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qemu/tcg/optimize.c
Richard Henderson cd0372c515 tcg/optimize: Flush data at labels not TCG_OPF_BB_END 
We can easily propagate temp values through the entire extended
basic block (in this case, the set of blocks connected by fallthru),
simply by not discarding the register state at the branch.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2020-10-27 09:48:07 -07:00

1552 lines
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/*
* Optimizations for Tiny Code Generator for QEMU
*
* Copyright (c) 2010 Samsung Electronics.
* Contributed by Kirill Batuzov <batuzovk@ispras.ru>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "tcg/tcg-op.h"
#define CASE_OP_32_64(x) \
glue(glue(case INDEX_op_, x), _i32): \
glue(glue(case INDEX_op_, x), _i64)
#define CASE_OP_32_64_VEC(x) \
glue(glue(case INDEX_op_, x), _i32): \
glue(glue(case INDEX_op_, x), _i64): \
glue(glue(case INDEX_op_, x), _vec)
struct tcg_temp_info {
bool is_const;
TCGTemp *prev_copy;
TCGTemp *next_copy;
tcg_target_ulong val;
tcg_target_ulong mask;
};
static inline struct tcg_temp_info *ts_info(TCGTemp *ts)
{
return ts->state_ptr;
}
static inline struct tcg_temp_info *arg_info(TCGArg arg)
{
return ts_info(arg_temp(arg));
}
static inline bool ts_is_const(TCGTemp *ts)
{
return ts_info(ts)->is_const;
}
static inline bool arg_is_const(TCGArg arg)
{
return ts_is_const(arg_temp(arg));
}
static inline bool ts_is_copy(TCGTemp *ts)
{
return ts_info(ts)->next_copy != ts;
}
/* Reset TEMP's state, possibly removing the temp for the list of copies. */
static void reset_ts(TCGTemp *ts)
{
struct tcg_temp_info *ti = ts_info(ts);
struct tcg_temp_info *pi = ts_info(ti->prev_copy);
struct tcg_temp_info *ni = ts_info(ti->next_copy);
ni->prev_copy = ti->prev_copy;
pi->next_copy = ti->next_copy;
ti->next_copy = ts;
ti->prev_copy = ts;
ti->is_const = false;
ti->mask = -1;
}
static void reset_temp(TCGArg arg)
{
reset_ts(arg_temp(arg));
}
/* Initialize and activate a temporary. */
static void init_ts_info(struct tcg_temp_info *infos,
TCGTempSet *temps_used, TCGTemp *ts)
{
size_t idx = temp_idx(ts);
if (!test_bit(idx, temps_used->l)) {
struct tcg_temp_info *ti = &infos[idx];
ts->state_ptr = ti;
ti->next_copy = ts;
ti->prev_copy = ts;
ti->is_const = false;
ti->mask = -1;
set_bit(idx, temps_used->l);
}
}
static void init_arg_info(struct tcg_temp_info *infos,
TCGTempSet *temps_used, TCGArg arg)
{
init_ts_info(infos, temps_used, arg_temp(arg));
}
static TCGTemp *find_better_copy(TCGContext *s, TCGTemp *ts)
{
TCGTemp *i;
/* If this is already a global, we can't do better. */
if (ts->temp_global) {
return ts;
}
/* Search for a global first. */
for (i = ts_info(ts)->next_copy; i != ts; i = ts_info(i)->next_copy) {
if (i->temp_global) {
return i;
}
}
/* If it is a temp, search for a temp local. */
if (!ts->temp_local) {
for (i = ts_info(ts)->next_copy; i != ts; i = ts_info(i)->next_copy) {
if (ts->temp_local) {
return i;
}
}
}
/* Failure to find a better representation, return the same temp. */
return ts;
}
static bool ts_are_copies(TCGTemp *ts1, TCGTemp *ts2)
{
TCGTemp *i;
if (ts1 == ts2) {
return true;
}
if (!ts_is_copy(ts1) || !ts_is_copy(ts2)) {
return false;
}
for (i = ts_info(ts1)->next_copy; i != ts1; i = ts_info(i)->next_copy) {
if (i == ts2) {
return true;
}
}
return false;
}
static bool args_are_copies(TCGArg arg1, TCGArg arg2)
{
return ts_are_copies(arg_temp(arg1), arg_temp(arg2));
}
static void tcg_opt_gen_movi(TCGContext *s, TCGOp *op, TCGArg dst, TCGArg val)
{
const TCGOpDef *def;
TCGOpcode new_op;
tcg_target_ulong mask;
struct tcg_temp_info *di = arg_info(dst);
def = &tcg_op_defs[op->opc];
if (def->flags & TCG_OPF_VECTOR) {
new_op = INDEX_op_dupi_vec;
} else if (def->flags & TCG_OPF_64BIT) {
new_op = INDEX_op_movi_i64;
} else {
new_op = INDEX_op_movi_i32;
}
op->opc = new_op;
/* TCGOP_VECL and TCGOP_VECE remain unchanged. */
op->args[0] = dst;
op->args[1] = val;
