static bool prefer_and_bit_test (enum machine_mode mode, int bitnum) { if (and_test == 0) { /* Set up rtxes for the two variations. Use NULL as a placeholder for the BITNUM-based constants. */ and_reg = gen_rtx_REG (mode, FIRST_PSEUDO_REGISTER); and_test = gen_rtx_AND (mode, and_reg, NULL); shift_test = gen_rtx_AND (mode, gen_rtx_ASHIFTRT (mode, and_reg, NULL), const1_rtx); } else { /* Change the mode of the previously-created rtxes. */ PUT_MODE (and_reg, mode); PUT_MODE (and_test, mode); PUT_MODE (shift_test, mode); PUT_MODE (XEXP (shift_test, 0), mode); } /* Fill in the integers. */ XEXP (and_test, 1) = immed_double_int_const (double_int_setbit (double_int_zero, bitnum), mode); XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum); return (rtx_cost (and_test, IF_THEN_ELSE, optimize_insn_for_speed_p ()) <= rtx_cost (shift_test, IF_THEN_ELSE, optimize_insn_for_speed_p ())); }
static bool prefer_and_bit_test (machine_mode mode, int bitnum) { bool speed_p; wide_int mask = wi::set_bit_in_zero (bitnum, GET_MODE_PRECISION (mode)); if (and_test == 0) { /* Set up rtxes for the two variations. Use NULL as a placeholder for the BITNUM-based constants. */ and_reg = gen_rtx_REG (mode, LAST_VIRTUAL_REGISTER + 1); and_test = gen_rtx_AND (mode, and_reg, NULL); shift_test = gen_rtx_AND (mode, gen_rtx_ASHIFTRT (mode, and_reg, NULL), const1_rtx); } else { /* Change the mode of the previously-created rtxes. */ PUT_MODE (and_reg, mode); PUT_MODE (and_test, mode); PUT_MODE (shift_test, mode); PUT_MODE (XEXP (shift_test, 0), mode); } /* Fill in the integers. */ XEXP (and_test, 1) = immed_wide_int_const (mask, mode); XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum); speed_p = optimize_insn_for_speed_p (); return (rtx_cost (and_test, mode, IF_THEN_ELSE, 0, speed_p) <= rtx_cost (shift_test, mode, IF_THEN_ELSE, 0, speed_p)); }
unsigned seq_cost (const_rtx seq, unsigned char speed) { unsigned cost = 0; rtx set; for (; seq; seq = (((seq)->u.fld[2]).rt_rtx)) { set = (((((enum rtx_code) (seq)->code) == INSN) || (((enum rtx_code) (seq)->code) == DEBUG_INSN) || (((enum rtx_code) (seq)->code) == JUMP_INSN) || (((enum rtx_code) (seq)->code) == CALL_INSN)) ? (((enum rtx_code) ((((seq)->u.fld[4]).rt_rtx))-> code) == SET ? (((seq)->u.fld[4]). rt_rtx) : single_set_2 (seq, (((seq)->u. fld[4]). rt_rtx))) : (rtx) 0); if (set) cost += rtx_cost (set, SET, speed); } }
static bool attempt_change (rtx new_addr, rtx inc_reg) { /* There are four cases: For the two cases that involve an add instruction, we are going to have to delete the add and insert a mov. We are going to assume that the mov is free. This is fairly early in the backend and there are a lot of opportunities for removing that move later. In particular, there is the case where the move may be dead, this is what dead code elimination passes are for. The two cases where we have an inc insn will be handled mov free. */ basic_block bb = BLOCK_FOR_INSN (mem_insn.insn); rtx mov_insn = NULL; int regno; rtx mem = *mem_insn.mem_loc; enum machine_mode mode = GET_MODE (mem); rtx new_mem; int old_cost = 0; int new_cost = 0; bool speed = optimize_bb_for_speed_p (bb); PUT_MODE (mem_tmp, mode); XEXP (mem_tmp, 0) = new_addr; old_cost = (rtx_cost (mem, SET, speed) + rtx_cost (PATTERN (inc_insn.insn), SET, speed)); new_cost = rtx_cost (mem_tmp, SET, speed); /* The first item of business is to see if this is profitable. */ if (old_cost < new_cost) { if (dump_file) fprintf (dump_file, "cost