3842 lines
122 KiB
C
3842 lines
122 KiB
C
/* Perform instruction reorganizations for delay slot filling.
|
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Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998,
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1999, 2000, 2001, 2002 Free Software Foundation, Inc.
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Contributed by Richard Kenner (kenner@vlsi1.ultra.nyu.edu).
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Hacked by Michael Tiemann (tiemann@cygnus.com).
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
|
||
Software Foundation; either version 2, or (at your option) any later
|
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
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for more details.
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||
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You should have received a copy of the GNU General Public License
|
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along with GCC; see the file COPYING. If not, write to the Free
|
||
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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02111-1307, USA. */
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/* Instruction reorganization pass.
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This pass runs after register allocation and final jump
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optimization. It should be the last pass to run before peephole.
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It serves primarily to fill delay slots of insns, typically branch
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and call insns. Other insns typically involve more complicated
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interactions of data dependencies and resource constraints, and
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are better handled by scheduling before register allocation (by the
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function `schedule_insns').
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The Branch Penalty is the number of extra cycles that are needed to
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execute a branch insn. On an ideal machine, branches take a single
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cycle, and the Branch Penalty is 0. Several RISC machines approach
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branch delays differently:
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The MIPS and AMD 29000 have a single branch delay slot. Most insns
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(except other branches) can be used to fill this slot. When the
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slot is filled, two insns execute in two cycles, reducing the
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branch penalty to zero.
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The Motorola 88000 conditionally exposes its branch delay slot,
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so code is shorter when it is turned off, but will run faster
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when useful insns are scheduled there.
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The IBM ROMP has two forms of branch and call insns, both with and
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without a delay slot. Much like the 88k, insns not using the delay
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slot can be shorted (2 bytes vs. 4 bytes), but will run slowed.
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The SPARC always has a branch delay slot, but its effects can be
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annulled when the branch is not taken. This means that failing to
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find other sources of insns, we can hoist an insn from the branch
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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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The TMS320C3x and C4x have three branch delay slots. When the three
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slots are filled, the branch penalty is zero. Most insns can fill the
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delay slots except jump insns.
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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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to fill delay slots. This pass first looks for insns which come
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from before the branch and which are safe to execute after the
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branch. Then it searches after the insn requiring delay slots or,
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in the case of a branch, for insns that are after the point at
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which the branch merges into the fallthrough code, if such a point
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exists. When such insns are found, the branch penalty decreases
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and no code expansion takes place.
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(2) `fill_eager_delay_slots' is more complicated: it is used for
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scheduling conditional jumps, or for scheduling jumps which cannot
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be filled using (1). A machine need not have annulled jumps to use
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this strategy, but it helps (by keeping more options open).
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`fill_eager_delay_slots' tries to guess the direction the branch
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will go; if it guesses right 100% of the time, it can reduce the
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branch penalty as much as `fill_simple_delay_slots' does. If it
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guesses wrong 100% of the time, it might as well schedule nops (or
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on the m88k, unexpose the branch slot). When
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`fill_eager_delay_slots' takes insns from the fall-through path of
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the jump, usually there is no code expansion; when it takes insns
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from the branch target, there is code expansion if it is not the
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only way to reach that target.
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(3) `relax_delay_slots' uses a set of rules to simplify code that
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has been reorganized by (1) and (2). It finds cases where
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conditional test can be eliminated, jumps can be threaded, extra
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insns can be eliminated, etc. It is the job of (1) and (2) to do a
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good job of scheduling locally; `relax_delay_slots' takes care of
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making the various individual schedules work well together. It is
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especially tuned to handle the control flow interactions of branch
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insns. It does nothing for insns with delay slots that do not
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branch.
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On machines that use CC0, we are very conservative. We will not make
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a copy of an insn involving CC0 since we want to maintain a 1-1
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correspondence between the insn that sets and uses CC0. The insns are
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allowed to be separated by placing an insn that sets CC0 (but not an insn
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that uses CC0; we could do this, but it doesn't seem worthwhile) in a
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delay slot. In that case, we point each insn at the other with REG_CC_USER
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and REG_CC_SETTER notes. Note that these restrictions affect very few
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machines because most RISC machines with delay slots will not use CC0
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(the RT is the only known exception at this point).
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Not yet implemented:
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The Acorn Risc Machine can conditionally execute most insns, so
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it is profitable to move single insns into a position to execute
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based on the condition code of the previous insn.
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The HP-PA can conditionally nullify insns, providing a similar
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effect to the ARM, differing mostly in which insn is "in charge". */
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#include "config.h"
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#include "system.h"
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#include "toplev.h"
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#include "rtl.h"
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#include "tm_p.h"
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#include "expr.h"
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#include "function.h"
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#include "insn-config.h"
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#include "conditions.h"
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#include "hard-reg-set.h"
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#include "basic-block.h"
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#include "regs.h"
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#include "recog.h"
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#include "flags.h"
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#include "output.h"
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#include "obstack.h"
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#include "insn-attr.h"
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#include "resource.h"
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#include "except.h"
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#include "params.h"
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#ifdef DELAY_SLOTS
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#ifndef ANNUL_IFTRUE_SLOTS
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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, 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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static struct obstack unfilled_slots_obstack;
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static rtx *unfilled_firstobj;
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/* Define macros to refer to the first and last slot containing unfilled
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insns. These are used because the list may move and its address
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should be recomputed at each use. */
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#define unfilled_slots_base \
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((rtx *) obstack_base (&unfilled_slots_obstack))
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#define unfilled_slots_next \
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((rtx *) obstack_next_free (&unfilled_slots_obstack))
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/* Points to the label before the end of the function. */
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static rtx end_of_function_label;
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/* Mapping between INSN_UID's and position in the code since INSN_UID's do
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not always monotonically increase. */
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static int *uid_to_ruid;
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/* Highest valid index in `uid_to_ruid'. */
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static int max_uid;
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static int stop_search_p PARAMS ((rtx, int));
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static int resource_conflicts_p PARAMS ((struct resources *,
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struct resources *));
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static int insn_references_resource_p PARAMS ((rtx, struct resources *, int));
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static int insn_sets_resource_p PARAMS ((rtx, struct resources *, int));
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static rtx find_end_label PARAMS ((void));
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static rtx emit_delay_sequence PARAMS ((rtx, rtx, int));
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static rtx add_to_delay_list PARAMS ((rtx, rtx));
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static rtx delete_from_delay_slot PARAMS ((rtx));
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static void delete_scheduled_jump PARAMS ((rtx));
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static void note_delay_statistics PARAMS ((int, int));
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#if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS)
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static rtx optimize_skip PARAMS ((rtx));
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#endif
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static int get_jump_flags PARAMS ((rtx, rtx));
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static int rare_destination PARAMS ((rtx));
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static int mostly_true_jump PARAMS ((rtx, rtx));
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static rtx get_branch_condition PARAMS ((rtx, rtx));
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static int condition_dominates_p PARAMS ((rtx, rtx));
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static int redirect_with_delay_slots_safe_p PARAMS ((rtx, rtx, rtx));
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static int redirect_with_delay_list_safe_p PARAMS ((rtx, rtx, rtx));
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static int check_annul_list_true_false PARAMS ((int, rtx));
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static rtx steal_delay_list_from_target PARAMS ((rtx, rtx, rtx, rtx,
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struct resources *,
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struct resources *,
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struct resources *,
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int, int *, int *, rtx *));
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static rtx steal_delay_list_from_fallthrough PARAMS ((rtx, rtx, rtx, rtx,
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struct resources *,
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struct resources *,
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struct resources *,
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int, int *, int *));
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static void try_merge_delay_insns PARAMS ((rtx, rtx));
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static rtx redundant_insn PARAMS ((rtx, rtx, rtx));
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static int own_thread_p PARAMS ((rtx, rtx, int));
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static void update_block PARAMS ((rtx, rtx));
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static int reorg_redirect_jump PARAMS ((rtx, rtx));
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static void update_reg_dead_notes PARAMS ((rtx, rtx));
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static void fix_reg_dead_note PARAMS ((rtx, rtx));
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static void update_reg_unused_notes PARAMS ((rtx, rtx));
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static void fill_simple_delay_slots PARAMS ((int));
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static rtx fill_slots_from_thread PARAMS ((rtx, rtx, rtx, rtx, int, int,
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int, int, int *, rtx));
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static void fill_eager_delay_slots PARAMS ((void));
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static void relax_delay_slots PARAMS ((rtx));
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#ifdef HAVE_return
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static void make_return_insns PARAMS ((rtx));
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#endif
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/* Return TRUE if this insn should stop the search for insn to fill delay
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slots. LABELS_P indicates that labels should terminate the search.
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In all cases, jumps terminate the search. */
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static int
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stop_search_p (insn, labels_p)
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rtx insn;
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int labels_p;
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{
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if (insn == 0)
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return 1;
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switch (GET_CODE (insn))
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{
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case NOTE:
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case CALL_INSN:
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return 0;
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case CODE_LABEL:
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return labels_p;
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case JUMP_INSN:
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case BARRIER:
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return 1;
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case INSN:
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/* OK unless it contains a delay slot or is an `asm' insn of some type.
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We don't know anything about these. */
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return (GET_CODE (PATTERN (insn)) == SEQUENCE
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|| GET_CODE (PATTERN (insn)) == ASM_INPUT
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|| asm_noperands (PATTERN (insn)) >= 0);
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default:
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abort ();
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}
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}
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/* Return TRUE if any resources are marked in both RES1 and RES2 or if either
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resource set contains a volatile memory reference. Otherwise, return FALSE. */
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static int
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resource_conflicts_p (res1, res2)
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struct resources *res1, *res2;
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{
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if ((res1->cc && res2->cc) || (res1->memory && res2->memory)
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|| (res1->unch_memory && res2->unch_memory)
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|| res1->volatil || res2->volatil)
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return 1;
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#ifdef HARD_REG_SET
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return (res1->regs & res2->regs) != HARD_CONST (0);
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#else
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{
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int i;
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for (i = 0; i < HARD_REG_SET_LONGS; i++)
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if ((res1->regs[i] & res2->regs[i]) != 0)
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return 1;
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return 0;
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}
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#endif
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}
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/* Return TRUE if any resource marked in RES, a `struct resources', is
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referenced by INSN. If INCLUDE_DELAYED_EFFECTS is set, return if the called
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routine is using those resources.
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We compute this by computing all the resources referenced by INSN and
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seeing if this conflicts with RES. It might be faster to directly check
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ourselves, and this is the way it used to work, but it means duplicating
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a large block of complex code. */
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static int
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insn_references_resource_p (insn, res, include_delayed_effects)
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rtx insn;
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struct resources *res;
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int include_delayed_effects;
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{
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struct resources insn_res;
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CLEAR_RESOURCE (&insn_res);
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mark_referenced_resources (insn, &insn_res, include_delayed_effects);
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return resource_conflicts_p (&insn_res, res);
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}
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/* Return TRUE if INSN modifies resources that are marked in RES.
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INCLUDE_DELAYED_EFFECTS is set if the actions of that routine should be
|
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included. CC0 is only modified if it is explicitly set; see comments
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in front of mark_set_resources for details. */
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static int
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insn_sets_resource_p (insn, res, include_delayed_effects)
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rtx insn;
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struct resources *res;
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int include_delayed_effects;
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{
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struct resources insn_sets;
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CLEAR_RESOURCE (&insn_sets);
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mark_set_resources (insn, &insn_sets, 0, include_delayed_effects);
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return resource_conflicts_p (&insn_sets, res);
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}
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/* Find a label at the end of the function or before a RETURN. If there is
|
||
none, make one. */
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||
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static rtx
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find_end_label ()
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||
{
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||
rtx insn;
|
||
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/* If we found one previously, return it. */
|
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if (end_of_function_label)
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return end_of_function_label;
|
||
|
||
/* Otherwise, see if there is a label at the end of the function. If there
|
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is, it must be that RETURN insns aren't needed, so that is our return
|
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label and we don't have to do anything else. */
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insn = get_last_insn ();
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while (GET_CODE (insn) == NOTE
|
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|| (GET_CODE (insn) == INSN
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&& (GET_CODE (PATTERN (insn)) == USE
|
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|| GET_CODE (PATTERN (insn)) == CLOBBER)))
|
||
insn = PREV_INSN (insn);
|
||
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||
/* When a target threads its epilogue we might already have a
|
||
suitable return insn. If so put a label before it for the
|
||
end_of_function_label. */
|
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if (GET_CODE (insn) == BARRIER
|
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&& GET_CODE (PREV_INSN (insn)) == JUMP_INSN
|
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&& GET_CODE (PATTERN (PREV_INSN (insn))) == RETURN)
|
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{
|
||
rtx temp = PREV_INSN (PREV_INSN (insn));
|
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end_of_function_label = gen_label_rtx ();
|
||
LABEL_NUSES (end_of_function_label) = 0;
|
||
|
||
/* Put the label before an USE insns that may proceed the RETURN insn. */
|
||
while (GET_CODE (temp) == USE)
|
||
temp = PREV_INSN (temp);
|
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emit_label_after (end_of_function_label, temp);
|
||
}
|
||
|
||
else if (GET_CODE (insn) == CODE_LABEL)
|
||
end_of_function_label = insn;
|
||
else
|
||
{
|
||
end_of_function_label = gen_label_rtx ();
|
||
LABEL_NUSES (end_of_function_label) = 0;
|
||
/* If the basic block reorder pass moves the return insn to
|
||
some other place try to locate it again and put our
|
||
end_of_function_label there. */
|
||
while (insn && ! (GET_CODE (insn) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (insn)) == RETURN)))
|
||
insn = PREV_INSN (insn);
|
||
if (insn)
|
||
{
|
||
insn = PREV_INSN (insn);
|
||
|
||
/* Put the label before an USE insns that may proceed the
|
||
RETURN insn. */
|
||
while (GET_CODE (insn) == USE)
|
||
insn = PREV_INSN (insn);
|
||
|
||
emit_label_after (end_of_function_label, insn);
|
||
}
|
||
else
|
||
{
|
||
/* Otherwise, make a new label and emit a RETURN and BARRIER,
|
||
if needed. */
|
||
emit_label (end_of_function_label);
|
||
#ifdef HAVE_return
|
||
if (HAVE_return)
|
||
{
|
||
/* The return we make may have delay slots too. */
|
||
rtx insn = gen_return ();
|
||
insn = emit_jump_insn (insn);
|
||
emit_barrier ();
|
||
if (num_delay_slots (insn) > 0)
|
||
obstack_ptr_grow (&unfilled_slots_obstack, insn);
|
||
}
|
||
#endif
|
||
}
|
||
}
|
||
|
||
/* Show one additional use for this label so it won't go away until
|
||
we are done. */
|
||
++LABEL_NUSES (end_of_function_label);
|
||
|
||
return end_of_function_label;
|
||
}
|
||
|
||
/* Put INSN and LIST together in a SEQUENCE rtx of LENGTH, and replace
|
||
the pattern of INSN with the SEQUENCE.
|
||
|
||
Chain the insns so that NEXT_INSN of each insn in the sequence points to
|
||
the next and NEXT_INSN of the last insn in the sequence points to
|
||
the first insn after the sequence. Similarly for PREV_INSN. This makes
|
||
it easier to scan all insns.
|
||
|
||
Returns the SEQUENCE that replaces INSN. */
|
||
|
||
static rtx
|
||
emit_delay_sequence (insn, list, length)
|
||
rtx insn;
|
||
rtx list;
|
||
int length;
|
||
{
|
||
int i = 1;
|
||
rtx li;
|
||
int had_barrier = 0;
|
||
|
||
/* Allocate the rtvec to hold the insns and the SEQUENCE. */
|
||
rtvec seqv = rtvec_alloc (length + 1);
|
||
rtx seq = gen_rtx_SEQUENCE (VOIDmode, seqv);
|
||
rtx seq_insn = make_insn_raw (seq);
|
||
rtx first = get_insns ();
|
||
rtx last = get_last_insn ();
|
||
|
||
/* Make a copy of the insn having delay slots. */
|
||
rtx delay_insn = copy_rtx (insn);
|
||
|
||
/* If INSN is followed by a BARRIER, delete the BARRIER since it will only
|
||
confuse further processing. Update LAST in case it was the last insn.
|
||
We will put the BARRIER back in later. */
|
||
if (NEXT_INSN (insn) && GET_CODE (NEXT_INSN (insn)) == BARRIER)
|
||
{
|
||
delete_related_insns (NEXT_INSN (insn));
|
||
last = get_last_insn ();
|
||
had_barrier = 1;
|
||
}
|
||
|
||
/* Splice our SEQUENCE into the insn stream where INSN used to be. */
|
||
NEXT_INSN (seq_insn) = NEXT_INSN (insn);
|
||
PREV_INSN (seq_insn) = PREV_INSN (insn);
|
||
|
||
if (insn != last)
|
||
PREV_INSN (NEXT_INSN (seq_insn)) = seq_insn;
|
||
|
||
if (insn != first)
|
||
NEXT_INSN (PREV_INSN (seq_insn)) = seq_insn;
|
||
|
||
/* Note the calls to set_new_first_and_last_insn must occur after
|
||
SEQ_INSN has been completely spliced into the insn stream.