reset_temp(dst);
di->is_const = true;
di->val = val;
mask = val;
if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_movi_i32) {
/* High bits of the destination are now garbage. */
mask |= ~0xffffffffull;
}
di->mask = mask;
}
static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, TCGArg dst, TCGArg src)
{
TCGTemp *dst_ts = arg_temp(dst);
TCGTemp *src_ts = arg_temp(src);
const TCGOpDef *def;
struct tcg_temp_info *di;
struct tcg_temp_info *si;
tcg_target_ulong mask;
TCGOpcode new_op;
if (ts_are_copies(dst_ts, src_ts)) {
tcg_op_remove(s, op);
return;
}
reset_ts(dst_ts);
di = ts_info(dst_ts);
si = ts_info(src_ts);
def = &tcg_op_defs[op->opc];
if (def->flags & TCG_OPF_VECTOR) {
new_op = INDEX_op_mov_vec;
} else if (def->flags & TCG_OPF_64BIT) {
new_op = INDEX_op_mov_i64;
} else {
new_op = INDEX_op_mov_i32;
}
op->opc = new_op;
/* TCGOP_VECL and TCGOP_VECE remain unchanged. */
op->args[0] = dst;
op->args[1] = src;
mask = si->mask;
if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_mov_i32) {
/* High bits of the destination are now garbage. */
mask |= ~0xffffffffull;
}
di->mask = mask;
if (src_ts->type == dst_ts->type) {
struct tcg_temp_info *ni = ts_info(si->next_copy);
di->next_copy = si->next_copy;
di->prev_copy = src_ts;
ni->prev_copy = dst_ts;
si->next_copy = dst_ts;
di->is_const = si->is_const;
di->val = si->val;
}
}
static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y)
{
uint64_t l64, h64;
switch (op) {
CASE_OP_32_64(add):
return x + y;
CASE_OP_32_64(sub):
return x - y;
CASE_OP_32_64(mul):
return x * y;
CASE_OP_32_64(and):
return x & y;
CASE_OP_32_64(or):
return x | y;
CASE_OP_32_64(xor):
return x ^ y;
case INDEX_op_shl_i32:
return (uint32_t)x << (y & 31);
case INDEX_op_shl_i64:
return (uint64_t)x << (y & 63);
case INDEX_op_shr_i32:
return (uint32_t)x >> (y & 31);
case INDEX_op_shr_i64:
return (uint64_t)x >> (y & 63);
case INDEX_op_sar_i32:
return (int32_t)x >> (y & 31);
case INDEX_op_sar_i64:
return (int64_t)x >> (y & 63);
case INDEX_op_rotr_i32:
return ror32(x, y & 31);
case INDEX_op_rotr_i64:
return ror64(x, y & 63);
case INDEX_op_rotl_i32:
return rol32(x, y & 31);
case INDEX_op_rotl_i64:
return rol64(x, y & 63);
CASE_OP_32_64(not):
return ~x;
CASE_OP_32_64(neg):
return -x;
CASE_OP_32_64(andc):
return x & ~y;
CASE_OP_32_64(orc):
return x | ~y;
CASE_OP_32_64(eqv):
return ~(x ^ y);
CASE_OP_32_64(nand):
return ~(x & y);
CASE_OP_32_64(nor):
return ~(x | y);
case INDEX_op_clz_i32:
return (uint32_t)x ? clz32(x) : y;
case INDEX_op_clz_i64:
return x ? clz64(x) : y;
case INDEX_op_ctz_i32:
return (uint32_t)x ? ctz32(x) : y;
case INDEX_op_ctz_i64:
return x ? ctz64(x) : y;
case INDEX_op_ctpop_i32:
return ctpop32(x);
case INDEX_op_ctpop_i64:
return ctpop64(x);
CASE_OP_32_64(ext8s):
return (int8_t)x;
CASE_OP_32_64(ext16s):
return (int16_t)x;
CASE_OP_32_64(ext8u):
return (uint8_t)x;
CASE_OP_32_64(ext16u):
return (uint16_t)x;
CASE_OP_32_64(bswap16):
return bswap16(x);
CASE_OP_32_64(bswap32):
return bswap32(x);
case INDEX_op_bswap64_i64:
return bswap64(x);
case INDEX_op_ext_i32_i64:
case INDEX_op_ext32s_i64:
return (int32_t)x;
case INDEX_op_extu_i32_i64:
case INDEX_op_extrl_i64_i32:
case INDEX_op_ext32u_i64:
return (uint32_t)x;
case INDEX_op_extrh_i64_i32:
return (uint64_t)x >> 32;
case INDEX_op_muluh_i32:
return ((uint64_t)(uint32_t)x * (uint32_t)y) >> 32;
case INDEX_op_mulsh_i32:
return ((int64_t)(int32_t)x * (int32_t)y) >> 32;
case INDEX_op_muluh_i64:
mulu64(&l64, &h64, x, y);
return h64;
case INDEX_op_mulsh_i64:
muls64(&l64, &h64, x, y);
return h64;
case INDEX_op_div_i32:
/* Avoid crashing on divide by zero, otherwise undefined. */
return (int32_t)x / ((int32_t)y ? : 1);
case INDEX_op_divu_i32:
return (uint32_t)x / ((uint32_t)y ? : 1);
case INDEX_op_div_i64:
return (int64_t)x / ((int64_t)y ? : 1);
case INDEX_op_divu_i64:
return (uint64_t)x / ((uint64_t)y ? : 1);
case INDEX_op_rem_i32:
return (int32_t)x % ((int32_t)y ? : 1);
case INDEX_op_remu_i32:
