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optimize.c
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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 "qemu/int128.h"
#include "tcg/tcg-op.h"
#include "tcg-internal.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)
typedef struct TempOptInfo {
bool is_const;
TCGTemp *prev_copy;
TCGTemp *next_copy;
uint64_t val;
uint64_t z_mask; /* mask bit is 0 if and only if value bit is 0 */
uint64_t s_mask; /* a left-aligned mask of clrsb(value) bits. */
} TempOptInfo;
typedef struct OptContext {
TCGContext *tcg;
TCGOp *prev_mb;
TCGTempSet temps_used;
/* In flight values from optimization. */
uint64_t a_mask; /* mask bit is 0 iff value identical to first input */
uint64_t z_mask; /* mask bit is 0 iff value bit is 0 */
uint64_t s_mask; /* mask of clrsb(value) bits */
TCGType type;
} OptContext;
/* Calculate the smask for a specific value. */
static uint64_t smask_from_value(uint64_t value)
{
int rep = clrsb64(value);
return ~(~0ull >> rep);
}
/*
* Calculate the smask for a given set of known-zeros.
* If there are lots of zeros on the left, we can consider the remainder
* an unsigned field, and thus the corresponding signed field is one bit
* larger.
*/
static uint64_t smask_from_zmask(uint64_t zmask)
{
/*
* Only the 0 bits are significant for zmask, thus the msb itself
* must be zero, else we have no sign information.
*/
int rep = clz64(zmask);
if (rep == 0) {
return 0;
}
rep -= 1;
return ~(~0ull >> rep);
}
/*
* Recreate a properly left-aligned smask after manipulation.
* Some bit-shuffling, particularly shifts and rotates, may
* retain sign bits on the left, but may scatter disconnected
* sign bits on the right. Retain only what remains to the left.
*/
static uint64_t smask_from_smask(int64_t smask)
{
/* Only the 1 bits are significant for smask */
return smask_from_zmask(~smask);
}
static inline TempOptInfo *ts_info(TCGTemp *ts)
{
return ts->state_ptr;
}
static inline TempOptInfo *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)
{
TempOptInfo *ti = ts_info(ts);
TempOptInfo *pi = ts_info(ti->prev_copy);
TempOptInfo *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->z_mask = -1;
ti->s_mask = 0;
}
static void reset_temp(TCGArg arg)
{
reset_ts(arg_temp(arg));
}
/* Initialize and activate a temporary. */
static void init_ts_info(OptContext *ctx, TCGTemp *ts)
{
size_t idx = temp_idx(ts);
TempOptInfo *ti;
if (test_bit(idx, ctx->temps_used.l)) {
return;
}
set_bit(idx, ctx->temps_used.l);
ti = ts->state_ptr;
if (ti == NULL) {
ti = tcg_malloc(sizeof(TempOptInfo));
ts->state_ptr = ti;
}
ti->next_copy = ts;
ti->prev_copy = ts;
if (ts->kind == TEMP_CONST) {
ti->is_const = true;
ti->val = ts->val;
ti->z_mask = ts->val;
ti->s_mask = smask_from_value(ts->val);
} else {
ti->is_const = false;
ti->z_mask = -1;
ti->s_mask = 0;
}
}
static TCGTemp *find_better_copy(TCGContext *s, TCGTemp *ts)
{
TCGTemp *i, *g, *l;
/* If this is already readonly, we can't do better. */
if (temp_readonly(ts)) {
return ts;
}
g = l = NULL;
for (i = ts_info(ts)->next_copy; i != ts; i = ts_info(i)->next_copy) {
if (temp_readonly(i)) {
return i;
} else if (i->kind > ts->kind) {
if (i->kind == TEMP_GLOBAL) {
g = i;
} else if (i->kind == TEMP_LOCAL) {
l = i;
}
}
}
/* If we didn't find a better representation, return the same temp. */
return g ? g : l ? l : 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 bool tcg_opt_gen_mov(OptContext *ctx, TCGOp *op, TCGArg dst, TCGArg src)
{
TCGTemp *dst_ts = arg_temp(dst);
TCGTemp *src_ts = arg_temp(src);
TempOptInfo *di;
TempOptInfo *si;