|
||
|
||
Otherwise CUR_INSN_UID will get set to an incorrect value because
|
||
set_new_first_and_last_insn will not find SEQ_INSN in the chain. */
|
||
if (insn == last)
|
||
set_new_first_and_last_insn (first, seq_insn);
|
||
|
||
if (insn == first)
|
||
set_new_first_and_last_insn (seq_insn, last);
|
||
|
||
/* Build our SEQUENCE and rebuild the insn chain. */
|
||
XVECEXP (seq, 0, 0) = delay_insn;
|
||
INSN_DELETED_P (delay_insn) = 0;
|
||
PREV_INSN (delay_insn) = PREV_INSN (seq_insn);
|
||
|
||
for (li = list; li; li = XEXP (li, 1), i++)
|
||
{
|
||
rtx tem = XEXP (li, 0);
|
||
rtx note, next;
|
||
|
||
/* Show that this copy of the insn isn't deleted. */
|
||
INSN_DELETED_P (tem) = 0;
|
||
|
||
XVECEXP (seq, 0, i) = tem;
|
||
PREV_INSN (tem) = XVECEXP (seq, 0, i - 1);
|
||
NEXT_INSN (XVECEXP (seq, 0, i - 1)) = tem;
|
||
|
||
for (note = REG_NOTES (tem); note; note = next)
|
||
{
|
||
next = XEXP (note, 1);
|
||
switch (REG_NOTE_KIND (note))
|
||
{
|
||
case REG_DEAD:
|
||
/* Remove any REG_DEAD notes because we can't rely on them now
|
||
that the insn has been moved. */
|
||
remove_note (tem, note);
|
||
break;
|
||
|
||
case REG_LABEL:
|
||
/* Keep the label reference count up to date. */
|
||
if (GET_CODE (XEXP (note, 0)) == CODE_LABEL)
|
||
LABEL_NUSES (XEXP (note, 0)) ++;
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
|
||
NEXT_INSN (XVECEXP (seq, 0, length)) = NEXT_INSN (seq_insn);
|
||
|
||
/* If the previous insn is a SEQUENCE, update the NEXT_INSN pointer on the
|
||
last insn in that SEQUENCE to point to us. Similarly for the first
|
||
insn in the following insn if it is a SEQUENCE. */
|
||
|
||
if (PREV_INSN (seq_insn) && GET_CODE (PREV_INSN (seq_insn)) == INSN
|
||
&& GET_CODE (PATTERN (PREV_INSN (seq_insn))) == SEQUENCE)
|
||
NEXT_INSN (XVECEXP (PATTERN (PREV_INSN (seq_insn)), 0,
|
||
XVECLEN (PATTERN (PREV_INSN (seq_insn)), 0) - 1))
|
||
= seq_insn;
|
||
|
||
if (NEXT_INSN (seq_insn) && GET_CODE (NEXT_INSN (seq_insn)) == INSN
|
||
&& GET_CODE (PATTERN (NEXT_INSN (seq_insn))) == SEQUENCE)
|
||
PREV_INSN (XVECEXP (PATTERN (NEXT_INSN (seq_insn)), 0, 0)) = seq_insn;
|
||
|
||
/* If there used to be a BARRIER, put it back. */
|
||
if (had_barrier)
|
||
emit_barrier_after (seq_insn);
|
||
|
||
if (i != length + 1)
|
||
abort ();
|
||
|
||
return seq_insn;
|
||
}
|
||
|
||
/* Add INSN to DELAY_LIST and return the head of the new list. The list must
|
||
be in the order in which the insns are to be executed. */
|
||
|
||
static rtx
|
||
add_to_delay_list (insn, delay_list)
|
||
rtx insn;
|
||
rtx delay_list;
|
||
{
|
||
/* If we have an empty list, just make a new list element. If
|
||
INSN has its block number recorded, clear it since we may
|
||
be moving the insn to a new block. */
|
||
|
||
if (delay_list == 0)
|
||
{
|
||
clear_hashed_info_for_insn (insn);
|
||
return gen_rtx_INSN_LIST (VOIDmode, insn, NULL_RTX);
|
||
}
|
||
|
||
/* Otherwise this must be an INSN_LIST. Add INSN to the end of the
|
||
list. */
|
||
XEXP (delay_list, 1) = add_to_delay_list (insn, XEXP (delay_list, 1));
|
||
|
||
return delay_list;
|
||
}
|
||
|
||
/* Delete INSN from the delay slot of the insn that it is in, which may
|
||
produce an insn with no delay slots. Return the new insn. */
|
||
|
||
static rtx
|
||
delete_from_delay_slot (insn)
|
||
rtx insn;
|
||
{
|
||
rtx trial, seq_insn, seq, prev;
|
||
rtx delay_list = 0;
|
||
int i;
|
||
|
||
/* We first must find the insn containing the SEQUENCE with INSN in its
|
||
delay slot. Do this by finding an insn, TRIAL, where
|
||
PREV_INSN (NEXT_INSN (TRIAL)) != TRIAL. */
|
||
|
||
for (trial = insn;
|
||
PREV_INSN (NEXT_INSN (trial)) == trial;
|
||
trial = NEXT_INSN (trial))
|
||
;
|
||
|
||
seq_insn = PREV_INSN (NEXT_INSN (trial));
|
||
seq = PATTERN (seq_insn);
|
||
|
||
/* Create a delay list consisting of all the insns other than the one
|
||
we are deleting (unless we were the only one). */
|
||
if (XVECLEN (seq, 0) > 2)
|
||
for (i = 1; i < XVECLEN (seq, 0); i++)
|
||
if (XVECEXP (seq, 0, i) != insn)
|
||
delay_list = add_to_delay_list (XVECEXP (seq, 0, i), delay_list);
|
||
|
||
/* Delete the old SEQUENCE, re-emit the insn that used to have the delay
|
||
list, and rebuild the delay list if non-empty. */
|
||
prev = PREV_INSN (seq_insn);
|
||
trial = XVECEXP (seq, 0, 0);
|
||
delete_related_insns (seq_insn);
|
||
add_insn_after (trial, prev);
|
||
|
||
if (GET_CODE (trial) == JUMP_INSN
|
||
&& (simplejump_p (trial) || GET_CODE (PATTERN (trial)) == RETURN))
|
||
emit_barrier_after (trial);
|
||
|
||
/* If there are any delay insns, remit them. Otherwise clear the
|
||
annul flag. */
|
||
if (delay_list)
|
||
trial = emit_delay_sequence (trial, delay_list, XVECLEN (seq, 0) - 2);
|
||
else if (GET_CODE (trial) == JUMP_INSN
|
||
|| GET_CODE (trial) == CALL_INSN
|
||
|| GET_CODE (trial) == INSN)
|
||
INSN_ANNULLED_BRANCH_P (trial) = 0;
|
||
|
||
INSN_FROM_TARGET_P (insn) = 0;
|
||
|
||
/* Show we need to fill this insn again. */
|
||
obstack_ptr_grow (&unfilled_slots_obstack, trial);
|
||
|
||
return trial;
|
||
}
|
||
|
||
/* Delete INSN, a JUMP_INSN. If it is a conditional jump, we must track down
|
||
the insn that sets CC0 for it and delete it too. */
|
||
|
||
static void
|
||
delete_scheduled_jump (insn)
|
||
rtx insn;
|
||
{
|
||
/* Delete the insn that sets cc0 for us. On machines without cc0, we could
|
||
delete the insn that sets the condition code, but it is hard to find it.
|
||
Since this case is rare anyway, don't bother trying; there would likely
|
||
be other insns that became dead anyway, which we wouldn't know to
|
||
delete. */
|
||
|
||
#ifdef HAVE_cc0
|
||
if (reg_mentioned_p (cc0_rtx, insn))
|
||
{
|
||
rtx note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
|
||
|
||
/* If a reg-note was found, it points to an insn to set CC0. This
|
||
insn is in the delay list of some other insn. So delete it from
|
||
the delay list it was in. */
|
||
if (note)
|
||
{
|
||
if (! FIND_REG_INC_NOTE (XEXP (note, 0), NULL_RTX)
|
||
&& sets_cc0_p (PATTERN (XEXP (note, 0))) == 1)
|
||
delete_from_delay_slot (XEXP (note, 0));
|
||
}
|
||
else
|
||
{
|
||
/* The insn setting CC0 is our previous insn, but it may be in
|
||
a delay slot. It will be the last insn in the delay slot, if
|
||
it is. */
|
||
rtx trial = previous_insn (insn);
|
||
if (GET_CODE (trial) == NOTE)
|
||
trial = prev_nonnote_insn (trial);
|
||
if (sets_cc0_p (PATTERN (trial)) != 1
|
||
|| FIND_REG_INC_NOTE (trial, NULL_RTX))
|
||
return;
|
||
if (PREV_INSN (NEXT_INSN (trial)) == trial)
|
||
delete_related_insns (trial);
|
||
else
|
||
delete_from_delay_slot (trial);
|
||
}
|
||
}
|
||
#endif
|
||
|
||
delete_related_insns (insn);
|
||
}
|
||
|
||
/* Counters for delay-slot filling. */
|
||
|
||
#define NUM_REORG_FUNCTIONS 2
|
||
#define MAX_DELAY_HISTOGRAM 3
|
||
#define MAX_REORG_PASSES 2
|
||
|
||
static int num_insns_needing_delays[NUM_REORG_FUNCTIONS][MAX_REORG_PASSES];
|
||
|
||
static int num_filled_delays[NUM_REORG_FUNCTIONS][MAX_DELAY_HISTOGRAM+1][MAX_REORG_PASSES];
|
||
|
||
static int reorg_pass_number;
|
||
|
||
static void
|
||
note_delay_statistics (slots_filled, index)
|
||
int slots_filled, index;
|
||
{
|
||
num_insns_needing_delays[index][reorg_pass_number]++;
|
||
if (slots_filled > MAX_DELAY_HISTOGRAM)
|
||
slots_filled = MAX_DELAY_HISTOGRAM;
|
||
num_filled_delays[index][slots_filled][reorg_pass_number]++;
|
||
}
|
||
|
||
#if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS)
|
||
|
||
/* Optimize the following cases:
|
||
|
||
1. When a conditional branch skips over only one instruction,
|
||
use an annulling branch and put that insn in the delay slot.
|
||
Use either a branch that annuls when the condition if true or
|
||
invert the test with a branch that annuls when the condition is
|
||
false. This saves insns, since otherwise we must copy an insn
|
||
from the L1 target.
|
||
|
||
(orig) (skip) (otherwise)
|
||
Bcc.n L1 Bcc',a L1 Bcc,a L1'
|
||
insn insn insn2
|
||
L1: L1: L1:
|
||
insn2 insn2 insn2
|
||
insn3 insn3 L1':
|
||
insn3
|
||
|
||
2. When a conditional branch skips over only one instruction,
|
||
and after that, it unconditionally branches somewhere else,
|
||
perform the similar optimization. This saves executing the
|
||
second branch in the case where the inverted condition is true.
|
||
|
||
Bcc.n L1 Bcc',a L2
|
||
insn insn
|
||
L1: L1:
|
||
Bra L2 Bra L2
|
||
|
||
INSN is a JUMP_INSN.
|
||
|
||
This should be expanded to skip over N insns, where N is the number
|
||
of delay slots required. */
|
||
|
||
static rtx
|
||
optimize_skip (insn)
|
||
rtx insn;
|
||
{
|
||
rtx trial = next_nonnote_insn (insn);
|
||
rtx next_trial = next_active_insn (trial);
|
||
rtx delay_list = 0;
|
||
rtx target_label;
|
||
int flags;
|
||
|
||
flags = get_jump_flags (insn, JUMP_LABEL (insn));
|
||
|
||
if (trial == 0
|
||
|| GET_CODE (trial) != INSN
|
||
|| GET_CODE (PATTERN (trial)) == SEQUENCE
|
||
|| recog_memoized (trial) < 0
|
||
|| (! eligible_for_annul_false (insn, 0, trial, flags)
|
||
&& ! eligible_for_annul_true (insn, 0, trial, flags))
|
||
|| can_throw_internal (trial))
|
||
return 0;
|
||
|
||
/* There are two cases where we are just executing one insn (we assume
|
||
here that a branch requires only one insn; this should be generalized
|
||
at some point): Where the branch goes around a single insn or where
|
||
we have one insn followed by a branch to the same label we branch to.
|
||
In both of these cases, inverting the jump and annulling the delay
|
||
slot give the same effect in fewer insns. */
|
||
if ((next_trial == next_active_insn (JUMP_LABEL (insn))
|
||
&& ! (next_trial == 0 && current_function_epilogue_delay_list != 0))
|
||
|| (next_trial != 0
|
||
&& GET_CODE (next_trial) == JUMP_INSN
|
||
&& JUMP_LABEL (insn) == JUMP_LABEL (next_trial)
|
||
&& (simplejump_p (next_trial)
|
||
|| GET_CODE (PATTERN (next_trial)) == RETURN)))
|
||
{
|
||
if (eligible_for_annul_false (insn, 0, trial, flags))
|
||
{
|
||
if (invert_jump (insn, JUMP_LABEL (insn), 1))
|
||
INSN_FROM_TARGET_P (trial) = 1;
|
||
else if (! eligible_for_annul_true (insn, 0, trial, flags))
|
||
return 0;
|
||
}
|
||
|
||
delay_list = add_to_delay_list (trial, NULL_RTX);
|
||
next_trial = next_active_insn (trial);
|
||
update_block (trial, trial);
|
||
delete_related_insns (trial);
|
||
|
||
/* Also, if we are targeting an unconditional
|
||
branch, thread our jump to the target of that branch. Don't
|
||
change this into a RETURN here, because it may not accept what
|
||
we have in the delay slot. We'll fix this up later. */
|
||
if (next_trial && GET_CODE (next_trial) == JUMP_INSN
|
||
&& (simplejump_p (next_trial)
|
||
|| GET_CODE (PATTERN (next_trial)) == RETURN))
|
||
{
|
||
target_label = JUMP_LABEL (next_trial);
|
||
if (target_label == 0)
|
||
target_label = find_end_label ();
|
||
|
||
/* Recompute the flags based on TARGET_LABEL since threading
|
||
the jump to TARGET_LABEL may change the direction of the
|
||
jump (which may change the circumstances in which the
|
||
delay slot is nullified). */
|
||
flags = get_jump_flags (insn, target_label);
|
||
if (eligible_for_annul_true (insn, 0, trial, flags))
|
||
reorg_redirect_jump (insn, target_label);
|
||
}
|
||
|
||
INSN_ANNULLED_BRANCH_P (insn) = 1;
|
||
}
|
||
|
||
return delay_list;
|
||
}
|
||
#endif
|
||
|
||
/* Encode and return branch direction and prediction information for
|
||
INSN assuming it will jump to LABEL.
|
||
|
||
Non conditional branches return no direction information and
|
||
are predicted as very likely taken. */
|
||
|
||
static int
|
||
get_jump_flags (insn, label)
|
||
rtx insn, label;
|
||
{
|
||
int flags;
|
||
|
||
/* get_jump_flags can be passed any insn with delay slots, these may
|
||
be INSNs, CALL_INSNs, or JUMP_INSNs. Only JUMP_INSNs have branch
|
||
direction information, and only if they are conditional jumps.
|
||
|
||
If LABEL is zero, then there is no way to determine the branch
|
||
direction. */
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& (condjump_p (insn) || condjump_in_parallel_p (insn))
|
||
&& INSN_UID (insn) <= max_uid
|
||
&& label != 0
|
||
&& INSN_UID (label) <= max_uid)
|
||
flags
|
||
= (uid_to_ruid[INSN_UID (label)] > uid_to_ruid[INSN_UID (insn)])
|
||
? ATTR_FLAG_forward : ATTR_FLAG_backward;
|
||
/* No valid direction information. */
|
||
else
|
||
flags = 0;
|
||
|
||
/* If insn is a conditional branch call mostly_true_jump to get
|
||
determine the branch prediction.
|
||
|
||
Non conditional branches are predicted as very likely taken. */
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& (condjump_p (insn) || condjump_in_parallel_p (insn)))
|
||
{
|
||
int prediction;
|
||
|
||
prediction = mostly_true_jump (insn, get_branch_condition (insn, label));
|
||
switch (prediction)
|
||
{
|
||
case 2:
|
||
flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely);
|
||
break;
|
||
case 1:
|
||
flags |= ATTR_FLAG_likely;
|
||
break;
|
||
case 0:
|
||
flags |= ATTR_FLAG_unlikely;
|
||
break;
|
||
case -1:
|
||
flags |= (ATTR_FLAG_very_unlikely | ATTR_FLAG_unlikely);
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
}
|
||
}
|
||
else
|
||
flags |= (ATTR_FLAG_very_likely | ATTR_FLAG_likely);
|
||
|
||
return flags;
|
||
}
|
||
|
||
/* Return 1 if INSN is a destination that will be branched to rarely (the
|
||
return point of a function); return 2 if DEST will be branched to very
|
||
rarely (a call to a function that doesn't return). Otherwise,
|
||
return 0. */
|
||
|
||
static int
|
||
rare_destination (insn)
|
||
rtx insn;
|
||
{
|
||
int jump_count = 0;
|
||
rtx next;
|
||
|
||
for (; insn; insn = next)
|
||
{
|
||
if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SEQUENCE)
|
||
insn = XVECEXP (PATTERN (insn), 0, 0);
|
||
|
||
next = NEXT_INSN (insn);
|
||
|
||
switch (GET_CODE (insn))
|
||
{
|
||
case CODE_LABEL:
|
||
return 0;
|
||
case BARRIER:
|
||
/* A BARRIER can either be after a JUMP_INSN or a CALL_INSN. We
|
||
don't scan past JUMP_INSNs, so any barrier we find here must
|
||
have been after a CALL_INSN and hence mean the call doesn't
|
||
return. */
|
||
return 2;
|
||
case JUMP_INSN:
|
||
if (GET_CODE (PATTERN (insn)) == RETURN)
|
||
return 1;
|
||
else if (simplejump_p (insn)
|
||
&& jump_count++ < 10)
|
||
next = JUMP_LABEL (insn);
|
||
else
|
||
return 0;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
/* If we got here it means we hit the end of the function. So this
|
||
is an unlikely destination. */
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Return truth value of the statement that this branch
|
||
is mostly taken. If we think that the branch is extremely likely
|
||
to be taken, we return 2. If the branch is slightly more likely to be
|
||
taken, return 1. If the branch is slightly less likely to be taken,
|
||
return 0 and if the branch is highly unlikely to be taken, return -1.
