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qemu-e2k/tcg/optimize.c
Richard Henderson 39004a71d8 tcg: Reorg function calls 
Pre-compute the function call layout for each helper at startup.
Drop TCG_CALL_DUMMY_ARG, as we no longer need to leave gaps
in the op->args[] array.  This allows several places to stop
checking for NULL TCGTemp, to which TCG_CALL_DUMMY_ARG mapped.

For tcg_gen_callN, loop over the arguments once.  Allocate the TCGOp
for the call early but delay emitting it, collecting arguments first.
This allows the argument processing loop to emit code for extensions
and have them sequenced before the call.

For tcg_reg_alloc_call, loop over the arguments in reverse order,
which allows stack slots to be filled first naturally.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-01-05 11:41:29 -08:00

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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_VEC(and):
return x & y;
CASE_OP_32_64_VEC(or):
return x | y;
CASE_OP_32_64_VEC(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_VEC(not):
return ~x;
CASE_OP_32_64(neg):
return -x;
CASE_OP_32_64_VEC(andc):
return x & ~y;
CASE_OP_32_64_VEC(orc):
return x | ~y;
CASE_OP_32_64_VEC(eqv):
return ~(x ^ y);
CASE_OP_32_64_VEC(nand):
return ~(x & y);
CASE_OP_32_64_VEC(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)
{
if (arg_is_const(x) && arg_is_const(y)) {
uint64_t xv = arg_info(x)->val;
uint64_t yv = arg_info(y)->val;
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) && arg_info(y)->val == 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]);
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_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_commutative(OptContext *ctx, TCGOp *op)
{
swap_commutative(op->args[0], &op->args[1], &op->args[2]);
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;
}
/* We cannot as yet do_constant_folding with vectors. */
static bool fold_add_vec(OptContext *ctx, TCGOp *op)
{
if (fold_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, 2);
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)
{
uint64_t z1;
if (fold_const2(ctx, op) ||
fold_xx_to_i(ctx, op, 0) ||
fold_xi_to_x(ctx, op, 0) ||
fold_ix_to_not(ctx, op, -1)) {
return true;
}
z1 = arg_info(op->args[1])->z_mask;
/*
* Known-zeros does not imply known-ones. Therefore unless
* arg2 is constant, we can't infer anything from it.
*/
if (arg_is_const(op->args[2])) {
uint64_t z2 = ~arg_info(op->args[2])->z_mask;
ctx->a_mask = z1 & ~z2;
z1 &= z2;
}
ctx->z_mask = z1;
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return fold_masks(ctx, op);
}
static bool fold_brcond(OptContext *ctx, TCGOp *op)
{
TCGCond cond = op->args[2];
int i;
if (swap_commutative(NO_DEST, &op->args[0], &op->args[1])) {
op->args[2] = cond = tcg_swap_cond(cond);
}
i = do_constant_folding_cond(ctx->type, op->args[0], op->args[1], cond);
if (i == 0) {
tcg_op_remove(ctx->tcg, op);
return true;
}
if (i > 0) {
op->opc = INDEX_op_br;
op->args[0] = op->args[3];
}
return false;
}
static bool fold_brcond2(OptContext *ctx, TCGOp *op)
{
TCGCond cond = op->args[4];
TCGArg label = op->args[5];
int i, inv = 0;
if (swap_commutative2(&op->args[0], &op->args[2])) {
op->args[4] = cond = tcg_swap_cond(cond);
}
i = do_constant_folding_cond2(&op->args[0], &op->args[2], cond);
if (i >= 0) {
goto do_brcond_const;
}
switch (cond) {
case TCG_COND_LT:
case TCG_COND_GE:
/*
* Simplify LT/GE comparisons vs zero to a single compare
* vs the high word of the input.
*/
if (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) {
goto do_brcond_high;
}
break;
case TCG_COND_NE:
inv = 1;
QEMU_FALLTHROUGH;
case TCG_COND_EQ:
/*
* Simplify EQ/NE comparisons where one of the pairs
* can be simplified.