TCGOpcode new_op;
if (ts_are_copies(dst_ts, src_ts)) {
tcg_op_remove(ctx->tcg, op);
return true;
}
reset_ts(dst_ts);
di = ts_info(dst_ts);
si = ts_info(src_ts);
switch (ctx->type) {
case TCG_TYPE_I32:
new_op = INDEX_op_mov_i32;
break;
case TCG_TYPE_I64:
new_op = INDEX_op_mov_i64;
break;
case TCG_TYPE_V64:
case TCG_TYPE_V128:
case TCG_TYPE_V256:
/* TCGOP_VECL and TCGOP_VECE remain unchanged. */
new_op = INDEX_op_mov_vec;
break;
default:
g_assert_not_reached();
}
op->opc = new_op;
op->args[0] = dst;
op->args[1] = src;
di->z_mask = si->z_mask;
di->s_mask = si->s_mask;
if (src_ts->type == dst_ts->type) {
TempOptInfo *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;
}
return true;
}
static bool tcg_opt_gen_movi(OptContext *ctx, TCGOp *op,
TCGArg dst, uint64_t val)
{
TCGTemp *tv;
if (ctx->type == TCG_TYPE_I32) {
val = (int32_t)val;
}
/* Convert movi to mov with constant temp. */
tv = tcg_constant_internal(ctx->type, val);
init_ts_info(ctx, tv);
return tcg_opt_gen_mov(ctx, op, dst, temp_arg(tv));
}
static uint64_t do_constant_folding_2(TCGOpcode op, uint64_t x, uint64_t 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):
x = bswap16(x);
return y & TCG_BSWAP_OS ? (int16_t)x : x;
CASE_OP_32_64(bswap32):
x = bswap32(x);
return y & TCG_BSWAP_OS ? (int32_t)x : 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 uint64_t do_constant_folding(TCGOpcode op, TCGType type,
uint64_t x, uint64_t y)
{
uint64_t res = do_constant_folding_2(op, x, y);
if (type == TCG_TYPE_I32) {
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 -1 if the condition can't be simplified,
* and the result of the condition (0 or 1) if it can.
*/
static int do_constant_folding_cond(TCGType type, TCGArg x,
TCGArg y, TCGCond c)
{
uint64_t xv = arg_info(x)->val;
uint64_t yv = arg_info(y)->val;
if (arg_is_const(x) && arg_is_const(y)) {
switch (type) {
case TCG_TYPE_I32:
return do_constant_folding_cond_32(xv, yv, c);
case TCG_TYPE_I64:
return do_constant_folding_cond_64(xv, yv, c);
default:
/* Only scalar comparisons are optimizable */
return -1;
}
} 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 -1;
}
}
return -1;
}
/*
* Return -1 if the condition can't be simplified,
* and the result of the condition (0 or 1) if it can.
*/
static int 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 -1;
}
/**
* swap_commutative:
* @dest: TCGArg of the destination argument, or NO_DEST.
* @p1: first paired argument
* @p2: second paired argument
*
* If *@p1 is a constant and *@p2 is not, swap.
* If *@p2 matches @dest, swap.
* Return true if a swap was performed.
*/
#define NO_DEST temp_arg(NULL)
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;
}
static void init_arguments(OptContext *ctx, TCGOp *op, int nb_args)
{
for (int i = 0; i < nb_args; i++) {
TCGTemp *ts = arg_temp(op->args[i]);
if (ts) {
init_ts_info(ctx, ts);
}
}
}
static void copy_propagate(OptContext *ctx, TCGOp *op,
int nb_oargs, int nb_iargs)
{
TCGContext *s = ctx->tcg;
for (int 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));
}
}
}
static void finish_folding(OptContext *ctx, TCGOp *op)
{
const TCGOpDef *def = &tcg_op_defs[op->opc];
int i, nb_oargs;
/*
* For an opcode that ends a BB, reset all temp data.
* We do no cross-BB optimization.
*/
if (def->flags & TCG_OPF_BB_END) {
memset(&ctx->temps_used, 0, sizeof(ctx->temps_used));
ctx->prev_mb = NULL;
return;
}
nb_oargs = def->nb_oargs;
for (i = 0; i < nb_oargs; i++) {
TCGTemp *ts = arg_temp(op->args[i]);
reset_ts(ts);
/*
* Save the corresponding known-zero/sign bits mask for the
* first output argument (only one supported so far).
