diff options
Diffstat (limited to 'gcc/combine.cc')
| -rw-r--r-- | gcc/combine.cc | 139 |
1 files changed, 94 insertions, 45 deletions
diff --git a/gcc/combine.cc b/gcc/combine.cc index ef13f5d..4dbc1f6 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; } @@ -456,6 +458,7 @@ static rtx simplify_shift_const (rtx, enum rtx_code, machine_mode, rtx, int); static int recog_for_combine (rtx *, rtx_insn *, rtx *, unsigned = 0, unsigned = 0); static rtx gen_lowpart_for_combine (machine_mode, rtx); +static rtx gen_lowpart_for_combine_no_emit (machine_mode, rtx); static enum rtx_code simplify_compare_const (enum rtx_code, machine_mode, rtx *, rtx *); static enum rtx_code simplify_comparison (enum rtx_code, rtx *, rtx *); @@ -472,7 +475,8 @@ 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); @@ -488,7 +492,7 @@ static rtx gen_lowpart_or_truncate (machine_mode, rtx); /* Our implementation of gen_lowpart never emits a new pseudo. */ #undef RTL_HOOKS_GEN_LOWPART_NO_EMIT -#define RTL_HOOKS_GEN_LOWPART_NO_EMIT gen_lowpart_for_combine +#define RTL_HOOKS_GEN_LOWPART_NO_EMIT gen_lowpart_for_combine_no_emit #undef RTL_HOOKS_REG_NONZERO_REG_BITS #define RTL_HOOKS_REG_NONZERO_REG_BITS reg_nonzero_bits_for_combine @@ -812,7 +816,7 @@ do_SUBST_LINK (struct insn_link **into, struct insn_link *newval) #define SUBST_LINK(oldval, newval) do_SUBST_LINK (&oldval, newval) /* Subroutine of try_combine. Determine whether the replacement patterns - NEWPAT, NEWI2PAT and NEWOTHERPAT are cheaper according to insn_cost + NEWPAT, NEWI2PAT and NEWOTHERPAT are more expensive according to insn_cost than the original sequence I0, I1, I2, I3 and undobuf.other_insn. Note that I0, I1 and/or NEWI2PAT may be NULL_RTX. Similarly, NEWOTHERPAT and undobuf.other_insn may also both be NULL_RTX. Return false if the cost @@ -4012,37 +4016,39 @@ 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. */ - 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) + 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 ((set_noop_p (set1) + || (!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)))) + && 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) - ) + && (!JUMP_P (i3) || SET_DEST (set0) == pc_rtx)) { newi2pat = set1; newpat = set0; } - else if (!modified_between_p (SET_SRC (set0), i2, i3) - && !(REG_P (SET_DEST (set0)) - && find_reg_note (i2, REG_DEAD, SET_DEST (set0))) - && !(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) + else if ((set_noop_p (set0) + || (!modified_between_p (SET_SRC (set0), i2, i3) + && !(REG_P (SET_DEST (set0)) + && find_reg_note (i2, REG_DEAD, SET_DEST (set0))) + && !(GET_CODE (SET_DEST (set0)) == SUBREG + && find_reg_note (i2, REG_DEAD, + SUBREG_REG (SET_DEST (set0)))) + && 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) - ) + && (!JUMP_P (i3) || SET_DEST (set1) == pc_rtx)) { newi2pat = set0; newpat = set1; @@ -4124,8 +4130,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, } } - /* Only allow this combination if insn_cost reports that the - replacement instructions are cheaper than the originals. */ + /* Reject this combination if insn_cost reports that the replacement + instructions are more expensive than the originals. */ if (!combine_validate_cost (i0, i1, i2, i3, newpat, newi2pat, other_pat)) { undo_all (); @@ -4208,16 +4214,13 @@ 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. */ @@ -4593,10 +4596,15 @@ 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)) { @@ -4785,6 +4793,9 @@ 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; @@ -5270,6 +5281,12 @@ find_split_point (rtx *loc, rtx_insn *insn, bool set_src) SUBST (XEXP (x, 0), XEXP (x, 1)); SUBST (XEXP (x, 1), tem); } + /* Many targets have a `(and (not X) Y)` and/or `(ior (not X) Y)` instructions. + Split at that insns. However if this is + the SET_SRC, we likely do not have such an instruction and it's + worthless to try this split. */ + if (!set_src && GET_CODE (XEXP (x, 0)) == NOT) + return loc; break; case PLUS: @@ -11874,6 +11891,22 @@ gen_lowpart_for_combine (machine_mode omode, rtx x) fail: return gen_rtx_CLOBBER (omode, const0_rtx); } + +/* Like gen_lowpart_for_combine but returns NULL_RTX + for an error instead of CLOBBER. + Note no_emit is not called directly from combine but rather from + simplify_rtx and is expecting a NULL on failure rather than + a CLOBBER. */ + +static rtx +gen_lowpart_for_combine_no_emit (machine_mode omode, rtx x) +{ + rtx tem = gen_lowpart_for_combine (omode, x); + if (!tem || GET_CODE (tem) == CLOBBER) + return NULL_RTX; + return tem; +} + /* Try to simplify a comparison between OP0 and a constant OP1, where CODE is the comparison code that will be tested, into a @@ -14984,10 +15017,15 @@ 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; @@ -15053,7 +15091,13 @@ 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)) @@ -15073,6 +15117,11 @@ 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. */ |