*/
i = do_constant_folding_cond(TCG_TYPE_I32, op->args[0],
op->args[2], cond);
switch (i ^ inv) {
case 0:
goto do_brcond_const;
case 1:
goto do_brcond_high;
}
i = do_constant_folding_cond(TCG_TYPE_I32, op->args[1],
op->args[3], cond);
switch (i ^ inv) {
case 0:
goto do_brcond_const;
case 1:
op->opc = INDEX_op_brcond_i32;
op->args[1] = op->args[2];
op->args[2] = cond;
op->args[3] = label;
break;
}
break;
default:
break;
do_brcond_high:
op->opc = INDEX_op_brcond_i32;
op->args[0] = op->args[1];
op->args[1] = op->args[3];
op->args[2] = cond;
op->args[3] = label;
break;
do_brcond_const:
if (i == 0) {
tcg_op_remove(ctx->tcg, op);
return true;
}
op->opc = INDEX_op_br;
op->args[0] = label;
break;
}
return false;
}
static bool fold_bswap(OptContext *ctx, TCGOp *op)
{
uint64_t z_mask, s_mask, sign;
if (arg_is_const(op->args[1])) {
uint64_t t = arg_info(op->args[1])->val;
t = do_constant_folding(op->opc, ctx->type, t, op->args[2]);
return tcg_opt_gen_movi(ctx, op, op->args[0], t);
}
z_mask = arg_info(op->args[1])->z_mask;
switch (op->opc) {
case INDEX_op_bswap16_i32:
case INDEX_op_bswap16_i64:
z_mask = bswap16(z_mask);
sign = INT16_MIN;
break;
case INDEX_op_bswap32_i32:
case INDEX_op_bswap32_i64:
z_mask = bswap32(z_mask);
sign = INT32_MIN;
break;
case INDEX_op_bswap64_i64:
z_mask = bswap64(z_mask);
sign = INT64_MIN;
break;
default:
g_assert_not_reached();
}
s_mask = smask_from_zmask(z_mask);
switch (op->args[2] & (TCG_BSWAP_OZ | TCG_BSWAP_OS)) {
case TCG_BSWAP_OZ:
break;
case TCG_BSWAP_OS:
/* If the sign bit may be 1, force all the bits above to 1. */
if (z_mask & sign) {
z_mask |= sign;
s_mask = sign << 1;
}
break;
default:
/* The high bits are undefined: force all bits above the sign to 1. */
z_mask |= sign << 1;
s_mask = 0;
break;
}
ctx->z_mask = z_mask;
ctx->s_mask = s_mask;
return fold_masks(ctx, op);
}
static bool fold_call(OptContext *ctx, TCGOp *op)
{
TCGContext *s = ctx->tcg;
int nb_oargs = TCGOP_CALLO(op);
int nb_iargs = TCGOP_CALLI(op);
int flags, i;
init_arguments(ctx, op, nb_oargs + nb_iargs);
copy_propagate(ctx, op, nb_oargs, nb_iargs);
/* If the function reads or writes globals, reset temp data. */
flags = tcg_call_flags(op);
if (!(flags & (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) {
int nb_globals = s->nb_globals;
for (i = 0; i < nb_globals; i++) {
if (test_bit(i, ctx->temps_used.l)) {
reset_ts(&ctx->tcg->temps[i]);
}
}
}
/* Reset temp data for outputs. */
for (i = 0; i < nb_oargs; i++) {
reset_temp(op->args[i]);
}
/* Stop optimizing MB across calls. */
ctx->prev_mb = NULL;
return true;
}
static bool fold_count_zeros(OptContext *ctx, TCGOp *op)
{
uint64_t z_mask;
if (arg_is_const(op->args[1])) {
uint64_t t = arg_info(op->args[1])->val;
if (t != 0) {
t = do_constant_folding(op->opc, ctx->type, t, 0);
return tcg_opt_gen_movi(ctx, op, op->args[0], t);
}
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[2]);
}
switch (ctx->type) {
case TCG_TYPE_I32:
z_mask = 31;
break;
case TCG_TYPE_I64:
z_mask = 63;
break;
default:
g_assert_not_reached();
}
ctx->z_mask = arg_info(op->args[2])->z_mask | z_mask;
ctx->s_mask = smask_from_zmask(ctx->z_mask);
return false;
}
static bool fold_ctpop(OptContext *ctx, TCGOp *op)
{
if (fold_const1(ctx, op)) {
return true;
}
switch (ctx->type) {
case TCG_TYPE_I32:
ctx->z_mask = 32 | 31;
break;
case TCG_TYPE_I64:
ctx->z_mask = 64 | 63;
break;
default:
g_assert_not_reached();
}
ctx->s_mask = smask_from_zmask(ctx->z_mask);
return false;
}
static bool fold_deposit(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 = deposit64(t1, op->args[3], op->args[4], t2);
return tcg_opt_gen_movi(ctx, op, op->args[0], t1);
}
ctx->z_mask = deposit64(arg_info(op->args[1])->z_mask,