*/
if (i == 0) {
ts_info(ts)->z_mask = ctx->z_mask;
ts_info(ts)->s_mask = ctx->s_mask;
}
}
}
/*
* The fold_* functions return true when processing is complete,
* usually by folding the operation to a constant or to a copy,
* and calling tcg_opt_gen_{mov,movi}. They may do other things,
* like collect information about the value produced, for use in
* optimizing a subsequent operation.
*
* These first fold_* functions are all helpers, used by other
* folders for more specific operations.
*/
static bool fold_const1(OptContext *ctx, TCGOp *op)
{
if (arg_is_const(op->args[1])) {
uint64_t t;
t = arg_info(op->args[1])->val;
t = do_constant_folding(op->opc, ctx->type, t, 0);
return tcg_opt_gen_movi(ctx, op, op->args[0], t);
}
return false;
}
static bool fold_const2(OptContext *ctx, TCGOp *op)
{
if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
uint64_t t1 = arg_info(op->args[1])->val;
uint64_t t2 = arg_info(op->args[2])->val;
t1 = do_constant_folding(op->opc, ctx->type, t1, t2);
return tcg_opt_gen_movi(ctx, op, op->args[0], t1);
}
return false;
}
static bool fold_const2_commutative(OptContext *ctx, TCGOp *op)
{
swap_commutative(op->args[0], &op->args[1], &op->args[2]);
return fold_const2(ctx, op);
}
static bool fold_masks(OptContext *ctx, TCGOp *op)
{
uint64_t a_mask = ctx->a_mask;
uint64_t z_mask = ctx->z_mask;
uint64_t s_mask = ctx->s_mask;
/*
* 32-bit ops generate 32-bit results, which for the purpose of
* simplifying tcg are sign-extended. Certainly that's how we
* represent our constants elsewhere. Note that the bits will
* be reset properly for a 64-bit value when encountering the
* type changing opcodes.
*/
if (ctx->type == TCG_TYPE_I32) {
a_mask = (int32_t)a_mask;
z_mask = (int32_t)z_mask;
s_mask |= MAKE_64BIT_MASK(32, 32);
ctx->z_mask = z_mask;
ctx->s_mask = s_mask;
}
if (z_mask == 0) {
return tcg_opt_gen_movi(ctx, op, op->args[0], 0);
}
if (a_mask == 0) {
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
}
return false;
}
/*
* Convert @op to NOT, if NOT is supported by the host.
* Return true f the conversion is successful, which will still
* indicate that the processing is complete.
*/
static bool fold_not(OptContext *ctx, TCGOp *op);
static bool fold_to_not(OptContext *ctx, TCGOp *op, int idx)
{
TCGOpcode not_op;
bool have_not;
switch (ctx->type) {
case TCG_TYPE_I32:
not_op = INDEX_op_not_i32;
have_not = TCG_TARGET_HAS_not_i32;
break;
case TCG_TYPE_I64:
not_op = INDEX_op_not_i64;
have_not = TCG_TARGET_HAS_not_i64;
break;
case TCG_TYPE_V64:
case TCG_TYPE_V128:
case TCG_TYPE_V256:
not_op = INDEX_op_not_vec;
have_not = TCG_TARGET_HAS_not_vec;
break;
default:
g_assert_not_reached();
}
if (have_not) {
op->opc = not_op;
op->args[1] = op->args[idx];
return fold_not(ctx, op);
}
return false;
}
/* If the binary operation has first argument @i, fold to @i. */
static bool fold_ix_to_i(OptContext *ctx, TCGOp *op, uint64_t i)
{
if (arg_is_const(op->args[1]) && arg_info(op->args[1])->val == i) {
return tcg_opt_gen_movi(ctx, op, op->args[0], i);
}
return false;
}
/* If the binary operation has first argument @i, fold to NOT. */
static bool fold_ix_to_not(OptContext *ctx, TCGOp *op, uint64_t i)
{
if (arg_is_const(op->args[1]) && arg_info(op->args[1])->val == i) {
return fold_to_not(ctx, op, 2);
}
return false;
}
/* If the binary operation has second argument @i, fold to @i. */
static bool fold_xi_to_i(OptContext *ctx, TCGOp *op, uint64_t i)
{
if (arg_is_const(op->args[2]) && arg_info(op->args[2])->val == i) {
