/* * 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-common.h" #include "exec/cpu-common.h" #include "tcg-op.h" #define CASE_OP_32_64(x) \ glue(glue(case INDEX_op_, x), _i32): \ glue(glue(case INDEX_op_, x), _i64) struct tcg_temp_info { bool is_const; uint16_t prev_copy; uint16_t next_copy; tcg_target_ulong val; tcg_target_ulong mask; }; static struct tcg_temp_info temps[TCG_MAX_TEMPS]; static TCGTempSet temps_used; static inline bool temp_is_const(TCGArg arg) { return temps[arg].is_const; } static inline bool temp_is_copy(TCGArg arg) { return temps[arg].next_copy != arg; } /* Reset TEMP's state, possibly removing the temp for the list of copies. */ static void reset_temp(TCGArg temp) { temps[temps[temp].next_copy].prev_copy = temps[temp].prev_copy; temps[temps[temp].prev_copy].next_copy = temps[temp].next_copy; temps[temp].next_copy = temp; temps[temp].prev_copy = temp; temps[temp].is_const = false; temps[temp].mask = -1; } /* Reset all temporaries, given that there are NB_TEMPS of them. */ static void reset_all_temps(int nb_temps) { bitmap_zero(temps_used.l, nb_temps); } /* Initialize and activate a temporary. */ static void init_temp_info(TCGArg temp) { if (!test_bit(temp, temps_used.l)) { temps[temp].next_copy = temp; temps[temp].prev_copy = temp; temps[temp].is_const = false; temps[temp].mask = -1; set_bit(temp, temps_used.l); } } static int op_bits(TCGOpcode op) { const TCGOpDef *def = &tcg_op_defs[op]; return def->flags & TCG_OPF_64BIT ? 64 : 32; } static TCGOpcode op_to_mov(TCGOpcode op) { switch (op_bits(op)) { case 32: return INDEX_op_mov_i32; case 64: return INDEX_op_mov_i64; default: fprintf(stderr, "op_to_mov: unexpected return value of " "function op_bits.\n"); tcg_abort(); } } static TCGOpcode op_to_movi(TCGOpcode op) { switch (op_bits(op)) { case 32: return INDEX_op_movi_i32; case 64: return INDEX_op_movi_i64; default: fprintf(stderr, "op_to_movi: unexpected return value of " "function op_bits.\n"); tcg_abort(); } } static TCGArg find_better_copy(TCGContext *s, TCGArg temp) { TCGArg i; /* If this is already a global, we can't do better. */ if (temp < s->nb_globals) { return temp; } /* Search for a global first. */ for (i = temps[temp].next_copy ; i != temp ; i = temps[i].next_copy) { if (i < s->nb_globals) { return i; } } /* If it is a temp, search for a temp local. */ if (!s->temps[temp].temp_local) { for (i = temps[temp].next_copy ; i != temp ; i = temps[i].next_copy) { if (s->temps[i].temp_local) { return i; } } } /* Failure to find a better representation, return the same temp. */ return temp; } static bool temps_are_copies(TCGArg arg1, TCGArg arg2) { TCGArg i; if (arg1 == arg2) { return true; } if (!temp_is_copy(arg1) || !temp_is_copy(arg2)) { return false; } for (i = temps[arg1].next_copy ; i != arg1 ; i = temps[i].next_copy) { if (i == arg2) { return true; } } return false; } static void tcg_opt_gen_movi(TCGContext *s, TCGOp *op, TCGArg *args, TCGArg dst, TCGArg val) { TCGOpcode new_op = op_to_movi(op->opc); tcg_target_ulong mask; op->opc = new_op; reset_temp(dst); temps[dst].is_const = true; temps[dst].val = val; mask = val; if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_movi_i32) { /* High bits of the destination are now garbage. */ mask |= ~0xffffffffull; } temps[dst].mask = mask; args[0] = dst; args[1] = val; } static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, TCGArg *args, TCGArg dst, TCGArg src) { if (temps_are_copies(dst, src)) { tcg_op_remove(s, op); return; } TCGOpcode new_op = op_to_mov(op->opc); tcg_target_ulong mask; op->opc = new_op; reset_temp(dst); mask = temps[src].mask; if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_mov_i32) { /* High bits of the destination are now garbage. */ mask |= ~0xffffffffull; } temps[dst].mask = mask; if (s->temps[src].type == s->temps[dst].type) { temps[dst].next_copy = temps[src].next_copy; temps[dst].prev_copy = src; temps[temps[dst].next_copy].prev_copy = dst; temps[src].next_copy = dst; temps[dst].is_const = temps[src].is_const; temps[dst].val = temps[src].val; } args[0] = dst; args[1] = src; } static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y) { uint64_t l64, h64; switch (op) { CASE_OP_32_64(add): return x + y; CASE_OP_32_64(sub): return x - y; CASE_OP_32_64(mul): return x * y; CASE_OP_32_64(and): return x & y; CASE_OP_32_64(or): return x | y; CASE_OP_32_64(xor): return x ^ y; case INDEX_op_shl_i32: return (uint32_t)x << (y & 31); case INDEX_op_shl_i64: return (uint64_t)x << (y & 63); case INDEX_op_shr_i32: return (uint32_t)x >> (y & 31); case INDEX_op_shr_i64: return (uint64_t)x >> (y & 63); case INDEX_op_sar_i32: return (int32_t)x >> (y & 31); case INDEX_op_sar_i64: return (int64_t)x >> (y & 63); case INDEX_op_rotr_i32: return ror32(x, y & 31); case INDEX_op_rotr_i64: return ror64(x, y & 63); case INDEX_op_rotl_i32: return rol32(x, y & 31); case INDEX_op_rotl_i64: return rol64(x, y & 63); CASE_OP_32_64(not): return ~x; CASE_OP_32_64(neg): return -x; CASE_OP_32_64(andc): return x & ~y; CASE_OP_32_64(orc): return x | ~y; CASE_OP_32_64(eqv): return ~(x ^ y); CASE_OP_32_64(nand): return ~(x & y); CASE_OP_32_64(nor): return ~(x | y); case INDEX_op_clz_i32: return (uint32_t)x ? clz32(x) : y; case INDEX_op_clz_i64: return x ? clz64(x) : y; case INDEX_op_ctz_i32: return (uint32_t)x ? ctz32(x) : y; case INDEX_op_ctz_i64: return x ? ctz64(x) : y; case INDEX_op_ctpop_i32: return ctpop32(x); case INDEX_op_ctpop_i64: return ctpop64(x); CASE_OP_32_64(ext8s): return (int8_t)x; CASE_OP_32_64(ext16s): return (int16_t)x; CASE_OP_32_64(ext8u): return (uint8_t)x; CASE_OP_32_64(ext16u): return (uint16_t)x; case INDEX_op_ext_i32_i64: case INDEX_op_ext32s_i64: return (int32_t)x; case INDEX_op_extu_i32_i64: case INDEX_op_extrl_i64_i32: case INDEX_op_ext32u_i64: return (uint32_t)x; case INDEX_op_extrh_i64_i32: return (uint64_t)x >> 32; case INDEX_op_muluh_i32: return ((uint64_t)(uint32_t)x * (uint32_t)y) >> 32; case INDEX_op_mulsh_i32: return ((int64_t)(int32_t)x * (int32_t)y) >> 32; case INDEX_op_muluh_i64: mulu64(&l64, &h64, x, y); return h64; case INDEX_op_mulsh_i64: muls64(&l64, &h64, x, y); return h64; case INDEX_op_div_i32: /* Avoid crashing on divide by zero, otherwise undefined. */ return (int32_t)x / ((int32_t)y ? : 1); case INDEX_op_divu_i32: return (uint32_t)x / ((uint32_t)y ? : 1); case INDEX_op_div_i64: return (int64_t)x / ((int64_t)y ? : 1); case INDEX_op_divu_i64: return (uint64_t)x / ((uint64_t)y ? : 1); case INDEX_op_rem_i32: return (int32_t)x % ((int32_t)y ? : 1); case INDEX_op_remu_i32: return (uint32_t)x % ((uint32_t)y ? : 1); case INDEX_op_rem_i64: return (int64_t)x % ((int64_t)y ? : 1); case INDEX_op_remu_i64: return (uint64_t)x % ((uint64_t)y ? : 1); default: fprintf(stderr, "Unrecognized operation %d in do_constant_folding.\n", op); tcg_abort(); } } static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y) { TCGArg res = do_constant_folding_2(op, x, y); if (op_bits(op) == 32) { res = (int32_t)res; } return res; } static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c) { switch (c) { case TCG_COND_EQ: return x == y; case TCG_COND_NE: return x != y; case TCG_COND_LT: return (int32_t)x < (int32_t)y; case TCG_COND_GE: return (int32_t)x >= (int32_t)y; case TCG_COND_LE: return (int32_t)x <= (int32_t)y; case TCG_COND_GT: return (int32_t)x > (int32_t)y; case TCG_COND_LTU: return x < y; case TCG_COND_GEU: return x >= y; case TCG_COND_LEU: return x <= y; case TCG_COND_GTU: return x > y; default: tcg_abort(); } } static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c) { switch (c) { case TCG_COND_EQ: return x == y; case TCG_COND_NE: return x != y; case TCG_COND_LT: return (int64_t)x < (int64_t)y; case TCG_COND_GE: return (int64_t)x >= (int64_t)y; case TCG_COND_LE: return (int64_t)x <= (int64_t)y; case TCG_COND_GT: return (int64_t)x > (int64_t)y; case TCG_COND_LTU: return x < y; case TCG_COND_GEU: return x >= y; case TCG_COND_LEU: return x <= y; case TCG_COND_GTU: return x > y; default: tcg_abort(); } } static bool do_constant_folding_cond_eq(TCGCond c) { switch (c) { case TCG_COND_GT: case TCG_COND_LTU: case TCG_COND_LT: case TCG_COND_GTU: case TCG_COND_NE: return 0; case TCG_COND_GE: case TCG_COND_GEU: case TCG_COND_LE: case TCG_COND_LEU: case TCG_COND_EQ: return 1; default: tcg_abort(); } } /* Return 2 if the condition can't be simplified, and the result of the condition (0 or 1) if it can */ static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x, TCGArg y, TCGCond c) { if (temp_is_const(x) && temp_is_const(y)) { switch (op_bits(op)) { case 32: return do_constant_folding_cond_32(temps[x].val, temps[y].val, c); case 64: return do_constant_folding_cond_64(temps[x].val, temps[y].val, c); default: tcg_abort(); } } else if (temps_are_copies(x, y)) { return do_constant_folding_cond_eq(c); } else if (temp_is_const(y) && temps[y].val == 0) { switch (c) { case TCG_COND_LTU: return 0; case TCG_COND_GEU: return 1; default: return 2; } } return 2; } /* Return 2 if the condition can't be simplified, and the result of the condition (0 or 1) if it can */ static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c) { TCGArg al = p1[0], ah = p1[1]; TCGArg bl = p2[0], bh = p2[1]; if (temp_is_const(bl) && temp_is_const(bh)) { uint64_t b = ((uint64_t)temps[bh].val << 32) | (uint32_t)temps[bl].val; if (temp_is_const(al) && temp_is_const(ah)) { uint64_t a; a = ((uint64_t)temps[ah].val << 32) | (uint32_t)temps[al].val; 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 (temps_are_copies(al, bl) && temps_are_copies(ah, bh)) { return do_constant_folding_cond_eq(c); } return 2; } static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2) { TCGArg a1 = *p1, a2 = *p2; int sum = 0; sum += temp_is_const(a1); sum -= temp_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 += temp_is_const(p1[0]); sum += temp_is_const(p1[1]); sum -= temp_is_const(p2[0]); sum -= temp_is_const(p2[1]); if (sum > 0) { TCGArg t; t = p1[0], p1[0] = p2[0], p2[0] = t; t = p1[1], p1[1] = p2[1], p2[1] = t; return true; } return false; } /* Propagate constants and copies, fold constant expressions. */ void tcg_optimize(TCGContext *s) { int oi, oi_next, nb_temps, nb_globals; TCGArg *prev_mb_args = NULL; /* Array VALS has an element for each temp. If this temp holds a constant then its value is kept in VALS' element. If this temp is a copy of other ones then the other copies are available through the doubly linked circular list. */ nb_temps = s->nb_temps; nb_globals = s->nb_globals; reset_all_temps(nb_temps); for (oi = s->gen_op_buf[0].next; oi != 0; oi = oi_next) { tcg_target_ulong mask, partmask, affected; int nb_oargs, nb_iargs, i; TCGArg tmp; TCGOp * const op = &s->gen_op_buf[oi]; TCGArg * const args = &s->gen_opparam_buf[op->args]; TCGOpcode opc = op->opc; const TCGOpDef *def = &tcg_op_defs[opc]; oi_next = op->next; /* Count the arguments, and initialize the temps that are going to be used */ if (opc == INDEX_op_call) { nb_oargs = op->callo; nb_iargs = op->calli; for (i = 0; i < nb_oargs + nb_iargs; i++) { tmp = args[i]; if (tmp != TCG_CALL_DUMMY_ARG) { init_temp_info(tmp); } } } else { nb_oargs = def->nb_oargs; nb_iargs = def->nb_iargs; for (i = 0; i < nb_oargs + nb_iargs; i++) { init_temp_info(args[i]); } } /* Do copy