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tcg-arm: Handle negated constant arguments to and/sub

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This greatly improves code generation for addition of small
negative constants.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2013-03-04 22:06:21 -08:00 committed by Aurelien Jarno
parent 19b62bf414
commit a9a86ae95d
1 changed files with 35 additions and 6 deletions
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41
tcg/arm/tcg-target.c
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@ -147,6 +147,7 @@ static void patch_reloc(uint8_t *code_ptr, int type,
#define TCG_CT_CONST_ARM 0x100
#define TCG_CT_CONST_INV 0x200
#define TCG_CT_CONST_NEG 0x400
/* parse target specific constraints */
static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
@ -161,6 +162,9 @@ static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
case 'K':
ct->ct |= TCG_CT_CONST_INV;
break;
case 'N': /* The gcc constraint letter is L, already used here. */
ct->ct |= TCG_CT_CONST_NEG;
break;
case 'r':
ct->ct |= TCG_CT_REG;
@ -291,6 +295,8 @@ static inline int tcg_target_const_match(tcg_target_long val,
return 1;
} else if ((ct & TCG_CT_CONST_INV) && check_fit_imm(~val)) {
return 1;
} else if ((ct & TCG_CT_CONST_NEG) && check_fit_imm(-val)) {
return 1;
} else {
return 0;
}
@ -512,6 +518,27 @@ static void tcg_out_dat_rIK(TCGContext *s, int cond, int opc, int opinv,
}
}
static void tcg_out_dat_rIN(TCGContext *s, int cond, int opc, int opneg,
TCGArg dst, TCGArg lhs, TCGArg rhs,
bool rhs_is_const)
{
/* Emit either the reg,imm or reg,reg form of a data-processing insn.
* rhs must satisfy the "rIN" constraint.
*/
if (rhs_is_const) {
int rot = encode_imm(rhs);
if (rot < 0) {
rhs = -rhs;
rot = encode_imm(rhs);
assert(rot >= 0);
opc = opneg;
}
tcg_out_dat_imm(s, cond, opc, dst, lhs, rotl(rhs, rot) | (rot << 7));
} else {
tcg_out_dat_reg(s, cond, opc, dst, lhs, rhs, SHIFT_IMM_LSL(0));
}
}
static inline void tcg_out_mul32(TCGContext *s,
int cond, int rd, int rs, int rm)
{
@ -1594,11 +1621,13 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
ARITH_MOV, args[0], 0, args[3], const_args[3]);
break;
case INDEX_op_add_i32:
c = ARITH_ADD;
goto gen_arith;
tcg_out_dat_rIN(s, COND_AL, ARITH_ADD, ARITH_SUB,
args[0], args[1], args[2], const_args[2]);
break;
case INDEX_op_sub_i32:
c = ARITH_SUB;
goto gen_arith;
tcg_out_dat_rIN(s, COND_AL, ARITH_SUB, ARITH_ADD,
args[0], args[1], args[2], const_args[2]);
break;
case INDEX_op_and_i32:
tcg_out_dat_rIK(s, COND_AL, ARITH_AND, ARITH_BIC,
args[0], args[1], args[2], const_args[2]);
@ -1789,8 +1818,8 @@ static const TCGTargetOpDef arm_op_defs[] = {
{ INDEX_op_st_i32, { "r", "r" } },
/* TODO: "r", "r", "ri" */
{ INDEX_op_add_i32, { "r", "r", "rI" } },
{ INDEX_op_sub_i32, { "r", "r", "rI" } },
{ INDEX_op_add_i32, { "r", "r", "rIN" } },
{ INDEX_op_sub_i32, { "r", "r", "rIN" } },
{ INDEX_op_mul_i32, { "r", "r", "r" } },
{ INDEX_op_mulu2_i32, { "r", "r", "r", "r" } },
{ INDEX_op_muls2_i32, { "r", "r", "r", "r" } },