diff options
Diffstat (limited to 'gcc/regrename.c')
| -rw-r--r-- | gcc/regrename.c | 46 |
1 files changed, 45 insertions, 1 deletions
diff --git a/gcc/regrename.c b/gcc/regrename.c index 5f383fc9ce2..d727dd9095b 100644 --- a/gcc/regrename.c +++ b/gcc/regrename.c @@ -130,6 +130,9 @@ static HARD_REG_SET live_hard_regs; record_operand_use. */ static operand_rr_info *cur_operand; +/* Set while scanning RTL if a register dies. Used to tie chains. */ +static struct du_head *terminated_this_insn; + /* Return the chain corresponding to id number ID. Take into account that chains may have been merged. */ du_head_p @@ -224,6 +227,8 @@ create_new_chain (unsigned this_regno, unsigned this_nregs, rtx *loc, head->nregs = this_nregs; head->need_caller_save_reg = 0; head->cannot_rename = 0; + head->renamed = 0; + head->tied_chain = NULL; id_to_chain.safe_push (head); head->id = current_id++; @@ -366,6 +371,13 @@ find_rename_reg (du_head_p this_head, enum reg_class super_class, preferred_class = (enum reg_class) targetm.preferred_rename_class (super_class); + /* Pick and check the register from the tied chain iff the tied chain + is not renamed. */ + if (this_head->tied_chain && !this_head->tied_chain->renamed + && check_new_reg_p (old_reg, this_head->tied_chain->regno, + this_head, *unavailable)) + return this_head->tied_chain->regno; + /* If PREFERRED_CLASS is not NO_REGS, we iterate in the first pass over registers that belong to PREFERRED_CLASS and try to find the best register within the class. If that failed, we iterate in @@ -960,6 +972,7 @@ regrename_do_replace (struct du_head *head, int reg) return false; mode = GET_MODE (*head->first->loc); + head->renamed = 1; head->regno = reg; head->nregs = hard_regno_nregs[reg][mode]; return true; @@ -1043,7 +1056,34 @@ scan_rtx_reg (rtx_insn *insn, rtx *loc, enum reg_class cl, enum scan_actions act if (action == mark_write) { if (type == OP_OUT) - create_new_chain (this_regno, this_nregs, loc, insn, cl); + { + du_head_p c; + rtx pat = PATTERN (insn); + + c = create_new_chain (this_regno, this_nregs, loc, insn, cl); + + /* We try to tie chains in a move instruction for + a single output. */ + if (recog_data.n_operands == 2 + && GET_CODE (pat) == SET + && GET_CODE (SET_DEST (pat)) == REG + && GET_CODE (SET_SRC (pat)) == REG + && terminated_this_insn) + { + gcc_assert (terminated_this_insn->regno + == REGNO (recog_data.operand[1])); + + c->tied_chain = terminated_this_insn; + terminated_this_insn->tied_chain = c; + + if (dump_file) + fprintf (dump_file, "Tying chain %s (%d) with %s (%d)\n", + reg_names[c->regno], c->id, + reg_names[terminated_this_insn->regno], + terminated_this_insn->id); + } + } + return; } @@ -1151,6 +1191,8 @@ scan_rtx_reg (rtx_insn *insn, rtx *loc, enum reg_class cl, enum scan_actions act SET_HARD_REG_BIT (live_hard_regs, head->regno + nregs); } + if (action == terminate_dead) + terminated_this_insn = *p; *p = next; if (dump_file) fprintf (dump_file, @@ -1707,6 +1749,8 @@ build_def_use (basic_block bb) scan_rtx (insn, &XEXP (note, 0), ALL_REGS, mark_read, OP_INOUT); + terminated_this_insn = NULL; + /* Step 4: Close chains for registers that die here, unless the register is mentioned in a REG_UNUSED note. In that case we keep the chain open until step #7 below to ensure |