reorg.c (ANNUL_IFTRUE_SLOTS, [...]): Add new flags variable to these dummy macros.
* reorg.c (ANNUL_IFTRUE_SLOTS, ANNUL_IFFALSE_SLOTS): Add new flags variable to these dummy macros. (get_jump_flags): New function. (optimize_skip): Get jump flags information from the delay insn. (steal_delay_list_from_target): Get jump flags information from the delay insn and the label of the trial jump. (steal_delay_list_from_fallthrough): Get jump flags information from the delay insn. (try_merge_delay_insns): Likewise. (fill_simple_delay_slots): Likewise. (fill_slots_from_thread): Likewise. (make_return_insn): Likewise. From-SVN: r3904
This commit is contained in:
Jeff Law
parent
0b0316dc43
commit
35523fce74
146
gcc/reorg.c
146
gcc/reorg.c
@ -53,6 +53,13 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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target that would only be safe to execute knowing that the branch
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is taken.
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The HP-PA always has a branch delay slot. For unconditional branches
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its effects can be annulled when the branch is taken. The effects
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of the delay slot in a conditional branch can be nullified for forward
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taken branches, or for untaken backward branches. This means
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we can hoist insns from the fall-through path for forward branches or
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steal insns from the target of backward branches.
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Three techniques for filling delay slots have been implemented so far:
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(1) `fill_simple_delay_slots' is the simplest, most efficient way
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@ -128,10 +135,10 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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#define obstack_chunk_free free
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#ifndef ANNUL_IFTRUE_SLOTS
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#define eligible_for_annul_true(INSN, SLOTS, TRIAL) 0
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#define eligible_for_annul_true(INSN, SLOTS, TRIAL, FLAGS) 0
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#endif
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#ifndef ANNUL_IFFALSE_SLOTS
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#define eligible_for_annul_false(INSN, SLOTS, TRIAL) 0
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#define eligible_for_annul_false(INSN, SLOTS, TRIAL, FLAGS) 0
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#endif
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/* Insns which have delay slots that have not yet been filled. */
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@ -221,6 +228,7 @@ static void delete_from_delay_slot PROTO((rtx));
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static void delete_scheduled_jump PROTO((rtx));
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static void note_delay_statistics PROTO((int, int));
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static rtx optimize_skip PROTO((rtx));
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static int get_jump_flags PROTO((rtx, rtx));
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static int mostly_true_jump PROTO((rtx, rtx));
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static rtx get_branch_condition PROTO((rtx, rtx));
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static int condition_dominates_p PROTO((rtx, rtx));
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@ -1048,13 +1056,16 @@ optimize_skip (insn)
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rtx next_trial = next_active_insn (trial);
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rtx delay_list = 0;
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rtx target_label;
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int flags;
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flags = get_jump_flags (insn, JUMP_LABEL (insn));
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if (trial == 0
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|| GET_CODE (trial) != INSN
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|| GET_CODE (PATTERN (trial)) == SEQUENCE
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|| recog_memoized (trial) < 0
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|| (! eligible_for_annul_false (insn, 0, trial)
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&& ! eligible_for_annul_true (insn, 0, trial)))
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|| (! eligible_for_annul_false (insn, 0, trial, flags)
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&& ! eligible_for_annul_true (insn, 0, trial, flags)))
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return 0;
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/* There are two cases where we are just executing one insn (we assume
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@ -1070,11 +1081,11 @@ optimize_skip (insn)
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&& (simplejump_p (next_trial)
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|| GET_CODE (PATTERN (next_trial)) == RETURN)))
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{
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if (eligible_for_annul_false (insn, 0, trial))
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if (eligible_for_annul_false (insn, 0, trial, flags))
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{
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if (invert_jump (insn, JUMP_LABEL (insn)))
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INSN_FROM_TARGET_P (trial) = 1;
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else if (! eligible_for_annul_true (insn, 0, trial))
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else if (! eligible_for_annul_true (insn, 0, trial, flags))
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return 0;
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}
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@ -1104,6 +1115,74 @@ optimize_skip (insn)
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}
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#endif
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/* Encode and return branch direction and prediction information for
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INSN assuming it will jump to LABEL.