return (uint32_t)x % ((uint32_t)y ? : 1);
case INDEX_op_rem_i64:
return (int64_t)x % ((int64_t)y ? : 1);
case INDEX_op_remu_i64:
return (uint64_t)x % ((uint64_t)y ? : 1);
default:
fprintf(stderr,
"Unrecognized operation %d in do_constant_folding.\n", op);
tcg_abort();
}
}
static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
{
const TCGOpDef *def = &tcg_op_defs[op];
TCGArg res = do_constant_folding_2(op, x, y);
if (!(def->flags & TCG_OPF_64BIT)) {
res = (int32_t)res;
}
return res;
}
static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c)
{
switch (c) {
case TCG_COND_EQ:
return x == y;
case TCG_COND_NE:
return x != y;
case TCG_COND_LT:
return (int32_t)x < (int32_t)y;
case TCG_COND_GE:
return (int32_t)x >= (int32_t)y;
case TCG_COND_LE:
return (int32_t)x <= (int32_t)y;
case TCG_COND_GT:
return (int32_t)x > (int32_t)y;
case TCG_COND_LTU:
return x < y;
case TCG_COND_GEU:
return x >= y;
case TCG_COND_LEU:
return x <= y;
case TCG_COND_GTU:
return x > y;
default:
tcg_abort();
}
}
static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c)
{
switch (c) {
case TCG_COND_EQ:
return x == y;
case TCG_COND_NE:
return x != y;
case TCG_COND_LT:
return (int64_t)x < (int64_t)y;
case TCG_COND_GE:
return (int64_t)x >= (int64_t)y;
case TCG_COND_LE:
return (int64_t)x <= (int64_t)y;
case TCG_COND_GT:
return (int64_t)x > (int64_t)y;
case TCG_COND_LTU:
return x < y;
case TCG_COND_GEU:
return x >= y;
case TCG_COND_LEU:
return x <= y;
case TCG_COND_GTU:
return x > y;
default:
tcg_abort();
}
}
static bool do_constant_folding_cond_eq(TCGCond c)
{
switch (c) {
case TCG_COND_GT:
case TCG_COND_LTU:
case TCG_COND_LT:
case TCG_COND_GTU:
case TCG_COND_NE:
return 0;
case TCG_COND_GE:
case TCG_COND_GEU:
case TCG_COND_LE:
case TCG_COND_LEU:
case TCG_COND_EQ:
return 1;
default:
tcg_abort();
}
}
/* 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_cond(TCGOpcode op, TCGArg x,
TCGArg y, TCGCond c)
{
tcg_target_ulong xv = arg_info(x)->val;
tcg_target_ulong yv = arg_info(y)->val;
if (arg_is_const(x) && arg_is_const(y)) {
const TCGOpDef *def = &tcg_op_defs[op];
tcg_debug_assert(!(def->flags & TCG_OPF_VECTOR));
if (def->flags & TCG_OPF_64BIT) {
return do_constant_folding_cond_64(xv, yv, c);
} else {
return do_constant_folding_cond_32(xv, yv, c);
}
} else if (args_are_copies(x, y)) {
return do_constant_folding_cond_eq(c);
} else if (arg_is_const(y) && yv == 0) {
switch (c) {
case TCG_COND_LTU:
return 0;
case TCG_COND_GEU:
return 1;
default:
return 2;
}
}
return 2;
}
/* 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 (arg_is_const(bl) && arg_is_const(bh)) {
tcg_target_ulong blv = arg_info(bl)->val;
tcg_target_ulong bhv = arg_info(bh)->val;
uint64_t b = deposit64(blv, 32, 32, bhv);
if (arg_is_const(al) && arg_is_const(ah)) {
tcg_target_ulong alv = arg_info(al)->val;
tcg_target_ulong ahv = arg_info(ah)->val;
uint64_t a = deposit64(alv, 32, 32, ahv);
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 (args_are_copies(al, bl) && args_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;
int sum = 0;
sum += arg_is_const(a1);
sum -= arg_is_const(a2);
/* Prefer the constant in second argument, and then the form
op a, a, b, which is better handled on non-RISC hosts. */
if (sum > 0 || (sum == 0 && dest == a2)) {
*p1 = a2;
*p2 = a1;
return true;
}
return false;
}
static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
{
int sum = 0;
sum += arg_is_const(p1[0]);
sum += arg_is_const(p1[1]);
sum -= arg_is_const(p2[0]);
sum -= arg_is_const(p2[1]);
if (sum > 0) {
TCGArg t;
t = p1[0], p1[0] = p2[0], p2[0] = t;
t = p1[1], p1[1] = p2[1], p2[1] = t;
return true;
}
return false;
}
/* Propagate constants and copies, fold constant expressions. */
void tcg_optimize(TCGContext *s)
{
int nb_temps, nb_globals;
TCGOp *op, *op_next, *prev_mb = NULL;
struct tcg_temp_info *infos;
TCGTempSet temps_used;
/* Array VALS has an element for each temp.
If this temp holds a constant then its value is kept in VALS' element.