|
||
|
||
CONDITION, if nonzero, is the condition that JUMP_INSN is testing. */
|
||
|
||
static int
|
||
mostly_true_jump (jump_insn, condition)
|
||
rtx jump_insn, condition;
|
||
{
|
||
rtx target_label = JUMP_LABEL (jump_insn);
|
||
rtx insn, note;
|
||
int rare_dest = rare_destination (target_label);
|
||
int rare_fallthrough = rare_destination (NEXT_INSN (jump_insn));
|
||
|
||
/* If branch probabilities are available, then use that number since it
|
||
always gives a correct answer. */
|
||
note = find_reg_note (jump_insn, REG_BR_PROB, 0);
|
||
if (note)
|
||
{
|
||
int prob = INTVAL (XEXP (note, 0));
|
||
|
||
if (prob >= REG_BR_PROB_BASE * 9 / 10)
|
||
return 2;
|
||
else if (prob >= REG_BR_PROB_BASE / 2)
|
||
return 1;
|
||
else if (prob >= REG_BR_PROB_BASE / 10)
|
||
return 0;
|
||
else
|
||
return -1;
|
||
}
|
||
|
||
/* ??? Ought to use estimate_probability instead. */
|
||
|
||
/* If this is a branch outside a loop, it is highly unlikely. */
|
||
if (GET_CODE (PATTERN (jump_insn)) == SET
|
||
&& GET_CODE (SET_SRC (PATTERN (jump_insn))) == IF_THEN_ELSE
|
||
&& ((GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 1)) == LABEL_REF
|
||
&& LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 1)))
|
||
|| (GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 2)) == LABEL_REF
|
||
&& LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 2)))))
|
||
return -1;
|
||
|
||
if (target_label)
|
||
{
|
||
/* If this is the test of a loop, it is very likely true. We scan
|
||
backwards from the target label. If we find a NOTE_INSN_LOOP_BEG
|
||
before the next real insn, we assume the branch is to the top of
|
||
the loop. */
|
||
for (insn = PREV_INSN (target_label);
|
||
insn && GET_CODE (insn) == NOTE;
|
||
insn = PREV_INSN (insn))
|
||
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
|
||
return 2;
|
||
|
||
/* If this is a jump to the test of a loop, it is likely true. We scan
|
||
forwards from the target label. If we find a NOTE_INSN_LOOP_VTOP
|
||
before the next real insn, we assume the branch is to the loop branch
|
||
test. */
|
||
for (insn = NEXT_INSN (target_label);
|
||
insn && GET_CODE (insn) == NOTE;
|
||
insn = PREV_INSN (insn))
|
||
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP)
|
||
return 1;
|
||
}
|
||
|
||
/* Look at the relative rarities of the fallthrough and destination. If
|
||
they differ, we can predict the branch that way. */
|
||
|
||
switch (rare_fallthrough - rare_dest)
|
||
{
|
||
case -2:
|
||
return -1;
|
||
case -1:
|
||
return 0;
|
||
case 0:
|
||
break;
|
||
case 1:
|
||
return 1;
|
||
case 2:
|
||
return 2;
|
||
}
|
||
|
||
/* If we couldn't figure out what this jump was, assume it won't be
|
||
taken. This should be rare. */
|
||
if (condition == 0)
|
||
return 0;
|
||
|
||
/* EQ tests are usually false and NE tests are usually true. Also,
|
||
most quantities are positive, so we can make the appropriate guesses
|
||
about signed comparisons against zero. */
|
||
switch (GET_CODE (condition))
|
||
{
|
||
case CONST_INT:
|
||
/* Unconditional branch. */
|
||
return 1;
|
||
case EQ:
|
||
return 0;
|
||
case NE:
|
||
return 1;
|
||
case LE:
|
||
case LT:
|
||
if (XEXP (condition, 1) == const0_rtx)
|
||
return 0;
|
||
break;
|
||
case GE:
|
||
case GT:
|
||
if (XEXP (condition, 1) == const0_rtx)
|
||
return 1;
|
||
break;
|
||
|
||
default:
|
||
break;
|
||
}
|
||
|
||
/* Predict backward branches usually take, forward branches usually not. If
|
||
we don't know whether this is forward or backward, assume the branch
|
||
will be taken, since most are. */
|
||
return (target_label == 0 || INSN_UID (jump_insn) > max_uid
|
||
|| INSN_UID (target_label) > max_uid
|
||
|| (uid_to_ruid[INSN_UID (jump_insn)]
|
||
> uid_to_ruid[INSN_UID (target_label)]));
|
||
}
|
||
|
||
/* Return the condition under which INSN will branch to TARGET. If TARGET
|
||
is zero, return the condition under which INSN will return. If INSN is
|
||
an unconditional branch, return const_true_rtx. If INSN isn't a simple
|
||
type of jump, or it doesn't go to TARGET, return 0. */
|
||
|
||
static rtx
|
||
get_branch_condition (insn, target)
|
||
rtx insn;
|
||
rtx target;
|
||
{
|
||
rtx pat = PATTERN (insn);
|
||
rtx src;
|
||
|
||
if (condjump_in_parallel_p (insn))
|
||
pat = XVECEXP (pat, 0, 0);
|
||
|
||
if (GET_CODE (pat) == RETURN)
|
||
return target == 0 ? const_true_rtx : 0;
|
||
|
||
else if (GET_CODE (pat) != SET || SET_DEST (pat) != pc_rtx)
|
||
return 0;
|
||
|
||
src = SET_SRC (pat);
|
||
if (GET_CODE (src) == LABEL_REF && XEXP (src, 0) == target)
|
||
return const_true_rtx;
|
||
|
||
else if (GET_CODE (src) == IF_THEN_ELSE
|
||
&& ((target == 0 && GET_CODE (XEXP (src, 1)) == RETURN)
|
||
|| (GET_CODE (XEXP (src, 1)) == LABEL_REF
|
||
&& XEXP (XEXP (src, 1), 0) == target))
|
||
&& XEXP (src, 2) == pc_rtx)
|
||
return XEXP (src, 0);
|
||
|
||
else if (GET_CODE (src) == IF_THEN_ELSE
|
||
&& ((target == 0 && GET_CODE (XEXP (src, 2)) == RETURN)
|
||
|| (GET_CODE (XEXP (src, 2)) == LABEL_REF
|
||
&& XEXP (XEXP (src, 2), 0) == target))
|
||
&& XEXP (src, 1) == pc_rtx)
|
||
{
|
||
enum rtx_code rev;
|
||
rev = reversed_comparison_code (XEXP (src, 0), insn);
|
||
if (rev != UNKNOWN)
|
||
return gen_rtx_fmt_ee (rev, GET_MODE (XEXP (src, 0)),
|
||
XEXP (XEXP (src, 0), 0),
|
||
XEXP (XEXP (src, 0), 1));
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return nonzero if CONDITION is more strict than the condition of
|
||
INSN, i.e., if INSN will always branch if CONDITION is true. */
|
||
|
||
static int
|
||
condition_dominates_p (condition, insn)
|
||
rtx condition;
|
||
rtx insn;
|
||
{
|
||
rtx other_condition = get_branch_condition (insn, JUMP_LABEL (insn));
|
||
enum rtx_code code = GET_CODE (condition);
|
||
enum rtx_code other_code;
|
||
|
||
if (rtx_equal_p (condition, other_condition)
|
||
|| other_condition == const_true_rtx)
|
||
return 1;
|
||
|
||
else if (condition == const_true_rtx || other_condition == 0)
|
||
return 0;
|
||
|
||
other_code = GET_CODE (other_condition);
|
||
if (GET_RTX_LENGTH (code) != 2 || GET_RTX_LENGTH (other_code) != 2
|
||
|| ! rtx_equal_p (XEXP (condition, 0), XEXP (other_condition, 0))
|
||
|| ! rtx_equal_p (XEXP (condition, 1), XEXP (other_condition, 1)))
|
||
return 0;
|
||
|
||
return comparison_dominates_p (code, other_code);
|
||
}
|
||
|
||
/* Return nonzero if redirecting JUMP to NEWLABEL does not invalidate
|
||
any insns already in the delay slot of JUMP. */
|
||
|
||
static int
|
||
redirect_with_delay_slots_safe_p (jump, newlabel, seq)
|
||
rtx jump, newlabel, seq;
|
||
{
|
||
int flags, i;
|
||
rtx pat = PATTERN (seq);
|
||
|
||
/* Make sure all the delay slots of this jump would still
|
||
be valid after threading the jump. If they are still
|
||
valid, then return nonzero. */
|
||
|
||
flags = get_jump_flags (jump, newlabel);
|
||
for (i = 1; i < XVECLEN (pat, 0); i++)
|
||
if (! (
|
||
#ifdef ANNUL_IFFALSE_SLOTS
|
||
(INSN_ANNULLED_BRANCH_P (jump)
|
||
&& INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)))
|
||
? eligible_for_annul_false (jump, i - 1,
|
||
XVECEXP (pat, 0, i), flags) :
|
||
#endif
|
||
#ifdef ANNUL_IFTRUE_SLOTS
|
||
(INSN_ANNULLED_BRANCH_P (jump)
|
||
&& ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)))
|
||
? eligible_for_annul_true (jump, i - 1,
|
||
XVECEXP (pat, 0, i), flags) :
|
||
#endif
|
||
eligible_for_delay (jump, i - 1, XVECEXP (pat, 0, i), flags)))
|
||
break;
|
||
|
||
return (i == XVECLEN (pat, 0));
|
||
}
|
||
|
||
/* Return nonzero if redirecting JUMP to NEWLABEL does not invalidate
|
||
any insns we wish to place in the delay slot of JUMP. */
|
||
|
||
static int
|
||
redirect_with_delay_list_safe_p (jump, newlabel, delay_list)
|
||
rtx jump, newlabel, delay_list;
|
||
{
|
||
int flags, i;
|
||
rtx li;
|
||
|
||
/* Make sure all the insns in DELAY_LIST would still be
|
||
valid after threading the jump. If they are still
|
||
valid, then return nonzero. */
|
||
|
||
flags = get_jump_flags (jump, newlabel);
|
||
for (li = delay_list, i = 0; li; li = XEXP (li, 1), i++)
|
||
if (! (
|
||
#ifdef ANNUL_IFFALSE_SLOTS
|
||
(INSN_ANNULLED_BRANCH_P (jump)
|
||
&& INSN_FROM_TARGET_P (XEXP (li, 0)))
|
||
? eligible_for_annul_false (jump, i, XEXP (li, 0), flags) :
|
||
#endif
|
||
#ifdef ANNUL_IFTRUE_SLOTS
|
||
(INSN_ANNULLED_BRANCH_P (jump)
|
||
&& ! INSN_FROM_TARGET_P (XEXP (li, 0)))
|
||
? eligible_for_annul_true (jump, i, XEXP (li, 0), flags) :
|
||
#endif
|
||
eligible_for_delay (jump, i, XEXP (li, 0), flags)))
|
||
break;
|
||
|
||
return (li == NULL);
|
||
}
|
||
|
||
/* DELAY_LIST is a list of insns that have already been placed into delay
|
||
slots. See if all of them have the same annulling status as ANNUL_TRUE_P.
|
||
If not, return 0; otherwise return 1. */
|
||
|
||
static int
|
||
check_annul_list_true_false (annul_true_p, delay_list)
|
||
int annul_true_p;
|
||
rtx delay_list;
|
||
{
|
||
rtx temp;
|
||
|
||
if (delay_list)
|
||
{
|
||
for (temp = delay_list; temp; temp = XEXP (temp, 1))
|
||
{
|
||
rtx trial = XEXP (temp, 0);
|
||
|
||
if ((annul_true_p && INSN_FROM_TARGET_P (trial))
|
||
|| (!annul_true_p && !INSN_FROM_TARGET_P (trial)))
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* INSN branches to an insn whose pattern SEQ is a SEQUENCE. Given that
|
||
the condition tested by INSN is CONDITION and the resources shown in
|
||
OTHER_NEEDED are needed after INSN, see whether INSN can take all the insns
|
||
from SEQ's delay list, in addition to whatever insns it may execute
|
||
(in DELAY_LIST). SETS and NEEDED are denote resources already set and
|
||
needed while searching for delay slot insns. Return the concatenated
|
||
delay list if possible, otherwise, return 0.
|
||
|
||
SLOTS_TO_FILL is the total number of slots required by INSN, and
|
||
PSLOTS_FILLED points to the number filled so far (also the number of
|
||
insns in DELAY_LIST). It is updated with the number that have been
|
||
filled from the SEQUENCE, if any.
|
||
|
||
PANNUL_P points to a nonzero value if we already know that we need
|
||
to annul INSN. If this routine determines that annulling is needed,
|
||
it may set that value nonzero.
|
||
|
||
PNEW_THREAD points to a location that is to receive the place at which
|
||
execution should continue. */
|
||
|
||
static rtx
|
||
steal_delay_list_from_target (insn, condition, seq, delay_list,
|
||
sets, needed, other_needed,
|
||
slots_to_fill, pslots_filled, pannul_p,
|
||
pnew_thread)
|
||
rtx insn, condition;
|
||
rtx seq;
|
||
rtx delay_list;
|
||
struct resources *sets, *needed, *other_needed;
|
||
int slots_to_fill;
|
||
int *pslots_filled;
|
||
int *pannul_p;
|
||
rtx *pnew_thread;
|
||
{
|
||
rtx temp;
|
||
int slots_remaining = slots_to_fill - *pslots_filled;
|
||
int total_slots_filled = *pslots_filled;
|
||
rtx new_delay_list = 0;
|
||
int must_annul = *pannul_p;
|
||
int used_annul = 0;
|
||
int i;
|
||
struct resources cc_set;
|
||
|
||
/* We can't do anything if there are more delay slots in SEQ than we
|
||
can handle, or if we don't know that it will be a taken branch.
|
||
We know that it will be a taken branch if it is either an unconditional
|
||
branch or a conditional branch with a stricter branch condition.
|
||
|
||
Also, exit if the branch has more than one set, since then it is computing
|
||
other results that can't be ignored, e.g. the HPPA mov&branch instruction.
|
||
??? It may be possible to move other sets into INSN in addition to
|
||
moving the instructions in the delay slots.
|
||
|
||
We can not steal the delay list if one of the instructions in the
|
||
current delay_list modifies the condition codes and the jump in the
|
||
sequence is a conditional jump. We can not do this because we can
|
||
not change the direction of the jump because the condition codes
|
||
will effect the direction of the jump in the sequence. */
|
||
|
||
CLEAR_RESOURCE (&cc_set);
|
||
for (temp = delay_list; temp; temp = XEXP (temp, 1))
|
||
{
|
||
rtx trial = XEXP (temp, 0);
|
||
|
||
mark_set_resources (trial, &cc_set, 0, MARK_SRC_DEST_CALL);
|
||
if (insn_references_resource_p (XVECEXP (seq , 0, 0), &cc_set, 0))
|
||
return delay_list;
|
||
}
|
||
|
||
if (XVECLEN (seq, 0) - 1 > slots_remaining
|
||
|| ! condition_dominates_p (condition, XVECEXP (seq, 0, 0))
|
||
|| ! single_set (XVECEXP (seq, 0, 0)))
|
||
return delay_list;
|
||
|
||
#ifdef MD_CAN_REDIRECT_BRANCH
|
||
/* On some targets, branches with delay slots can have a limited
|
||
displacement. Give the back end a chance to tell us we can't do
|
||
this. */
|
||
if (! MD_CAN_REDIRECT_BRANCH (insn, XVECEXP (seq, 0, 0)))
|
||
return delay_list;
|
||
#endif
|
||
|
||
for (i = 1; i < XVECLEN (seq, 0); i++)
|
||
{
|
||
rtx trial = XVECEXP (seq, 0, i);
|
||
int flags;
|
||
|
||
if (insn_references_resource_p (trial, sets, 0)
|
||
|| insn_sets_resource_p (trial, needed, 0)
|
||
|| insn_sets_resource_p (trial, sets, 0)
|
||
#ifdef HAVE_cc0
|
||
/* If TRIAL sets CC0, we can't copy it, so we can't steal this
|
||
delay list. */
|
||
|| find_reg_note (trial, REG_CC_USER, NULL_RTX)
|
||
#endif
|
||
/* If TRIAL is from the fallthrough code of an annulled branch insn
|
||
in SEQ, we cannot use it. */
|
||
|| (INSN_ANNULLED_BRANCH_P (XVECEXP (seq, 0, 0))
|
||
&& ! INSN_FROM_TARGET_P (trial)))
|
||
return delay_list;
|
||
|
||
/* If this insn was already done (usually in a previous delay slot),
|
||
pretend we put it in our delay slot. */
|
||
if (redundant_insn (trial, insn, new_delay_list))
|
||
continue;
|
||
|
||
/* We will end up re-vectoring this branch, so compute flags
|
||
based on jumping to the new label. */
|
||
flags = get_jump_flags (insn, JUMP_LABEL (XVECEXP (seq, 0, 0)));
|
||
|
||
if (! must_annul
|
||
&& ((condition == const_true_rtx
|
||
|| (! insn_sets_resource_p (trial, other_needed, 0)
|
||
&& ! may_trap_p (PATTERN (trial)))))
|
||
? eligible_for_delay (insn, total_slots_filled, trial, flags)
|
||
: (must_annul || (delay_list == NULL && new_delay_list == NULL))
|
||
&& (must_annul = 1,
|
||
check_annul_list_true_false (0, delay_list)
|
||
&& check_annul_list_true_false (0, new_delay_list)
|
||
&& eligible_for_annul_false (insn, total_slots_filled,
|
||
trial, flags)))
|
||
{
|
||
if (must_annul)
|
||
used_annul = 1;
|
||
temp = copy_rtx (trial);
|
||
INSN_FROM_TARGET_P (temp) = 1;
|
||
new_delay_list = add_to_delay_list (temp, new_delay_list);
|
||
total_slots_filled++;
|
||
|
||
if (--slots_remaining == 0)
|
||
break;
|
||
}
|
||
else
|
||
return delay_list;
|
||
}
|
||
|
||
/* Show the place to which we will be branching. */
|
||
*pnew_thread = next_active_insn (JUMP_LABEL (XVECEXP (seq, 0, 0)));
|
||
|
||
/* Add any new insns to the delay list and update the count of the
|
||
number of slots filled. */
|
||
*pslots_filled = total_slots_filled;
|
||
if (used_annul)
|
||
*pannul_p = 1;
|
||
|
||
if (delay_list == 0)
|
||
return new_delay_list;
|
||
|
||
for (temp = new_delay_list; temp; temp = XEXP (temp, 1))
|
||
delay_list = add_to_delay_list (XEXP (temp, 0), delay_list);
|
||
|
||
return delay_list;
|
||
}
|
||
|
||
/* Similar to steal_delay_list_from_target except that SEQ is on the
|
||
fallthrough path of INSN. Here we only do something if the delay insn
|
||
of SEQ is an unconditional branch. In that case we steal its delay slot
|
||
for INSN since unconditional branches are much easier to fill. */
|
||
|
||
static rtx
|
||
steal_delay_list_from_fallthrough (insn, condition, seq,
|
||
delay_list, sets, needed, other_needed,
|
||
slots_to_fill, pslots_filled, pannul_p)
|
||
rtx insn, condition;
|
||
rtx seq;
|
||
rtx delay_list;
|
||
struct resources *sets, *needed, *other_needed;
|
||
int slots_to_fill;
|
||
int *pslots_filled;
|
||
int *pannul_p;
|
||
{
|
||
int i;
|
||
int flags;
|
||
int must_annul = *pannul_p;
|
||
int used_annul = 0;
|
||
|
||
flags = get_jump_flags (insn, JUMP_LABEL (insn));
|
||
|
||
/* We can't do anything if SEQ's delay insn isn't an
|
||
unconditional branch. */
|
||
|
||
if (! simplejump_p (XVECEXP (seq, 0, 0))
|
||
&& GET_CODE (PATTERN (XVECEXP (seq, 0, 0))) != RETURN)
|
||
return delay_list;
|
||
|
||
for (i = 1; i < XVECLEN (seq, 0); i++)
|
||
{
|
||
rtx trial = XVECEXP (seq, 0, i);
|
||
|
||
/* If TRIAL sets CC0, stealing it will move it too far from the use
|
||
of CC0. */
|
||
if (insn_references_resource_p (trial, sets, 0)
|
||
|| insn_sets_resource_p (trial, needed, 0)
|
||
|| insn_sets_resource_p (trial, sets, 0)
|
||
#ifdef HAVE_cc0
|
||
|| sets_cc0_p (PATTERN (trial))
|
||
#endif
|
||
)
|
||
|
||
break;
|
||
|
||
/* If this insn was already done, we don't need it. */
|
||
if (redundant_insn (trial, insn, delay_list))
|
||
{
|
||
delete_from_delay_slot (trial);
|
||
continue;
|
||
}
|
||
|
||
if (! must_annul
|
||
&& ((condition == const_true_rtx
|
||
|| (! insn_sets_resource_p (trial, other_needed, 0)
|
||
&& ! may_trap_p (PATTERN (trial)))))
|
||
? eligible_for_delay (insn, *pslots_filled, trial, flags)
|
||
: (must_annul || delay_list == NULL) && (must_annul = 1,
|
||
check_annul_list_true_false (1, delay_list)
|
||
&& eligible_for_annul_true (insn, *pslots_filled, trial, flags)))
|
||
{
|
||
if (must_annul)
|
||
used_annul = 1;
|
||
delete_from_delay_slot (trial);
|
||
delay_list = add_to_delay_list (trial, delay_list);
|
||
|
||
if (++(*pslots_filled) == slots_to_fill)
|
||
break;
|
||
}
|
||
else
|
||
break;
|
||
}
|
||
|
||
if (used_annul)
|
||
*pannul_p = 1;
|
||
return delay_list;
|
||
}
|
||
|
||
/* Try merging insns starting at THREAD which match exactly the insns in
|
||
INSN's delay list.
|
||
|
||
If all insns were matched and the insn was previously annulling, the
|
||
annul bit will be cleared.