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Non conditional branches return no direction information and
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are predicted as very likely taken. */
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static int
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get_jump_flags (insn, label)
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rtx insn, label;
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{
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int flags;
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/* get_jump_flags can be passed any insn with delay slots, these may
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be INSNs, CALL_INSNs, or JUMP_INSNs. Only JUMP_INSNs have branch
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direction information, and only if they are conditional jumps.
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If LABEL is zero, then there is no way to determine the branch
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direction. */
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if (GET_CODE (insn) == JUMP_INSN
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&& condjump_p (insn)
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&& INSN_UID (insn) <= max_uid
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&& INSN_UID (label) <= max_uid
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&& label != 0)
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flags
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= (uid_to_ruid[INSN_UID (label)] > uid_to_ruid[INSN_UID (insn)])
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? ATTR_FLAG_forward : ATTR_FLAG_backward;
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/* No valid direction information. */
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else
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flags = 0;
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/* If insn is a conditional branch call mostly_true_jump to get
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determine the branch prediction.
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Non conditional branches are predicted as very likely taken. */
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if (GET_CODE (insn) == JUMP_INSN
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&& condjump_p (insn))
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{
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int prediction;
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prediction = mostly_true_jump (insn, get_branch_condition (insn, label));
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switch (prediction)
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{
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case 2:
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flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely);
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break;
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case 1:
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flags |= ATTR_FLAG_likely;
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break;
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case 0:
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flags |= ATTR_FLAG_unlikely;
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break;
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/* mostly_true_jump does not return -1 for very unlikely jumps
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yet, but it should in the future. */
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case -1:
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flags |= (ATTR_FLAG_very_unlikely | ATTR_FLAG_unlikely);
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break;
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default:
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abort();
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}
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}
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else
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flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely);
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return flags;
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}
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/* Return truth value of the statement that this branch
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is mostly taken. If we think that the branch is extremely likely
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to be taken, we return 2. If the branch is slightly more likely to be
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@ -1315,6 +1394,7 @@ steal_delay_list_from_target (insn, condition, seq, delay_list,
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for (i = 1; i < XVECLEN (seq, 0); i++)
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{
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rtx trial = XVECEXP (seq, 0, i);
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int flags;
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if (insn_references_resource_p (trial, sets, 0)
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|| insn_sets_resource_p (trial, needed, 0)
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@ -1335,13 +1415,17 @@ steal_delay_list_from_target (insn, condition, seq, delay_list,
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if (redundant_insn_p (trial, insn, new_delay_list))
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continue;
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/* We will end up re-vectoring this branch, so compute flags
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based on jumping to the new label. */
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flags = get_jump_flags (insn, JUMP_LABEL (XVECEXP (seq, 0, 0)));
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if (! must_annul
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&& ((condition == const_true_rtx
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|| (! insn_sets_resource_p (trial, other_needed, 0)
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&& ! may_trap_p (PATTERN (trial)))))
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? eligible_for_delay (insn, total_slots_filled, trial)
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? eligible_for_delay (insn, total_slots_filled, trial, flags)
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: (must_annul = 1,
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eligible_for_annul_false (insn, total_slots_filled, trial)))
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eligible_for_annul_false (insn, total_slots_filled, trial, flags)))
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{
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temp = copy_rtx (trial);
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INSN_FROM_TARGET_P (temp) = 1;
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@ -1390,6 +1474,9 @@ steal_delay_list_from_fallthrough (insn, condition, seq,
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int *pannul_p;
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{