propagation */ for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) { if (temp_is_copy(args[i])) { args[i] = find_better_copy(s, args[i]); } } /* For commutative operations make constant second argument */ switch (opc) { CASE_OP_32_64(add): CASE_OP_32_64(mul): CASE_OP_32_64(and): CASE_OP_32_64(or): CASE_OP_32_64(xor): CASE_OP_32_64(eqv): CASE_OP_32_64(nand): CASE_OP_32_64(nor): CASE_OP_32_64(muluh): CASE_OP_32_64(mulsh): swap_commutative(args[0], &args[1], &args[2]); break; CASE_OP_32_64(brcond): if (swap_commutative(-1, &args[0], &args[1])) { args[2] = tcg_swap_cond(args[2]); } break; CASE_OP_32_64(setcond): if (swap_commutative(args[0], &args[1], &args[2])) { args[3] = tcg_swap_cond(args[3]); } break; CASE_OP_32_64(movcond): if (swap_commutative(-1, &args[1], &args[2])) { args[5] = tcg_swap_cond(args[5]); } /* For movcond, we canonicalize the "false" input reg to match the destination reg so that the tcg backend can implement a "move if true" operation. */ if (swap_commutative(args[0], &args[4], &args[3])) { args[5] = tcg_invert_cond(args[5]); } break; CASE_OP_32_64(add2): swap_commutative(args[0], &args[2], &args[4]); swap_commutative(args[1], &args[3], &args[5]); break; CASE_OP_32_64(mulu2): CASE_OP_32_64(muls2): swap_commutative(args[0], &args[2], &args[3]); break; case INDEX_op_brcond2_i32: if (swap_commutative2(&args[0], &args[2])) { args[4] = tcg_swap_cond(args[4]); } break; case INDEX_op_setcond2_i32: if (swap_commutative2(&args[1], &args[3])) { args[5] = tcg_swap_cond(args[5]); } break; default: break; } /* Simplify expressions for "shift/rot r, 0, a => movi r, 0", and "sub r, 0, a => neg r, a" case. */ switch (opc) { CASE_OP_32_64(shl): CASE_OP_32_64(shr): CASE_OP_32_64(sar): CASE_OP_32_64(rotl): CASE_OP_32_64(rotr): if (temp_is_const(args[1]) && temps[args[1]].val == 0) { tcg_opt_gen_movi(s, op, args, args[0], 0); continue; } break; CASE_OP_32_64(sub): { TCGOpcode neg_op; bool have_neg; if (temp_is_const(args[2])) { /* Proceed with possible constant folding. */ break; } if (opc == INDEX_op_sub_i32) { neg_op = INDEX_op_neg_i32; have_neg = TCG_TARGET_HAS_neg_i32; } else { neg_op = INDEX_op_neg_i64; have_neg = TCG_TARGET_HAS_neg_i64; } if (!have_neg) { break; } if (temp_is_const(args[1]) && temps[args[1]].val == 0) { op->opc = neg_op; reset_temp(args[0]); args[1] = args[2]; continue; } } break; CASE_OP_32_64(xor): CASE_OP_32_64(nand): if (!temp_is_const(args[1]) && temp_is_const(args[2]) && temps[args[2]].val == -1) { i = 1; goto try_not; } break; CASE_OP_32_64(nor): if (!temp_is_const(args[1]) && temp_is_const(args[2]) && temps[args[2]].val == 0) { i = 1; goto try_not; } break; CASE_OP_32_64(andc): if (!temp_is_const(args[2]) && temp_is_const(args[1]) && temps[args[1]].val == -1) { i = 2; goto try_not; } break; CASE_OP_32_64(orc): CASE_OP_32_64(eqv): if (!temp_is_const(args[2]) && temp_is_const(args[1]) && temps[args[1]].val == 0) { i = 2; goto try_not; } break; try_not: { TCGOpcode not_op; bool have_not; if (def->flags & TCG_OPF_64BIT) { not_op = INDEX_op_not_i64; have_not = TCG_TARGET_HAS_not_i64; } else { not_op = INDEX_op_not_i32; have_not = TCG_TARGET_HAS_not_i32; } if (!have_not) { break; } op->opc = not_op; reset_temp(args[0]); args[1] = args[i]; continue; } default: break; } /* Simplify expression for "op r, a, const => mov r, a" cases */ switch (opc) { CASE_OP_32_64(add): CASE_OP_32_64(sub): CASE_OP_32_64(shl): CASE_OP_32_64(shr): CASE_OP_32_64(sar): CASE_OP_32_64(rotl): CASE_OP_32_64(rotr): CASE_OP_32_64(or): CASE_OP_32_64(xor): CASE_OP_32_64(andc): if (!temp_is_const(args[1]) && temp_is_const(args[2]) && temps[args[2]].val == 0) { tcg_opt_gen_mov(s, op, args, args[0], args[1]); continue; } break; CASE_OP_32_64(and): CASE_OP_32_64(orc): CASE_OP_32_64(eqv): if (!temp_is_const(args[1]) && temp_is_const(args[2]) && temps[args[2]].val == -1) { tcg_opt_gen_mov(s, op, args, args[0], args[1]); continue; } break; default: break; } /* Simplify using known-zero bits. Currently only ops with a single output argument is supported. */ mask = -1; affected = -1; switch (opc) { CASE_OP_32_64(ext8s): if ((temps[args[1]].mask & 0x80) != 0) { break; } CASE_OP_32_64(ext8u): mask = 0xff; goto and_const; CASE_OP_32_64(ext16s): if ((temps[args[1]].mask & 0x8000) != 0) { break; } CASE_OP_32_64(ext16u): mask = 0xffff; goto and_const; case INDEX_op_ext32s_i64: if ((temps[args[1]].mask & 0x80000000) != 0) { break; } case INDEX_op_ext32u_i64: mask = 0xffffffffU; goto and_const; CASE_OP_32_64(and): mask = temps[args[2]].mask; if (temp_is_const(args[2])) { and_const: affected = temps[args[1]].mask & ~mask; } mask = temps[args[1]].mask & mask; break; case INDEX_op_ext_i32_i64: if ((temps[args[1]].mask & 0x80000000) != 0) { break; } case INDEX_op_extu_i32_i64: /* We do not compute affected as it is a size changing op. */ mask = (uint32_t)temps[args[1]].mask; break; CASE_OP_32_64(andc): /* Known-zeros does not imply known-ones. Therefore unless args[2] is constant, we can't infer anything from it. */ if (temp_is_const(args[2])) { mask = ~temps[args[2]].mask; goto and_const; } /* But we certainly know nothing outside args[1] may be set. */ mask = temps[args[1]].mask; break; case INDEX_op_sar_i32: if (temp_is_const(args[2])) { tmp = temps[args[2]].val & 31; mask = (int32_t)temps[args[1]].mask >> tmp; } break; case INDEX_op_sar_i64: if (temp_is_const(args[2])) { tmp = temps[args[2]].val & 63; mask = (int64_t)temps[args[1]].mask >> tmp; } break; case INDEX_op_shr_i32: if (temp_is_const(args[2])) { tmp = temps[args[2]].val & 31; mask = (uint32_t)temps[args[1]].mask >> tmp; } break; case INDEX_op_shr_i64: if (temp_is_const(args[2])) { tmp = temps[args[2]].val & 63; mask = (uint64_t)temps[args[1]].mask >> tmp; } break; case INDEX_op_extrl_i64_i32: mask = (uint32_t)temps[args[1]].mask; break; case INDEX_op_extrh_i64_i32: mask = (uint64_t)temps[args[1]].mask >> 32; break; CASE_OP_32_64(shl): if (temp_is_const(args[2])) { tmp = temps[args[2]].val & (TCG_TARGET_REG_BITS - 1); mask = temps[args[1]].mask << tmp; } break; CASE_OP_32_64(neg): /* Set to 1 all bits to the left of the rightmost. */ mask = -(temps[args[1]].mask & -temps[args[1]].mask); break; CASE_OP_32_64(deposit): mask = deposit64(temps[args[1]].mask, args[3], args[4], temps[args[2]].mask); break; CASE_OP_32_64(extract): mask = extract64(temps[args[1]].mask, args[2], args[3]); if (args[2] == 0) { affected = temps[args[1]].mask & ~mask; } break; CASE_OP_32_64(sextract): mask = sextract64(temps[args[1]].mask, args[2], args[3]); if (args[2] == 0 && (tcg_target_long)mask >= 0) { affected = temps[args[1]].mask & ~mask; } break; CASE_OP_32_64(or): CASE_OP_32_64(xor): mask = temps[args[1]].mask | temps[args[2]].mask; break; case INDEX_op_clz_i32: case INDEX_op_ctz_i32: mask = temps[args[2]].mask | 31; break; case INDEX_op_clz_i64: case INDEX_op_ctz_i64: mask = temps[args[2]].mask | 63; break; case INDEX_op_ctpop_i32: mask = 32 | 31; break; case INDEX_op_ctpop_i64: mask = 64 | 63; break; CASE_OP_32_64(setcond): case INDEX_op_setcond2_i32: mask = 1; break; CASE_OP_32_64(movcond): mask = temps[args[3]].mask | temps[args[4]].mask; break; CASE_OP_32_64(ld8u): mask = 0xff; break; CASE_OP_32_64(ld16u): mask = 0xffff; break; case INDEX_op_ld32u_i64: mask = 0xffffffffu; break; CASE_OP_32_64(qemu_ld): { TCGMemOpIdx oi = args[nb_oargs + nb_iargs]; TCGMemOp mop = get_memop(oi); if (!