failure old=%d new=%d\n", old_cost, new_cost); return false; } /* Jump thru a lot of hoops to keep the attributes up to date. We do not want to call one of the change address variants that take an offset even though we know the offset in many cases. These assume you are changing where the address is pointing by the offset. */ new_mem = replace_equiv_address_nv (mem, new_addr); if (! validate_change (mem_insn.insn, mem_insn.mem_loc, new_mem, 0)) { if (dump_file) fprintf (dump_file, "validation failure\n"); return false; } /* From here to the end of the function we are committed to the change, i.e. nothing fails. Generate any necessary movs, move any regnotes, and fix up the reg_next_{use,inc_use,def}. */ switch (inc_insn.form) { case FORM_PRE_ADD: /* Replace the addition with a move. Do it at the location of the addition since the operand of the addition may change before the memory reference. */ mov_insn = insert_move_insn_before (inc_insn.insn, inc_insn.reg_res, inc_insn.reg0); move_dead_notes (mov_insn, inc_insn.insn, inc_insn.reg0); regno = REGNO (inc_insn.reg_res); reg_next_def[regno] = mov_insn; reg_next_use[regno] = NULL; regno = REGNO (inc_insn.reg0); reg_next_use[regno] = mov_insn; df_recompute_luids (bb); break; case FORM_POST_INC: regno = REGNO (inc_insn.reg_res); if (reg_next_use[regno] == reg_next_inc_use[regno]) reg_next_inc_use[regno] = NULL; /* Fallthru. */ case FORM_PRE_INC: regno = REGNO (inc_insn.reg_res); reg_next_def[regno] = mem_insn.insn; reg_next_use[regno] = NULL; break; case FORM_POST_ADD: mov_insn = insert_move_insn_before (mem_insn.insn, inc_insn.reg_res, inc_insn.reg0); move_dead_notes (mov_insn, inc_insn.insn, inc_insn.reg0); /* Do not move anything to the mov insn because the instruction pointer for the main iteration has not yet hit that. It is still pointing to the mem insn. */ regno = REGNO (inc_insn.reg_res); reg_next_def[regno] = mem_insn.insn; reg_next_use[regno] = NULL; regno = REGNO (inc_insn.reg0); reg_next_use[regno] = mem_insn.insn; if ((reg_next_use[regno] == reg_next_inc_use[regno]) || (reg_next_inc_use[regno] == inc_insn.insn)) reg_next_inc_use[regno] = NULL; df_recompute_luids (bb); break; case FORM_last: default: gcc_unreachable (); } if (!inc_insn.reg1_is_const) { regno = REGNO (inc_insn.reg1); reg_next_use[regno] = mem_insn.insn; if ((reg_next_use[regno] == reg_next_inc_use[regno]) || (reg_next_inc_use[regno] == inc_insn.insn)) reg_next_inc_use[regno] = NULL; } delete_insn (inc_insn.insn); if (dump_file && mov_insn) { fprintf (dump_file, "inserting mov "); dump_insn_slim (dump_file, mov_insn); } /* Record that this insn has an implicit side effect. */ add_reg_note (mem_insn.insn, REG_INC, inc_reg); if (dump_file) { fprintf (dump_file, "****success "); dump_insn_slim (dump_file, mem_insn.insn); } return true; }
static int reload_cse_simplify_operands (rtx insn, rtx testreg) { int i, j; /* For each operand, all registers that are equivalent to it. */ HARD_REG_SET equiv_regs[MAX_RECOG_OPERANDS]; const char *constraints[MAX_RECOG_OPERANDS]; /* Vector recording how bad an alternative is. */ int *alternative_reject; /* Vector recording how many registers can be introduced by choosing this alternative. */ int *alternative_nregs; /* Array of vectors recording, for each operand and each alternative, which hard register to substitute, or -1 if the operand should be left as it is. */ int *op_alt_regno[MAX_RECOG_OPERANDS]; /* Array of alternatives, sorted in