, arg2, 0);
}
} else {
tcg_out_modrm(s, 0x01 | (ARITH_CMP << 3), arg2, arg1);
@ -961,7 +967,7 @@ static inline void tcg_out_op(TCGContext *s, int opc,
c = ARITH_ADD;
gen_arith:
if (const_args[2]) {
tgen_arithi(s, c, args[0], args[2]);
tgen_arithi(s, c, args[0], args[2], 0);
} else {
tcg_out_modrm(s, 0x01 | (c << 3), args[2], args[0]);
}
@ -1019,21 +1025,21 @@ static inline void tcg_out_op(TCGContext *s, int opc,
case INDEX_op_add2_i32:
if (const_args[4])
tgen_arithi(s, ARITH_ADD, args[0], args[4]);
tgen_arithi(s, ARITH_ADD, args[0], args[4], 1);
else
tcg_out_modrm(s, 0x01 | (ARITH_ADD << 3), args[4], args[0]);
if (const_args[5])
tgen_arithi(s, ARITH_ADC, args[1], args[5]);
tgen_arithi(s, ARITH_ADC, args[1], args[5], 1);
else
tcg_out_modrm(s, 0x01 | (ARITH_ADC << 3), args[5], args[1]);
break;
case INDEX_op_sub2_i32:
if (const_args[4])
tgen_arithi(s, ARITH_SUB, args[0], args[4]);
tgen_arithi(s, ARITH_SUB, args[0], args[4], 1);
else
tcg_out_modrm(s, 0x01 | (ARITH_SUB << 3), args[4], args[0]);
if (const_args[5])
tgen_arithi(s, ARITH_SBB, args[1], args[5]);
tgen_arithi(s, ARITH_SBB, args[1], args[5], 1);
else
tcg_out_modrm(s, 0x01 | (ARITH_SBB << 3), args[5], args[1]);
break;