/* Control flow optimization code for GNU compiler.
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
-/* This file contains optimizer of the control flow. The main entrypoint is
+/* This file contains optimizer of the control flow. The main entry point is
cleanup_cfg. Following optimizations are performed:
- Unreachable blocks removal
- - Edge forwarding (edge to the forwarder block is forwarded to it's
+ - Edge forwarding (edge to the forwarder block is forwarded to its
successor. Simplification of the branch instruction is performed by
underlying infrastructure so branch can be converted to simplejump or
eliminated).
#include "tm.h"
#include "rtl.h"
#include "hard-reg-set.h"
-#include "basic-block.h"
+#include "regs.h"
#include "timevar.h"
#include "output.h"
#include "insn-config.h"
#include "params.h"
#include "tm_p.h"
#include "target.h"
-
-/* cleanup_cfg maintains following flags for each basic block. */
-
-enum bb_flags
-{
- /* Set if BB is the forwarder block to avoid too many
- forwarder_block_p calls. */
- BB_FORWARDER_BLOCK = 1,
- BB_NONTHREADABLE_BLOCK = 2
-};
-
-#define BB_FLAGS(BB) (enum bb_flags) (BB)->aux
-#define BB_SET_FLAG(BB, FLAG) \
- (BB)->aux = (void *) (long) ((enum bb_flags) (BB)->aux | (FLAG))
-#define BB_CLEAR_FLAG(BB, FLAG) \
- (BB)->aux = (void *) (long) ((enum bb_flags) (BB)->aux & ~(FLAG))
-
-#define FORWARDER_BLOCK_P(BB) (BB_FLAGS (BB) & BB_FORWARDER_BLOCK)
-
-static bool try_crossjump_to_edge PARAMS ((int, edge, edge));
-static bool try_crossjump_bb PARAMS ((int, basic_block));
-static bool outgoing_edges_match PARAMS ((int,
- basic_block, basic_block));
-static int flow_find_cross_jump PARAMS ((int, basic_block, basic_block,
- rtx *, rtx *));
-static bool insns_match_p PARAMS ((int, rtx, rtx));
-
-static bool label_is_jump_target_p PARAMS ((rtx, rtx));
-static bool tail_recursion_label_p PARAMS ((rtx));
-static void merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
- basic_block));
-static void merge_blocks_move_successor_nojumps PARAMS ((basic_block,
- basic_block));
-static bool merge_blocks PARAMS ((edge,basic_block,basic_block,
- int));
-static bool try_optimize_cfg PARAMS ((int));
-static bool try_simplify_condjump PARAMS ((basic_block));
-static bool try_forward_edges PARAMS ((int, basic_block));
-static edge thread_jump PARAMS ((int, edge, basic_block));
-static bool mark_effect PARAMS ((rtx, bitmap));
-static void notice_new_block PARAMS ((basic_block));
-static void update_forwarder_flag PARAMS ((basic_block));
-static int mentions_nonequal_regs PARAMS ((rtx *, void *));
+#include "cfglayout.h"
+#include "emit-rtl.h"
+#include "tree-pass.h"
+#include "cfgloop.h"
+#include "expr.h"
+
+#define FORWARDER_BLOCK_P(BB) ((BB)->flags & BB_FORWARDER_BLOCK)
+
+/* Set to true when we are running first pass of try_optimize_cfg loop. */
+static bool first_pass;
+static bool try_crossjump_to_edge (int, edge, edge);
+static bool try_crossjump_bb (int, basic_block);
+static bool outgoing_edges_match (int, basic_block, basic_block);
+static int flow_find_cross_jump (int, basic_block, basic_block, rtx *, rtx *);
+static bool old_insns_match_p (int, rtx, rtx);
+
+static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block);
+static void merge_blocks_move_successor_nojumps (basic_block, basic_block);
+static bool try_optimize_cfg (int);
+static bool try_simplify_condjump (basic_block);
+static bool try_forward_edges (int, basic_block);
+static edge thread_jump (int, edge, basic_block);
+static bool mark_effect (rtx, bitmap);
+static void notice_new_block (basic_block);
+static void update_forwarder_flag (basic_block);
+static int mentions_nonequal_regs (rtx *, void *);
+static void merge_memattrs (rtx, rtx);
\f
/* Set flags for newly created block. */
static void
-notice_new_block (bb)
- basic_block bb;
+notice_new_block (basic_block bb)
{
if (!bb)
return;
if (forwarder_block_p (bb))
- BB_SET_FLAG (bb, BB_FORWARDER_BLOCK);
+ bb->flags |= BB_FORWARDER_BLOCK;
}
/* Recompute forwarder flag after block has been modified. */
static void
-update_forwarder_flag (bb)
- basic_block bb;
+update_forwarder_flag (basic_block bb)
{
if (forwarder_block_p (bb))
- BB_SET_FLAG (bb, BB_FORWARDER_BLOCK);
+ bb->flags |= BB_FORWARDER_BLOCK;
else
- BB_CLEAR_FLAG (bb, BB_FORWARDER_BLOCK);
+ bb->flags &= ~BB_FORWARDER_BLOCK;
}
\f
/* Simplify a conditional jump around an unconditional jump.
