- /* If cost is too great, set target to NULL and
- let the iteration happen. */
- if (shift_seq != NULL)
- {
- int cost = 0;
- rtx insn;
-
- for (insn = shift_seq; insn != NULL_RTX; insn = NEXT_INSN (insn))
- if (INSN_P (insn))
- cost += insn_rtx_cost (PATTERN (insn));
-
- /* The computation up to here is essentially independent
- of the arguments and could be precomputed. It may
- not be worth doing so. We could precompute if
- worthwhile or at least cache the results. The result
- technically depends on SHIFT, ACCESS_SIZE, and
- GET_MODE_CLASS (READ_MODE). But in practice the
- answer will depend only on ACCESS_SIZE. */
-
- if (cost <= COSTS_N_INSNS (1))
- {
- /* We found an acceptable shift. Generate a move to
- take the value from the store and put it into the
- shift pseudo, then shift it, then generate another
- move to put in into the target of the read. */
- start_sequence ();
- emit_move_insn (new_reg, gen_lowpart (new_mode, store_info->rhs));
- emit_insn (shift_seq);
- convert_move (read_reg, new_reg, 1);
-
- if (dump_file)
- {
- fprintf (dump_file, " -- adding extract insn r%d:%s = r%d:%s\n",
- REGNO (new_reg), GET_MODE_NAME (new_mode),
- REGNO (store_info->rhs), GET_MODE_NAME (store_mode));
-
- fprintf (dump_file, " -- with shift of r%d by %d\n",
- REGNO(new_reg), shift);
- fprintf (dump_file, " -- and second extract insn r%d:%s = r%d:%s\n",
- REGNO (read_reg), GET_MODE_NAME (read_mode),
- REGNO (new_reg), GET_MODE_NAME (new_mode));
- }
-
- /* Get the three insn sequence and return it. */
- shift_seq = get_insns ();
- end_sequence ();
- return shift_seq;
- }
- }
- }
- else
- /* End the sequence. */
- end_sequence ();
+ if (target != new_reg || shift_seq == NULL)
+ continue;
+
+ cost = 0;
+ for (insn = shift_seq; insn != NULL_RTX; insn = NEXT_INSN (insn))
+ if (INSN_P (insn))
+ cost += insn_rtx_cost (PATTERN (insn));
+
+ /* The computation up to here is essentially independent
+ of the arguments and could be precomputed. It may
+ not be worth doing so. We could precompute if
+ worthwhile or at least cache the results. The result
+ technically depends on both SHIFT and ACCESS_SIZE,
+ but in practice the answer will depend only on ACCESS_SIZE. */
+
+ if (cost > COSTS_N_INSNS (1))
+ continue;
+
+ /* We found an acceptable shift. Generate a move to
+ take the value from the store and put it into the
+ shift pseudo, then shift it, then generate another
+ move to put in into the target of the read. */
+ emit_move_insn (new_reg, new_lhs);
+ emit_insn (shift_seq);
+ read_reg = extract_low_bits (read_mode, new_mode, new_reg);
+ break;