return tcg_opt_gen_movi(ctx, op, op->args[0], i);
}
return false;
}
/* If the binary operation has second argument @i, fold to identity. */
static bool fold_xi_to_x(OptContext *ctx, TCGOp *op, uint64_t i)
{
if (arg_is_const(op->args[2]) && arg_info(op->args[2])->val == i) {
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
}
return false;
}
/* If the binary operation has second argument @i, fold to NOT. */
static bool fold_xi_to_not(OptContext *ctx, TCGOp *op, uint64_t i)
{
if (arg_is_const(op->args[2]) && arg_info(op->args[2])->val == i) {
return fold_to_not(ctx, op, 1);
}
return false;
}
/* If the binary operation has both arguments equal, fold to @i. */
static bool fold_xx_to_i(OptContext *ctx, TCGOp *op, uint64_t i)
{
if (args_are_copies(op->args[1], op->args[2])) {
return tcg_opt_gen_movi(ctx, op, op->args[0], i);
}
return false;
}
/* If the binary operation has both arguments equal, fold to identity. */
static bool fold_xx_to_x(OptContext *ctx, TCGOp *op)
{
if (args_are_copies(op->args[1], op->args[2])) {
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
}
return false;
}
/*
* These outermost fold_<op> functions are sorted alphabetically.
*
* The ordering of the transformations should be:
* 1) those that produce a constant
* 2) those that produce a copy
* 3) those that produce information about the result value.
*/
static bool fold_add(OptContext *ctx, TCGOp *op)
{
if (fold_const2_commutative(ctx, op) ||
fold_xi_to_x(ctx, op, 0)) {
return true;
}
return false;
}
static bool fold_addsub2(OptContext *ctx, TCGOp *op, bool add)
{
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])) {
uint64_t al = arg_info(op->args[2])->val;
uint64_t ah = arg_info(op->args[3])->val;
uint64_t bl = arg_info(op->args[4])->val;
uint64_t bh = arg_info(op->args[5])->val;
TCGArg rl, rh;
TCGOp *op2;
if (ctx->type == TCG_TYPE_I32) {
uint64_t a = deposit64(al, 32, 32, ah);
uint64_t b = deposit64(bl, 32, 32, bh);
if (add) {
a += b;
} else {
a -= b;
}
al = sextract64(a, 0, 32);
ah = sextract64(a, 32, 32);
} else {
Int128 a = int128_make128(al, ah);
Int128 b = int128_make128(bl, bh);
if (add) {
a = int128_add(a, b);
} else {
a = int128_sub(a, b);
}
al = int128_getlo(a);
ah = int128_gethi(a);
}
rl = op->args[0];
rh = op->args[1];
/* The proper opcode is supplied by tcg_opt_gen_mov. */
op2 = tcg_op_insert_before(ctx->tcg, op, 0);
tcg_opt_gen_movi(ctx, op, rl, al);
tcg_opt_gen_movi(ctx, op2, rh, ah);
return true;
}
return false;
}
static bool fold_add2(OptContext *ctx, TCGOp *op)
{
/* Note that the high and low parts may be independently swapped. */
swap_commutative(op->args[0], &op->args[2], &op->args[4]);
swap_commutative(op->args[1], &op->args[3], &op->args[5]);
return fold_addsub2(ctx, op, true);
}
static bool fold_and(OptContext *ctx, TCGOp *op)
{
uint64_t z1, z2;
if (fold_const2_commutative(ctx, op) ||
fold_xi_to_i(ctx, op, 0) ||
fold_xi_to_x(ctx, op, -1) ||
fold_xx_to_x(ctx, op)) {
return true;
}
z1 = arg_info(op->args[1])->z_mask;
z2 = arg_info(op->args[2])->z_mask;
ctx->z_mask = z1 & z2;
/*
* Sign repetitions are perforce all identical, whether they are 1 or 0.
* Bitwise operations preserve the relative quantity of the repetitions.
*/
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
/*
* Known-zeros does not imply known-ones. Therefore unless
* arg2 is constant, we can't infer affected bits from it.
*/
if (arg_is_const(op->args[2])) {
ctx->a_mask = z1 & ~z2;
}
return fold_masks(ctx, op);
}
static bool fold_andc(OptContext *ctx, TCGOp *op)