order of decreasing desirability. */ int *alternative_order; extract_insn (insn); if (recog_data.n_alternatives == 0 || recog_data.n_operands == 0) return 0; /* Figure out which alternative currently matches. */ if (! constrain_operands (1)) fatal_insn_not_found (insn); alternative_reject = XALLOCAVEC (int, recog_data.n_alternatives); alternative_nregs = XALLOCAVEC (int, recog_data.n_alternatives); alternative_order = XALLOCAVEC (int, recog_data.n_alternatives); memset (alternative_reject, 0, recog_data.n_alternatives * sizeof (int)); memset (alternative_nregs, 0, recog_data.n_alternatives * sizeof (int)); /* For each operand, find out which regs are equivalent. */ for (i = 0; i < recog_data.n_operands; i++) { cselib_val *v; struct elt_loc_list *l; rtx op; enum machine_mode mode; CLEAR_HARD_REG_SET (equiv_regs[i]); /* cselib blows up on CODE_LABELs. Trying to fix that doesn't seem right, so avoid the problem here. Likewise if we have a constant and the insn pattern doesn't tell us the mode we need. */ if (LABEL_P (recog_data.operand[i]) || (CONSTANT_P (recog_data.operand[i]) && recog_data.operand_mode[i] == VOIDmode)) continue; op = recog_data.operand[i]; mode = GET_MODE (op); #ifdef LOAD_EXTEND_OP if (MEM_P (op) && GET_MODE_BITSIZE (mode) < BITS_PER_WORD && LOAD_EXTEND_OP (mode) != UNKNOWN) { rtx set = single_set (insn); /* We might have multiple sets, some of which do implicit extension. Punt on this for now. */ if (! set) continue; /* If the destination is also a MEM or a STRICT_LOW_PART, no extension applies. Also, if there is an explicit extension, we don't have to worry about an implicit one. */ else if (MEM_P (SET_DEST (set)) || GET_CODE (SET_DEST (set)) == STRICT_LOW_PART || GET_CODE (SET_SRC (set)) == ZERO_EXTEND || GET_CODE (SET_SRC (set)) == SIGN_EXTEND) ; /* Continue ordinary processing. */ #ifdef CANNOT_CHANGE_MODE_CLASS /* If the register cannot change mode to word_mode, it follows that it cannot have been used in word_mode. */ else if (REG_P (SET_DEST (set)) && CANNOT_CHANGE_MODE_CLASS (GET_MODE (SET_DEST (set)), word_mode, REGNO_REG_CLASS (REGNO (SET_DEST (set))))) ; /* Continue ordinary processing. */ #endif /* If this is a straight load, make the extension explicit. */ else if (REG_P (SET_DEST (set)) && recog_data.n_operands == 2 && SET_SRC (set) == op && SET_DEST (set) == recog_data.operand[1-i]) { validate_change (insn, recog_data.operand_loc[i], gen_rtx_fmt_e (LOAD_EXTEND_OP (mode), word_mode, op), 1); validate_change (insn, recog_data.operand_loc[1-i], gen_rtx_REG (word_mode, REGNO (SET_DEST (set))), 1); if (! apply_change_group ()) return 0; return reload_cse_simplify_operands (insn, testreg); } else /* ??? There might be arithmetic operations with memory that are safe to optimize, but is it worth the trouble? */ continue; } #endif /* LOAD_EXTEND_OP */ v = cselib_lookup (op, recog_data.operand_mode[i], 0); if (! v) continue; for (l = v->locs; l; l = l->next) if (REG_P (l->loc)) SET_HARD_REG_BIT (equiv_regs[i], REGNO (l->loc)); } for (i = 0; i < recog_data.n_operands; i++) { enum machine_mode mode; int regno; const char *p; op_alt_regno[i] = XALLOCAVEC (int, recog_data.n_alternatives); for (j = 0; j < recog_data.n_alternatives; j++) op_alt_regno[i][j] = -1; p = constraints[i] = recog_data.constraints[i]; mode = recog_data.operand_mode[i]; /* Add the reject values for each alternative given by the constraints for this operand. */ j = 0; while (*p != '\0') { char c = *p++; if (c == ',') j++; else if (c == '?') alternative_reject[j] += 3; else if (c == '!') alternative_reject[j] += 300; } /* We won't change operands which are already registers. We also don't want to modify output operands. */ regno = true_regnum (recog_data.operand[i]); if (regno >= 0 || constraints[i][0] == '=' || constraints[i][0] == '+') continue; for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) { int rclass = (int) NO_REGS; if (! TEST_HARD_REG_BIT (equiv_regs[i], regno)) continue; SET_REGNO (testreg, regno); PUT_MODE (testreg, mode); /* We found a register equal to this operand. Now look for all alternatives that can accept this register and have not been assigned a register they can use yet. */ j = 0; p = constraints[i]; for (;;) { char c = *p; switch (c) { case '=': case '+': case '?': case '#': case '&': case '!': case '*': case '%': case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': case '<': case '>': case 'V': case 'o': case 'E': case 'F': case 'G': case 'H': case 's': case 'i': case 'n': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N': case 'O': case 'P': case 'p': case 'X': case TARGET_MEM_CONSTRAINT: /* These don't say anything we care about. */ break; case 'g': case 'r': rclass = reg_class_subunion[(int) rclass][(int) GENERAL_REGS]; break; default: rclass = (reg_class_subunion [(int) rclass] [(int) REG_CLASS_FROM_CONSTRAINT ((unsigned char) c, p)]); break; case ',': case '\0': /* See if REGNO fits this alternative, and set it up as the replacement register if we don't have one for this alternative yet and the operand being replaced is not a cheap CONST_INT. */ if (op_alt_regno[i][j] == -1 && reg_fits_class_p (testreg, rclass, 0, mode) && (GET_CODE (recog_data.operand[i]) != CONST_INT || (rtx_cost (recog_data.operand[i], SET, optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn))) > rtx_cost (testreg, SET, optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)))))) { alternative_nregs[j]++; op_alt_regno[i][j] = regno; } j++; rclass = (int) NO_REGS; break; } p += CONSTRAINT_LEN (c, p); if (c == '\0') break; } } } /* Record all alternatives which are better or equal to the currently matching one in the alternative_order array. */ for (i = j = 0; i < recog_data.n_alternatives; i++) if (alternative_reject[i] <= alternative_reject[which_alternative]) alternative_order[j++] = i; recog_data.n_alternatives = j; /* Sort it. Given a small number of alternatives, a dumb algorithm won't hurt too much. */ for (i = 0; i < recog_data.n_alternatives - 1; i++) { int best = i; int best_reject = alternative_reject[alternative_order[i]]; int best_nregs = alternative_nregs[alternative_order[i]]; int tmp; for (j = i + 1; j < recog_data.n_alternatives; j++) { int this_reject = alternative_reject[alternative_order[j]]; int this_nregs = alternative_nregs[alternative_order[j]]; if (this_reject < best_reject || (this_reject == best_reject && this_nregs > best_nregs)) { best = j; best_reject = this_reject; best_nregs = this_nregs; } } tmp = alternative_order[best]; alternative_order[best] = alternative_order[i]; alternative_order[i] = tmp; } /* Substitute the operands as determined by op_alt_regno for the best alternative. */ j = alternative_order[0]; for (i = 0; i < recog_data.n_operands; i++) { enum machine_mode mode = recog_data.operand_mode[i]; if (op_alt_regno[i][j] == -1) continue; validate_change (insn, recog_data.operand_loc[i], gen_rtx_REG (mode, op_alt_regno[i][j]), 1); } for (i = recog_data.n_dups - 1; i >= 0; i--) { int op = recog_data.dup_num[i]; enum machine_mode mode = recog_data.operand_mode[op]; if (op_alt_regno[op][j] == -1) continue; validate_change (insn, recog_data.dup_loc[i], gen_rtx_REG (mode, op_alt_regno[op][j]), 1); } return apply_change_group (); }