|
||
|
||
For each insn that is merged, if the branch is or will be non-annulling,
|
||
we delete the merged insn. */
|
||
|
||
static void
|
||
try_merge_delay_insns (insn, thread)
|
||
rtx insn, thread;
|
||
{
|
||
rtx trial, next_trial;
|
||
rtx delay_insn = XVECEXP (PATTERN (insn), 0, 0);
|
||
int annul_p = INSN_ANNULLED_BRANCH_P (delay_insn);
|
||
int slot_number = 1;
|
||
int num_slots = XVECLEN (PATTERN (insn), 0);
|
||
rtx next_to_match = XVECEXP (PATTERN (insn), 0, slot_number);
|
||
struct resources set, needed;
|
||
rtx merged_insns = 0;
|
||
int i;
|
||
int flags;
|
||
|
||
flags = get_jump_flags (delay_insn, JUMP_LABEL (delay_insn));
|
||
|
||
CLEAR_RESOURCE (&needed);
|
||
CLEAR_RESOURCE (&set);
|
||
|
||
/* If this is not an annulling branch, take into account anything needed in
|
||
INSN's delay slot. This prevents two increments from being incorrectly
|
||
folded into one. If we are annulling, this would be the correct
|
||
thing to do. (The alternative, looking at things set in NEXT_TO_MATCH
|
||
will essentially disable this optimization. This method is somewhat of
|
||
a kludge, but I don't see a better way.) */
|
||
if (! annul_p)
|
||
for (i = 1 ; i < num_slots; i++)
|
||
if (XVECEXP (PATTERN (insn), 0, i))
|
||
mark_referenced_resources (XVECEXP (PATTERN (insn), 0, i), &needed, 1);
|
||
|
||
for (trial = thread; !stop_search_p (trial, 1); trial = next_trial)
|
||
{
|
||
rtx pat = PATTERN (trial);
|
||
rtx oldtrial = trial;
|
||
|
||
next_trial = next_nonnote_insn (trial);
|
||
|
||
/* TRIAL must be a CALL_INSN or INSN. Skip USE and CLOBBER. */
|
||
if (GET_CODE (trial) == INSN
|
||
&& (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER))
|
||
continue;
|
||
|
||
if (GET_CODE (next_to_match) == GET_CODE (trial)
|
||
#ifdef HAVE_cc0
|
||
/* We can't share an insn that sets cc0. */
|
||
&& ! sets_cc0_p (pat)
|
||
#endif
|
||
&& ! insn_references_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &needed, 1)
|
||
&& (trial = try_split (pat, trial, 0)) != 0
|
||
/* Update next_trial, in case try_split succeeded. */
|
||
&& (next_trial = next_nonnote_insn (trial))
|
||
/* Likewise THREAD. */
|
||
&& (thread = oldtrial == thread ? trial : thread)
|
||
&& rtx_equal_p (PATTERN (next_to_match), PATTERN (trial))
|
||
/* Have to test this condition if annul condition is different
|
||
from (and less restrictive than) non-annulling one. */
|
||
&& eligible_for_delay (delay_insn, slot_number - 1, trial, flags))
|
||
{
|
||
|
||
if (! annul_p)
|
||
{
|
||
update_block (trial, thread);
|
||
if (trial == thread)
|
||
thread = next_active_insn (thread);
|
||
|
||
delete_related_insns (trial);
|
||
INSN_FROM_TARGET_P (next_to_match) = 0;
|
||
}
|
||
else
|
||
merged_insns = gen_rtx_INSN_LIST (VOIDmode, trial, merged_insns);
|
||
|
||
if (++slot_number == num_slots)
|
||
break;
|
||
|
||
next_to_match = XVECEXP (PATTERN (insn), 0, slot_number);
|
||
}
|
||
|
||
mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (trial, &needed, 1);
|
||
}
|
||
|
||
/* See if we stopped on a filled insn. If we did, try to see if its
|
||
delay slots match. */
|
||
if (slot_number != num_slots
|
||
&& trial && GET_CODE (trial) == INSN
|
||
&& GET_CODE (PATTERN (trial)) == SEQUENCE
|
||
&& ! INSN_ANNULLED_BRANCH_P (XVECEXP (PATTERN (trial), 0, 0)))
|
||
{
|
||
rtx pat = PATTERN (trial);
|
||
rtx filled_insn = XVECEXP (pat, 0, 0);
|
||
|
||
/* Account for resources set/needed by the filled insn. */
|
||
mark_set_resources (filled_insn, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (filled_insn, &needed, 1);
|
||
|
||
for (i = 1; i < XVECLEN (pat, 0); i++)
|
||
{
|
||
rtx dtrial = XVECEXP (pat, 0, i);
|
||
|
||
if (! insn_references_resource_p (dtrial, &set, 1)
|
||
&& ! insn_sets_resource_p (dtrial, &set, 1)
|
||
&& ! insn_sets_resource_p (dtrial, &needed, 1)
|
||
#ifdef HAVE_cc0
|
||
&& ! sets_cc0_p (PATTERN (dtrial))
|
||
#endif
|
||
&& rtx_equal_p (PATTERN (next_to_match), PATTERN (dtrial))
|
||
&& eligible_for_delay (delay_insn, slot_number - 1, dtrial, flags))
|
||
{
|
||
if (! annul_p)
|
||
{
|
||
rtx new;
|
||
|
||
update_block (dtrial, thread);
|
||
new = delete_from_delay_slot (dtrial);
|
||
if (INSN_DELETED_P (thread))
|
||
thread = new;
|
||
INSN_FROM_TARGET_P (next_to_match) = 0;
|
||
}
|
||
else
|
||
merged_insns = gen_rtx_INSN_LIST (SImode, dtrial,
|
||
merged_insns);
|
||
|
||
if (++slot_number == num_slots)
|
||
break;
|
||
|
||
next_to_match = XVECEXP (PATTERN (insn), 0, slot_number);
|
||
}
|
||
else
|
||
{
|
||
/* Keep track of the set/referenced resources for the delay
|
||
slots of any trial insns we encounter. */
|
||
mark_set_resources (dtrial, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (dtrial, &needed, 1);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* If all insns in the delay slot have been matched and we were previously
|
||
annulling the branch, we need not any more. In that case delete all the
|
||
merged insns. Also clear the INSN_FROM_TARGET_P bit of each insn in
|
||
the delay list so that we know that it isn't only being used at the
|
||
target. */
|
||
if (slot_number == num_slots && annul_p)
|
||
{
|
||
for (; merged_insns; merged_insns = XEXP (merged_insns, 1))
|
||
{
|
||
if (GET_MODE (merged_insns) == SImode)
|
||
{
|
||
rtx new;
|
||
|
||
update_block (XEXP (merged_insns, 0), thread);
|
||
new = delete_from_delay_slot (XEXP (merged_insns, 0));
|
||
if (INSN_DELETED_P (thread))
|
||
thread = new;
|
||
}
|
||
else
|
||
{
|
||
update_block (XEXP (merged_insns, 0), thread);
|
||
delete_related_insns (XEXP (merged_insns, 0));
|
||
}
|
||
}
|
||
|
||
INSN_ANNULLED_BRANCH_P (delay_insn) = 0;
|
||
|
||
for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
|
||
INSN_FROM_TARGET_P (XVECEXP (PATTERN (insn), 0, i)) = 0;
|
||
}
|
||
}
|
||
|
||
/* See if INSN is redundant with an insn in front of TARGET. Often this
|
||
is called when INSN is a candidate for a delay slot of TARGET.
|
||
DELAY_LIST are insns that will be placed in delay slots of TARGET in front
|
||
of INSN. Often INSN will be redundant with an insn in a delay slot of
|
||
some previous insn. This happens when we have a series of branches to the
|
||
same label; in that case the first insn at the target might want to go
|
||
into each of the delay slots.
|
||
|
||
If we are not careful, this routine can take up a significant fraction
|
||
of the total compilation time (4%), but only wins rarely. Hence we
|
||
speed this routine up by making two passes. The first pass goes back
|
||
until it hits a label and sees if it find an insn with an identical
|
||
pattern. Only in this (relatively rare) event does it check for
|
||
data conflicts.
|
||
|
||
We do not split insns we encounter. This could cause us not to find a
|
||
redundant insn, but the cost of splitting seems greater than the possible
|
||
gain in rare cases. */
|
||
|
||
static rtx
|
||
redundant_insn (insn, target, delay_list)
|
||
rtx insn;
|
||
rtx target;
|
||
rtx delay_list;
|
||
{
|
||
rtx target_main = target;
|
||
rtx ipat = PATTERN (insn);
|
||
rtx trial, pat;
|
||
struct resources needed, set;
|
||
int i;
|
||
unsigned insns_to_search;
|
||
|
||
/* If INSN has any REG_UNUSED notes, it can't match anything since we
|
||
are allowed to not actually assign to such a register. */
|
||
if (find_reg_note (insn, REG_UNUSED, NULL_RTX) != 0)
|
||
return 0;
|
||
|
||
/* Scan backwards looking for a match. */
|
||
for (trial = PREV_INSN (target),
|
||
insns_to_search = MAX_DELAY_SLOT_INSN_SEARCH;
|
||
trial && insns_to_search > 0;
|
||
trial = PREV_INSN (trial), --insns_to_search)
|
||
{
|
||
if (GET_CODE (trial) == CODE_LABEL)
|
||
return 0;
|
||
|
||
if (! INSN_P (trial))
|
||
continue;
|
||
|
||
pat = PATTERN (trial);
|
||
if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
|
||
continue;
|
||
|
||
if (GET_CODE (pat) == SEQUENCE)
|
||
{
|
||
/* Stop for a CALL and its delay slots because it is difficult to
|
||
track its resource needs correctly. */
|
||
if (GET_CODE (XVECEXP (pat, 0, 0)) == CALL_INSN)
|
||
return 0;
|
||
|
||
/* Stop for an INSN or JUMP_INSN with delayed effects and its delay
|
||
slots because it is difficult to track its resource needs
|
||
correctly. */
|
||
|
||
#ifdef INSN_SETS_ARE_DELAYED
|
||
if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0)))
|
||
return 0;
|
||
#endif
|
||
|
||
#ifdef INSN_REFERENCES_ARE_DELAYED
|
||
if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0)))
|
||
return 0;
|
||
#endif
|
||
|
||
/* See if any of the insns in the delay slot match, updating
|
||
resource requirements as we go. */
|
||
for (i = XVECLEN (pat, 0) - 1; i > 0; i--)
|
||
if (GET_CODE (XVECEXP (pat, 0, i)) == GET_CODE (insn)
|
||
&& rtx_equal_p (PATTERN (XVECEXP (pat, 0, i)), ipat)
|
||
&& ! find_reg_note (XVECEXP (pat, 0, i), REG_UNUSED, NULL_RTX))
|
||
break;
|
||
|
||
/* If found a match, exit this loop early. */
|
||
if (i > 0)
|
||
break;
|
||
}
|
||
|
||
else if (GET_CODE (trial) == GET_CODE (insn) && rtx_equal_p (pat, ipat)
|
||
&& ! find_reg_note (trial, REG_UNUSED, NULL_RTX))
|
||
break;
|
||
}
|
||
|
||
/* If we didn't find an insn that matches, return 0. */
|
||
if (trial == 0)
|
||
return 0;
|
||
|
||
/* See what resources this insn sets and needs. If they overlap, or
|
||
if this insn references CC0, it can't be redundant. */
|
||
|
||
CLEAR_RESOURCE (&needed);
|
||
CLEAR_RESOURCE (&set);
|
||
mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (insn, &needed, 1);
|
||
|
||
/* If TARGET is a SEQUENCE, get the main insn. */
|
||
if (GET_CODE (target) == INSN && GET_CODE (PATTERN (target)) == SEQUENCE)
|
||
target_main = XVECEXP (PATTERN (target), 0, 0);
|
||
|
||
if (resource_conflicts_p (&needed, &set)
|
||
#ifdef HAVE_cc0
|
||
|| reg_mentioned_p (cc0_rtx, ipat)
|
||
#endif
|
||
/* The insn requiring the delay may not set anything needed or set by
|
||
INSN. */
|
||
|| insn_sets_resource_p (target_main, &needed, 1)
|
||
|| insn_sets_resource_p (target_main, &set, 1))
|
||
return 0;
|
||
|
||
/* Insns we pass may not set either NEEDED or SET, so merge them for
|
||
simpler tests. */
|
||
needed.memory |= set.memory;
|
||
needed.unch_memory |= set.unch_memory;
|
||
IOR_HARD_REG_SET (needed.regs, set.regs);
|
||
|
||
/* This insn isn't redundant if it conflicts with an insn that either is
|
||
or will be in a delay slot of TARGET. */
|
||
|
||
while (delay_list)
|
||
{
|
||
if (insn_sets_resource_p (XEXP (delay_list, 0), &needed, 1))
|
||
return 0;
|
||
delay_list = XEXP (delay_list, 1);
|
||
}
|
||
|
||
if (GET_CODE (target) == INSN && GET_CODE (PATTERN (target)) == SEQUENCE)
|
||
for (i = 1; i < XVECLEN (PATTERN (target), 0); i++)
|
||
if (insn_sets_resource_p (XVECEXP (PATTERN (target), 0, i), &needed, 1))
|
||
return 0;
|
||
|
||
/* Scan backwards until we reach a label or an insn that uses something
|
||
INSN sets or sets something insn uses or sets. */
|
||
|
||
for (trial = PREV_INSN (target),
|
||
insns_to_search = MAX_DELAY_SLOT_INSN_SEARCH;
|
||
trial && GET_CODE (trial) != CODE_LABEL && insns_to_search > 0;
|
||
trial = PREV_INSN (trial), --insns_to_search)
|
||
{
|
||
if (GET_CODE (trial) != INSN && GET_CODE (trial) != CALL_INSN
|
||
&& GET_CODE (trial) != JUMP_INSN)
|
||
continue;
|
||
|
||
pat = PATTERN (trial);
|
||
if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
|
||
continue;
|
||
|
||
if (GET_CODE (pat) == SEQUENCE)
|
||
{
|
||
/* If this is a CALL_INSN and its delay slots, it is hard to track
|
||
the resource needs properly, so give up. */
|
||
if (GET_CODE (XVECEXP (pat, 0, 0)) == CALL_INSN)
|
||
return 0;
|
||
|
||
/* If this is an INSN or JUMP_INSN with delayed effects, it
|
||
is hard to track the resource needs properly, so give up. */
|
||
|
||
#ifdef INSN_SETS_ARE_DELAYED
|
||
if (INSN_SETS_ARE_DELAYED (XVECEXP (pat, 0, 0)))
|
||
return 0;
|
||
#endif
|
||
|
||
#ifdef INSN_REFERENCES_ARE_DELAYED
|
||
if (INSN_REFERENCES_ARE_DELAYED (XVECEXP (pat, 0, 0)))
|
||
return 0;
|
||
#endif
|
||
|
||
/* See if any of the insns in the delay slot match, updating
|
||
resource requirements as we go. */
|
||
for (i = XVECLEN (pat, 0) - 1; i > 0; i--)
|
||
{
|
||
rtx candidate = XVECEXP (pat, 0, i);
|
||
|
||
/* If an insn will be annulled if the branch is false, it isn't
|
||
considered as a possible duplicate insn. */
|
||
if (rtx_equal_p (PATTERN (candidate), ipat)
|
||
&& ! (INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0))
|
||
&& INSN_FROM_TARGET_P (candidate)))
|
||
{
|
||
/* Show that this insn will be used in the sequel. */
|
||
INSN_FROM_TARGET_P (candidate) = 0;
|
||
return candidate;
|
||
}
|
||
|
||
/* Unless this is an annulled insn from the target of a branch,
|
||
we must stop if it sets anything needed or set by INSN. */
|
||
if ((! INSN_ANNULLED_BRANCH_P (XVECEXP (pat, 0, 0))
|
||
|| ! INSN_FROM_TARGET_P (candidate))
|
||
&& insn_sets_resource_p (candidate, &needed, 1))
|
||
return 0;
|
||
}
|
||
|
||
/* If the insn requiring the delay slot conflicts with INSN, we
|
||
must stop. */
|
||
if (insn_sets_resource_p (XVECEXP (pat, 0, 0), &needed, 1))
|
||
return 0;
|
||
}
|
||
else
|
||
{
|
||
/* See if TRIAL is the same as INSN. */
|
||
pat = PATTERN (trial);
|
||
if (rtx_equal_p (pat, ipat))
|
||
return trial;
|
||
|
||
/* Can't go any further if TRIAL conflicts with INSN. */
|
||
if (insn_sets_resource_p (trial, &needed, 1))
|
||
return 0;
|
||
}
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
/* Return 1 if THREAD can only be executed in one way. If LABEL is nonzero,
|
||
it is the target of the branch insn being scanned. If ALLOW_FALLTHROUGH
|
||
is nonzero, we are allowed to fall into this thread; otherwise, we are
|
||
not.
|
||
|
||
If LABEL is used more than one or we pass a label other than LABEL before
|
||
finding an active insn, we do not own this thread. */
|
||
|
||
static int
|
||
own_thread_p (thread, label, allow_fallthrough)
|
||
rtx thread;
|
||
rtx label;
|
||
int allow_fallthrough;
|
||
{
|
||
rtx active_insn;
|
||
rtx insn;
|
||
|
||
/* We don't own the function end. */
|
||
if (thread == 0)
|
||
return 0;
|
||
|
||
/* Get the first active insn, or THREAD, if it is an active insn. */
|
||
active_insn = next_active_insn (PREV_INSN (thread));
|
||
|
||
for (insn = thread; insn != active_insn; insn = NEXT_INSN (insn))
|
||
if (GET_CODE (insn) == CODE_LABEL
|
||
&& (insn != label || LABEL_NUSES (insn) != 1))
|
||
return 0;
|
||
|
||
if (allow_fallthrough)
|
||
return 1;
|
||
|
||
/* Ensure that we reach a BARRIER before any insn or label. */
|
||
for (insn = prev_nonnote_insn (thread);
|
||
insn == 0 || GET_CODE (insn) != BARRIER;
|
||
insn = prev_nonnote_insn (insn))
|
||
if (insn == 0
|
||
|| GET_CODE (insn) == CODE_LABEL
|
||
|| (GET_CODE (insn) == INSN
|
||
&& GET_CODE (PATTERN (insn)) != USE
|
||
&& GET_CODE (PATTERN (insn)) != CLOBBER))
|
||
return 0;
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Called when INSN is being moved from a location near the target of a jump.
|
||
We leave a marker of the form (use (INSN)) immediately in front
|
||
of WHERE for mark_target_live_regs. These markers will be deleted when
|
||
reorg finishes.
|
||
|
||
We used to try to update the live status of registers if WHERE is at
|
||
the start of a basic block, but that can't work since we may remove a
|
||
BARRIER in relax_delay_slots. */
|
||
|
||
static void
|
||
update_block (insn, where)
|
||
rtx insn;
|
||
rtx where;
|
||
{
|
||
/* Ignore if this was in a delay slot and it came from the target of
|
||
a branch. */
|
||
if (INSN_FROM_TARGET_P (insn))
|
||
return;
|
||
|
||
emit_insn_before (gen_rtx_USE (VOIDmode, insn), where);
|
||
|
||
/* INSN might be making a value live in a block where it didn't use to
|
||
be. So recompute liveness information for this block. */
|
||
|
||
incr_ticks_for_insn (insn);
|
||
}
|
||
|
||
/* Similar to REDIRECT_JUMP except that we update the BB_TICKS entry for
|
||
the basic block containing the jump. */
|
||
|
||
static int
|
||
reorg_redirect_jump (jump, nlabel)
|
||
rtx jump;
|
||
rtx nlabel;
|
||
{
|
||
incr_ticks_for_insn (jump);
|
||
return redirect_jump (jump, nlabel, 1);
|
||
}
|
||
|
||
/* Called when INSN is being moved forward into a delay slot of DELAYED_INSN.