Return true if something changed. */
static bool
-try_simplify_condjump (cbranch_block)
- basic_block cbranch_block;
+try_simplify_condjump (basic_block cbranch_block)
{
basic_block jump_block, jump_dest_block, cbranch_dest_block;
edge cbranch_jump_edge, cbranch_fallthru_edge;
rtx cbranch_insn;
/* Verify that there are exactly two successors. */
- if (!cbranch_block->succ
- || !cbranch_block->succ->succ_next
- || cbranch_block->succ->succ_next->succ_next)
+ if (EDGE_COUNT (cbranch_block->succs) != 2)
return false;
/* Verify that we've got a normal conditional branch at the end
of the block. */
- cbranch_insn = cbranch_block->end;
+ cbranch_insn = BB_END (cbranch_block);
if (!any_condjump_p (cbranch_insn))
return false;
be the last block in the function, and must contain just the
unconditional jump. */
jump_block = cbranch_fallthru_edge->dest;
- if (jump_block->pred->pred_next
+ if (!single_pred_p (jump_block)
|| jump_block->next_bb == EXIT_BLOCK_PTR
|| !FORWARDER_BLOCK_P (jump_block))
return false;
- jump_dest_block = jump_block->succ->dest;
+ jump_dest_block = single_succ (jump_block);
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (jump_block) != BB_PARTITION (jump_dest_block)
+ || (cbranch_jump_edge->flags & EDGE_CROSSING))
+ return false;
/* The conditional branch must target the block after the
unconditional branch. */
cbranch_dest_block = cbranch_jump_edge->dest;
- if (!can_fallthru (jump_block, cbranch_dest_block))
+ if (cbranch_dest_block == EXIT_BLOCK_PTR
+ || !can_fallthru (jump_block, cbranch_dest_block))
return false;
/* Invert the conditional branch. */
if (!invert_jump (cbranch_insn, block_label (jump_dest_block), 0))
return false;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Simplifying condjump %i around jump %i\n",
- INSN_UID (cbranch_insn), INSN_UID (jump_block->end));
+ if (dump_file)
+ fprintf (dump_file, "Simplifying condjump %i around jump %i\n",
+ INSN_UID (cbranch_insn), INSN_UID (BB_END (jump_block)));
/* Success. Update the CFG to match. Note that after this point
the edge variable names appear backwards; the redirection is done
update_br_prob_note (cbranch_block);
/* Delete the block with the unconditional jump, and clean up the mess. */
- flow_delete_block (jump_block);
- tidy_fallthru_edge (cbranch_jump_edge, cbranch_block, cbranch_dest_block);
+ delete_basic_block (jump_block);
+ tidy_fallthru_edge (cbranch_jump_edge);
+ update_forwarder_flag (cbranch_block);
return true;
}
on register. Used by jump threading. */
static bool
-mark_effect (exp, nonequal)
- rtx exp;
- regset nonequal;
+mark_effect (rtx exp, regset nonequal)
{
int regno;
rtx dest;
CLEAR_REGNO_REG_SET (nonequal, regno);
if (regno < FIRST_PSEUDO_REGISTER)
{
- int n = HARD_REGNO_NREGS (regno, GET_MODE (dest));
+ int n = hard_regno_nregs[regno][GET_MODE (dest)];
while (--n > 0)
CLEAR_REGNO_REG_SET (nonequal, regno + n);
}
SET_REGNO_REG_SET (nonequal, regno);
if (regno < FIRST_PSEUDO_REGISTER)
{
- int n = HARD_REGNO_NREGS (regno, GET_MODE (dest));
+ int n = hard_regno_nregs[regno][GET_MODE (dest)];
while (--n > 0)
SET_REGNO_REG_SET (nonequal, regno + n);
}
}
}
-/* Return nonzero if X is an register set in regset DATA.