op->args[3], op->args[4],
arg_info(op->args[2])->z_mask);
return false;
}
static bool fold_divide(OptContext *ctx, TCGOp *op)
{
if (fold_const2(ctx, op) ||
fold_xi_to_x(ctx, op, 1)) {
return true;
}
return false;
}
static bool fold_dup(OptContext *ctx, TCGOp *op)
{
if (arg_is_const(op->args[1])) {
uint64_t t = arg_info(op->args[1])->val;
t = dup_const(TCGOP_VECE(op), t);
return tcg_opt_gen_movi(ctx, op, op->args[0], t);
}
return false;
}
static bool fold_dup2(OptContext *ctx, TCGOp *op)
{
if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
uint64_t t = deposit64(arg_info(op->args[1])->val, 32, 32,
arg_info(op->args[2])->val);
return tcg_opt_gen_movi(ctx, op, op->args[0], t);
}
if (args_are_copies(op->args[1], op->args[2])) {
op->opc = INDEX_op_dup_vec;
TCGOP_VECE(op) = MO_32;
}
return false;
}
static bool fold_eqv(OptContext *ctx, TCGOp *op)
{
if (fold_const2_commutative(ctx, op) ||
fold_xi_to_x(ctx, op, -1) ||
fold_xi_to_not(ctx, op, 0)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
static bool fold_extract(OptContext *ctx, TCGOp *op)
{
uint64_t z_mask_old, z_mask;
int pos = op->args[2];
int len = op->args[3];
if (arg_is_const(op->args[1])) {
uint64_t t;
t = arg_info(op->args[1])->val;
t = extract64(t, pos, len);
return tcg_opt_gen_movi(ctx, op, op->args[0], t);
}
z_mask_old = arg_info(op->args[1])->z_mask;
z_mask = extract64(z_mask_old, pos, len);
if (pos == 0) {
ctx->a_mask = z_mask_old ^ z_mask;
}
ctx->z_mask = z_mask;
ctx->s_mask = smask_from_zmask(z_mask);
return fold_masks(ctx, op);
}
static bool fold_extract2(OptContext *ctx, TCGOp *op)
{
if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
uint64_t v1 = arg_info(op->args[1])->val;
uint64_t v2 = arg_info(op->args[2])->val;
int shr = op->args[3];
if (op->opc == INDEX_op_extract2_i64) {
v1 >>= shr;
v2 <<= 64 - shr;
} else {
v1 = (uint32_t)v1 >> shr;
v2 = (uint64_t)((int32_t)v2 << (32 - shr));
}
return tcg_opt_gen_movi(ctx, op, op->args[0], v1 | v2);
}
return false;
}
static bool fold_exts(OptContext *ctx, TCGOp *op)
{
uint64_t s_mask_old, s_mask, z_mask, sign;
bool type_change = false;
if (fold_const1(ctx, op)) {
return true;
}
z_mask = arg_info(op->args[1])->z_mask;
s_mask = arg_info(op->args[1])->s_mask;
s_mask_old = s_mask;
switch (op->opc) {
CASE_OP_32_64(ext8s):
sign = INT8_MIN;
z_mask = (uint8_t)z_mask;
break;
CASE_OP_32_64(ext16s):
sign = INT16_MIN;
z_mask = (uint16_t)z_mask;
break;
case INDEX_op_ext_i32_i64:
type_change = true;
QEMU_FALLTHROUGH;
case INDEX_op_ext32s_i64:
sign = INT32_MIN;
z_mask = (uint32_t)z_mask;
break;
default:
g_assert_not_reached();
}
if (z_mask & sign) {
z_mask |= sign;
}
s_mask |= sign << 1;
ctx->z_mask = z_mask;
ctx->s_mask = s_mask;
if (!type_change) {
ctx->a_mask = s_mask & ~s_mask_old;
}
return fold_masks(ctx, op);
}
static bool fold_extu(OptContext *ctx, TCGOp *op)
{
uint64_t z_mask_old, z_mask;
bool type_change = false;
if (fold_const1(ctx, op)) {
return true;
}
z_mask_old = z_mask = arg_info(op->args[1])->z_mask;
switch (op->opc) {
CASE_OP_32_64(ext8u):
z_mask = (uint8_t)z_mask;
break;
CASE_OP_32_64(ext16u):
z_mask = (uint16_t)z_mask;
break;
case INDEX_op_extrl_i64_i32:
case INDEX_op_extu_i32_i64:
type_change = true;
QEMU_FALLTHROUGH;
case INDEX_op_ext32u_i64:
z_mask = (uint32_t)z_mask;
break;
case INDEX_op_extrh_i64_i32:
type_change = true;
z_mask >>= 32;
break;
default:
g_assert_not_reached();
}
ctx->z_mask = z_mask;
ctx->s_mask = smask_from_zmask(z_mask);
if (!type_change) {
ctx->a_mask = z_mask_old ^ z_mask;
}
return fold_masks(ctx, op);
}
static bool fold_mb(OptContext *ctx, TCGOp *op)
{
/* Eliminate duplicate and redundant fence instructions. */
if (ctx->prev_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.