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int i;
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int flags;
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flags = get_jump_flags (insn, JUMP_LABEL (insn));
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/* We can't do anything if SEQ's delay insn isn't an
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unconditional branch. */
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@ -1425,9 +1512,9 @@ steal_delay_list_from_fallthrough (insn, condition, seq,
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&& ((condition == const_true_rtx
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|| (! insn_sets_resource_p (trial, other_needed, 0)
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&& ! may_trap_p (PATTERN (trial)))))
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? eligible_for_delay (insn, *pslots_filled, trial)
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? eligible_for_delay (insn, *pslots_filled, trial, flags)
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: (*pannul_p = 1,
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eligible_for_annul_true (insn, *pslots_filled, trial)))
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eligible_for_annul_true (insn, *pslots_filled, trial, flags)))
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{
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delete_from_delay_slot (trial);
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delay_list = add_to_delay_list (trial, delay_list);
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@ -1464,6 +1551,9 @@ try_merge_delay_insns (insn, thread)
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struct resources set, needed;
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rtx merged_insns = 0;
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int i;
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int flags;
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flags = get_jump_flags (insn, JUMP_LABEL (insn));
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CLEAR_RESOURCE (&needed);
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CLEAR_RESOURCE (&set);
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@ -1500,7 +1590,7 @@ try_merge_delay_insns (insn, thread)
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&& rtx_equal_p (PATTERN (next_to_match), PATTERN (trial))
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/* Have to test this condition if annul condition is different
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from (and less restrictive than) non-annulling one. */
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&& eligible_for_delay (delay_insn, slot_number - 1, trial))
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&& eligible_for_delay (delay_insn, slot_number - 1, trial, flags))
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{
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next_trial = next_nonnote_insn (trial);
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@ -1545,7 +1635,7 @@ try_merge_delay_insns (insn, thread)
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&& ! sets_cc0_p (PATTERN (dtrial))
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#endif
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&& rtx_equal_p (PATTERN (next_to_match), PATTERN (dtrial))
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&& eligible_for_delay (delay_insn, slot_number - 1, dtrial))
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&& eligible_for_delay (delay_insn, slot_number - 1, dtrial, flags))
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{
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if (! annul_p)
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{
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@ -2396,6 +2486,7 @@ fill_simple_delay_slots (first, non_jumps_p)
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for (i = 0; i < num_unfilled_slots; i++)
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{
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int flags;
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/* Get the next insn to fill. If it has already had any slots assigned,
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we can't do anything with it. Maybe we'll improve this later. */
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@ -2407,7 +2498,8 @@ fill_simple_delay_slots (first, non_jumps_p)
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|| (GET_CODE (insn) == JUMP_INSN && non_jumps_p)
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|| (GET_CODE (insn) != JUMP_INSN && ! non_jumps_p))
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continue;
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flags = get_jump_flags (insn, JUMP_LABEL (insn));
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slots_to_fill = num_delay_slots (insn);
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if (slots_to_fill == 0)
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abort ();
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@ -2433,7 +2525,7 @@ fill_simple_delay_slots (first, non_jumps_p)
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&& (trial = next_active_insn (insn))
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&& GET_CODE (trial) == JUMP_INSN
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&& simplejump_p (trial)
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&& eligible_for_delay (insn, slots_filled, trial)
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&& eligible_for_delay (insn, slots_filled, trial, flags)
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&& no_labels_between_p (insn, trial))
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{
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slots_filled++;
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@ -2497,7 +2589,7 @@ fill_simple_delay_slots (first, non_jumps_p)
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{
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trial = try_split (pat, trial, 1);
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next_trial = prev_nonnote_insn (trial);
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if (eligible_for_delay (insn, slots_filled, trial))
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if (eligible_for_delay (insn, slots_filled, trial, flags))
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{
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/* In this case, we are searching backward, so if we
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find insns to put on the delay list, we want
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@ -2653,7 +2745,7 @@ fill_simple_delay_slots (first, non_jumps_p)
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#endif
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&& ! (maybe_never && may_trap_p (pat))
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&& (trial = try_split (pat, trial, 0))
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&& eligible_for_delay (insn, slots_filled, trial))
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&& eligible_for_delay (insn, slots_filled, trial, flags))
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{