If this temp is a copy of other ones then the other copies are
available through the doubly linked circular list. */
nb_temps = s->nb_temps;
nb_globals = s->nb_globals;
bitmap_zero(temps_used.l, nb_temps);
infos = tcg_malloc(sizeof(struct tcg_temp_info) * nb_temps);
QTAILQ_FOREACH_SAFE(op, &s->ops, link, op_next) {
tcg_target_ulong mask, partmask, affected;
int nb_oargs, nb_iargs, i;
TCGArg tmp;
TCGOpcode opc = op->opc;
const TCGOpDef *def = &tcg_op_defs[opc];
/* Count the arguments, and initialize the temps that are
going to be used */
if (opc == INDEX_op_call) {
nb_oargs = TCGOP_CALLO(op);
nb_iargs = TCGOP_CALLI(op);
for (i = 0; i < nb_oargs + nb_iargs; i++) {
TCGTemp *ts = arg_temp(op->args[i]);
if (ts) {
init_ts_info(infos, &temps_used, ts);
}
}
} else {
nb_oargs = def->nb_oargs;
nb_iargs = def->nb_iargs;
for (i = 0; i < nb_oargs + nb_iargs; i++) {
init_arg_info(infos, &temps_used, op->args[i]);
}
}
/* Do copy propagation */
for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) {
TCGTemp *ts = arg_temp(op->args[i]);
if (ts && ts_is_copy(ts)) {
op->args[i] = temp_arg(find_better_copy(s, ts));
}
}
/* For commutative operations make constant second argument */
switch (opc) {
CASE_OP_32_64_VEC(add):
CASE_OP_32_64_VEC(mul):
CASE_OP_32_64_VEC(and):
CASE_OP_32_64_VEC(or):
CASE_OP_32_64_VEC(xor):
CASE_OP_32_64(eqv):
CASE_OP_32_64(nand):
CASE_OP_32_64(nor):
CASE_OP_32_64(muluh):
CASE_OP_32_64(mulsh):
swap_commutative(op->args[0], &op->args[1], &op->args[2]);
break;
CASE_OP_32_64(brcond):
if (swap_commutative(-1, &op->args[0], &op->args[1])) {
op->args[2] = tcg_swap_cond(op->args[2]);
}
break;
CASE_OP_32_64(setcond):
if (swap_commutative(op->args[0], &op->args[1], &op->args[2])) {
op->args[3] = tcg_swap_cond(op->args[3]);
}
break;
CASE_OP_32_64(movcond):
if (swap_commutative(-1, &op->args[1], &op->args[2])) {
op->args[5] = tcg_swap_cond(op->args[5]);
}
/* For movcond, we canonicalize the "false" input reg to match
the destination reg so that the tcg backend can implement
a "move if true" operation. */
if (swap_commutative(op->args[0], &op->args[4], &op->args[3])) {
op->args[5] = tcg_invert_cond(op->args[5]);
}
break;
CASE_OP_32_64(add2):
swap_commutative(op->args[0], &op->args[2], &op->args[4]);
swap_commutative(op->args[1], &op->args[3], &op->args[5]);
break;
CASE_OP_32_64(mulu2):
CASE_OP_32_64(muls2):
swap_commutative(op->args[0], &op->args[2], &op->args[3]);
break;
case INDEX_op_brcond2_i32:
if (swap_commutative2(&op->args[0], &op->args[2])) {
op->args[4] = tcg_swap_cond(op->args[4]);
}
break;
case INDEX_op_setcond2_i32:
if (swap_commutative2(&op->args[1], &op->args[3])) {
op->args[5] = tcg_swap_cond(op->args[5]);
}
break;
default:
break;
}
/* Simplify expressions for "shift/rot r, 0, a => movi r, 0",
and "sub r, 0, a => neg r, a" case. */
switch (opc) {
CASE_OP_32_64(shl):
CASE_OP_32_64(shr):
CASE_OP_32_64(sar):
CASE_OP_32_64(rotl):
CASE_OP_32_64(rotr):
if (arg_is_const(op->args[1])
&& arg_info(op->args[1])->val == 0) {
tcg_opt_gen_movi(s, op, op->args[0], 0);
continue;
}
break;
CASE_OP_32_64_VEC(sub):
{
TCGOpcode neg_op;
bool have_neg;
if (arg_is_const(op->args[2])) {
/* Proceed with possible constant folding. */
break;
}
if (opc == INDEX_op_sub_i32) {
neg_op = INDEX_op_neg_i32;
have_neg = TCG_TARGET_HAS_neg_i32;
} else if (opc == INDEX_op_sub_i64) {
neg_op = INDEX_op_neg_i64;
have_neg = TCG_TARGET_HAS_neg_i64;
} else if (TCG_TARGET_HAS_neg_vec) {
TCGType type = TCGOP_VECL(op) + TCG_TYPE_V64;
unsigned vece = TCGOP_VECE(op);
neg_op = INDEX_op_neg_vec;
have_neg = tcg_can_emit_vec_op(neg_op, type, vece) > 0;
} else {
break;
}
if (!have_neg) {
break;
}
if (arg_is_const(op->args[1])
&& arg_info(op->args[1])->val == 0) {
op->opc = neg_op;
reset_temp(op->args[0]);
op->args[1] = op->args[2];
continue;
}
}
break;
CASE_OP_32_64_VEC(xor):
CASE_OP_32_64(nand):
if (!arg_is_const(op->args[1])
&& arg_is_const(op->args[2])
&& arg_info(op->args[2])->val == -1) {
i = 1;
goto try_not;
}
break;
CASE_OP_32_64(nor):
if (!arg_is_const(op->args[1])
&& arg_is_const(op->args[2])
&& arg_info(op->args[2])->val == 0) {
i = 1;
goto try_not;
}
break;
CASE_OP_32_64_VEC(andc):
if (!arg_is_const(op->args[2])
&& arg_is_const(op->args[1])
&& arg_info(op->args[1])->val == -1) {
i = 2;
goto try_not;
}
break;
CASE_OP_32_64_VEC(orc):
CASE_OP_32_64(eqv):
if (!arg_is_const(op->args[2])
&& arg_is_const(op->args[1])
&& arg_info(op->args[1])->val == 0) {
i = 2;