*/
ctx->prev_mb->args[0] |= op->args[0];
tcg_op_remove(ctx->tcg, op);
} else {
ctx->prev_mb = op;
}
return true;
}
static bool fold_mov(OptContext *ctx, TCGOp *op)
{
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]);
}
static bool fold_movcond(OptContext *ctx, TCGOp *op)
{
TCGCond cond = op->args[5];
int i;
if (swap_commutative(NO_DEST, &op->args[1], &op->args[2])) {
op->args[5] = cond = tcg_swap_cond(cond);
}
/*
* 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] = cond = tcg_invert_cond(cond);
}
i = do_constant_folding_cond(ctx->type, op->args[1], op->args[2], cond);
if (i >= 0) {
return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[4 - i]);
}
ctx->z_mask = arg_info(op->args[3])->z_mask
| arg_info(op->args[4])->z_mask;
ctx->s_mask = arg_info(op->args[3])->s_mask
& arg_info(op->args[4])->s_mask;
if (arg_is_const(op->args[3]) && arg_is_const(op->args[4])) {
uint64_t tv = arg_info(op->args[3])->val;
uint64_t fv = arg_info(op->args[4])->val;
TCGOpcode opc;
switch (ctx->type) {
case TCG_TYPE_I32:
opc = INDEX_op_setcond_i32;
break;
case TCG_TYPE_I64:
opc = INDEX_op_setcond_i64;
break;
default:
g_assert_not_reached();
}
if (tv == 1 && fv == 0) {
op->opc = opc;
op->args[3] = cond;
} else if (fv == 1 && tv == 0) {
op->opc = opc;
op->args[3] = tcg_invert_cond(cond);
}
}
return false;
}
static bool fold_mul(OptContext *ctx, TCGOp *op)
{
if (fold_const2(ctx, op) ||
fold_xi_to_i(ctx, op, 0) ||
fold_xi_to_x(ctx, op, 1)) {
return true;
}
return false;
}
static bool fold_mul_highpart(OptContext *ctx, TCGOp *op)
{
if (fold_const2_commutative(ctx, op) ||
fold_xi_to_i(ctx, op, 0)) {
return true;
}
return false;
}
static bool fold_multiply2(OptContext *ctx, TCGOp *op)
{
swap_commutative(op->args[0], &op->args[2], &op->args[3]);
if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])) {
uint64_t a = arg_info(op->args[2])->val;
uint64_t b = arg_info(op->args[3])->val;
uint64_t h, l;
TCGArg rl, rh;
TCGOp *op2;
switch (op->opc) {
case INDEX_op_mulu2_i32:
l = (uint64_t)(uint32_t)a * (uint32_t)b;
h = (int32_t)(l >> 32);
l = (int32_t)l;
break;
case INDEX_op_muls2_i32:
l = (int64_t)(int32_t)a * (int32_t)b;
h = l >> 32;
l = (int32_t)l;
break;
case INDEX_op_mulu2_i64:
mulu64(&l, &h, a, b);
break;
case INDEX_op_muls2_i64:
muls64(&l, &h, a, b);
break;
default:
g_assert_not_reached();
}
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, 2);
tcg_opt_gen_movi(ctx, op, rl, l);
tcg_opt_gen_movi(ctx, op2, rh, h);
return true;
}
return false;
}
static bool fold_nand(OptContext *ctx, TCGOp *op)
{
if (fold_const2_commutative(ctx, op) ||
fold_xi_to_not(ctx, op, -1)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
static bool fold_neg(OptContext *ctx, TCGOp *op)
{
uint64_t z_mask;
if (fold_const1(ctx, op)) {
return true;
}
/* Set to 1 all bits to the left of the rightmost. */
z_mask = arg_info(op->args[1])->z_mask;
ctx->z_mask = -(z_mask & -z_mask);
/*
* Because of fold_sub_to_neg, we want to always return true,
* via finish_folding.