(mop & MO_SIGN)) { mask = (2ULL << ((8 << (mop & MO_SIZE)) - 1)) - 1; } } break; default: break; } /* 32-bit ops generate 32-bit results. For the result is zero test below, we can ignore high bits, but for further optimizations we need to record that the high bits contain garbage. */ partmask = mask; if (!(def->flags & TCG_OPF_64BIT)) { mask |= ~(tcg_target_ulong)0xffffffffu; partmask &= 0xffffffffu; affected &= 0xffffffffu; } if (partmask == 0) { tcg_debug_assert(nb_oargs == 1); tcg_opt_gen_movi(s, op, args, args[0], 0); continue; } if (affected == 0) { tcg_debug_assert(nb_oargs == 1); tcg_opt_gen_mov(s, op, args, args[0], args[1]); continue; } /* Simplify expression for "op r, a, 0 => movi r, 0" cases */ switch (opc) { CASE_OP_32_64(and): CASE_OP_32_64(mul): CASE_OP_32_64(muluh): CASE_OP_32_64(mulsh): if ((temp_is_const(args[2]) && temps[args[2]].val == 0)) { tcg_opt_gen_movi(s, op, args, args[0], 0); continue; } break; default: break; } /* Simplify expression for "op r, a, a => mov r, a" cases */ switch (opc) { CASE_OP_32_64(or): CASE_OP_32_64(and): if (temps_are_copies(args[1], args[2])) { tcg_opt_gen_mov(s, op, args, args[0], args[1]); continue; } break; default: break; } /* Simplify expression for "op r, a, a => movi r, 0" cases */ switch (opc) { CASE_OP_32_64(andc): CASE_OP_32_64(sub): CASE_OP_32_64(xor): if (temps_are_copies(args[1], args[2])) { tcg_opt_gen_movi(s, op, args, args[0], 0); continue; } break; default: break; } /* Propagate constants through copy operations and do constant folding. Constants will be substituted to arguments by register allocator where needed and possible. Also detect copies. */ switch (opc) { CASE_OP_32_64(mov): tcg_opt_gen_mov(s, op, args, args[0], args[1]); break; CASE_OP_32_64(movi): tcg_opt_gen_movi(s, op, args, args[0], args[1]); break; CASE_OP_32_64(not): CASE_OP_32_64(neg): CASE_OP_32_64(ext8s): CASE_OP_32_64(ext8u): CASE_OP_32_64(ext16s): CASE_OP_32_64(ext16u): CASE_OP_32_64(ctpop): case INDEX_op_ext32s_i64: case INDEX_op_ext32u_i64: case INDEX_op_ext_i32_i64: case INDEX_op_extu_i32_i64: case INDEX_op_extrl_i64_i32: case INDEX_op_extrh_i64_i32: if (temp_is_const(args[1])) { tmp = do_constant_folding(opc, temps[args[1]].val, 0); tcg_opt_gen_movi(s, op, args, args[0], tmp); break; } goto do_default; CASE_OP_32_64(add): CASE_OP_32_64(sub): CASE_OP_32_64(mul): CASE_OP_32_64(or): CASE_OP_32_64(and): CASE_OP_32_64(xor): CASE_OP_32_64(shl): CASE_OP_32_64(shr): CASE_OP_32_64(sar): CASE_OP_32_64(rotl): CASE_OP_32_64(rotr): CASE_OP_32_64(andc): CASE_OP_32_64(orc): CASE_OP_32_64(eqv): CASE_OP_32_64(nand): CASE_OP_32_64(nor): CASE_OP_32_64(muluh): CASE_OP_32_64(mulsh): CASE_OP_32_64(div): CASE_OP_32_64(divu): CASE_OP_32_64(rem): CASE_OP_32_64(remu): if (temp_is_const(args[1]) && temp_is_const(args[2])) { tmp = do_constant_folding(opc, temps[args[1]].val, temps[args[2]].val); tcg_opt_gen_movi(s, op, args, args[0], tmp); break; } goto do_default; CASE_OP_32_64(clz): CASE_OP_32_64(ctz): if (temp_is_const(args[1])) { TCGArg v = temps[args[1]].val; if (v != 0) { tmp = do_constant_folding(opc, v, 0); tcg_opt_gen_movi(s, op, args, args[0], tmp); } else { tcg_opt_gen_mov(s, op, args, args[0], args[2]); } break; } goto do_default; CASE_OP_32_64(deposit): if (temp_is_const(args[1]) && temp_is_const(args[2])) { tmp = deposit64(temps[args[1]].val, args[3], args[4], temps[args[2]].val); tcg_opt_gen_movi(s, op, args, args[0], tmp); break; } goto do_default; CASE_OP_32_64(extract): if (temp_is_const(args[1])) { tmp = extract64(temps[args[1]].val, args[2], args[3]); tcg_opt_gen_movi(s, op, args, args[0], tmp); break; } goto do_default; CASE_OP_32_64(sextract): if (temp_is_const(args[1])) { tmp = sextract64(temps[args[1]].val, args[2], args[3]); tcg_opt_gen_movi(s, op, args, args[0], tmp); break; } goto do_default; CASE_OP_32_64(setcond): tmp = do_constant_folding_cond(opc, args[1], args[2], args[3]); if (tmp != 2) { tcg_opt_gen_movi(s, op, args, args[0], tmp); break; } goto do_default; CASE_OP_32_64(brcond): tmp = do_constant_folding_cond(opc, args[0], args[1], args[2]); if (tmp != 2) { if (tmp) { reset_all_temps(nb_temps); op->opc = INDEX_op_br; args[0] = args[3]; } else { tcg_op_remove(s, op); } break; } goto do_default; CASE_OP_32_64(movcond): tmp = do_constant_folding_cond(opc, args[1], args[2], args[5]); if (tmp != 2) { tcg_opt_gen_mov(s, op, args, args[0], args[4-tmp]); break; } if (temp_is_const(args[3]) && temp_is_const(args[4])) { tcg_target_ulong tv = temps[args[3]].val; tcg_target_ulong fv = temps[args[4]].val; TCGCond cond = args[5]; if (fv == 1 && tv == 0) { cond = tcg_invert_cond(cond); } else if (!(tv == 1 && fv == 0)) { goto do_default; } args[3] = cond; op->opc = opc = (opc == INDEX_op_movcond_i32 ? INDEX_op_setcond_i32 : INDEX_op_setcond_i64); nb_iargs = 2; } goto do_default; case INDEX_op_add2_i32: case INDEX_op_sub2_i32: if (temp_is_const(args[2]) && temp_is_const(args[3]) && temp_is_const(args[4]) && temp_is_const(args[5])) { uint32_t al = temps[args[2]].val; uint32_t ah = temps[args[3]].val; uint32_t bl = temps[args[4]].val; uint32_t bh = temps[args[5]].val; uint64_t a = ((uint64_t)ah << 32) | al; uint64_t b = ((uint64_t)bh << 32) | bl; TCGArg rl, rh; TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32, 2); TCGArg *args2 = &s->gen_opparam_buf[op2->args]; if (opc == INDEX_op_add2_i32) { a += b; } else { a -= b; } rl = args[0]; rh = args[1]; tcg_opt_gen_movi(s, op, args, rl, (int32_t)a); tcg_opt_gen_movi(s, op2, args2, rh, (int32_t)(a >> 32)); /* We've done all we need to do with the movi. Skip it. */ oi_next = op2->next; break; } goto do_default; case INDEX_op_mulu2_i32: if (temp_is_const(args[2]) && temp_is_const(args[3])) { uint32_t a = temps[args[2]].val; uint32_t b = temps[args[3]].val; uint64_t r = (uint64_t)a * b; TCGArg rl, rh; TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32, 2); TCGArg *args2 = &s->gen_opparam_buf[op2->args]; rl = args[0]; rh = args[1]; tcg_opt_gen_movi(s, op, args, rl, (int32_t)r); tcg_opt_gen_movi(s, op2, args2, rh, (int32_t)(r >> 32)); /* We've done all we need to do with the movi. Skip it. */ oi_next = op2->next; break; } goto do_default; case INDEX_op_brcond2_i32: tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]); if (tmp != 2) { if (tmp) { do_brcond_true: reset_all_temps(nb_temps); op->opc = INDEX_op_br; args[0] = args[5]; } else { do_brcond_false: tcg_op_remove(s, op); } } else if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE) && temp_is_const(args[2]) && temps[args[2]].val == 0 && temp_is_const(args[3]) && temps[args[3]].val == 0) { /* Simplify LT/GE comparisons vs zero to a single compare vs the high word of the input. */ do_brcond_high: reset_all_temps(nb_temps); op->opc = INDEX_op_brcond_i32; args[0] = args[1]; args[1] = args[3]; args[2] = args[4]; args[3] = args[5]; } else if (args[4] == TCG_COND_EQ) { /* Simplify EQ comparisons where one of the pairs can be simplified. */ tmp = do_constant_folding_cond(INDEX_op_brcond_i32, args[0], args[2], TCG_COND_EQ); if (tmp == 0) { goto do_brcond_false; } else if (tmp == 1) { goto do_brcond_high; } tmp = do_constant_folding_cond(INDEX_op_brcond_i32, args[1], args[3], TCG_COND_EQ); if (tmp == 0) { goto do_brcond_false; } else if (tmp != 1) { goto do_default; } do_brcond_low: reset_all_temps(nb_temps); op->opc = INDEX_op_brcond_i32; args[1] = args[2]; args[2] = args[4]; args[3] = args[5]; } else if (args[4] == TCG_COND_NE) { /* Simplify NE comparisons where one of the pairs can be simplified. */ tmp = do_constant_folding_cond(INDEX_op_brcond_i32, args[0], args[2], TCG_COND_NE); if (tmp == 0) { goto do_brcond_high; } else