goto try_not;
}
break;
try_not:
{
TCGOpcode not_op;
bool have_not;
if (def->flags & TCG_OPF_VECTOR) {
not_op = INDEX_op_not_vec;
have_not = TCG_TARGET_HAS_not_vec;
} else if (def->flags & TCG_OPF_64BIT) {
not_op = INDEX_op_not_i64;
have_not = TCG_TARGET_HAS_not_i64;
} else {
not_op = INDEX_op_not_i32;
have_not = TCG_TARGET_HAS_not_i32;
}
if (!have_not) {
break;
}
op->opc = not_op;
reset_temp(op->args[0]);
op->args[1] = op->args[i];
continue;
}
default:
break;
}
/* Simplify expression for "op r, a, const => mov r, a" cases */
switch (opc) {
CASE_OP_32_64_VEC(add):
CASE_OP_32_64_VEC(sub):
CASE_OP_32_64_VEC(or):
CASE_OP_32_64_VEC(xor):
CASE_OP_32_64_VEC(andc):
CASE_OP_32_64(shl):
CASE_OP_32_64(shr):
CASE_OP_32_64(sar):
CASE_OP_32_64(rotl):
CASE_OP_32_64(rotr):
if (!arg_is_const(op->args[1])
&& arg_is_const(op->args[2])
&& arg_info(op->args[2])->val == 0) {
tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
continue;
}
break;
CASE_OP_32_64_VEC(and):
CASE_OP_32_64_VEC(orc):
CASE_OP_32_64(eqv):
if (!arg_is_const(op->args[1])
&& arg_is_const(op->args[2])
&& arg_info(op->args[2])->val == -1) {
tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
continue;
}
break;
default:
break;
}
/* Simplify using known-zero bits. Currently only ops with a single
output argument is supported. */
mask = -1;
affected = -1;
switch (opc) {
CASE_OP_32_64(ext8s):
if ((arg_info(op->args[1])->mask & 0x80) != 0) {
break;
}
CASE_OP_32_64(ext8u):
mask = 0xff;
goto and_const;
CASE_OP_32_64(ext16s):
if ((arg_info(op->args[1])->mask & 0x8000) != 0) {
break;
}
CASE_OP_32_64(ext16u):
mask = 0xffff;
goto and_const;
case INDEX_op_ext32s_i64:
if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
break;
}
case INDEX_op_ext32u_i64:
mask = 0xffffffffU;
goto and_const;
CASE_OP_32_64(and):
mask = arg_info(op->args[2])->mask;
if (arg_is_const(op->args[2])) {
and_const:
affected = arg_info(op->args[1])->mask & ~mask;
}
mask = arg_info(op->args[1])->mask & mask;
break;
case INDEX_op_ext_i32_i64:
if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
break;
}
case INDEX_op_extu_i32_i64:
/* We do not compute affected as it is a size changing op. */
mask = (uint32_t)arg_info(op->args[1])->mask;
break;
CASE_OP_32_64(andc):
/* Known-zeros does not imply known-ones. Therefore unless
op->args[2] is constant, we can't infer anything from it. */
if (arg_is_const(op->args[2])) {
mask = ~arg_info(op->args[2])->mask;
goto and_const;
}
/* But we certainly know nothing outside args[1] may be set. */
mask = arg_info(op->args[1])->mask;
break;
case INDEX_op_sar_i32:
if (arg_is_const(op->args[2])) {
tmp = arg_info(op->args[2])->val & 31;
mask = (int32_t)arg_info(op->args[1])->mask >> tmp;
}
break;
case INDEX_op_sar_i64:
if (arg_is_const(op->args[2])) {
tmp = arg_info(op->args[2])->val & 63;
mask = (int64_t)arg_info(op->args[1])->mask >> tmp;
}
break;
case INDEX_op_shr_i32:
if (arg_is_const(op->args[2])) {
tmp = arg_info(op->args[2])->val & 31;
mask = (uint32_t)arg_info(op->args[1])->mask >> tmp;
}
break;
case INDEX_op_shr_i64:
if (arg_is_const(op->args[2])) {
tmp = arg_info(op->args[2])->val & 63;
mask = (uint64_t)arg_info(op->args[1])->mask >> tmp;
}
break;
case INDEX_op_extrl_i64_i32:
mask = (uint32_t)arg_info(op->args[1])->mask;
break;
case INDEX_op_extrh_i64_i32:
mask = (uint64_t)arg_info(op->args[1])->mask >> 32;
break;
CASE_OP_32_64(shl):
if (arg_is_const(op->args[2])) {
tmp = arg_info(op->args[2])->val & (TCG_TARGET_REG_BITS - 1);
mask = arg_info(op->args[1])->mask << tmp;
}
break;
CASE_OP_32_64(neg):
/* Set to 1 all bits to the left of the rightmost. */
mask = -(arg_info(op->args[1])->mask
& -arg_info(op->args[1])->mask);
break;
CASE_OP_32_64(deposit):
mask = deposit64(arg_info(op->args[1])->mask,
op->args[3], op->args[4],
arg_info(op->args[2])->mask);
break;
CASE_OP_32_64(extract):
mask = extract64(arg_info(op->args[1])->mask,
op->args[2], op->args[3]);
if (op->args[2] == 0) {
affected = arg_info(op->args[1])->mask & ~mask;
}
break;
CASE_OP_32_64(sextract):
mask = sextract64(arg_info(op->args[1])->mask,
op->args[2], op->args[3]);
if (op->args[2] == 0 && (tcg_target_long)mask >= 0) {
affected = arg_info(op->args[1])->mask & ~mask;
}
break;
CASE_OP_32_64(or):
CASE_OP_32_64(xor):
mask = arg_info(op->args[1])->mask | arg_info(op->args[2])->mask;
break;
case INDEX_op_clz_i32:
case INDEX_op_ctz_i32:
mask = arg_info(op->args[2])->mask | 31;
break;
case INDEX_op_clz_i64:
case INDEX_op_ctz_i64:
