diff options
Diffstat (limited to 'gcc/combine.cc')
| -rw-r--r-- | gcc/combine.cc | 122 |
1 files changed, 82 insertions, 40 deletions
diff --git a/gcc/combine.cc b/gcc/combine.cc index 1b2bd34..5f08518 100644 --- a/gcc/combine.cc +++ b/gcc/combine.cc @@ -309,6 +309,7 @@ static int *uid_insn_cost; struct insn_link { rtx_insn *insn; unsigned int regno; + int insn_count; struct insn_link *next; }; @@ -342,6 +343,7 @@ alloc_insn_link (rtx_insn *insn, unsigned int regno, struct insn_link *next) sizeof (struct insn_link)); l->insn = insn; l->regno = regno; + l->insn_count = 0; l->next = next; return l; } @@ -454,7 +456,7 @@ static bool merge_outer_ops (enum rtx_code *, HOST_WIDE_INT *, enum rtx_code, static rtx simplify_shift_const_1 (enum rtx_code, machine_mode, rtx, int); static rtx simplify_shift_const (rtx, enum rtx_code, machine_mode, rtx, int); -static int recog_for_combine (rtx *, rtx_insn *, rtx *); +static int recog_for_combine (rtx *, rtx_insn *, rtx *, unsigned = 0, unsigned = 0); static rtx gen_lowpart_for_combine (machine_mode, rtx); static enum rtx_code simplify_compare_const (enum rtx_code, machine_mode, rtx *, rtx *); @@ -472,7 +474,8 @@ static void move_deaths (rtx, rtx, int, rtx_insn *, rtx *); static bool reg_bitfield_target_p (rtx, rtx); static void distribute_notes (rtx, rtx_insn *, rtx_insn *, rtx_insn *, rtx, rtx, rtx); -static void distribute_links (struct insn_link *); +static void distribute_links (struct insn_link *, rtx_insn * = nullptr, + int limit = INT_MAX); static void mark_used_regs_combine (rtx); static void record_promoted_value (rtx_insn *, rtx); static bool unmentioned_reg_p (rtx, rtx); @@ -515,18 +518,22 @@ target_canonicalize_comparison (enum rtx_code *code, rtx *op0, rtx *op1, /* Try to split PATTERN found in INSN. This returns NULL_RTX if PATTERN cannot be split. Otherwise, it returns an insn sequence. + Updates OLD_NREGS with the max number of regs before the split + and NEW_NREGS after the split. This is a wrapper around split_insns which ensures that the reg_stat vector is made larger if the splitter creates a new register. */ static rtx_insn * -combine_split_insns (rtx pattern, rtx_insn *insn) +combine_split_insns (rtx pattern, rtx_insn *insn, + unsigned int *old_nregs, + unsigned int *new_regs) { rtx_insn *ret; unsigned int nregs; - + *old_nregs = max_reg_num (); ret = split_insns (pattern, insn); - nregs = max_reg_num (); + *new_regs = nregs = max_reg_num (); if (nregs > reg_stat.length ()) reg_stat.safe_grow_cleared (nregs, true); return ret; @@ -3566,12 +3573,13 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, { rtx parallel, *split; rtx_insn *m_split_insn; + unsigned int old_nregs, new_nregs; /* See if the MD file can split NEWPAT. If it can't, see if letting it use I2DEST as a scratch register will help. In the latter case, convert I2DEST to the mode of the source of NEWPAT if we can. */ - m_split_insn = combine_split_insns (newpat, i3); + m_split_insn = combine_split_insns (newpat, i3, &old_nregs, &new_nregs); /* We can only use I2DEST as a scratch reg if it doesn't overlap any inputs of NEWPAT. */ @@ -3599,7 +3607,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, gen_rtvec (2, newpat, gen_rtx_CLOBBER (VOIDmode, i2dest))); - m_split_insn = combine_split_insns (parallel, i3); + m_split_insn = combine_split_insns (parallel, i3, &old_nregs, &new_nregs); /* If that didn't work, try changing the mode of I2DEST if we can. */ @@ -3624,7 +3632,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, gen_rtvec (2, newpat, gen_rtx_CLOBBER (VOIDmode, ni2dest)))); - m_split_insn = combine_split_insns (parallel, i3); + m_split_insn = combine_split_insns (parallel, i3, &old_nregs, &new_nregs); if (m_split_insn == 0 && REGNO (i2dest) >= FIRST_PSEUDO_REGISTER) @@ -3647,13 +3655,14 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, if (m_split_insn == 0 && newpat_vec_with_clobbers) { parallel = gen_rtx_PARALLEL (VOIDmode, newpat_vec_with_clobbers); - m_split_insn = combine_split_insns (parallel, i3); + m_split_insn = combine_split_insns (parallel, i3, &old_nregs, &new_nregs); } if (m_split_insn && NEXT_INSN (m_split_insn) == NULL_RTX) { rtx m_split_pat = PATTERN (m_split_insn); - insn_code_number = recog_for_combine (&m_split_pat, i3, &new_i3_notes); + insn_code_number = recog_for_combine (&m_split_pat, i3, &new_i3_notes, + old_nregs, new_nregs); if (insn_code_number >= 0) newpat = m_split_pat; } @@ -3678,7 +3687,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, && (next_nonnote_nondebug_insn (i2) == i3 || ! reg_used_between_p (SET_DEST (i2set), i2, i3))) insn_code_number = recog_for_combine (&newi3pat, i3, - &new_i3_notes); + &new_i3_notes, + old_nregs, new_nregs); if (insn_code_number >= 0) newpat = newi3pat; @@ -4005,18 +4015,19 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, rtx set1 = XVECEXP (newpat, 0, 1); /* Normally, it doesn't matter which of the two is done first, but - one which uses any regs/memory set in between i2 and i3 can't - be first. The PARALLEL might also have been pre-existing in i3, - so we need to make sure that we won't wrongly hoist a SET to i2 - that would conflict with a death note present in there, or would - have its dest modified between i2 and i3. */ + one which uses any regs/memory set or used in between i2 and i3 + can't be first. The PARALLEL might also have been pre-existing + in i3, so we need to make sure that we won't wrongly hoist a SET + to i2 that would conflict with a death note present in there, or + would have its dest modified or used between i2 and i3. */ if (!modified_between_p (SET_SRC (set1), i2, i3) && !(REG_P (SET_DEST (set1)) && find_reg_note (i2, REG_DEAD, SET_DEST (set1))) && !(GET_CODE (SET_DEST (set1)) == SUBREG && find_reg_note (i2, REG_DEAD, SUBREG_REG (SET_DEST (set1)))) - && !modified_between_p (SET_DEST (set1), i2, i3) + && SET_DEST (set1) != pc_rtx + && !reg_used_between_p (SET_DEST (set1), i2, i3) /* If I3 is a jump, ensure that set0 is a jump so that we do not create invalid RTL. */ && (!JUMP_P (i3) || SET_DEST (set0) == pc_rtx) @@ -4031,7 +4042,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, && !(GET_CODE (SET_DEST (set0)) == SUBREG && find_reg_note (i2, REG_DEAD, SUBREG_REG (SET_DEST (set0)))) - && !modified_between_p (SET_DEST (set0), i2, i3) + && SET_DEST (set0) != pc_rtx + && !reg_used_between_p (SET_DEST (set0), i2, i3) /* If I3 is a jump, ensure that set1 is a jump so that we do not create invalid RTL. */ && (!JUMP_P (i3) || SET_DEST (set1) == pc_rtx) @@ -4201,16 +4213,13 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, adjust_for_new_dest (i3); } - /* If I2 didn't change, this is not a combination (but a simplification or - canonicalisation with context), which should not be done here. Doing - it here explodes the algorithm. Don't. */ - if (rtx_equal_p (newi2pat, PATTERN (i2))) - { - if (dump_file) - fprintf (dump_file, "i2 didn't change, not doing this\n"); - undo_all (); - return 0; - } + bool only_i3_changed = !i0 && !i1 && rtx_equal_p (newi2pat, PATTERN (i2)); + + /* If only i3 has changed, any split of the combined instruction just + restored i2 to its original state. No destinations moved from i3 + to i2. */ + if (only_i3_changed) + split_i2i3 = false; /* We now know that we can do this combination. Merge the insns and update the status of registers and LOG_LINKS. */ @@ -4586,10 +4595,15 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, NULL_RTX, NULL_RTX, NULL_RTX); } - distribute_links (i3links); - distribute_links (i2links); - distribute_links (i1links); - distribute_links (i0links); + if (only_i3_changed) + distribute_links (i3links, i3, param_max_combine_search_insns); + else + { + distribute_links (i3links); + distribute_links (i2links, i2); + distribute_links (i1links); + distribute_links (i0links); + } if (REG_P (i2dest)) { @@ -4778,6 +4792,9 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, combine_successes++; undo_commit (); + if (only_i3_changed) + return i3; + rtx_insn *ret = newi2pat ? i2 : i3; if (added_links_insn && DF_INSN_LUID (added_links_insn) < DF_INSN_LUID (ret)) ret = added_links_insn; @@ -4915,8 +4932,9 @@ find_split_point (rtx *loc, rtx_insn *insn, bool set_src) MEM_ADDR_SPACE (x))) { rtx reg = regno_reg_rtx[FIRST_PSEUDO_REGISTER]; + unsigned int old_nregs, new_nregs; rtx_insn *seq = combine_split_insns (gen_rtx_SET (reg, XEXP (x, 0)), - subst_insn); + subst_insn, &old_nregs, &new_nregs); /* This should have produced two insns, each of which sets our placeholder. If the source of the second is a valid address, @@ -11418,7 +11436,8 @@ simplify_shift_const (rtx x, enum rtx_code code, machine_mode result_mode, return value. */ static int -recog_for_combine_1 (rtx *pnewpat, rtx_insn *insn, rtx *pnotes) +recog_for_combine_1 (rtx *pnewpat, rtx_insn *insn, rtx *pnotes, + unsigned old_nregs, unsigned new_nregs) { rtx pat = *pnewpat; rtx pat_without_clobbers; @@ -11534,6 +11553,9 @@ recog_for_combine_1 (rtx *pnewpat, rtx_insn *insn, rtx *pnotes) if (insn_code_number >= 0 && insn_code_number != NOOP_MOVE_INSN_CODE) { + /* Create the reg dead notes if needed for the regs that were created via split. */ + for (; old_nregs < new_nregs; old_nregs++) + notes = alloc_reg_note (REG_DEAD, regno_reg_rtx[old_nregs], notes); old_pat = PATTERN (insn); old_notes = REG_NOTES (insn); old_icode = INSN_CODE (insn); @@ -11705,15 +11727,18 @@ change_zero_ext (rtx pat) PNOTES is a pointer to a location where any REG_UNUSED notes added for the CLOBBERs are placed. + If OLD_NREGS != NEW_NREGS, then PNOTES also includes REG_DEAD notes added. The value is the final insn code from the pattern ultimately matched, or -1. */ static int -recog_for_combine (rtx *pnewpat, rtx_insn *insn, rtx *pnotes) +recog_for_combine (rtx *pnewpat, rtx_insn *insn, rtx *pnotes, + unsigned int old_nregs, unsigned int new_nregs) { rtx pat = *pnewpat; - int insn_code_number = recog_for_combine_1 (pnewpat, insn, pnotes); + int insn_code_number = recog_for_combine_1 (pnewpat, insn, pnotes, + old_nregs, new_nregs); if (insn_code_number >= 0 || check_asm_operands (pat)) return insn_code_number; @@ -11755,7 +11780,8 @@ recog_for_combine (rtx *pnewpat, rtx_insn *insn, rtx *pnotes) if (changed) { - insn_code_number = recog_for_combine_1 (pnewpat, insn, pnotes); + insn_code_number = recog_for_combine_1 (pnewpat, insn, pnotes, + old_nregs, new_nregs); if (insn_code_number < 0) undo_to_marker (marker); @@ -14968,10 +14994,15 @@ distribute_notes (rtx notes, rtx_insn *from_insn, rtx_insn *i3, rtx_insn *i2, /* Similarly to above, distribute the LOG_LINKS that used to be present on I3, I2, and I1 to new locations. This is also called to add a link - pointing at I3 when I3's destination is changed. */ + pointing at I3 when I3's destination is changed. + + If START is nonnull and an insn, we know that the next location for each + link is no earlier than START. LIMIT is the maximum number of nondebug + instructions that can be scanned when looking for the next use of a + definition. */ static void -distribute_links (struct insn_link *links) +distribute_links (struct insn_link *links, rtx_insn *start, int limit) { struct insn_link *link, *next_link; @@ -15037,7 +15068,13 @@ distribute_links (struct insn_link *links) I3 to I2. Also note that not much searching is typically done here since most links don't point very far away. */ - for (insn = NEXT_INSN (link->insn); + int count = 0; + insn = start; + if (!insn || NOTE_P (insn)) + insn = NEXT_INSN (link->insn); + else + count = link->insn_count; + for (; (insn && (this_basic_block->next_bb == EXIT_BLOCK_PTR_FOR_FN (cfun) || BB_HEAD (this_basic_block->next_bb) != insn)); insn = NEXT_INSN (insn)) @@ -15057,6 +15094,11 @@ distribute_links (struct insn_link *links) } else if (INSN_P (insn) && reg_set_p (reg, insn)) break; + else if (count >= limit) + break; + else + count += 1; + link->insn_count = count; /* If we found a place to put the link, place it there unless there is already a link to the same insn as LINK at that point. */ |