|
||
We check every instruction between INSN and DELAYED_INSN for REG_DEAD notes
|
||
that reference values used in INSN. If we find one, then we move the
|
||
REG_DEAD note to INSN.
|
||
|
||
This is needed to handle the case where an later insn (after INSN) has a
|
||
REG_DEAD note for a register used by INSN, and this later insn subsequently
|
||
gets moved before a CODE_LABEL because it is a redundant insn. In this
|
||
case, mark_target_live_regs may be confused into thinking the register
|
||
is dead because it sees a REG_DEAD note immediately before a CODE_LABEL. */
|
||
|
||
static void
|
||
update_reg_dead_notes (insn, delayed_insn)
|
||
rtx insn, delayed_insn;
|
||
{
|
||
rtx p, link, next;
|
||
|
||
for (p = next_nonnote_insn (insn); p != delayed_insn;
|
||
p = next_nonnote_insn (p))
|
||
for (link = REG_NOTES (p); link; link = next)
|
||
{
|
||
next = XEXP (link, 1);
|
||
|
||
if (REG_NOTE_KIND (link) != REG_DEAD
|
||
|| GET_CODE (XEXP (link, 0)) != REG)
|
||
continue;
|
||
|
||
if (reg_referenced_p (XEXP (link, 0), PATTERN (insn)))
|
||
{
|
||
/* Move the REG_DEAD note from P to INSN. */
|
||
remove_note (p, link);
|
||
XEXP (link, 1) = REG_NOTES (insn);
|
||
REG_NOTES (insn) = link;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Called when an insn redundant with start_insn is deleted. If there
|
||
is a REG_DEAD note for the target of start_insn between start_insn
|
||
and stop_insn, then the REG_DEAD note needs to be deleted since the
|
||
value no longer dies there.
|
||
|
||
If the REG_DEAD note isn't deleted, then mark_target_live_regs may be
|
||
confused into thinking the register is dead. */
|
||
|
||
static void
|
||
fix_reg_dead_note (start_insn, stop_insn)
|
||
rtx start_insn, stop_insn;
|
||
{
|
||
rtx p, link, next;
|
||
|
||
for (p = next_nonnote_insn (start_insn); p != stop_insn;
|
||
p = next_nonnote_insn (p))
|
||
for (link = REG_NOTES (p); link; link = next)
|
||
{
|
||
next = XEXP (link, 1);
|
||
|
||
if (REG_NOTE_KIND (link) != REG_DEAD
|
||
|| GET_CODE (XEXP (link, 0)) != REG)
|
||
continue;
|
||
|
||
if (reg_set_p (XEXP (link, 0), PATTERN (start_insn)))
|
||
{
|
||
remove_note (p, link);
|
||
return;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Delete any REG_UNUSED notes that exist on INSN but not on REDUNDANT_INSN.
|
||
|
||
This handles the case of udivmodXi4 instructions which optimize their
|
||
output depending on whether any REG_UNUSED notes are present.
|
||
we must make sure that INSN calculates as many results as REDUNDANT_INSN
|
||
does. */
|
||
|
||
static void
|
||
update_reg_unused_notes (insn, redundant_insn)
|
||
rtx insn, redundant_insn;
|
||
{
|
||
rtx link, next;
|
||
|
||
for (link = REG_NOTES (insn); link; link = next)
|
||
{
|
||
next = XEXP (link, 1);
|
||
|
||
if (REG_NOTE_KIND (link) != REG_UNUSED
|
||
|| GET_CODE (XEXP (link, 0)) != REG)
|
||
continue;
|
||
|
||
if (! find_regno_note (redundant_insn, REG_UNUSED,
|
||
REGNO (XEXP (link, 0))))
|
||
remove_note (insn, link);
|
||
}
|
||
}
|
||
|
||
/* Scan a function looking for insns that need a delay slot and find insns to
|
||
put into the delay slot.
|
||
|
||
NON_JUMPS_P is nonzero if we are to only try to fill non-jump insns (such
|
||
as calls). We do these first since we don't want jump insns (that are
|
||
easier to fill) to get the only insns that could be used for non-jump insns.
|
||
When it is zero, only try to fill JUMP_INSNs.
|
||
|
||
When slots are filled in this manner, the insns (including the
|
||
delay_insn) are put together in a SEQUENCE rtx. In this fashion,
|
||
it is possible to tell whether a delay slot has really been filled
|
||
or not. `final' knows how to deal with this, by communicating
|
||
through FINAL_SEQUENCE. */
|
||
|
||
static void
|
||
fill_simple_delay_slots (non_jumps_p)
|
||
int non_jumps_p;
|
||
{
|
||
rtx insn, pat, trial, next_trial;
|
||
int i;
|
||
int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base;
|
||
struct resources needed, set;
|
||
int slots_to_fill, slots_filled;
|
||
rtx delay_list;
|
||
|
||
for (i = 0; i < num_unfilled_slots; i++)
|
||
{
|
||
int flags;
|
||
/* Get the next insn to fill. If it has already had any slots assigned,
|
||
we can't do anything with it. Maybe we'll improve this later. */
|
||
|
||
insn = unfilled_slots_base[i];
|
||
if (insn == 0
|
||
|| INSN_DELETED_P (insn)
|
||
|| (GET_CODE (insn) == INSN
|
||
&& GET_CODE (PATTERN (insn)) == SEQUENCE)
|
||
|| (GET_CODE (insn) == JUMP_INSN && non_jumps_p)
|
||
|| (GET_CODE (insn) != JUMP_INSN && ! non_jumps_p))
|
||
continue;
|
||
|
||
/* It may have been that this insn used to need delay slots, but
|
||
now doesn't; ignore in that case. This can happen, for example,
|
||
on the HP PA RISC, where the number of delay slots depends on
|
||
what insns are nearby. */
|
||
slots_to_fill = num_delay_slots (insn);
|
||
|
||
/* Some machine description have defined instructions to have
|
||
delay slots only in certain circumstances which may depend on
|
||
nearby insns (which change due to reorg's actions).
|
||
|
||
For example, the PA port normally has delay slots for unconditional
|
||
jumps.
|
||
|
||
However, the PA port claims such jumps do not have a delay slot
|
||
if they are immediate successors of certain CALL_INSNs. This
|
||
allows the port to favor filling the delay slot of the call with
|
||
the unconditional jump. */
|
||
if (slots_to_fill == 0)
|
||
continue;
|
||
|
||
/* This insn needs, or can use, some delay slots. SLOTS_TO_FILL
|
||
says how many. After initialization, first try optimizing
|
||
|
||
call _foo call _foo
|
||
nop add %o7,.-L1,%o7
|
||
b,a L1
|
||
nop
|
||
|
||
If this case applies, the delay slot of the call is filled with
|
||
the unconditional jump. This is done first to avoid having the
|
||
delay slot of the call filled in the backward scan. Also, since
|
||
the unconditional jump is likely to also have a delay slot, that
|
||
insn must exist when it is subsequently scanned.
|
||
|
||
This is tried on each insn with delay slots as some machines
|
||
have insns which perform calls, but are not represented as
|
||
CALL_INSNs. */
|
||
|
||
slots_filled = 0;
|
||
delay_list = 0;
|
||
|
||
if (GET_CODE (insn) == JUMP_INSN)
|
||
flags = get_jump_flags (insn, JUMP_LABEL (insn));
|
||
else
|
||
flags = get_jump_flags (insn, NULL_RTX);
|
||
|
||
if ((trial = next_active_insn (insn))
|
||
&& GET_CODE (trial) == JUMP_INSN
|
||
&& simplejump_p (trial)
|
||
&& eligible_for_delay (insn, slots_filled, trial, flags)
|
||
&& no_labels_between_p (insn, trial)
|
||
&& ! can_throw_internal (trial))
|
||
{
|
||
rtx *tmp;
|
||
slots_filled++;
|
||
delay_list = add_to_delay_list (trial, delay_list);
|
||
|
||
/* TRIAL may have had its delay slot filled, then unfilled. When
|
||
the delay slot is unfilled, TRIAL is placed back on the unfilled
|
||
slots obstack. Unfortunately, it is placed on the end of the
|
||
obstack, not in its original location. Therefore, we must search
|
||
from entry i + 1 to the end of the unfilled slots obstack to
|
||
try and find TRIAL. */
|
||
tmp = &unfilled_slots_base[i + 1];
|
||
while (*tmp != trial && tmp != unfilled_slots_next)
|
||
tmp++;
|
||
|
||
/* Remove the unconditional jump from consideration for delay slot
|
||
filling and unthread it. */
|
||
if (*tmp == trial)
|
||
*tmp = 0;
|
||
{
|
||
rtx next = NEXT_INSN (trial);
|
||
rtx prev = PREV_INSN (trial);
|
||
if (prev)
|
||
NEXT_INSN (prev) = next;
|
||
if (next)
|
||
PREV_INSN (next) = prev;
|
||
}
|
||
}
|
||
|
||
/* Now, scan backwards from the insn to search for a potential
|
||
delay-slot candidate. Stop searching when a label or jump is hit.
|
||
|
||
For each candidate, if it is to go into the delay slot (moved
|
||
forward in execution sequence), it must not need or set any resources
|
||
that were set by later insns and must not set any resources that
|
||
are needed for those insns.
|
||
|
||
The delay slot insn itself sets resources unless it is a call
|
||
(in which case the called routine, not the insn itself, is doing
|
||
the setting). */
|
||
|
||
if (slots_filled < slots_to_fill)
|
||
{
|
||
CLEAR_RESOURCE (&needed);
|
||
CLEAR_RESOURCE (&set);
|
||
mark_set_resources (insn, &set, 0, MARK_SRC_DEST);
|
||
mark_referenced_resources (insn, &needed, 0);
|
||
|
||
for (trial = prev_nonnote_insn (insn); ! stop_search_p (trial, 1);
|
||
trial = next_trial)
|
||
{
|
||
next_trial = prev_nonnote_insn (trial);
|
||
|
||
/* This must be an INSN or CALL_INSN. */
|
||
pat = PATTERN (trial);
|
||
|
||
/* USE and CLOBBER at this level was just for flow; ignore it. */
|
||
if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
|
||
continue;
|
||
|
||
/* Check for resource conflict first, to avoid unnecessary
|
||
splitting. */
|
||
if (! insn_references_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &needed, 1)
|
||
#ifdef HAVE_cc0
|
||
/* Can't separate set of cc0 from its use. */
|
||
&& ! (reg_mentioned_p (cc0_rtx, pat) && ! sets_cc0_p (pat))
|
||
#endif
|
||
&& ! can_throw_internal (trial))
|
||
{
|
||
trial = try_split (pat, trial, 1);
|
||
next_trial = prev_nonnote_insn (trial);
|
||
if (eligible_for_delay (insn, slots_filled, trial, flags))
|
||
{
|
||
/* In this case, we are searching backward, so if we
|
||
find insns to put on the delay list, we want
|
||
to put them at the head, rather than the
|
||
tail, of the list. */
|
||
|
||
update_reg_dead_notes (trial, insn);
|
||
delay_list = gen_rtx_INSN_LIST (VOIDmode,
|
||
trial, delay_list);
|
||
update_block (trial, trial);
|
||
delete_related_insns (trial);
|
||
if (slots_to_fill == ++slots_filled)
|
||
break;
|
||
continue;
|
||
}
|
||
}
|
||
|
||
mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (trial, &needed, 1);
|
||
}
|
||
}
|
||
|
||
/* If all needed slots haven't been filled, we come here. */
|
||
|
||
/* Try to optimize case of jumping around a single insn. */
|
||
#if defined(ANNUL_IFFALSE_SLOTS) || defined(ANNUL_IFTRUE_SLOTS)
|
||
if (slots_filled != slots_to_fill
|
||
&& delay_list == 0
|
||
&& GET_CODE (insn) == JUMP_INSN
|
||
&& (condjump_p (insn) || condjump_in_parallel_p (insn)))
|
||
{
|
||
delay_list = optimize_skip (insn);
|
||
if (delay_list)
|
||
slots_filled += 1;
|
||
}
|
||
#endif
|
||
|
||
/* Try to get insns from beyond the insn needing the delay slot.
|
||
These insns can neither set or reference resources set in insns being
|
||
skipped, cannot set resources in the insn being skipped, and, if this
|
||
is a CALL_INSN (or a CALL_INSN is passed), cannot trap (because the
|
||
call might not return).
|
||
|
||
There used to be code which continued past the target label if
|
||
we saw all uses of the target label. This code did not work,
|
||
because it failed to account for some instructions which were
|
||
both annulled and marked as from the target. This can happen as a
|
||
result of optimize_skip. Since this code was redundant with
|
||
fill_eager_delay_slots anyways, it was just deleted. */
|
||
|
||
if (slots_filled != slots_to_fill
|
||
/* If this instruction could throw an exception which is
|
||
caught in the same function, then it's not safe to fill
|
||
the delay slot with an instruction from beyond this
|
||
point. For example, consider:
|
||
|
||
int i = 2;
|
||
|
||
try {
|
||
f();
|
||
i = 3;
|
||
} catch (...) {}
|
||
|
||
return i;
|
||
|
||
Even though `i' is a local variable, we must be sure not
|
||
to put `i = 3' in the delay slot if `f' might throw an
|
||
exception.
|
||
|
||
Presumably, we should also check to see if we could get
|
||
back to this function via `setjmp'. */
|
||
&& ! can_throw_internal (insn)
|
||
&& (GET_CODE (insn) != JUMP_INSN
|
||
|| ((condjump_p (insn) || condjump_in_parallel_p (insn))
|
||
&& ! simplejump_p (insn)
|
||
&& JUMP_LABEL (insn) != 0)))
|
||
{
|
||
/* Invariant: If insn is a JUMP_INSN, the insn's jump
|
||
label. Otherwise, zero. */
|
||
rtx target = 0;
|
||
int maybe_never = 0;
|
||
rtx pat, trial_delay;
|
||
|
||
CLEAR_RESOURCE (&needed);
|
||
CLEAR_RESOURCE (&set);
|
||
|
||
if (GET_CODE (insn) == CALL_INSN)
|
||
{
|
||
mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (insn, &needed, 1);
|
||
maybe_never = 1;
|
||
}
|
||
else
|
||
{
|
||
mark_set_resources (insn, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (insn, &needed, 1);
|
||
if (GET_CODE (insn) == JUMP_INSN)
|
||
target = JUMP_LABEL (insn);
|
||
}
|
||
|
||
if (target == 0)
|
||
for (trial = next_nonnote_insn (insn); trial; trial = next_trial)
|
||
{
|
||
next_trial = next_nonnote_insn (trial);
|
||
|
||
if (GET_CODE (trial) == CODE_LABEL
|
||
|| GET_CODE (trial) == BARRIER)
|
||
break;
|
||
|
||
/* We must have an INSN, JUMP_INSN, or CALL_INSN. */
|
||
pat = PATTERN (trial);
|
||
|
||
/* Stand-alone USE and CLOBBER are just for flow. */
|
||
if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
|
||
continue;
|
||
|
||
/* If this already has filled delay slots, get the insn needing
|
||
the delay slots. */
|
||
if (GET_CODE (pat) == SEQUENCE)
|
||
trial_delay = XVECEXP (pat, 0, 0);
|
||
else
|
||
trial_delay = trial;
|
||
|
||
/* Stop our search when seeing an unconditional jump. */
|
||
if (GET_CODE (trial_delay) == JUMP_INSN)
|
||
break;
|
||
|
||
/* See if we have a resource problem before we try to
|
||
split. */
|
||
if (GET_CODE (pat) != SEQUENCE
|
||
&& ! insn_references_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &needed, 1)
|
||
#ifdef HAVE_cc0
|
||
&& ! (reg_mentioned_p (cc0_rtx, pat) && ! sets_cc0_p (pat))
|
||
#endif
|
||
&& ! (maybe_never && may_trap_p (pat))
|
||
&& (trial = try_split (pat, trial, 0))
|
||
&& eligible_for_delay (insn, slots_filled, trial, flags)
|
||
&& ! can_throw_internal(trial))
|
||
{
|
||
next_trial = next_nonnote_insn (trial);
|
||
delay_list = add_to_delay_list (trial, delay_list);
|
||
|
||
#ifdef HAVE_cc0
|
||
if (reg_mentioned_p (cc0_rtx, pat))
|
||
link_cc0_insns (trial);
|
||
#endif
|
||
|
||
delete_related_insns (trial);
|
||
if (slots_to_fill == ++slots_filled)
|
||
break;
|
||
continue;
|
||
}
|
||
|
||
mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (trial, &needed, 1);
|
||
|
||
/* Ensure we don't put insns between the setting of cc and the
|
||
comparison by moving a setting of cc into an earlier delay
|
||
slot since these insns could clobber the condition code. */
|
||
set.cc = 1;
|
||
|
||
/* If this is a call or jump, we might not get here. */
|
||
if (GET_CODE (trial_delay) == CALL_INSN
|
||
|| GET_CODE (trial_delay) == JUMP_INSN)
|
||
maybe_never = 1;
|
||
}
|
||
|
||
/* If there are slots left to fill and our search was stopped by an
|
||
unconditional branch, try the insn at the branch target. We can
|
||
redirect the branch if it works.
|
||
|
||
Don't do this if the insn at the branch target is a branch. */
|
||
if (slots_to_fill != slots_filled
|
||
&& trial
|
||
&& GET_CODE (trial) == JUMP_INSN
|
||
&& simplejump_p (trial)
|
||
&& (target == 0 || JUMP_LABEL (trial) == target)
|
||
&& (next_trial = next_active_insn (JUMP_LABEL (trial))) != 0
|
||
&& ! (GET_CODE (next_trial) == INSN
|
||
&& GET_CODE (PATTERN (next_trial)) == SEQUENCE)
|
||
&& GET_CODE (next_trial) != JUMP_INSN
|
||
&& ! insn_references_resource_p (next_trial, &set, 1)
|
||
&& ! insn_sets_resource_p (next_trial, &set, 1)
|
||
&& ! insn_sets_resource_p (next_trial, &needed, 1)
|
||
#ifdef HAVE_cc0
|
||
&& ! reg_mentioned_p (cc0_rtx, PATTERN (next_trial))
|
||
#endif
|
||
&& ! (maybe_never && may_trap_p (PATTERN (next_trial)))
|
||
&& (next_trial = try_split (PATTERN (next_trial), next_trial, 0))
|
||
&& eligible_for_delay (insn, slots_filled, next_trial, flags)
|
||
&& ! can_throw_internal (trial))
|
||
{
|
||
rtx new_label = next_active_insn (next_trial);
|
||
|
||
if (new_label != 0)
|
||
new_label = get_label_before (new_label);
|
||
else
|
||
new_label = find_end_label ();
|
||
|
||
delay_list
|
||
= add_to_delay_list (copy_rtx (next_trial), delay_list);
|
||
slots_filled++;
|
||
reorg_redirect_jump (trial, new_label);
|
||
|
||
/* If we merged because we both jumped to the same place,
|
||
redirect the original insn also. */
|
||
if (target)
|
||
reorg_redirect_jump (insn, new_label);
|
||
}
|
||
}
|
||
|
||
/* If this is an unconditional jump, then try to get insns from the
|
||
target of the jump. */
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& simplejump_p (insn)
|
||
&& slots_filled != slots_to_fill)
|
||
delay_list
|
||
= fill_slots_from_thread (insn, const_true_rtx,
|
||
next_active_insn (JUMP_LABEL (insn)),
|
||
NULL, 1, 1,
|
||
own_thread_p (JUMP_LABEL (insn),
|
||
JUMP_LABEL (insn), 0),
|
||
slots_to_fill, &slots_filled,
|
||
delay_list);
|
||
|
||
if (delay_list)
|
||
unfilled_slots_base[i]
|
||
= emit_delay_sequence (insn, delay_list, slots_filled);
|
||
|
||
if (slots_to_fill == slots_filled)
|
||
unfilled_slots_base[i] = 0;
|
||
|
||
note_delay_statistics (slots_filled, 0);
|
||
}
|
||
|
||
#ifdef DELAY_SLOTS_FOR_EPILOGUE
|
||
/* See if the epilogue needs any delay slots. Try to fill them if so.