mask = arg_info(op->args[2])->mask | 63;
break;
case INDEX_op_ctpop_i32:
mask = 32 | 31;
break;
case INDEX_op_ctpop_i64:
mask = 64 | 63;
break;
CASE_OP_32_64(setcond):
case INDEX_op_setcond2_i32:
mask = 1;
break;
CASE_OP_32_64(movcond):
mask = arg_info(op->args[3])->mask | arg_info(op->args[4])->mask;
break;
CASE_OP_32_64(ld8u):
mask = 0xff;
break;
CASE_OP_32_64(ld16u):
mask = 0xffff;
break;
case INDEX_op_ld32u_i64:
mask = 0xffffffffu;
break;
CASE_OP_32_64(qemu_ld):
{
TCGMemOpIdx oi = op->args[nb_oargs + nb_iargs];
MemOp mop = get_memop(oi);
if (!(mop & MO_SIGN)) {
mask = (2ULL << ((8 << (mop & MO_SIZE)) - 1)) - 1;
}
}
break;
default:
break;
}
/* 32-bit ops generate 32-bit results. For the result is zero test
below, we can ignore high bits, but for further optimizations we
need to record that the high bits contain garbage. */
partmask = mask;
if (!(def->flags & TCG_OPF_64BIT)) {
mask |= ~(tcg_target_ulong)0xffffffffu;
partmask &= 0xffffffffu;
affected &= 0xffffffffu;
}
if (partmask == 0) {
tcg_debug_assert(nb_oargs == 1);
tcg_opt_gen_movi(s, op, op->args[0], 0);
continue;
}
if (affected == 0) {
tcg_debug_assert(nb_oargs == 1);
tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
continue;
}
/* Simplify expression for "op r, a, 0 => movi r, 0" cases */
switch (opc) {
CASE_OP_32_64_VEC(and):
CASE_OP_32_64_VEC(mul):
CASE_OP_32_64(muluh):
CASE_OP_32_64(mulsh):
if (arg_is_const(op->args[2])
&& arg_info(op->args[2])->val == 0) {
tcg_opt_gen_movi(s, op, op->args[0], 0);
continue;
}
break;
default:
break;
}
/* Simplify expression for "op r, a, a => mov r, a" cases */
switch (opc) {
CASE_OP_32_64_VEC(or):
CASE_OP_32_64_VEC(and):
if (args_are_copies(op->args[1], op->args[2])) {
tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
continue;
}
break;
default:
break;
}
/* Simplify expression for "op r, a, a => movi r, 0" cases */
switch (opc) {
CASE_OP_32_64_VEC(andc):
CASE_OP_32_64_VEC(sub):
CASE_OP_32_64_VEC(xor):
if (args_are_copies(op->args[1], op->args[2])) {
tcg_opt_gen_movi(s, op, op->args[0], 0);
continue;
}
break;
default:
break;
}
/* Propagate constants through copy operations and do constant
folding. Constants will be substituted to arguments by register
allocator where needed and possible. Also detect copies. */
switch (opc) {
CASE_OP_32_64_VEC(mov):
tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
break;
CASE_OP_32_64(movi):
case INDEX_op_dupi_vec:
tcg_opt_gen_movi(s, op, op->args[0], op->args[1]);
break;
case INDEX_op_dup_vec:
if (arg_is_const(op->args[1])) {
tmp = arg_info(op->args[1])->val;
tmp = dup_const(TCGOP_VECE(op), tmp);
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
case INDEX_op_dup2_vec:
assert(TCG_TARGET_REG_BITS == 32);
if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
tmp = arg_info(op->args[1])->val;
if (tmp == arg_info(op->args[2])->val) {
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
} else if (args_are_copies(op->args[1], op->args[2])) {
op->opc = INDEX_op_dup_vec;
TCGOP_VECE(op) = MO_32;
nb_iargs = 1;
}
goto do_default;
CASE_OP_32_64(not):
CASE_OP_32_64(neg):
CASE_OP_32_64(ext8s):
CASE_OP_32_64(ext8u):
CASE_OP_32_64(ext16s):
CASE_OP_32_64(ext16u):
CASE_OP_32_64(ctpop):
CASE_OP_32_64(bswap16):
CASE_OP_32_64(bswap32):
case INDEX_op_bswap64_i64:
case INDEX_op_ext32s_i64:
case INDEX_op_ext32u_i64:
case INDEX_op_ext_i32_i64:
case INDEX_op_extu_i32_i64:
case INDEX_op_extrl_i64_i32:
case INDEX_op_extrh_i64_i32:
if (arg_is_const(op->args[1])) {
tmp = do_constant_folding(opc, arg_info(op->args[1])->val, 0);
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
CASE_OP_32_64(add):
CASE_OP_32_64(sub):
CASE_OP_32_64(mul):
CASE_OP_32_64(or):
CASE_OP_32_64(and):
CASE_OP_32_64(xor):
CASE_OP_32_64(shl):
CASE_OP_32_64(shr):
CASE_OP_32_64(sar):
CASE_OP_32_64(rotl):
CASE_OP_32_64(rotr):
CASE_OP_32_64(andc):
CASE_OP_32_64(orc):
CASE_OP_32_64(eqv):
CASE_OP_32_64(nand):
CASE_OP_32_64(nor):
CASE_OP_32_64(muluh):
CASE_OP_32_64(mulsh):
CASE_OP_32_64(div):
CASE_OP_32_64(divu):
CASE_OP_32_64(rem):
CASE_OP_32_64(remu):
if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
tmp = do_constant_folding(opc, arg_info(op->args[1])->val,
arg_info(op->args[2])->val);
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
CASE_OP_32_64(clz):
CASE_OP_32_64(ctz):
if (arg_is_const(op->args[1])) {
TCGArg v = arg_info(op->args[1])->val;
if (v != 0) {
tmp = do_constant_folding(opc, v, 0);