static int reload_cse_simplify_set (rtx set, rtx insn) { int did_change = 0; int dreg; rtx src; enum reg_class dclass; int old_cost; cselib_val *val; struct elt_loc_list *l; #ifdef LOAD_EXTEND_OP enum rtx_code extend_op = UNKNOWN; #endif bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn)); dreg = true_regnum (SET_DEST (set)); if (dreg < 0) return 0; src = SET_SRC (set); if (side_effects_p (src) || true_regnum (src) >= 0) return 0; dclass = REGNO_REG_CLASS (dreg); #ifdef LOAD_EXTEND_OP /* When replacing a memory with a register, we need to honor assumptions that combine made wrt the contents of sign bits. We'll do this by generating an extend instruction instead of a reg->reg copy. Thus the destination must be a register that we can widen. */ if (MEM_P (src) && GET_MODE_BITSIZE (GET_MODE (src)) < BITS_PER_WORD && (extend_op = LOAD_EXTEND_OP (GET_MODE (src))) != UNKNOWN && !REG_P (SET_DEST (set))) return 0; #endif val = cselib_lookup (src, GET_MODE (SET_DEST (set)), 0); if (! val) return 0; /* If memory loads are cheaper than register copies, don't change them. */ if (MEM_P (src)) old_cost = MEMORY_MOVE_COST (GET_MODE (src), dclass, 1); else if (REG_P (src)) old_cost = REGISTER_MOVE_COST (GET_MODE (src), REGNO_REG_CLASS (REGNO (src)), dclass); else old_cost = rtx_cost (src, SET, speed); for (l = val->locs; l; l = l->next) { rtx this_rtx = l->loc; int this_cost; if (CONSTANT_P (this_rtx) && ! references_value_p (this_rtx, 0)) { #ifdef LOAD_EXTEND_OP if (extend_op != UNKNOWN) { HOST_WIDE_INT this_val; /* ??? I'm lazy and don't wish to handle CONST_DOUBLE. Other constants, such as SYMBOL_REF, cannot be extended. */ if (GET_CODE (this_rtx) != CONST_INT) continue; this_val = INTVAL (this_rtx); switch (extend_op) { case ZERO_EXTEND: this_val &= GET_MODE_MASK (GET_MODE (src)); break; case SIGN_EXTEND: /* ??? In theory we're already extended. */ if (this_val == trunc_int_for_mode (this_val, GET_MODE (src))) break; default: gcc_unreachable (); } this_rtx = GEN_INT (this_val); } #endif this_cost = rtx_cost (this_rtx, SET, speed); } else if (REG_P (this_rtx)) { #ifdef LOAD_EXTEND_OP if (extend_op != UNKNOWN) { this_rtx = gen_rtx_fmt_e (extend_op, word_mode, this_rtx); this_cost = rtx_cost (this_rtx, SET, speed); } else #endif this_cost = REGISTER_MOVE_COST (GET_MODE (this_rtx), REGNO_REG_CLASS (REGNO (this_rtx)), dclass); } else continue; /* If equal costs, prefer registers over anything else. That tends to lead to smaller instructions on some machines. */ if (this_cost < old_cost || (this_cost == old_cost && REG_P (this_rtx) && !REG_P (SET_SRC (set)))) { #ifdef LOAD_EXTEND_OP if (GET_MODE_BITSIZE (GET_MODE (SET_DEST (set))) < BITS_PER_WORD && extend_op != UNKNOWN #ifdef CANNOT_CHANGE_MODE_CLASS && !CANNOT_CHANGE_MODE_CLASS (GET_MODE (SET_DEST (set)), word_mode, REGNO_REG_CLASS (REGNO (SET_DEST (set)))) #endif ) { rtx wide_dest = gen_rtx_REG (word_mode, REGNO (SET_DEST (set))); ORIGINAL_REGNO (wide_dest) = ORIGINAL_REGNO (SET_DEST (set)); validate_change (insn, &SET_DEST (set), wide_dest, 1); } #endif validate_unshare_change (insn, &SET_SRC (set), this_rtx, 1); old_cost = this_cost, did_change = 1; } } return did_change; }