*/
finish_folding(ctx, op);
return true;
}
static bool fold_nor(OptContext *ctx, TCGOp *op)
{
if (fold_const2_commutative(ctx, op) ||
fold_xi_to_not(ctx, op, 0)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
static bool fold_not(OptContext *ctx, TCGOp *op)
{
if (fold_const1(ctx, op)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask;
/* Because of fold_to_not, we want to always return true, via finish. */
finish_folding(ctx, op);
return true;
}
static bool fold_or(OptContext *ctx, TCGOp *op)
{
if (fold_const2_commutative(ctx, op) ||
fold_xi_to_x(ctx, op, 0) ||
fold_xx_to_x(ctx, op)) {
return true;
}
ctx->z_mask = arg_info(op->args[1])->z_mask
| arg_info(op->args[2])->z_mask;
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return fold_masks(ctx, op);
}
static bool fold_orc(OptContext *ctx, TCGOp *op)
{
if (fold_const2(ctx, op) ||
fold_xx_to_i(ctx, op, -1) ||
fold_xi_to_x(ctx, op, -1) ||
fold_ix_to_not(ctx, op, 0)) {
return true;
}
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return false;
}
static bool fold_qemu_ld(OptContext *ctx, TCGOp *op)
{
const TCGOpDef *def = &tcg_op_defs[op->opc];
MemOpIdx oi = op->args[def->nb_oargs + def->nb_iargs];
MemOp mop = get_memop(oi);
int width = 8 * memop_size(mop);
if (width < 64) {
ctx->s_mask = MAKE_64BIT_MASK(width, 64 - width);
if (!(mop & MO_SIGN)) {
ctx->z_mask = MAKE_64BIT_MASK(0, width);
ctx->s_mask <<= 1;
}
}
/* Opcodes that touch guest memory stop the mb optimization. */
ctx->prev_mb = NULL;
return false;
}
static bool fold_qemu_st(OptContext *ctx, TCGOp *op)
{
/* Opcodes that touch guest memory stop the mb optimization. */
ctx->prev_mb = NULL;
return false;
}
static bool fold_remainder(OptContext *ctx, TCGOp *op)
{
if (fold_const2(ctx, op) ||
fold_xx_to_i(ctx, op, 0)) {
return true;
}
return false;
}
static bool fold_setcond(OptContext *ctx, TCGOp *op)
{
TCGCond cond = op->args[3];
int i;
if (swap_commutative(op->args[0], &op->args[1], &op->args[2])) {
op->args[3] = cond = tcg_swap_cond(cond);
}
i = do_constant_folding_cond(ctx->type, op->args[1], op->args[2], cond);
if (i >= 0) {
return tcg_opt_gen_movi(ctx, op, op->args[0], i);
}
ctx->z_mask = 1;
ctx->s_mask = smask_from_zmask(1);
return false;
}
static bool fold_setcond2(OptContext *ctx, TCGOp *op)
{
TCGCond cond = op->args[5];
int i, inv = 0;
if (swap_commutative2(&op->args[1], &op->args[3])) {
op->args[5] = cond = tcg_swap_cond(cond);
}
i = do_constant_folding_cond2(&op->args[1], &op->args[3], cond);
if (i >= 0) {
goto do_setcond_const;
}
switch (cond) {
case TCG_COND_LT:
case TCG_COND_GE:
/*
* Simplify LT/GE comparisons vs zero to a single compare
* vs the high word of the input.
*/
if (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) {
goto do_setcond_high;
}
break;
case TCG_COND_NE:
inv = 1;
QEMU_FALLTHROUGH;
case TCG_COND_EQ:
/*
* Simplify EQ/NE comparisons where one of the pairs
* can be simplified.