tcg_opt_gen_movi(s, op, op->args[0], tmp);
} else {
tcg_opt_gen_mov(s, op, op->args[0], op->args[2]);
}
break;
}
goto do_default;
CASE_OP_32_64(deposit):
if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
tmp = deposit64(arg_info(op->args[1])->val,
op->args[3], op->args[4],
arg_info(op->args[2])->val);
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
CASE_OP_32_64(extract):
if (arg_is_const(op->args[1])) {
tmp = extract64(arg_info(op->args[1])->val,
op->args[2], op->args[3]);
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
CASE_OP_32_64(sextract):
if (arg_is_const(op->args[1])) {
tmp = sextract64(arg_info(op->args[1])->val,
op->args[2], op->args[3]);
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
CASE_OP_32_64(extract2):
if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
TCGArg v1 = arg_info(op->args[1])->val;
TCGArg v2 = arg_info(op->args[2])->val;
if (opc == INDEX_op_extract2_i64) {
tmp = (v1 >> op->args[3]) | (v2 << (64 - op->args[3]));
} else {
tmp = (int32_t)(((uint32_t)v1 >> op->args[3]) |
((uint32_t)v2 << (32 - op->args[3])));
}
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
CASE_OP_32_64(setcond):
tmp = do_constant_folding_cond(opc, op->args[1],
op->args[2], op->args[3]);
if (tmp != 2) {
tcg_opt_gen_movi(s, op, op->args[0], tmp);
break;
}
goto do_default;
CASE_OP_32_64(brcond):
tmp = do_constant_folding_cond(opc, op->args[0],
op->args[1], op->args[2]);
if (tmp != 2) {
if (tmp) {
bitmap_zero(temps_used.l, nb_temps);
op->opc = INDEX_op_br;
op->args[0] = op->args[3];
} else {
tcg_op_remove(s, op);
}
break;
}
goto do_default;
CASE_OP_32_64(movcond):
tmp = do_constant_folding_cond(opc, op->args[1],
op->args[2], op->args[5]);
if (tmp != 2) {
tcg_opt_gen_mov(s, op, op->args[0], op->args[4-tmp]);
break;
}
if (arg_is_const(op->args[3]) && arg_is_const(op->args[4])) {
tcg_target_ulong tv = arg_info(op->args[3])->val;
tcg_target_ulong fv = arg_info(op->args[4])->val;
TCGCond cond = op->args[5];
if (fv == 1 && tv == 0) {
cond = tcg_invert_cond(cond);
} else if (!(tv == 1 && fv == 0)) {
goto do_default;
}
op->args[3] = cond;
op->opc = opc = (opc == INDEX_op_movcond_i32
? INDEX_op_setcond_i32
: INDEX_op_setcond_i64);
nb_iargs = 2;
}
goto do_default;
case INDEX_op_add2_i32:
case INDEX_op_sub2_i32:
if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])
&& arg_is_const(op->args[4]) && arg_is_const(op->args[5])) {
uint32_t al = arg_info(op->args[2])->val;
uint32_t ah = arg_info(op->args[3])->val;
uint32_t bl = arg_info(op->args[4])->val;
uint32_t bh = arg_info(op->args[5])->val;
uint64_t a = ((uint64_t)ah << 32) | al;
uint64_t b = ((uint64_t)bh << 32) | bl;
TCGArg rl, rh;
TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32);
if (opc == INDEX_op_add2_i32) {
a += b;
} else {
a -= b;
}
rl = op->args[0];
rh = op->args[1];
tcg_opt_gen_movi(s, op, rl, (int32_t)a);
tcg_opt_gen_movi(s, op2, rh, (int32_t)(a >> 32));
break;
}
goto do_default;
case INDEX_op_mulu2_i32:
if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])) {
uint32_t a = arg_info(op->args[2])->val;
uint32_t b = arg_info(op->args[3])->val;
uint64_t r = (uint64_t)a * b;
TCGArg rl, rh;
TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32);
rl = op->args[0];
rh = op->args[1];
tcg_opt_gen_movi(s, op, rl, (int32_t)r);
tcg_opt_gen_movi(s, op2, rh, (int32_t)(r >> 32));
break;
}
goto do_default;
case INDEX_op_brcond2_i32:
tmp = do_constant_folding_cond2(&op->args[0], &op->args[2],
op->args[4]);
if (tmp != 2) {
if (tmp) {
do_brcond_true:
bitmap_zero(temps_used.l, nb_temps);
op->opc = INDEX_op_br;
op->args[0] = op->args[5];
} else {
do_brcond_false:
tcg_op_remove(s, op);
}
} else if ((op->args[4] == TCG_COND_LT
|| op->args[4] == TCG_COND_GE)
&& arg_is_const(op->args[2])
&& arg_info(op->args[2])->val == 0
&& arg_is_const(op->args[3])
&& arg_info(op->args[3])->val == 0) {
/* Simplify LT/GE comparisons vs zero to a single compare
vs the high word of the input. */
do_brcond_high:
bitmap_zero(temps_used.l, nb_temps);
op->opc = INDEX_op_brcond_i32;
op->args[0] = op->args[1];
op->args[1] = op->args[3];
op->args[2] = op->args[4];
op->args[3] = op->args[5];
} else if (op->args[4] == TCG_COND_EQ) {
/* Simplify EQ comparisons where one of the pairs
can be simplified. */
tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
op->args[0], op->args[2],
TCG_COND_EQ);
if (tmp == 0) {
goto do_brcond_false;
} else if (tmp == 1) {
goto do_brcond_high;
}
tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
op->args[1], op->args[3],
TCG_COND_EQ);
if (tmp == 0) {
goto do_brcond_false;
} else if (tmp != 1) {
goto do_default;
}
do_brcond_low:
bitmap_zero(temps_used.l, nb_temps);
op->opc = INDEX_op_brcond_i32;
op->args[1] = op->args[2];
op->args[2] = op->args[4];
op->args[3] = op->args[5];
} else if (op->args[4] == TCG_COND_NE) {
/* Simplify NE comparisons where one of the pairs
can be simplified. */
tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
op->args[0], op->args[2],
TCG_COND_NE);
if (tmp == 0) {
goto do_brcond_high;
} else if (tmp == 1) {
goto do_brcond_true;
}
tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
op->args[1], op->args[3],
TCG_COND_NE);
if (tmp == 0) {
goto do_brcond_low;
} else if (tmp == 1) {
goto do_brcond_true;
}
goto do_default;
} else {
goto do_default;
}
break;
case INDEX_op_setcond2_i32:
tmp = do_constant_folding_cond2(&op->args[1], &op->args[3],
op->args[5]);
if (tmp != 2) {
do_setcond_const:
tcg_opt_gen_movi(s, op, op->args[0], tmp);
} else if ((op->args[5] == TCG_COND_LT
|| op->args[5] == TCG_COND_GE)
&& arg_is_const(op->args[3])
&& arg_info(op->args[3])->val == 0
&& arg_is_const(op->args[4])
&& arg_info(op->args[4])->val == 0) {
/* Simplify LT/GE comparisons vs zero to a single compare
vs the high word of the input. */
do_setcond_high:
reset_temp(op->args[0]);
arg_info(op->args[0])->mask = 1;
op->opc = INDEX_op_setcond_i32;
op->args[1] = op->args[2];
op->args[2] = op->args[4];
op->args[3] = op->args[5];
} else if (op->args[5] == TCG_COND_EQ) {
/* Simplify EQ comparisons where one of the pairs
can be simplified. */
tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
op->args[1], op->args[3],
TCG_COND_EQ);
if (tmp == 0) {
goto do_setcond_const;
} else if (tmp == 1) {
goto do_setcond_high;
}
tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
op->args[2], op->args[4],
TCG_COND_EQ);
if (tmp == 0) {
goto do_setcond_high;
} else if (tmp != 1) {
goto do_default;
}
do_setcond_low:
reset_temp(op->args[0]);
arg_info(op->args[0])->mask = 1;
op->opc = INDEX_op_setcond_i32;
op->args[2] = op->args[3];
op->args[3] = op->args[5];
} else if (op->args[5] == TCG_COND_NE) {
/* Simplify NE comparisons where one of the pairs
can be simplified. */
tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
op->args[1], op->args[3],
TCG_COND_NE);
if (tmp == 0) {
goto do_setcond_high;
} else if (tmp == 1) {
goto do_setcond_const;
}
tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
op->args[2], op->args[4],
TCG_COND_NE);
if (tmp == 0) {
goto do_setcond_low;
} else if (tmp == 1) {
goto do_setcond_const;
}
goto do_default;
} else {
goto do_default;
}
break;
case INDEX_op_call:
if (!(op->args[nb_oargs + nb_iargs + 1]
& (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) {
for (i = 0; i < nb_globals; i++) {
if (test_bit(i, temps_used.l)) {
reset_ts(&s->temps[i]);
}
}
}
/* fall through */
default:
do_default:
/*
* Default case: we know nothing about operation (or were unable
* to compute the operation result) so no propagation is done.
*/
for (i = 0; i < nb_oargs; i++) {
reset_temp(op->args[i]);
/*
* Save the corresponding known-zero bits mask for the
* first output argument (only one supported so far).
*/
if (i == 0) {
arg_info(op->args[i])->mask = mask;
}
}
break;
case INDEX_op_set_label:
/* Trash everything at the start of a new extended bb. */
bitmap_zero(temps_used.l, nb_temps);
break;
}
/* Eliminate duplicate and redundant fence instructions. */
if (prev_mb) {
switch (opc) {
case INDEX_op_mb:
/* Merge two barriers of the same type into one,
* or a weaker barrier into a stronger one,
* or two weaker barriers into a stronger one.
* mb X; mb Y => mb X|Y
* mb; strl => mb; st
* ldaq; mb => ld; mb
* ldaq; strl => ld; mb; st
* Other combinations are also merged into a strong
* barrier. This is stricter than specified but for
* the purposes of TCG is better than not optimizing.
*/
prev_mb->args[0] |= op->args[0];
tcg_op_remove(s, op);
break;
default:
/* Opcodes that end the block stop the optimization. */
if ((def->flags & TCG_OPF_BB_END) == 0) {
break;
}
/* fallthru */
case INDEX_op_qemu_ld_i32:
case INDEX_op_qemu_ld_i64:
case INDEX_op_qemu_st_i32:
case INDEX_op_qemu_st_i64:
case INDEX_op_call:
/* Opcodes that touch guest memory stop the optimization. */
prev_mb = NULL;
break;
}
} else if (opc == INDEX_op_mb) {
prev_mb = op;
}
}
}
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