static bool combine_set_extension (ext_cand *cand, rtx curr_insn, rtx *orig_set) { rtx orig_src = SET_SRC (*orig_set); enum machine_mode orig_mode = GET_MODE (SET_DEST (*orig_set)); rtx new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (*orig_set))); rtx new_set; /* Merge constants by directly moving the constant into the register under some conditions. Recall that RTL constants are sign-extended. */ if (GET_CODE (orig_src) == CONST_INT && HOST_BITS_PER_WIDE_INT >= GET_MODE_BITSIZE (cand->mode)) { if (INTVAL (orig_src) >= 0 || cand->code == SIGN_EXTEND) new_set = gen_rtx_SET (VOIDmode, new_reg, orig_src); else { /* Zero-extend the negative constant by masking out the bits outside the source mode. */ rtx new_const_int = GEN_INT (INTVAL (orig_src) & GET_MODE_MASK (orig_mode)); new_set = gen_rtx_SET (VOIDmode, new_reg, new_const_int); } } else if (GET_MODE (orig_src) == VOIDmode) { /* This is mostly due to a call insn that should not be optimized. */ return false; } else if (GET_CODE (orig_src) == cand->code) { /* Here is a sequence of two extensions. Try to merge them. */ rtx temp_extension = gen_rtx_fmt_e (cand->code, cand->mode, XEXP (orig_src, 0)); rtx simplified_temp_extension = simplify_rtx (temp_extension); if (simplified_temp_extension) temp_extension = simplified_temp_extension; new_set = gen_rtx_SET (VOIDmode, new_reg, temp_extension); } else if (GET_CODE (orig_src) == IF_THEN_ELSE) { /* Only IF_THEN_ELSE of phi-type copies are combined. Otherwise, in general, IF_THEN_ELSE should not be combined. */ return false; } else { /* This is the normal case. */ rtx temp_extension = gen_rtx_fmt_e (cand->code, cand->mode, orig_src); rtx simplified_temp_extension = simplify_rtx (temp_extension); if (simplified_temp_extension) temp_extension = simplified_temp_extension; new_set = gen_rtx_SET (VOIDmode, new_reg, temp_extension); } /* This change is a part of a group of changes. Hence, validate_change will not try to commit the change. */ if (validate_change (curr_insn, orig_set, new_set, true) && update_reg_equal_equiv_notes (curr_insn, cand->mode, orig_mode, cand->code)) { if (dump_file) { fprintf (dump_file, "Tentatively merged extension with definition:\n"); print_rtl_single (dump_file, curr_insn); } return true; } return false; }
static bool combine_set_extension (ext_cand *cand, rtx_insn *curr_insn, rtx *orig_set) { rtx orig_src = SET_SRC (*orig_set); machine_mode orig_mode = GET_MODE (SET_DEST (*orig_set)); rtx new_set; rtx cand_pat = PATTERN (cand->insn); /* If the extension's source/destination registers are not the same then we need to change the original load to reference the destination of the extension. Then we need to emit a copy from that destination to the original destination of the load. */ rtx new_reg; bool copy_needed = (REGNO (SET_DEST (cand_pat)) != REGNO (XEXP (SET_SRC (cand_pat), 0))); if (copy_needed) new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (cand_pat))); else new_reg = gen_rtx_REG (cand->mode, REGNO (SET_DEST (*orig_set))); #if 0 /* Rethinking test. Temporarily disabled. */ /* We're going to be widening the result of DEF_INSN, ensure that doing so doesn't change the number of hard registers needed for the result. */ if (HARD_REGNO_NREGS (REGNO (new_reg), cand->mode) != HARD_REGNO_NREGS (REGNO (SET_DEST (*orig_set)), GET_MODE (SET_DEST (*orig_set)))) return false; #endif /* Merge constants by directly moving the constant into the register under some conditions. Recall that RTL constants are sign-extended. */ if (GET_CODE (orig_src) == CONST_INT && HOST_BITS_PER_WIDE_INT >= GET_MODE_BITSIZE (cand->mode)) { if (INTVAL (orig_src) >= 0 || cand->code == SIGN_EXTEND) new_set = gen_rtx_SET (new_reg, orig_src); else { /* Zero-extend the negative constant by masking out the bits outside the source mode. */ rtx new_const_int = gen_int_mode (INTVAL (orig_src) & GET_MODE_MASK (orig_mode), GET_MODE (new_reg)); new_set = gen_rtx_SET (new_reg, new_const_int); } } else if (GET_MODE (orig_src) == VOIDmode) { /* This is mostly due to a call insn that should not be optimized. */ return false; } else if (GET_CODE (orig_src) == cand->code) { /* Here is a sequence of two extensions. Try to merge them. */ rtx temp_extension = gen_rtx_fmt_e (cand->code, cand->mode, XEXP (orig_src, 0)); rtx simplified_temp_extension = simplify_rtx (temp_extension); if (simplified_temp_extension) temp_extension = simplified_temp_extension; new_set = gen_rtx_SET (new_reg, temp_extension); } else if (GET_CODE (orig_src) == IF_THEN_ELSE) { /* Only IF_THEN_ELSE of phi-type copies are combined. Otherwise, in general, IF_THEN_ELSE should not be combined. */ return false; } else { /* This is the normal case. */ rtx temp_extension = gen_rtx_fmt_e (cand->code, cand->mode, orig_src); rtx simplified_temp_extension = simplify_rtx (temp_extension); if (simplified_temp_extension) temp_extension = simplified_temp_extension; new_set = gen_rtx_SET (new_reg, temp_extension); } /* This change is a part of a group of changes. Hence, validate_change will not try to commit the change. */ if (validate_change (curr_insn, orig_set, new_set, true) && update_reg_equal_equiv_notes (curr_insn, cand->mode, orig_mode, cand->code)) { if (dump_file) { fprintf (dump_file, "Tentatively merged extension with definition %s:\n", (copy_needed) ? "(copy needed)" : ""); print_rtl_single (dump_file, curr_insn); } return true; } return false; }
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 (); }
/* Scan X and replace any eliminable registers (such as fp) with a replacement (such as sp) if SUBST_P, plus an offset. The offset is a change in the offset between the eliminable register and its substitution if UPDATE_P, or the full offset if FULL_P, or otherwise zero. If FULL_P, we also use the SP offsets for elimination to SP. If UPDATE_P, use UPDATE_SP_OFFSET for updating offsets of register elimnable to SP. If UPDATE_SP_OFFSET is non-zero, don't use difference of the offset and the previous offset. MEM_MODE is the mode of an enclosing MEM. We need this to know how much to adjust a register for, e.g., PRE_DEC. Also, if we are inside a MEM, we are allowed to replace a sum of a hard register and the constant zero with the hard register, which we cannot do outside a MEM. In addition, we need to record the fact that a hard register is referenced outside a MEM. If we make full substitution to SP for non-null INSN, add the insn sp offset. */ rtx lra_eliminate_regs_1 (rtx_insn *insn, rtx x, machine_mode mem_mode, bool subst_p, bool update_p, HOST_WIDE_INT update_sp_offset, bool full_p) { enum rtx_code code = GET_CODE (x); struct lra_elim_table *ep; rtx new_rtx; int i, j; const char *fmt; int copied = 0; lra_assert (!update_p || !full_p); lra_assert (update_sp_offset == 0 || (!subst_p && update_p && !full_p)); if (! current_function_decl) return x; switch (code) { CASE_CONST_ANY: case CONST: case SYMBOL_REF: case CODE_LABEL: case PC: case CC0: case ASM_INPUT: case ADDR_VEC: case ADDR_DIFF_VEC: case RETURN: return x; case REG: /* First handle the case where we encounter a bare hard register that is eliminable. Replace it with a PLUS. */ if ((ep = get_elimination (x)) != NULL) { rtx to = subst_p ? ep->to_rtx : ep->from_rtx; if (update_sp_offset != 0) { if (ep->to_rtx == stack_pointer_rtx) return plus_constant (Pmode, to, update_sp_offset); return to; } else if (update_p) return plus_constant (Pmode, to, ep->offset - ep->previous_offset); else if (full_p) return plus_constant (Pmode, to, ep->offset - (insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx ? lra_get_insn_recog_data (insn)->sp_offset : 0)); else return to; } return x; case PLUS: /* If this is the sum of an eliminable register and a constant, rework the sum. */ if (REG_P (XEXP (x, 0)) && CONSTANT_P (XEXP (x, 1))) { if ((ep = get_elimination (XEXP (x, 0))) != NULL) { HOST_WIDE_INT offset; rtx to = subst_p ? ep->to_rtx : ep->from_rtx; if (! update_p && ! full_p) return gen_rtx_PLUS (Pmode, to, XEXP (x, 1)); if (update_sp_offset != 0) offset = ep->to_rtx == stack_pointer_rtx ? update_sp_offset : 0; else offset = (update_p ? ep->offset - ep->previous_offset : ep->offset); if (full_p && insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx) offset -= lra_get_insn_recog_data (insn)->sp_offset; if (CONST_INT_P (XEXP (x, 1)) && INTVAL (XEXP (x, 1)) == -offset) return to; else return gen_rtx_PLUS (Pmode, to, plus_constant (Pmode, XEXP (x, 1), offset)); } /* If the hard register is not eliminable, we are done since the other operand is a constant. */ return x; } /* If this is part of an address, we want to bring any constant to the outermost PLUS. We will do this by doing hard register replacement in our operands and seeing if a constant shows up in one of them. Note that there is no risk of modifying the structure of the insn, since we only get called for its operands, thus we are either modifying the address inside a MEM, or something like an address operand of a load-address insn. */ { rtx new0 = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, subst_p, update_p, update_sp_offset, full_p); rtx new1 = lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, subst_p, update_p, update_sp_offset, full_p); new0 = move_plus_up (new0); new1 = move_plus_up (new1); if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1)) return form_sum (new0, new1); } return x; case MULT: /* If this is the product of an eliminable hard register and a constant, apply the distribute law and move the constant out so that we have (plus (mult ..) ..). This is needed in order to keep load-address insns valid. This case is pathological. We ignore the possibility of overflow here. */ if (REG_P (XEXP (x, 0)) && CONST_INT_P (XEXP (x, 1)) && (ep = get_elimination (XEXP (x, 0))) != NULL) { rtx to = subst_p ? ep->to_rtx : ep->from_rtx; if (update_sp_offset != 0) { if (ep->to_rtx == stack_pointer_rtx) return plus_constant (Pmode, gen_rtx_MULT (Pmode, to, XEXP (x, 1)), update_sp_offset * INTVAL (XEXP (x, 1))); return gen_rtx_MULT (Pmode, to, XEXP (x, 1)); } else if (update_p) return plus_constant (Pmode, gen_rtx_MULT (Pmode, to, XEXP (x, 1)), (ep->offset - ep->previous_offset) * INTVAL (XEXP (x, 1))); else if (full_p) { HOST_WIDE_INT offset = ep->offset; if (insn != NULL_RTX && ep->to_rtx == stack_pointer_rtx) offset -= lra_get_insn_recog_data (insn)->sp_offset; return plus_constant (Pmode, gen_rtx_MULT (Pmode, to, XEXP (x, 1)), offset * INTVAL (XEXP (x, 1))); } else return gen_rtx_MULT (Pmode, to, XEXP (x, 1)); } /* fall through */ case CALL: case COMPARE: /* See comments before PLUS about handling MINUS. */ case MINUS: case DIV: case UDIV: case MOD: case UMOD: case AND: case IOR: case XOR: case ROTATERT: case ROTATE: case ASHIFTRT: case LSHIFTRT: case ASHIFT: case NE: case EQ: case GE: case GT: case GEU: case GTU: case LE: case LT: case LEU: case LTU: { rtx new0 = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, subst_p, update_p, update_sp_offset, full_p); rtx new1 = XEXP (x, 1) ? lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, subst_p, update_p, update_sp_offset, full_p) : 0; if (new0 != XEXP (x, 0) || new1 != XEXP (x, 1)) return gen_rtx_fmt_ee (code, GET_MODE (x), new0, new1); } return x; case EXPR_LIST: /* If we have something in XEXP (x, 0), the usual case, eliminate it. */ if (XEXP (x, 0)) { new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != XEXP (x, 0)) { /* If this is a REG_DEAD note, it is not valid anymore. Using the eliminated version could result in creating a REG_DEAD note for the stack or frame pointer. */ if (REG_NOTE_KIND (x) == REG_DEAD) return (XEXP (x, 1) ? lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, subst_p, update_p, update_sp_offset, full_p) : NULL_RTX); x = alloc_reg_note (REG_NOTE_KIND (x), new_rtx, XEXP (x, 1)); } } /* fall through */ case INSN_LIST: case INT_LIST: /* Now do eliminations in the rest of the chain. If this was an EXPR_LIST, this might result in allocating more memory than is strictly needed, but it simplifies the code. */ if (XEXP (x, 1)) { new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 1), mem_mode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != XEXP (x, 1)) return gen_rtx_fmt_ee (GET_CODE (x), GET_MODE (x), XEXP (x, 0), new_rtx); } return x; case PRE_INC: case POST_INC: case PRE_DEC: case POST_DEC: /* We do not support elimination of a register that is modified. elimination_effects has already make sure that this does not happen. */ return x; case PRE_MODIFY: case POST_MODIFY: /* We do not support elimination of a hard register that is modified. LRA has already make sure that this does not happen. The only remaining case we need to consider here is that the increment value may be an eliminable register. */ if (GET_CODE (XEXP (x, 1)) == PLUS && XEXP (XEXP (x, 1), 0) == XEXP (x, 0)) { rtx new_rtx = lra_eliminate_regs_1 (insn, XEXP (XEXP (x, 1), 1), mem_mode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != XEXP (XEXP (x, 1), 1)) return gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (x, 0), gen_rtx_PLUS (GET_MODE (x), XEXP (x, 0), new_rtx)); } return x; case STRICT_LOW_PART: case NEG: case NOT: case SIGN_EXTEND: case ZERO_EXTEND: case TRUNCATE: case FLOAT_EXTEND: case FLOAT_TRUNCATE: case FLOAT: case FIX: case UNSIGNED_FIX: case UNSIGNED_FLOAT: case ABS: case SQRT: case FFS: case CLZ: case CTZ: case POPCOUNT: case PARITY: case BSWAP: new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), mem_mode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != XEXP (x, 0)) return gen_rtx_fmt_e (code, GET_MODE (x), new_rtx); return x; case SUBREG: new_rtx = lra_eliminate_regs_1 (insn, SUBREG_REG (x), mem_mode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != SUBREG_REG (x)) { int x_size = GET_MODE_SIZE (GET_MODE (x)); int new_size = GET_MODE_SIZE (GET_MODE (new_rtx)); if (MEM_P (new_rtx) && x_size <= new_size) { SUBREG_REG (x) = new_rtx; alter_subreg (&x, false); return x; } else if (! subst_p) { /* LRA can transform subregs itself. So don't call simplify_gen_subreg until LRA transformations are finished. Function simplify_gen_subreg can do non-trivial transformations (like truncation) which might make LRA work to fail. */ SUBREG_REG (x) = new_rtx; return x; } else return simplify_gen_subreg (GET_MODE (x), new_rtx, GET_MODE (new_rtx), SUBREG_BYTE (x)); } return x; case MEM: /* Our only special processing is to pass the mode of the MEM to our recursive call and copy the flags. While we are here, handle this case more efficiently. */ return replace_equiv_address_nv (x, lra_eliminate_regs_1 (insn, XEXP (x, 0), GET_MODE (x), subst_p, update_p, update_sp_offset, full_p)); case USE: /* Handle insn_list USE that a call to a pure function may generate. */ new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, 0), VOIDmode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != XEXP (x, 0)) return gen_rtx_USE (GET_MODE (x), new_rtx); return x; case CLOBBER: case SET: gcc_unreachable (); default: break; } /* Process each of our operands recursively. If any have changed, make a copy of the rtx. */ fmt = GET_RTX_FORMAT (code); for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++) { if (*fmt == 'e') { new_rtx = lra_eliminate_regs_1 (insn, XEXP (x, i), mem_mode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != XEXP (x, i) && ! copied) { x = shallow_copy_rtx (x); copied = 1; } XEXP (x, i) = new_rtx; } else if (*fmt == 'E') { int copied_vec = 0; for (j = 0; j < XVECLEN (x, i); j++) { new_rtx = lra_eliminate_regs_1 (insn, XVECEXP (x, i, j), mem_mode, subst_p, update_p, update_sp_offset, full_p); if (new_rtx != XVECEXP (x, i, j) && ! copied_vec) { rtvec new_v = gen_rtvec_v (XVECLEN (x, i), XVEC (x, i)->elem); if (! copied) { x = shallow_copy_rtx (x); copied = 1; } XVEC (x, i) = new_v; copied_vec = 1; } XVECEXP (x, i, j) = new_rtx; } } } return x; }
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; }