|
||
The only thing we can do is scan backwards from the end of the
|
||
function. If we did this in a previous pass, it is incorrect to do it
|
||
again. */
|
||
if (current_function_epilogue_delay_list)
|
||
return;
|
||
|
||
slots_to_fill = DELAY_SLOTS_FOR_EPILOGUE;
|
||
if (slots_to_fill == 0)
|
||
return;
|
||
|
||
slots_filled = 0;
|
||
CLEAR_RESOURCE (&set);
|
||
|
||
/* The frame pointer and stack pointer are needed at the beginning of
|
||
the epilogue, so instructions setting them can not be put in the
|
||
epilogue delay slot. However, everything else needed at function
|
||
end is safe, so we don't want to use end_of_function_needs here. */
|
||
CLEAR_RESOURCE (&needed);
|
||
if (frame_pointer_needed)
|
||
{
|
||
SET_HARD_REG_BIT (needed.regs, FRAME_POINTER_REGNUM);
|
||
#if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM
|
||
SET_HARD_REG_BIT (needed.regs, HARD_FRAME_POINTER_REGNUM);
|
||
#endif
|
||
#ifdef EXIT_IGNORE_STACK
|
||
if (! EXIT_IGNORE_STACK
|
||
|| current_function_sp_is_unchanging)
|
||
#endif
|
||
SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM);
|
||
}
|
||
else
|
||
SET_HARD_REG_BIT (needed.regs, STACK_POINTER_REGNUM);
|
||
|
||
#ifdef EPILOGUE_USES
|
||
for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
|
||
{
|
||
if (EPILOGUE_USES (i))
|
||
SET_HARD_REG_BIT (needed.regs, i);
|
||
}
|
||
#endif
|
||
|
||
for (trial = get_last_insn (); ! stop_search_p (trial, 1);
|
||
trial = PREV_INSN (trial))
|
||
{
|
||
if (GET_CODE (trial) == NOTE)
|
||
continue;
|
||
pat = PATTERN (trial);
|
||
if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
|
||
continue;
|
||
|
||
if (! insn_references_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &needed, 1)
|
||
&& ! insn_sets_resource_p (trial, &set, 1)
|
||
#ifdef HAVE_cc0
|
||
/* Don't want to mess with cc0 here. */
|
||
&& ! reg_mentioned_p (cc0_rtx, pat)
|
||
#endif
|
||
&& ! can_throw_internal (trial))
|
||
{
|
||
trial = try_split (pat, trial, 1);
|
||
if (ELIGIBLE_FOR_EPILOGUE_DELAY (trial, slots_filled))
|
||
{
|
||
/* Here as well we are searching backward, so put the
|
||
insns we find on the head of the list. */
|
||
|
||
current_function_epilogue_delay_list
|
||
= gen_rtx_INSN_LIST (VOIDmode, trial,
|
||
current_function_epilogue_delay_list);
|
||
mark_end_of_function_resources (trial, 1);
|
||
update_block (trial, trial);
|
||
delete_related_insns (trial);
|
||
|
||
/* Clear deleted bit so final.c will output the insn. */
|
||
INSN_DELETED_P (trial) = 0;
|
||
|
||
if (slots_to_fill == ++slots_filled)
|
||
break;
|
||
continue;
|
||
}
|
||
}
|
||
|
||
mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (trial, &needed, 1);
|
||
}
|
||
|
||
note_delay_statistics (slots_filled, 0);
|
||
#endif
|
||
}
|
||
|
||
/* Try to find insns to place in delay slots.
|
||
|
||
INSN is the jump needing SLOTS_TO_FILL delay slots. It tests CONDITION
|
||
or is an unconditional branch if CONDITION is const_true_rtx.
|
||
*PSLOTS_FILLED is updated with the number of slots that we have filled.
|
||
|
||
THREAD is a flow-of-control, either the insns to be executed if the
|
||
branch is true or if the branch is false, THREAD_IF_TRUE says which.
|
||
|
||
OPPOSITE_THREAD is the thread in the opposite direction. It is used
|
||
to see if any potential delay slot insns set things needed there.
|
||
|
||
LIKELY is nonzero if it is extremely likely that the branch will be
|
||
taken and THREAD_IF_TRUE is set. This is used for the branch at the
|
||
end of a loop back up to the top.
|
||
|
||
OWN_THREAD and OWN_OPPOSITE_THREAD are true if we are the only user of the
|
||
thread. I.e., it is the fallthrough code of our jump or the target of the
|
||
jump when we are the only jump going there.
|
||
|
||
If OWN_THREAD is false, it must be the "true" thread of a jump. In that
|
||
case, we can only take insns from the head of the thread for our delay
|
||
slot. We then adjust the jump to point after the insns we have taken. */
|
||
|
||
static rtx
|
||
fill_slots_from_thread (insn, condition, thread, opposite_thread, likely,
|
||
thread_if_true, own_thread,
|
||
slots_to_fill, pslots_filled, delay_list)
|
||
rtx insn;
|
||
rtx condition;
|
||
rtx thread, opposite_thread;
|
||
int likely;
|
||
int thread_if_true;
|
||
int own_thread;
|
||
int slots_to_fill, *pslots_filled;
|
||
rtx delay_list;
|
||
{
|
||
rtx new_thread;
|
||
struct resources opposite_needed, set, needed;
|
||
rtx trial;
|
||
int lose = 0;
|
||
int must_annul = 0;
|
||
int flags;
|
||
|
||
/* Validate our arguments. */
|
||
if ((condition == const_true_rtx && ! thread_if_true)
|
||
|| (! own_thread && ! thread_if_true))
|
||
abort ();
|
||
|
||
flags = get_jump_flags (insn, JUMP_LABEL (insn));
|
||
|
||
/* If our thread is the end of subroutine, we can't get any delay
|
||
insns from that. */
|
||
if (thread == 0)
|
||
return delay_list;
|
||
|
||
/* If this is an unconditional branch, nothing is needed at the
|
||
opposite thread. Otherwise, compute what is needed there. */
|
||
if (condition == const_true_rtx)
|
||
CLEAR_RESOURCE (&opposite_needed);
|
||
else
|
||
mark_target_live_regs (get_insns (), opposite_thread, &opposite_needed);
|
||
|
||
/* If the insn at THREAD can be split, do it here to avoid having to
|
||
update THREAD and NEW_THREAD if it is done in the loop below. Also
|
||
initialize NEW_THREAD. */
|
||
|
||
new_thread = thread = try_split (PATTERN (thread), thread, 0);
|
||
|
||
/* Scan insns at THREAD. We are looking for an insn that can be removed
|
||
from THREAD (it neither sets nor references resources that were set
|
||
ahead of it and it doesn't set anything needs by the insns ahead of
|
||
it) and that either can be placed in an annulling insn or aren't
|
||
needed at OPPOSITE_THREAD. */
|
||
|
||
CLEAR_RESOURCE (&needed);
|
||
CLEAR_RESOURCE (&set);
|
||
|
||
/* If we do not own this thread, we must stop as soon as we find
|
||
something that we can't put in a delay slot, since all we can do
|
||
is branch into THREAD at a later point. Therefore, labels stop
|
||
the search if this is not the `true' thread. */
|
||
|
||
for (trial = thread;
|
||
! stop_search_p (trial, ! thread_if_true) && (! lose || own_thread);
|
||
trial = next_nonnote_insn (trial))
|
||
{
|
||
rtx pat, old_trial;
|
||
|
||
/* If we have passed a label, we no longer own this thread. */
|
||
if (GET_CODE (trial) == CODE_LABEL)
|
||
{
|
||
own_thread = 0;
|
||
continue;
|
||
}
|
||
|
||
pat = PATTERN (trial);
|
||
if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
|
||
continue;
|
||
|
||
/* If TRIAL conflicts with the insns ahead of it, we lose. Also,
|
||
don't separate or copy insns that set and use CC0. */
|
||
if (! insn_references_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &set, 1)
|
||
&& ! insn_sets_resource_p (trial, &needed, 1)
|
||
#ifdef HAVE_cc0
|
||
&& ! (reg_mentioned_p (cc0_rtx, pat)
|
||
&& (! own_thread || ! sets_cc0_p (pat)))
|
||
#endif
|
||
&& ! can_throw_internal (trial))
|
||
{
|
||
rtx prior_insn;
|
||
|
||
/* If TRIAL is redundant with some insn before INSN, we don't
|
||
actually need to add it to the delay list; we can merely pretend
|
||
we did. */
|
||
if ((prior_insn = redundant_insn (trial, insn, delay_list)))
|
||
{
|
||
fix_reg_dead_note (prior_insn, insn);
|
||
if (own_thread)
|
||
{
|
||
update_block (trial, thread);
|
||
if (trial == thread)
|
||
{
|
||
thread = next_active_insn (thread);
|
||
if (new_thread == trial)
|
||
new_thread = thread;
|
||
}
|
||
|
||
delete_related_insns (trial);
|
||
}
|
||
else
|
||
{
|
||
update_reg_unused_notes (prior_insn, trial);
|
||
new_thread = next_active_insn (trial);
|
||
}
|
||
|
||
continue;
|
||
}
|
||
|
||
/* There are two ways we can win: If TRIAL doesn't set anything
|
||
needed at the opposite thread and can't trap, or if it can
|
||
go into an annulled delay slot. */
|
||
if (!must_annul
|
||
&& (condition == const_true_rtx
|
||
|| (! insn_sets_resource_p (trial, &opposite_needed, 1)
|
||
&& ! may_trap_p (pat))))
|
||
{
|
||
old_trial = trial;
|
||
trial = try_split (pat, trial, 0);
|
||
if (new_thread == old_trial)
|
||
new_thread = trial;
|
||
if (thread == old_trial)
|
||
thread = trial;
|
||
pat = PATTERN (trial);
|
||
if (eligible_for_delay (insn, *pslots_filled, trial, flags))
|
||
goto winner;
|
||
}
|
||
else if (0
|
||
#ifdef ANNUL_IFTRUE_SLOTS
|
||
|| ! thread_if_true
|
||
#endif
|
||
#ifdef ANNUL_IFFALSE_SLOTS
|
||
|| thread_if_true
|
||
#endif
|
||
)
|
||
{
|
||
old_trial = trial;
|
||
trial = try_split (pat, trial, 0);
|
||
if (new_thread == old_trial)
|
||
new_thread = trial;
|
||
if (thread == old_trial)
|
||
thread = trial;
|
||
pat = PATTERN (trial);
|
||
if ((must_annul || delay_list == NULL) && (thread_if_true
|
||
? check_annul_list_true_false (0, delay_list)
|
||
&& eligible_for_annul_false (insn, *pslots_filled, trial, flags)
|
||
: check_annul_list_true_false (1, delay_list)
|
||
&& eligible_for_annul_true (insn, *pslots_filled, trial, flags)))
|
||
{
|
||
rtx temp;
|
||
|
||
must_annul = 1;
|
||
winner:
|
||
|
||
#ifdef HAVE_cc0
|
||
if (reg_mentioned_p (cc0_rtx, pat))
|
||
link_cc0_insns (trial);
|
||
#endif
|
||
|
||
/* If we own this thread, delete the insn. If this is the
|
||
destination of a branch, show that a basic block status
|
||
may have been updated. In any case, mark the new
|
||
starting point of this thread. */
|
||
if (own_thread)
|
||
{
|
||
rtx note;
|
||
|
||
update_block (trial, thread);
|
||
if (trial == thread)
|
||
{
|
||
thread = next_active_insn (thread);
|
||
if (new_thread == trial)
|
||
new_thread = thread;
|
||
}
|
||
|
||
/* We are moving this insn, not deleting it. We must
|
||
temporarily increment the use count on any referenced
|
||
label lest it be deleted by delete_related_insns. */
|
||
note = find_reg_note (trial, REG_LABEL, 0);
|
||
/* REG_LABEL could be NOTE_INSN_DELETED_LABEL too. */
|
||
if (note && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
|
||
LABEL_NUSES (XEXP (note, 0))++;
|
||
|
||
delete_related_insns (trial);
|
||
|
||
if (note && GET_CODE (XEXP (note, 0)) == CODE_LABEL)
|
||
LABEL_NUSES (XEXP (note, 0))--;
|
||
}
|
||
else
|
||
new_thread = next_active_insn (trial);
|
||
|
||
temp = own_thread ? trial : copy_rtx (trial);
|
||
if (thread_if_true)
|
||
INSN_FROM_TARGET_P (temp) = 1;
|
||
|
||
delay_list = add_to_delay_list (temp, delay_list);
|
||
|
||
if (slots_to_fill == ++(*pslots_filled))
|
||
{
|
||
/* Even though we have filled all the slots, we
|
||
may be branching to a location that has a
|
||
redundant insn. Skip any if so. */
|
||
while (new_thread && ! own_thread
|
||
&& ! insn_sets_resource_p (new_thread, &set, 1)
|
||
&& ! insn_sets_resource_p (new_thread, &needed, 1)
|
||
&& ! insn_references_resource_p (new_thread,
|
||
&set, 1)
|
||
&& (prior_insn
|
||
= redundant_insn (new_thread, insn,
|
||
delay_list)))
|
||
{
|
||
/* We know we do not own the thread, so no need
|
||
to call update_block and delete_insn. */
|
||
fix_reg_dead_note (prior_insn, insn);
|
||
update_reg_unused_notes (prior_insn, new_thread);
|
||
new_thread = next_active_insn (new_thread);
|
||
}
|
||
break;
|
||
}
|
||
|
||
continue;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* This insn can't go into a delay slot. */
|
||
lose = 1;
|
||
mark_set_resources (trial, &set, 0, MARK_SRC_DEST_CALL);
|
||
mark_referenced_resources (trial, &needed, 1);
|
||
|
||
/* Ensure we don't put insns between the setting of cc and the comparison
|
||
by moving a setting of cc into an earlier delay slot since these insns
|
||
could clobber the condition code. */
|
||
set.cc = 1;
|
||
|
||
/* If this insn is a register-register copy and the next insn has
|
||
a use of our destination, change it to use our source. That way,
|
||
it will become a candidate for our delay slot the next time
|
||
through this loop. This case occurs commonly in loops that
|
||
scan a list.
|
||
|
||
We could check for more complex cases than those tested below,
|
||
but it doesn't seem worth it. It might also be a good idea to try
|
||
to swap the two insns. That might do better.
|
||
|
||
We can't do this if the next insn modifies our destination, because
|
||
that would make the replacement into the insn invalid. We also can't
|
||
do this if it modifies our source, because it might be an earlyclobber
|
||
operand. This latter test also prevents updating the contents of
|
||
a PRE_INC. */
|
||
|
||
if (GET_CODE (trial) == INSN && GET_CODE (pat) == SET
|
||
&& GET_CODE (SET_SRC (pat)) == REG
|
||
&& GET_CODE (SET_DEST (pat)) == REG)
|
||
{
|
||
rtx next = next_nonnote_insn (trial);
|
||
|
||
if (next && GET_CODE (next) == INSN
|
||
&& GET_CODE (PATTERN (next)) != USE
|
||
&& ! reg_set_p (SET_DEST (pat), next)
|
||
&& ! reg_set_p (SET_SRC (pat), next)
|
||
&& reg_referenced_p (SET_DEST (pat), PATTERN (next))
|
||
&& ! modified_in_p (SET_DEST (pat), next))
|
||
validate_replace_rtx (SET_DEST (pat), SET_SRC (pat), next);
|
||
}
|
||
}
|
||
|
||
/* If we stopped on a branch insn that has delay slots, see if we can
|
||
steal some of the insns in those slots. */
|
||
if (trial && GET_CODE (trial) == INSN
|
||
&& GET_CODE (PATTERN (trial)) == SEQUENCE
|
||
&& GET_CODE (XVECEXP (PATTERN (trial), 0, 0)) == JUMP_INSN)
|
||
{
|
||
/* If this is the `true' thread, we will want to follow the jump,
|
||
so we can only do this if we have taken everything up to here. */
|
||
if (thread_if_true && trial == new_thread)
|
||
{
|
||
delay_list
|
||
= steal_delay_list_from_target (insn, condition, PATTERN (trial),
|
||
delay_list, &set, &needed,
|
||
&opposite_needed, slots_to_fill,
|
||
pslots_filled, &must_annul,
|
||
&new_thread);
|
||
/* If we owned the thread and are told that it branched
|
||
elsewhere, make sure we own the thread at the new location. */
|
||
if (own_thread && trial != new_thread)
|
||
own_thread = own_thread_p (new_thread, new_thread, 0);
|
||
}
|
||
else if (! thread_if_true)
|
||
delay_list
|
||
= steal_delay_list_from_fallthrough (insn, condition,
|
||
PATTERN (trial),
|
||
delay_list, &set, &needed,
|
||
&opposite_needed, slots_to_fill,
|
||
pslots_filled, &must_annul);
|
||
}
|
||
|
||
/* If we haven't found anything for this delay slot and it is very
|
||
likely that the branch will be taken, see if the insn at our target
|
||
increments or decrements a register with an increment that does not
|
||
depend on the destination register. If so, try to place the opposite
|
||
arithmetic insn after the jump insn and put the arithmetic insn in the
|
||
delay slot. If we can't do this, return. */
|
||
if (delay_list == 0 && likely && new_thread
|
||
&& GET_CODE (new_thread) == INSN
|
||
&& GET_CODE (PATTERN (new_thread)) != ASM_INPUT
|
||
&& asm_noperands (PATTERN (new_thread)) < 0)
|
||
{
|
||
rtx pat = PATTERN (new_thread);
|
||
rtx dest;
|
||
rtx src;
|
||
|
||
trial = new_thread;
|
||
pat = PATTERN (trial);
|
||
|
||
if (GET_CODE (trial) != INSN
|
||
|| GET_CODE (pat) != SET
|
||
|| ! eligible_for_delay (insn, 0, trial, flags)
|
||
|| can_throw_internal (trial))
|
||
return 0;
|
||
|
||
dest = SET_DEST (pat), src = SET_SRC (pat);
|
||
if ((GET_CODE (src) == PLUS || GET_CODE (src) == MINUS)
|
||
&& rtx_equal_p (XEXP (src, 0), dest)
|
||
&& ! reg_overlap_mentioned_p (dest, XEXP (src, 1))
|
||
&& ! side_effects_p (pat))
|
||
{
|
||
rtx other = XEXP (src, 1);
|
||
rtx new_arith;
|
||
rtx ninsn;
|
||
|
||
/* If this is a constant adjustment, use the same code with
|
||
the negated constant. Otherwise, reverse the sense of the
|
||
arithmetic. */
|
||
if (GET_CODE (other) == CONST_INT)
|
||
new_arith = gen_rtx_fmt_ee (GET_CODE (src), GET_MODE (src), dest,
|
||
negate_rtx (GET_MODE (src), other));
|
||
else
|
||
new_arith = gen_rtx_fmt_ee (GET_CODE (src) == PLUS ? MINUS : PLUS,
|
||
GET_MODE (src), dest, other);
|
||
|
||
ninsn = emit_insn_after (gen_rtx_SET (VOIDmode, dest, new_arith),
|
||
insn);
|
||
|
||
if (recog_memoized (ninsn) < 0
|
||
|| (extract_insn (ninsn), ! constrain_operands (1)))
|
||
{
|
||
delete_related_insns (ninsn);
|
||
return 0;
|
||
}
|
||
|
||
if (own_thread)
|
||
{
|
||
update_block (trial, thread);
|
||
if (trial == thread)
|
||
{
|
||
thread = next_active_insn (thread);
|
||
if (new_thread == trial)
|
||
new_thread = thread;
|
||
}
|
||
delete_related_insns (trial);
|
||
}
|
||
else
|
||
new_thread = next_active_insn (trial);
|
||
|
||
ninsn = own_thread ? trial : copy_rtx (trial);
|
||
if (thread_if_true)
|
||
INSN_FROM_TARGET_P (ninsn) = 1;
|
||
|
||
delay_list = add_to_delay_list (ninsn, NULL_RTX);
|
||
(*pslots_filled)++;
|
||
}
|
||
}
|
||
|
||
if (delay_list && must_annul)
|
||
INSN_ANNULLED_BRANCH_P (insn) = 1;
|
||
|
||
/* If we are to branch into the middle of this thread, find an appropriate
|
||
label or make a new one if none, and redirect INSN to it. If we hit the
|
||
end of the function, use the end-of-function label. */
|
||
if (new_thread != thread)
|
||
{
|
||
rtx label;
|
||
|
||
if (! thread_if_true)
|
||
abort ();
|
||
|
||
if (new_thread && GET_CODE (new_thread) == JUMP_INSN
|
||
&& (simplejump_p (new_thread)
|
||
|| GET_CODE (PATTERN (new_thread)) == RETURN)
|
||
&& redirect_with_delay_list_safe_p (insn,
|
||
JUMP_LABEL (new_thread),
|
||
delay_list))
|
||
new_thread = follow_jumps (JUMP_LABEL (new_thread));
|
||
|
||
if (new_thread == 0)
|
||
label = find_end_label ();
|
||
else if (GET_CODE (new_thread) == CODE_LABEL)
|
||
label = new_thread;
|
||
else
|
||
label = get_label_before (new_thread);
|
||
|
||
reorg_redirect_jump (insn, label);
|
||
}
|
||
|
||
return delay_list;
|
||
}
|
||
|
||
/* Make another attempt to find insns to place in delay slots.