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next_trial = next_nonnote_insn (trial);
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delay_list = add_to_delay_list (trial, delay_list);
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@ -2704,7 +2796,7 @@ fill_simple_delay_slots (first, non_jumps_p)
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#endif
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&& ! (maybe_never && may_trap_p (PATTERN (next_trial)))
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&& (next_trial = try_split (PATTERN (next_trial), next_trial, 0))
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&& eligible_for_delay (insn, slots_filled, next_trial))
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&& eligible_for_delay (insn, slots_filled, next_trial, flags))
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{
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rtx new_label = next_active_insn (next_trial);
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@ -2839,12 +2931,15 @@ fill_slots_from_thread (insn, condition, thread, opposite_thread, likely,
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rtx trial;
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int lose = 0;
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int must_annul = 0;
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int flags;
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/* Validate our arguments. */
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if ((condition == const_true_rtx && ! thread_if_true)
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|| (! own_thread && ! thread_if_true))
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abort ();
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flags = get_jump_flags (insn, JUMP_LABEL (insn));
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/* If our thread is the end of subroutine, we can't get any delay
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insns from that. */
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if (thread == 0)
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@ -2930,7 +3025,7 @@ fill_slots_from_thread (insn, condition, thread, opposite_thread, likely,
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{
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trial = try_split (pat, trial, 0);
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pat = PATTERN (trial);
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if (eligible_for_delay (insn, *pslots_filled, trial))
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if (eligible_for_delay (insn, *pslots_filled, trial, flags))
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goto winner;
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}
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else if (0
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@ -2945,8 +3040,8 @@ fill_slots_from_thread (insn, condition, thread, opposite_thread, likely,
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trial = try_split (pat, trial, 0);
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pat = PATTERN (trial);
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if ((thread_if_true
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? eligible_for_annul_false (insn, *pslots_filled, trial)
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: eligible_for_annul_true (insn, *pslots_filled, trial)))
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? eligible_for_annul_false (insn, *pslots_filled, trial, flags)
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: eligible_for_annul_true (insn, *pslots_filled, trial, flags)))
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{
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rtx temp;
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@ -3075,7 +3170,7 @@ fill_slots_from_thread (insn, condition, thread, opposite_thread, likely,
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pat = PATTERN (trial);
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if (GET_CODE (trial) != INSN || GET_CODE (pat) != SET
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|| ! eligible_for_delay (insn, 0, trial))
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|| ! eligible_for_delay (insn, 0, trial, flags))
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return 0;
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dest = SET_DEST (pat), src = SET_SRC (pat);
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@ -3589,6 +3684,8 @@ make_return_insns (first)
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for (insn = first; insn; insn = NEXT_INSN (insn))
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{
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int flags;
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/* Only look at filled JUMP_INSNs that go to the end of function
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label. */
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if (GET_CODE (insn) != INSN
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@ -3612,6 +3709,7 @@ make_return_insns (first)
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It can if it has more or an equal number of slots and the contents
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of each is valid. */
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flags = get_jump_flags (jump_insn, JUMP_LABEL (jump_insn));
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slots = num_delay_slots (jump_insn);
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if (slots >= XVECLEN (pat, 0) - 1)
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{
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@ -3621,15 +3719,15 @@ make_return_insns (first)
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(INSN_ANNULLED_BRANCH_P (jump_insn)
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&& INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)))
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? eligible_for_annul_false (jump_insn, i - 1,
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XVECEXP (pat, 0, i)) :
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XVECEXP (pat, 0, i), flags) :
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#endif
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#ifdef ANNUL_IFTRUE_SLOTS
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(INSN_ANNULLED_BRANCH_P (jump_insn)
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&& ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)))
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? eligible_for_annul_true (jump_insn, i - 1,
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XVECEXP (pat, 0, i)) :
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XVECEXP (pat, 0, i), flags) :
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#endif
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eligible_for_delay (jump_insn, i -1, XVECEXP (pat, 0, i))))
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eligible_for_delay (jump_insn, i -1, XVECEXP (pat, 0, i), flags)))
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break;
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}
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else
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