qemu

optimize.c (58828B)

---

 /*
  * 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]);
         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_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);
 
         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);
 
         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);
         }
     }
 }