|
||
|
||
We previously looked for insns located in front of the delay insn
|
||
and, for non-jump delay insns, located behind the delay insn.
|
||
|
||
Here only try to schedule jump insns and try to move insns from either
|
||
the target or the following insns into the delay slot. If annulling is
|
||
supported, we will be likely to do this. Otherwise, we can do this only
|
||
if safe. */
|
||
|
||
static void
|
||
fill_eager_delay_slots ()
|
||
{
|
||
rtx insn;
|
||
int i;
|
||
int num_unfilled_slots = unfilled_slots_next - unfilled_slots_base;
|
||
|
||
for (i = 0; i < num_unfilled_slots; i++)
|
||
{
|
||
rtx condition;
|
||
rtx target_label, insn_at_target, fallthrough_insn;
|
||
rtx delay_list = 0;
|
||
int own_target;
|
||
int own_fallthrough;
|
||
int prediction, slots_to_fill, slots_filled;
|
||
|
||
insn = unfilled_slots_base[i];
|
||
if (insn == 0
|
||
|| INSN_DELETED_P (insn)
|
||
|| GET_CODE (insn) != JUMP_INSN
|
||
|| ! (condjump_p (insn) || condjump_in_parallel_p (insn)))
|
||
continue;
|
||
|
||
slots_to_fill = num_delay_slots (insn);
|
||
/* Some machine description have defined instructions to have
|
||
delay slots only in certain circumstances which may depend on
|
||
nearby insns (which change due to reorg's actions).
|
||
|
||
For example, the PA port normally has delay slots for unconditional
|
||
jumps.
|
||
|
||
However, the PA port claims such jumps do not have a delay slot
|
||
if they are immediate successors of certain CALL_INSNs. This
|
||
allows the port to favor filling the delay slot of the call with
|
||
the unconditional jump. */
|
||
if (slots_to_fill == 0)
|
||
continue;
|
||
|
||
slots_filled = 0;
|
||
target_label = JUMP_LABEL (insn);
|
||
condition = get_branch_condition (insn, target_label);
|
||
|
||
if (condition == 0)
|
||
continue;
|
||
|
||
/* Get the next active fallthrough and target insns and see if we own
|
||
them. Then see whether the branch is likely true. We don't need
|
||
to do a lot of this for unconditional branches. */
|
||
|
||
insn_at_target = next_active_insn (target_label);
|
||
own_target = own_thread_p (target_label, target_label, 0);
|
||
|
||
if (condition == const_true_rtx)
|
||
{
|
||
own_fallthrough = 0;
|
||
fallthrough_insn = 0;
|
||
prediction = 2;
|
||
}
|
||
else
|
||
{
|
||
fallthrough_insn = next_active_insn (insn);
|
||
own_fallthrough = own_thread_p (NEXT_INSN (insn), NULL_RTX, 1);
|
||
prediction = mostly_true_jump (insn, condition);
|
||
}
|
||
|
||
/* If this insn is expected to branch, first try to get insns from our
|
||
target, then our fallthrough insns. If it is not expected to branch,
|
||
try the other order. */
|
||
|
||
if (prediction > 0)
|
||
{
|
||
delay_list
|
||
= fill_slots_from_thread (insn, condition, insn_at_target,
|
||
fallthrough_insn, prediction == 2, 1,
|
||
own_target,
|
||
slots_to_fill, &slots_filled, delay_list);
|
||
|
||
if (delay_list == 0 && own_fallthrough)
|
||
{
|
||
/* Even though we didn't find anything for delay slots,
|
||
we might have found a redundant insn which we deleted
|
||
from the thread that was filled. So we have to recompute
|
||
the next insn at the target. */
|
||
target_label = JUMP_LABEL (insn);
|
||
insn_at_target = next_active_insn (target_label);
|
||
|
||
delay_list
|
||
= fill_slots_from_thread (insn, condition, fallthrough_insn,
|
||
insn_at_target, 0, 0,
|
||
own_fallthrough,
|
||
slots_to_fill, &slots_filled,
|
||
delay_list);
|
||
}
|
||
}
|
||
else
|
||
{
|
||
if (own_fallthrough)
|
||
delay_list
|
||
= fill_slots_from_thread (insn, condition, fallthrough_insn,
|
||
insn_at_target, 0, 0,
|
||
own_fallthrough,
|
||
slots_to_fill, &slots_filled,
|
||
delay_list);
|
||
|
||
if (delay_list == 0)
|
||
delay_list
|
||
= fill_slots_from_thread (insn, condition, insn_at_target,
|
||
next_active_insn (insn), 0, 1,
|
||
own_target,
|
||
slots_to_fill, &slots_filled,
|
||
delay_list);
|
||
}
|
||
|
||
if (delay_list)
|
||
unfilled_slots_base[i]
|
||
= emit_delay_sequence (insn, delay_list, slots_filled);
|
||
|
||
if (slots_to_fill == slots_filled)
|
||
unfilled_slots_base[i] = 0;
|
||
|
||
note_delay_statistics (slots_filled, 1);
|
||
}
|
||
}
|
||
|
||
/* Once we have tried two ways to fill a delay slot, make a pass over the
|
||
code to try to improve the results and to do such things as more jump
|
||
threading. */
|
||
|
||
static void
|
||
relax_delay_slots (first)
|
||
rtx first;
|
||
{
|
||
rtx insn, next, pat;
|
||
rtx trial, delay_insn, target_label;
|
||
|
||
/* Look at every JUMP_INSN and see if we can improve it. */
|
||
for (insn = first; insn; insn = next)
|
||
{
|
||
rtx other;
|
||
|
||
next = next_active_insn (insn);
|
||
|
||
/* If this is a jump insn, see if it now jumps to a jump, jumps to
|
||
the next insn, or jumps to a label that is not the last of a
|
||
group of consecutive labels. */
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& (condjump_p (insn) || condjump_in_parallel_p (insn))
|
||
&& (target_label = JUMP_LABEL (insn)) != 0)
|
||
{
|
||
target_label = follow_jumps (target_label);
|
||
target_label = prev_label (next_active_insn (target_label));
|
||
|
||
if (target_label == 0)
|
||
target_label = find_end_label ();
|
||
|
||
if (next_active_insn (target_label) == next
|
||
&& ! condjump_in_parallel_p (insn))
|
||
{
|
||
delete_jump (insn);
|
||
continue;
|
||
}
|
||
|
||
if (target_label != JUMP_LABEL (insn))
|
||
reorg_redirect_jump (insn, target_label);
|
||
|
||
/* See if this jump branches around an unconditional jump.
|
||
If so, invert this jump and point it to the target of the
|
||
second jump. */
|
||
if (next && GET_CODE (next) == JUMP_INSN
|
||
&& (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN)
|
||
&& next_active_insn (target_label) == next_active_insn (next)
|
||
&& no_labels_between_p (insn, next))
|
||
{
|
||
rtx label = JUMP_LABEL (next);
|
||
|
||
/* Be careful how we do this to avoid deleting code or
|
||
labels that are momentarily dead. See similar optimization
|
||
in jump.c.
|
||
|
||
We also need to ensure we properly handle the case when
|
||
invert_jump fails. */
|
||
|
||
++LABEL_NUSES (target_label);
|
||
if (label)
|
||
++LABEL_NUSES (label);
|
||
|
||
if (invert_jump (insn, label, 1))
|
||
{
|
||
delete_related_insns (next);
|
||
next = insn;
|
||
}
|
||
|
||
if (label)
|
||
--LABEL_NUSES (label);
|
||
|
||
if (--LABEL_NUSES (target_label) == 0)
|
||
delete_related_insns (target_label);
|
||
|
||
continue;
|
||
}
|
||
}
|
||
|
||
/* If this is an unconditional jump and the previous insn is a
|
||
conditional jump, try reversing the condition of the previous
|
||
insn and swapping our targets. The next pass might be able to
|
||
fill the slots.
|
||
|
||
Don't do this if we expect the conditional branch to be true, because
|
||
we would then be making the more common case longer. */
|
||
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& (simplejump_p (insn) || GET_CODE (PATTERN (insn)) == RETURN)
|
||
&& (other = prev_active_insn (insn)) != 0
|
||
&& (condjump_p (other) || condjump_in_parallel_p (other))
|
||
&& no_labels_between_p (other, insn)
|
||
&& 0 > mostly_true_jump (other,
|
||
get_branch_condition (other,
|
||
JUMP_LABEL (other))))
|
||
{
|
||
rtx other_target = JUMP_LABEL (other);
|
||
target_label = JUMP_LABEL (insn);
|
||
|
||
if (invert_jump (other, target_label, 0))
|
||
reorg_redirect_jump (insn, other_target);
|
||
}
|
||
|
||
/* Now look only at cases where we have filled a delay slot. */
|
||
if (GET_CODE (insn) != INSN
|
||
|| GET_CODE (PATTERN (insn)) != SEQUENCE)
|
||
continue;
|
||
|
||
pat = PATTERN (insn);
|
||
delay_insn = XVECEXP (pat, 0, 0);
|
||
|
||
/* See if the first insn in the delay slot is redundant with some
|
||
previous insn. Remove it from the delay slot if so; then set up
|
||
to reprocess this insn. */
|
||
if (redundant_insn (XVECEXP (pat, 0, 1), delay_insn, 0))
|
||
{
|
||
delete_from_delay_slot (XVECEXP (pat, 0, 1));
|
||
next = prev_active_insn (next);
|
||
continue;
|
||
}
|
||
|
||
/* See if we have a RETURN insn with a filled delay slot followed
|
||
by a RETURN insn with an unfilled a delay slot. If so, we can delete
|
||
the first RETURN (but not it's delay insn). This gives the same
|
||
effect in fewer instructions.
|
||
|
||
Only do so if optimizing for size since this results in slower, but
|
||
smaller code. */
|
||
if (optimize_size
|
||
&& GET_CODE (PATTERN (delay_insn)) == RETURN
|
||
&& next
|
||
&& GET_CODE (next) == JUMP_INSN
|
||
&& GET_CODE (PATTERN (next)) == RETURN)
|
||
{
|
||
rtx after;
|
||
int i;
|
||
|
||
/* Delete the RETURN and just execute the delay list insns.
|
||
|
||
We do this by deleting the INSN containing the SEQUENCE, then
|
||
re-emitting the insns separately, and then deleting the RETURN.
|
||
This allows the count of the jump target to be properly
|
||
decremented. */
|
||
|
||
/* Clear the from target bit, since these insns are no longer
|
||
in delay slots. */
|
||
for (i = 0; i < XVECLEN (pat, 0); i++)
|
||
INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0;
|
||
|
||
trial = PREV_INSN (insn);
|
||
delete_related_insns (insn);
|
||
if (GET_CODE (pat) != SEQUENCE)
|
||
abort ();
|
||
after = trial;
|
||
for (i = 0; i < XVECLEN (pat, 0); i++)
|
||
{
|
||
rtx this_insn = XVECEXP (pat, 0, i);
|
||
add_insn_after (this_insn, after);
|
||
after = this_insn;
|
||
}
|
||
delete_scheduled_jump (delay_insn);
|
||
continue;
|
||
}
|
||
|
||
/* Now look only at the cases where we have a filled JUMP_INSN. */
|
||
if (GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) != JUMP_INSN
|
||
|| ! (condjump_p (XVECEXP (PATTERN (insn), 0, 0))
|
||
|| condjump_in_parallel_p (XVECEXP (PATTERN (insn), 0, 0))))
|
||
continue;
|
||
|
||
target_label = JUMP_LABEL (delay_insn);
|
||
|
||
if (target_label)
|
||
{
|
||
/* If this jump goes to another unconditional jump, thread it, but
|
||
don't convert a jump into a RETURN here. */
|
||
trial = follow_jumps (target_label);
|
||
/* We use next_real_insn instead of next_active_insn, so that
|
||
the special USE insns emitted by reorg won't be ignored.
|
||
If they are ignored, then they will get deleted if target_label
|
||
is now unreachable, and that would cause mark_target_live_regs
|
||
to fail. */
|
||
trial = prev_label (next_real_insn (trial));
|
||
if (trial == 0 && target_label != 0)
|
||
trial = find_end_label ();
|
||
|
||
if (trial != target_label
|
||
&& redirect_with_delay_slots_safe_p (delay_insn, trial, insn))
|
||
{
|
||
reorg_redirect_jump (delay_insn, trial);
|
||
target_label = trial;
|
||
}
|
||
|
||
/* If the first insn at TARGET_LABEL is redundant with a previous
|
||
insn, redirect the jump to the following insn process again. */
|
||
trial = next_active_insn (target_label);
|
||
if (trial && GET_CODE (PATTERN (trial)) != SEQUENCE
|
||
&& redundant_insn (trial, insn, 0)
|
||
&& ! can_throw_internal (trial))
|
||
{
|
||
rtx tmp;
|
||
|
||
/* Figure out where to emit the special USE insn so we don't
|
||
later incorrectly compute register live/death info. */
|
||
tmp = next_active_insn (trial);
|
||
if (tmp == 0)
|
||
tmp = find_end_label ();
|
||
|
||
/* Insert the special USE insn and update dataflow info. */
|
||
update_block (trial, tmp);
|
||
|
||
/* Now emit a label before the special USE insn, and
|
||
redirect our jump to the new label. */
|
||
target_label = get_label_before (PREV_INSN (tmp));
|
||
reorg_redirect_jump (delay_insn, target_label);
|
||
next = insn;
|
||
continue;
|
||
}
|
||
|
||
/* Similarly, if it is an unconditional jump with one insn in its
|
||
delay list and that insn is redundant, thread the jump. */
|
||
if (trial && GET_CODE (PATTERN (trial)) == SEQUENCE
|
||
&& XVECLEN (PATTERN (trial), 0) == 2
|
||
&& GET_CODE (XVECEXP (PATTERN (trial), 0, 0)) == JUMP_INSN
|
||
&& (simplejump_p (XVECEXP (PATTERN (trial), 0, 0))
|
||
|| GET_CODE (PATTERN (XVECEXP (PATTERN (trial), 0, 0))) == RETURN)
|
||
&& redundant_insn (XVECEXP (PATTERN (trial), 0, 1), insn, 0))
|
||
{
|
||
target_label = JUMP_LABEL (XVECEXP (PATTERN (trial), 0, 0));
|
||
if (target_label == 0)
|
||
target_label = find_end_label ();
|
||
|
||
if (redirect_with_delay_slots_safe_p (delay_insn, target_label,
|
||
insn))
|
||
{
|
||
reorg_redirect_jump (delay_insn, target_label);
|
||
next = insn;
|
||
continue;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (! INSN_ANNULLED_BRANCH_P (delay_insn)
|
||
&& prev_active_insn (target_label) == insn
|
||
&& ! condjump_in_parallel_p (delay_insn)
|
||
#ifdef HAVE_cc0
|
||
/* If the last insn in the delay slot sets CC0 for some insn,
|
||
various code assumes that it is in a delay slot. We could
|
||
put it back where it belonged and delete the register notes,
|
||
but it doesn't seem worthwhile in this uncommon case. */
|
||
&& ! find_reg_note (XVECEXP (pat, 0, XVECLEN (pat, 0) - 1),
|
||
REG_CC_USER, NULL_RTX)
|
||
#endif
|
||
)
|
||
{
|
||
rtx after;
|
||
int i;
|
||
|
||
/* All this insn does is execute its delay list and jump to the
|
||
following insn. So delete the jump and just execute the delay
|
||
list insns.
|
||
|
||
We do this by deleting the INSN containing the SEQUENCE, then
|
||
re-emitting the insns separately, and then deleting the jump.