*/
i = do_constant_folding_cond(TCG_TYPE_I32, op->args[1],
op->args[3], cond);
switch (i ^ inv) {
case 0:
goto do_setcond_const;
case 1:
goto do_setcond_high;
}
i = do_constant_folding_cond(TCG_TYPE_I32, op->args[2],
op->args[4], cond);
switch (i ^ inv) {
case 0:
goto do_setcond_const;
case 1:
op->args[2] = op->args[3];
op->args[3] = cond;
op->opc = INDEX_op_setcond_i32;
break;
}
break;
default:
break;
do_setcond_high:
op->args[1] = op->args[2];
op->args[2] = op->args[4];
op->args[3] = cond;
op->opc = INDEX_op_setcond_i32;
break;
}
ctx->z_mask = 1;
ctx->s_mask = smask_from_zmask(1);
return false;
do_setcond_const:
return tcg_opt_gen_movi(ctx, op, op->args[0], i);
}
static bool fold_sextract(OptContext *ctx, TCGOp *op)
{
uint64_t z_mask, s_mask, s_mask_old;
int pos = op->args[2];
int len = op->args[3];
if (arg_is_const(op->args[1])) {
uint64_t t;
t = arg_info(op->args[1])->val;
t = sextract64(t, pos, len);
return tcg_opt_gen_movi(ctx, op, op->args[0], t);
}
z_mask = arg_info(op->args[1])->z_mask;
z_mask = sextract64(z_mask, pos, len);
ctx->z_mask = z_mask;
s_mask_old = arg_info(op->args[1])->s_mask;
s_mask = sextract64(s_mask_old, pos, len);
s_mask |= MAKE_64BIT_MASK(len, 64 - len);
ctx->s_mask = s_mask;
if (pos == 0) {
ctx->a_mask = s_mask & ~s_mask_old;
}
return fold_masks(ctx, op);
}
static bool fold_shift(OptContext *ctx, TCGOp *op)
{
uint64_t s_mask, z_mask, sign;
if (fold_const2(ctx, op) ||
fold_ix_to_i(ctx, op, 0) ||
fold_xi_to_x(ctx, op, 0)) {
return true;
}
s_mask = arg_info(op->args[1])->s_mask;
z_mask = arg_info(op->args[1])->z_mask;
if (arg_is_const(op->args[2])) {
int sh = arg_info(op->args[2])->val;
ctx->z_mask = do_constant_folding(op->opc, ctx->type, z_mask, sh);
s_mask = do_constant_folding(op->opc, ctx->type, s_mask, sh);
ctx->s_mask = smask_from_smask(s_mask);
return fold_masks(ctx, op);
}
switch (op->opc) {
CASE_OP_32_64(sar):
/*
* Arithmetic right shift will not reduce the number of
* input sign repetitions.
*/
ctx->s_mask = s_mask;
break;
CASE_OP_32_64(shr):
/*
* If the sign bit is known zero, then logical right shift
* will not reduced the number of input sign repetitions.
*/
sign = (s_mask & -s_mask) >> 1;
if (!(z_mask & sign)) {
ctx->s_mask = s_mask;
}
break;
default:
break;
}
return false;
}
static bool fold_sub_to_neg(OptContext *ctx, TCGOp *op)
{
TCGOpcode neg_op;
bool have_neg;
if (!arg_is_const(op->args[1]) || arg_info(op->args[1])->val != 0) {
return false;
}
switch (ctx->type) {
case TCG_TYPE_I32:
neg_op = INDEX_op_neg_i32;
have_neg = TCG_TARGET_HAS_neg_i32;
break;
case TCG_TYPE_I64:
neg_op = INDEX_op_neg_i64;
have_neg = TCG_TARGET_HAS_neg_i64;
break;
case TCG_TYPE_V64:
case TCG_TYPE_V128:
case TCG_TYPE_V256:
neg_op = INDEX_op_neg_vec;
have_neg = (TCG_TARGET_HAS_neg_vec &&