if (tmp == 1) { goto do_brcond_true; } tmp = do_constant_folding_cond(INDEX_op_brcond_i32, args[1], args[3], TCG_COND_NE); if (tmp == 0) { goto do_brcond_low; } else if (tmp == 1) { goto do_brcond_true; } goto do_default; } else { goto do_default; } break; case INDEX_op_setcond2_i32: tmp = do_constant_folding_cond2(&args[1], &args[3], args[5]); if (tmp != 2) { do_setcond_const: tcg_opt_gen_movi(s, op, args, args[0], tmp); } else if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE) && temp_is_const(args[3]) && temps[args[3]].val == 0 && temp_is_const(args[4]) && temps[args[4]].val == 0) { /* Simplify LT/GE comparisons vs zero to a single compare vs the high word of the input. */ do_setcond_high: reset_temp(args[0]); temps[args[0]].mask = 1; op->opc = INDEX_op_setcond_i32; args[1] = args[2]; args[2] = args[4]; args[3] = args[5]; } else if (args[5] == TCG_COND_EQ) { /* Simplify EQ comparisons where one of the pairs can be simplified. */ tmp = do_constant_folding_cond(INDEX_op_setcond_i32, args[1], args[3], TCG_COND_EQ); if (tmp == 0) { goto do_setcond_const; } else if (tmp == 1) { goto do_setcond_high; } tmp = do_constant_folding_cond(INDEX_op_setcond_i32, args[2], args[4], TCG_COND_EQ); if (tmp == 0) { goto do_setcond_high; } else if (tmp != 1) { goto do_default; } do_setcond_low: reset_temp(args[0]); temps[args[0]].mask = 1; op->opc = INDEX_op_setcond_i32; args[2] = args[3]; args[3] = args[5]; } else if (args[5] == TCG_COND_NE) { /* Simplify NE comparisons where one of the pairs can be simplified. */ tmp = do_constant_folding_cond(INDEX_op_setcond_i32, args[1], args[3], TCG_COND_NE); if (tmp == 0) { goto do_setcond_high; } else if (tmp == 1) { goto do_setcond_const; } tmp = do_constant_folding_cond(INDEX_op_setcond_i32, args[2], args[4], TCG_COND_NE); if (tmp == 0) { goto do_setcond_low; } else if (tmp == 1) { goto do_setcond_const; } goto do_default; } else { goto do_default; } break; case INDEX_op_call: if (!(args[nb_oargs + nb_iargs + 1] & (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) { for (i = 0; i < nb_globals; i++) { if (test_bit(i, temps_used.l)) { reset_temp(i); } } } goto do_reset_output; default: do_default: /* Default case: we know nothing about operation (or were unable to compute the operation result) so no propagation is done. We trash everything if the operation is the end of a basic block, otherwise we only trash the output args. "mask" is the non-zero bits mask for the first output arg. */ if (def->flags & TCG_OPF_BB_END) { reset_all_temps(nb_temps); } else { do_reset_output: for (i = 0; i < nb_oargs; i++) { reset_temp(args[i]); /* Save the corresponding known-zero bits mask for the first output argument (only one supported so far). */ if (i == 0) { temps[args[i]].mask = mask; } } } break; } /* Eliminate duplicate and redundant fence instructions. */ if (prev_mb_args) { switch (opc) { case INDEX_op_mb: /* Merge two barriers of the same type into one, * or a weaker barrier into a stronger one, * or two weaker barriers into a stronger one. * mb X; mb Y => mb X|Y * mb; strl => mb; st * ldaq; mb => ld; mb * ldaq; strl => ld; mb; st * Other combinations are also merged into a strong * barrier. This is stricter than specified but for * the purposes of TCG is better than not optimizing. */ prev_mb_args[0] |= args[0]; tcg_op_remove(s, op); break; default: /* Opcodes that end the block stop the optimization. */ if ((def->flags & TCG_OPF_BB_END) == 0) { break; } /* fallthru */ case INDEX_op_qemu_ld_i32: case INDEX_op_qemu_ld_i64: case INDEX_op_qemu_st_i32: case INDEX_op_qemu_st_i64: case INDEX_op_call: /* Opcodes that touch guest memory stop the optimization. */ prev_mb_args = NULL; break; } } else if (opc == INDEX_op_mb) { prev_mb_args = args; } } }