|
||
This allows the count of the jump target to be properly
|
||
decremented. */
|
||
|
||
/* Clear the from target bit, since these insns are no longer
|
||
in delay slots. */
|
||
for (i = 0; i < XVECLEN (pat, 0); i++)
|
||
INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0;
|
||
|
||
trial = PREV_INSN (insn);
|
||
delete_related_insns (insn);
|
||
if (GET_CODE (pat) != SEQUENCE)
|
||
abort ();
|
||
after = trial;
|
||
for (i = 0; i < XVECLEN (pat, 0); i++)
|
||
{
|
||
rtx this_insn = XVECEXP (pat, 0, i);
|
||
add_insn_after (this_insn, after);
|
||
after = this_insn;
|
||
}
|
||
delete_scheduled_jump (delay_insn);
|
||
continue;
|
||
}
|
||
|
||
/* See if this is an unconditional jump around a single insn which is
|
||
identical to the one in its delay slot. In this case, we can just
|
||
delete the branch and the insn in its delay slot. */
|
||
if (next && GET_CODE (next) == INSN
|
||
&& prev_label (next_active_insn (next)) == target_label
|
||
&& simplejump_p (insn)
|
||
&& XVECLEN (pat, 0) == 2
|
||
&& rtx_equal_p (PATTERN (next), PATTERN (XVECEXP (pat, 0, 1))))
|
||
{
|
||
delete_related_insns (insn);
|
||
continue;
|
||
}
|
||
|
||
/* See if this jump (with its delay slots) branches around another
|
||
jump (without delay slots). If so, invert this jump and point
|
||
it to the target of the second jump. We cannot do this for
|
||
annulled jumps, though. Again, don't convert a jump to a RETURN
|
||
here. */
|
||
if (! INSN_ANNULLED_BRANCH_P (delay_insn)
|
||
&& next && GET_CODE (next) == JUMP_INSN
|
||
&& (simplejump_p (next) || GET_CODE (PATTERN (next)) == RETURN)
|
||
&& next_active_insn (target_label) == next_active_insn (next)
|
||
&& no_labels_between_p (insn, next))
|
||
{
|
||
rtx label = JUMP_LABEL (next);
|
||
rtx old_label = JUMP_LABEL (delay_insn);
|
||
|
||
if (label == 0)
|
||
label = find_end_label ();
|
||
|
||
/* find_end_label can generate a new label. Check this first. */
|
||
if (no_labels_between_p (insn, next)
|
||
&& redirect_with_delay_slots_safe_p (delay_insn, label, insn))
|
||
{
|
||
/* Be careful how we do this to avoid deleting code or labels
|
||
that are momentarily dead. See similar optimization in
|
||
jump.c */
|
||
if (old_label)
|
||
++LABEL_NUSES (old_label);
|
||
|
||
if (invert_jump (delay_insn, label, 1))
|
||
{
|
||
int i;
|
||
|
||
/* Must update the INSN_FROM_TARGET_P bits now that
|
||
the branch is reversed, so that mark_target_live_regs
|
||
will handle the delay slot insn correctly. */
|
||
for (i = 1; i < XVECLEN (PATTERN (insn), 0); i++)
|
||
{
|
||
rtx slot = XVECEXP (PATTERN (insn), 0, i);
|
||
INSN_FROM_TARGET_P (slot) = ! INSN_FROM_TARGET_P (slot);
|
||
}
|
||
|
||
delete_related_insns (next);
|
||
next = insn;
|
||
}
|
||
|
||
if (old_label && --LABEL_NUSES (old_label) == 0)
|
||
delete_related_insns (old_label);
|
||
continue;
|
||
}
|
||
}
|
||
|
||
/* If we own the thread opposite the way this insn branches, see if we
|
||
can merge its delay slots with following insns. */
|
||
if (INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1))
|
||
&& own_thread_p (NEXT_INSN (insn), 0, 1))
|
||
try_merge_delay_insns (insn, next);
|
||
else if (! INSN_FROM_TARGET_P (XVECEXP (pat, 0, 1))
|
||
&& own_thread_p (target_label, target_label, 0))
|
||
try_merge_delay_insns (insn, next_active_insn (target_label));
|
||
|
||
/* If we get here, we haven't deleted INSN. But we may have deleted
|
||
NEXT, so recompute it. */
|
||
next = next_active_insn (insn);
|
||
}
|
||
}
|
||
|
||
#ifdef HAVE_return
|
||
|
||
/* Look for filled jumps to the end of function label. We can try to convert
|
||
them into RETURN insns if the insns in the delay slot are valid for the
|
||
RETURN as well. */
|
||
|
||
static void
|
||
make_return_insns (first)
|
||
rtx first;
|
||
{
|
||
rtx insn, jump_insn, pat;
|
||
rtx real_return_label = end_of_function_label;
|
||
int slots, i;
|
||
|
||
#ifdef DELAY_SLOTS_FOR_EPILOGUE
|
||
/* If a previous pass filled delay slots in the epilogue, things get a
|
||
bit more complicated, as those filler insns would generally (without
|
||
data flow analysis) have to be executed after any existing branch
|
||
delay slot filler insns. It is also unknown whether such a
|
||
transformation would actually be profitable. Note that the existing
|
||
code only cares for branches with (some) filled delay slots. */
|
||
if (current_function_epilogue_delay_list != NULL)
|
||
return;
|
||
#endif
|
||
|
||
/* See if there is a RETURN insn in the function other than the one we
|
||
made for END_OF_FUNCTION_LABEL. If so, set up anything we can't change
|
||
into a RETURN to jump to it. */
|
||
for (insn = first; insn; insn = NEXT_INSN (insn))
|
||
if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == RETURN)
|
||
{
|
||
real_return_label = get_label_before (insn);
|
||
break;
|
||
}
|
||
|
||
/* Show an extra usage of REAL_RETURN_LABEL so it won't go away if it
|
||
was equal to END_OF_FUNCTION_LABEL. */
|
||
LABEL_NUSES (real_return_label)++;
|
||
|
||
/* Clear the list of insns to fill so we can use it. */
|
||
obstack_free (&unfilled_slots_obstack, unfilled_firstobj);
|
||
|
||
for (insn = first; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
int flags;
|
||
|
||
/* Only look at filled JUMP_INSNs that go to the end of function
|
||
label. */
|
||
if (GET_CODE (insn) != INSN
|
||
|| GET_CODE (PATTERN (insn)) != SEQUENCE
|
||
|| GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) != JUMP_INSN
|
||
|| JUMP_LABEL (XVECEXP (PATTERN (insn), 0, 0)) != end_of_function_label)
|
||
continue;
|
||
|
||
pat = PATTERN (insn);
|
||
jump_insn = XVECEXP (pat, 0, 0);
|
||
|
||
/* If we can't make the jump into a RETURN, try to redirect it to the best
|
||
RETURN and go on to the next insn. */
|
||
if (! reorg_redirect_jump (jump_insn, NULL_RTX))
|
||
{
|
||
/* Make sure redirecting the jump will not invalidate the delay
|
||
slot insns. */
|
||
if (redirect_with_delay_slots_safe_p (jump_insn,
|
||
real_return_label,
|
||
insn))
|
||
reorg_redirect_jump (jump_insn, real_return_label);
|
||
continue;
|
||
}
|
||
|
||
/* See if this RETURN can accept the insns current in its delay slot.
|
||
It can if it has more or an equal number of slots and the contents
|
||
of each is valid. */
|
||
|
||
flags = get_jump_flags (jump_insn, JUMP_LABEL (jump_insn));
|
||
slots = num_delay_slots (jump_insn);
|
||
if (slots >= XVECLEN (pat, 0) - 1)
|
||
{
|
||
for (i = 1; i < XVECLEN (pat, 0); i++)
|
||
if (! (
|
||
#ifdef ANNUL_IFFALSE_SLOTS
|
||
(INSN_ANNULLED_BRANCH_P (jump_insn)
|
||
&& INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)))
|
||
? eligible_for_annul_false (jump_insn, i - 1,
|
||
XVECEXP (pat, 0, i), flags) :
|
||
#endif
|
||
#ifdef ANNUL_IFTRUE_SLOTS
|
||
(INSN_ANNULLED_BRANCH_P (jump_insn)
|
||
&& ! INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)))
|
||
? eligible_for_annul_true (jump_insn, i - 1,
|
||
XVECEXP (pat, 0, i), flags) :
|
||
#endif
|
||
eligible_for_delay (jump_insn, i - 1,
|
||
XVECEXP (pat, 0, i), flags)))
|
||
break;
|
||
}
|
||
else
|
||
i = 0;
|
||
|
||
if (i == XVECLEN (pat, 0))
|
||
continue;
|
||
|
||
/* We have to do something with this insn. If it is an unconditional
|
||
RETURN, delete the SEQUENCE and output the individual insns,
|
||
followed by the RETURN. Then set things up so we try to find
|
||
insns for its delay slots, if it needs some. */
|
||
if (GET_CODE (PATTERN (jump_insn)) == RETURN)
|
||
{
|
||
rtx prev = PREV_INSN (insn);
|
||
|
||
delete_related_insns (insn);
|
||
for (i = 1; i < XVECLEN (pat, 0); i++)
|
||
prev = emit_insn_after (PATTERN (XVECEXP (pat, 0, i)), prev);
|
||
|
||
insn = emit_jump_insn_after (PATTERN (jump_insn), prev);
|
||
emit_barrier_after (insn);
|
||
|
||
if (slots)
|
||
obstack_ptr_grow (&unfilled_slots_obstack, insn);
|
||
}
|
||
else
|
||
/* It is probably more efficient to keep this with its current
|
||
delay slot as a branch to a RETURN. */
|
||
reorg_redirect_jump (jump_insn, real_return_label);
|
||
}
|
||
|
||
/* Now delete REAL_RETURN_LABEL if we never used it. Then try to fill any
|
||
new delay slots we have created. */
|
||
if (--LABEL_NUSES (real_return_label) == 0)
|
||
delete_related_insns (real_return_label);
|
||
|
||
fill_simple_delay_slots (1);
|
||
fill_simple_delay_slots (0);
|
||
}
|
||
#endif
|
||
|
||
/* Try to find insns to place in delay slots. */
|
||
|
||
void
|
||
dbr_schedule (first, file)
|
||
rtx first;
|
||
FILE *file;
|
||
{
|
||
rtx insn, next, epilogue_insn = 0;
|
||
int i;
|
||
#if 0
|
||
int old_flag_no_peephole = flag_no_peephole;
|
||
|
||
/* Execute `final' once in prescan mode to delete any insns that won't be
|
||
used. Don't let final try to do any peephole optimization--it will
|
||
ruin dataflow information for this pass. */
|
||
|
||
flag_no_peephole = 1;
|
||
final (first, 0, NO_DEBUG, 1, 1);
|
||
flag_no_peephole = old_flag_no_peephole;
|
||
#endif
|
||
|
||
/* If the current function has no insns other than the prologue and
|
||
epilogue, then do not try to fill any delay slots. */
|
||
if (n_basic_blocks == 0)
|
||
return;
|
||
|
||
/* Find the highest INSN_UID and allocate and initialize our map from
|
||
INSN_UID's to position in code. */
|
||
for (max_uid = 0, insn = first; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
if (INSN_UID (insn) > max_uid)
|
||
max_uid = INSN_UID (insn);
|
||
if (GET_CODE (insn) == NOTE
|
||
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG)
|
||
epilogue_insn = insn;
|
||
}
|
||
|
||
uid_to_ruid = (int *) xmalloc ((max_uid + 1) * sizeof (int));
|
||
for (i = 0, insn = first; insn; i++, insn = NEXT_INSN (insn))
|
||
uid_to_ruid[INSN_UID (insn)] = i;
|
||
|
||
/* Initialize the list of insns that need filling. */
|
||
if (unfilled_firstobj == 0)
|
||
{
|
||
gcc_obstack_init (&unfilled_slots_obstack);
|
||
unfilled_firstobj = (rtx *) obstack_alloc (&unfilled_slots_obstack, 0);
|
||
}
|
||
|
||
for (insn = next_active_insn (first); insn; insn = next_active_insn (insn))
|
||
{
|
||
rtx target;
|
||
|
||
INSN_ANNULLED_BRANCH_P (insn) = 0;
|
||
INSN_FROM_TARGET_P (insn) = 0;
|
||
|
||
/* Skip vector tables. We can't get attributes for them. */
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& (GET_CODE (PATTERN (insn)) == ADDR_VEC
|
||
|| GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC))
|
||
continue;
|
||
|
||
if (num_delay_slots (insn) > 0)
|
||
obstack_ptr_grow (&unfilled_slots_obstack, insn);
|
||
|
||
/* Ensure all jumps go to the last of a set of consecutive labels. */
|
||
if (GET_CODE (insn) == JUMP_INSN
|
||
&& (condjump_p (insn) || condjump_in_parallel_p (insn))
|
||
&& JUMP_LABEL (insn) != 0
|
||
&& ((target = prev_label (next_active_insn (JUMP_LABEL (insn))))
|
||
!= JUMP_LABEL (insn)))
|
||
redirect_jump (insn, target, 1);
|
||
}
|
||
|
||
init_resource_info (epilogue_insn);
|
||
|
||
/* Show we haven't computed an end-of-function label yet. */
|
||
end_of_function_label = 0;
|
||
|
||
/* Initialize the statistics for this function. */
|
||
memset ((char *) num_insns_needing_delays, 0, sizeof num_insns_needing_delays);
|
||
memset ((char *) num_filled_delays, 0, sizeof num_filled_delays);
|
||
|
||
/* Now do the delay slot filling. Try everything twice in case earlier
|
||
changes make more slots fillable. */
|
||
|
||
for (reorg_pass_number = 0;
|
||
reorg_pass_number < MAX_REORG_PASSES;
|
||
reorg_pass_number++)
|
||
{
|
||
fill_simple_delay_slots (1);
|
||
fill_simple_delay_slots (0);
|
||
fill_eager_delay_slots ();
|
||
relax_delay_slots (first);
|
||
}
|
||
|
||
/* Delete any USE insns made by update_block; subsequent passes don't need
|
||
them or know how to deal with them. */
|
||
for (insn = first; insn; insn = next)
|
||
{
|
||
next = NEXT_INSN (insn);
|
||
|
||
if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == USE
|
||
&& INSN_P (XEXP (PATTERN (insn), 0)))
|
||
next = delete_related_insns (insn);
|
||
}
|
||
|
||
/* If we made an end of function label, indicate that it is now
|
||
safe to delete it by undoing our prior adjustment to LABEL_NUSES.
|
||
If it is now unused, delete it. */
|
||
if (end_of_function_label && --LABEL_NUSES (end_of_function_label) == 0)
|
||
delete_related_insns (end_of_function_label);
|
||
|
||
#ifdef HAVE_return
|
||
if (HAVE_return && end_of_function_label != 0)
|
||
make_return_insns (first);
|
||
#endif
|
||
|
||
obstack_free (&unfilled_slots_obstack, unfilled_firstobj);
|
||
|
||
/* It is not clear why the line below is needed, but it does seem to be. */
|
||
unfilled_firstobj = (rtx *) obstack_alloc (&unfilled_slots_obstack, 0);
|
||
|
||
if (file)
|
||
{
|
||
int i, j, need_comma;
|
||
int total_delay_slots[MAX_DELAY_HISTOGRAM + 1];
|
||
int total_annul_slots[MAX_DELAY_HISTOGRAM + 1];
|
||
|
||
for (reorg_pass_number = 0;
|
||
reorg_pass_number < MAX_REORG_PASSES;
|
||
reorg_pass_number++)
|
||
{
|
||
fprintf (file, ";; Reorg pass #%d:\n", reorg_pass_number + 1);
|
||
for (i = 0; i < NUM_REORG_FUNCTIONS; i++)
|
||
{
|
||
need_comma = 0;
|
||
fprintf (file, ";; Reorg function #%d\n", i);
|
||
|
||
fprintf (file, ";; %d insns needing delay slots\n;; ",
|
||
num_insns_needing_delays[i][reorg_pass_number]);
|
||
|
||
for (j = 0; j < MAX_DELAY_HISTOGRAM + 1; j++)
|
||
if (num_filled_delays[i][j][reorg_pass_number])
|
||
{
|
||
if (need_comma)
|
||
fprintf (file, ", ");
|
||
need_comma = 1;
|
||
fprintf (file, "%d got %d delays",
|
||
num_filled_delays[i][j][reorg_pass_number], j);
|
||
}
|
||
fprintf (file, "\n");
|
||
}
|
||
}
|
||
memset ((char *) total_delay_slots, 0, sizeof total_delay_slots);
|
||
memset ((char *) total_annul_slots, 0, sizeof total_annul_slots);
|
||
for (insn = first; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
if (! INSN_DELETED_P (insn)
|
||
&& GET_CODE (insn) == INSN
|
||
&& GET_CODE (PATTERN (insn)) != USE
|
||
&& GET_CODE (PATTERN (insn)) != CLOBBER)
|
||
{
|
||
if (GET_CODE (PATTERN (insn)) == SEQUENCE)
|
||
{
|
||
j = XVECLEN (PATTERN (insn), 0) - 1;
|
||
if (j > MAX_DELAY_HISTOGRAM)
|
||
j = MAX_DELAY_HISTOGRAM;
|
||
if (INSN_ANNULLED_BRANCH_P (XVECEXP (PATTERN (insn), 0, 0)))
|
||
total_annul_slots[j]++;
|
||
else
|
||
total_delay_slots[j]++;
|
||
}
|
||
else if (num_delay_slots (insn) > 0)
|
||
total_delay_slots[0]++;
|
||
}
|
||
}
|
||
fprintf (file, ";; Reorg totals: ");
|
||
need_comma = 0;
|
||
for (j = 0; j < MAX_DELAY_HISTOGRAM + 1; j++)
|
||
{
|
||
if (total_delay_slots[j])
|
||
{
|
||
if (need_comma)
|
||
fprintf (file, ", ");
|
||
need_comma = 1;
|
||
fprintf (file, "%d got %d delays", total_delay_slots[j], j);
|
||
}
|
||
}
|
||
fprintf (file, "\n");
|
||
#if defined (ANNUL_IFTRUE_SLOTS) || defined (ANNUL_IFFALSE_SLOTS)
|
||
fprintf (file, ";; Reorg annuls: ");
|
||
need_comma = 0;
|
||
for (j = 0; j < MAX_DELAY_HISTOGRAM + 1; j++)
|
||
{
|
||
if (total_annul_slots[j])
|
||
{
|
||
if (need_comma)
|
||
fprintf (file, ", ");
|
||
need_comma = 1;
|
||
fprintf (file, "%d got %d delays", total_annul_slots[j], j);
|
||
}
|
||
}
|
||
fprintf (file, "\n");
|
||
#endif
|
||
fprintf (file, "\n");
|
||
}
|
||
|
||
/* For all JUMP insns, fill in branch prediction notes, so that during
|
||
assembler output a target can set branch prediction bits in the code.
|
||
We have to do this now, as up until this point the destinations of
|
||
JUMPS can be moved around and changed, but past right here that cannot
|
||
happen. */
|
||
for (insn = first; insn; insn = NEXT_INSN (insn))
|
||
{
|
||
int pred_flags;
|
||
|
||
if (GET_CODE (insn) == INSN)
|
||
{
|
||
rtx pat = PATTERN (insn);
|
||
|
||
if (GET_CODE (pat) == SEQUENCE)
|
||
insn = XVECEXP (pat, 0, 0);
|
||
}
|
||
if (GET_CODE (insn) != JUMP_INSN)
|
||
continue;
|
||
|
||
pred_flags = get_jump_flags (insn, JUMP_LABEL (insn));
|
||
REG_NOTES (insn) = gen_rtx_EXPR_LIST (REG_BR_PRED,
|
||
GEN_INT (pred_flags),
|
||
REG_NOTES (insn));
|
||
}
|
||
free_resource_info ();
|
||
free (uid_to_ruid);
|
||
}
|
||
#endif /* DELAY_SLOTS */
|