tcg_can_emit_vec_op(neg_op, ctx->type, TCGOP_VECE(op)) > 0);
break;
default:
g_assert_not_reached();
}
if (have_neg) {
op->opc = neg_op;
op->args[1] = op->args[2];
return fold_neg(ctx, op);
}
return false;
}
/* We cannot as yet do_constant_folding with vectors. */
static bool fold_sub_vec(OptContext *ctx, TCGOp *op)
{
if (fold_xx_to_i(ctx, op, 0) ||
fold_xi_to_x(ctx, op, 0) ||
fold_sub_to_neg(ctx, op)) {
return true;
}
return false;
}
static bool fold_sub(OptContext *ctx, TCGOp *op)
{
return fold_const2(ctx, op) || fold_sub_vec(ctx, op);
}
static bool fold_sub2(OptContext *ctx, TCGOp *op)
{
return fold_addsub2(ctx, op, false);
}
static bool fold_tcg_ld(OptContext *ctx, TCGOp *op)
{
/* We can't do any folding with a load, but we can record bits. */
switch (op->opc) {
CASE_OP_32_64(ld8s):
ctx->s_mask = MAKE_64BIT_MASK(8, 56);
break;
CASE_OP_32_64(ld8u):
ctx->z_mask = MAKE_64BIT_MASK(0, 8);
ctx->s_mask = MAKE_64BIT_MASK(9, 55);
break;
CASE_OP_32_64(ld16s):
ctx->s_mask = MAKE_64BIT_MASK(16, 48);
break;
CASE_OP_32_64(ld16u):
ctx->z_mask = MAKE_64BIT_MASK(0, 16);
ctx->s_mask = MAKE_64BIT_MASK(17, 47);
break;
case INDEX_op_ld32s_i64:
ctx->s_mask = MAKE_64BIT_MASK(32, 32);
break;
case INDEX_op_ld32u_i64:
ctx->z_mask = MAKE_64BIT_MASK(0, 32);
ctx->s_mask = MAKE_64BIT_MASK(33, 31);
break;
default:
g_assert_not_reached();
}
return false;
}
static bool fold_xor(OptContext *ctx, TCGOp *op)
{
if (fold_const2_commutative(ctx, op) ||
fold_xx_to_i(ctx, op, 0) ||
fold_xi_to_x(ctx, op, 0) ||
fold_xi_to_not(ctx, op, -1)) {
return true;
}
ctx->z_mask = arg_info(op->args[1])->z_mask
| arg_info(op->args[2])->z_mask;
ctx->s_mask = arg_info(op->args[1])->s_mask
& arg_info(op->args[2])->s_mask;
return fold_masks(ctx, op);
}
/* Propagate constants and copies, fold constant expressions. */
void tcg_optimize(TCGContext *s)
{
int nb_temps, i;
TCGOp *op, *op_next;
OptContext ctx = { .tcg = s };
/* 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;
for (i = 0; i < nb_temps; ++i) {
s->temps[i].state_ptr = NULL;
}
QTAILQ_FOREACH_SAFE(op, &s->ops, link, op_next) {
TCGOpcode opc = op->opc;
const TCGOpDef *def;
bool done = false;
/* Calls are special. */
if (opc == INDEX_op_call) {
fold_call(&ctx, op);
continue;
}
def = &tcg_op_defs[opc];
init_arguments(&ctx, op, def->nb_oargs + def->nb_iargs);
copy_propagate(&ctx, op, def->nb_oargs, def->nb_iargs);
/* Pre-compute the type of the operation. */
if (def->flags & TCG_OPF_VECTOR) {
ctx.type = TCG_TYPE_V64 + TCGOP_VECL(op);
} else if (def->flags & TCG_OPF_64BIT) {
ctx.type = TCG_TYPE_I64;
} else {
ctx.type = TCG_TYPE_I32;
}
/* Assume all bits affected, no bits known zero, no sign reps. */
ctx.a_mask = -1;
ctx.z_mask = -1;
ctx.s_mask = 0;
/*
* Process each opcode.
* Sorted alphabetically by opcode as much as possible.
*/
switch (opc) {
CASE_OP_32_64(add):
done = fold_add(&ctx, op);
break;
case INDEX_op_add_vec:
done = fold_add_vec(&ctx, op);
break;
CASE_OP_32_64(add2):
done = fold_add2(&ctx, op);
break;
CASE_OP_32_64_VEC(and):
done = fold_and(&ctx, op);
break;
CASE_OP_32_64_VEC(andc):
done = fold_andc(&ctx, op);
break;
CASE_OP_32_64(brcond):
done = fold_brcond(&ctx, op);
break;
case INDEX_op_brcond2_i32:
done = fold_brcond2(&ctx, op);
break;
CASE_OP_32_64(bswap16):
CASE_OP_32_64(bswap32):
case INDEX_op_bswap64_i64:
done = fold_bswap(&ctx, op);
break;
CASE_OP_32_64(clz):
CASE_OP_32_64(ctz):
done = fold_count_zeros(&ctx, op);
break;
CASE_OP_32_64(ctpop):
done = fold_ctpop(&ctx, op);
break;
CASE_OP_32_64(deposit):
done = fold_deposit(&ctx, op);
break;
CASE_OP_32_64(div):
CASE_OP_32_64(divu):
done = fold_divide(&ctx, op);
break;
case INDEX_op_dup_vec:
done = fold_dup(&ctx, op);
break;
case INDEX_op_dup2_vec:
done = fold_dup2(&ctx, op);
break;
CASE_OP_32_64_VEC(eqv):
done = fold_eqv(&ctx, op);
break;
CASE_OP_32_64(extract):
done = fold_extract(&ctx, op);
break;
CASE_OP_32_64(extract2):
done = fold_extract2(&ctx, op);
break;
CASE_OP_32_64(ext8s):
CASE_OP_32_64(ext16s):
case INDEX_op_ext32s_i64:
case INDEX_op_ext_i32_i64:
done = fold_exts(&ctx, op);
break;
CASE_OP_32_64(ext8u):
CASE_OP_32_64(ext16u):
case INDEX_op_ext32u_i64:
case INDEX_op_extu_i32_i64:
case INDEX_op_extrl_i64_i32:
case INDEX_op_extrh_i64_i32:
done = fold_extu(&ctx, op);
break;
CASE_OP_32_64(ld8s):
CASE_OP_32_64(ld8u):
CASE_OP_32_64(ld16s):
CASE_OP_32_64(ld16u):
case INDEX_op_ld32s_i64:
case INDEX_op_ld32u_i64:
done = fold_tcg_ld(&ctx, op);
break;
case INDEX_op_mb:
done = fold_mb(&ctx, op);
break;
CASE_OP_32_64_VEC(mov):
done = fold_mov(&ctx, op);
break;
CASE_OP_32_64(movcond):
done = fold_movcond(&ctx, op);
break;
CASE_OP_32_64(mul):
done = fold_mul(&ctx, op);
break;
CASE_OP_32_64(mulsh):
CASE_OP_32_64(muluh):
done = fold_mul_highpart(&ctx, op);
break;
CASE_OP_32_64(muls2):
CASE_OP_32_64(mulu2):
done = fold_multiply2(&ctx, op);
break;
CASE_OP_32_64_VEC(nand):
done = fold_nand(&ctx, op);
break;
CASE_OP_32_64(neg):
done = fold_neg(&ctx, op);
break;
CASE_OP_32_64_VEC(nor):
done = fold_nor(&ctx, op);
break;
CASE_OP_32_64_VEC(not):
done = fold_not(&ctx, op);
break;
CASE_OP_32_64_VEC(or):
done = fold_or(&ctx, op);
break;
CASE_OP_32_64_VEC(orc):
done = fold_orc(&ctx, op);
break;
case INDEX_op_qemu_ld_i32:
case INDEX_op_qemu_ld_i64:
done = fold_qemu_ld(&ctx, op);
break;
case INDEX_op_qemu_st_i32:
case INDEX_op_qemu_st8_i32:
case INDEX_op_qemu_st_i64:
done = fold_qemu_st(&ctx, op);
break;
CASE_OP_32_64(rem):
CASE_OP_32_64(remu):
done = fold_remainder(&ctx, op);
break;
CASE_OP_32_64(rotl):
CASE_OP_32_64(rotr):
CASE_OP_32_64(sar):
CASE_OP_32_64(shl):
CASE_OP_32_64(shr):
done = fold_shift(&ctx, op);
break;
CASE_OP_32_64(setcond):
done = fold_setcond(&ctx, op);
break;
case INDEX_op_setcond2_i32:
done = fold_setcond2(&ctx, op);
break;
CASE_OP_32_64(sextract):
done = fold_sextract(&ctx, op);
break;
CASE_OP_32_64(sub):
done = fold_sub(&ctx, op);
break;
case INDEX_op_sub_vec:
done = fold_sub_vec(&ctx, op);
break;
CASE_OP_32_64(sub2):
done = fold_sub2(&ctx, op);
break;
CASE_OP_32_64_VEC(xor):
done = fold_xor(&ctx, op);
break;
default:
break;
}
if (!done) {
finish_folding(&ctx, op);
}
}
}
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