+/* Return nonzero if X is a register set in regset DATA.
Called via for_each_rtx. */
static int
-mentions_nonequal_regs (x, data)
- rtx *x;
- void *data;
+mentions_nonequal_regs (rtx *x, void *data)
{
regset nonequal = (regset) data;
if (REG_P (*x))
return 1;
if (regno < FIRST_PSEUDO_REGISTER)
{
- int n = HARD_REGNO_NREGS (regno, GET_MODE (*x));
+ int n = hard_regno_nregs[regno][GET_MODE (*x)];
while (--n > 0)
if (REGNO_REG_SET_P (nonequal, regno + n))
return 1;
if exist, NULL otherwise. */
static edge
-thread_jump (mode, e, b)
- int mode;
- edge e;
- basic_block b;
+thread_jump (int mode, edge e, basic_block b)
{
rtx set1, set2, cond1, cond2, insn;
enum rtx_code code1, code2, reversed_code2;
bool reverse1 = false;
- int i;
+ unsigned i;
regset nonequal;
bool failed = false;
+ reg_set_iterator rsi;
- if (BB_FLAGS (b) & BB_NONTHREADABLE_BLOCK)
+ if (b->flags & BB_NONTHREADABLE_BLOCK)
return NULL;
/* At the moment, we do handle only conditional jumps, but later we may
want to extend this code to tablejumps and others. */
- if (!e->src->succ->succ_next || e->src->succ->succ_next->succ_next)
+ if (EDGE_COUNT (e->src->succs) != 2)
return NULL;
- if (!b->succ || !b->succ->succ_next || b->succ->succ_next->succ_next)
+ if (EDGE_COUNT (b->succs) != 2)
{
- BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK);
+ b->flags |= BB_NONTHREADABLE_BLOCK;
return NULL;
}
/* Second branch must end with onlyjump, as we will eliminate the jump. */
- if (!any_condjump_p (e->src->end))
+ if (!any_condjump_p (BB_END (e->src)))
return NULL;
- if (!any_condjump_p (b->end) || !onlyjump_p (b->end))
+ if (!any_condjump_p (BB_END (b)) || !onlyjump_p (BB_END (b)))
{
- BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK);
+ b->flags |= BB_NONTHREADABLE_BLOCK;
return NULL;
}
- set1 = pc_set (e->src->end);
- set2 = pc_set (b->end);
+ set1 = pc_set (BB_END (e->src));
+ set2 = pc_set (BB_END (b));
if (((e->flags & EDGE_FALLTHRU) != 0)
!= (XEXP (SET_SRC (set1), 1) == pc_rtx))
reverse1 = true;
cond1 = XEXP (SET_SRC (set1), 0);
cond2 = XEXP (SET_SRC (set2), 0);
if (reverse1)
- code1 = reversed_comparison_code (cond1, e->src->end);
+ code1 = reversed_comparison_code (cond1, BB_END (e->src));
else
code1 = GET_CODE (cond1);
code2 = GET_CODE (cond2);
- reversed_code2 = reversed_comparison_code (cond2, b->end);
+ reversed_code2 = reversed_comparison_code (cond2, BB_END (b));
if (!comparison_dominates_p (code1, code2)
&& !comparison_dominates_p (code1, reversed_code2))
/* Short circuit cases where block B contains some side effects, as we can't
safely bypass it. */
- for (insn = NEXT_INSN (b->head); insn != NEXT_INSN (b->end);
+ for (insn = NEXT_INSN (BB_HEAD (b)); insn != NEXT_INSN (BB_END (b));
insn = NEXT_INSN (insn))
if (INSN_P (insn) && side_effects_p (PATTERN (insn)))
{
- BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK);
+ b->flags |= BB_NONTHREADABLE_BLOCK;
return NULL;
}
- cselib_init ();
+ cselib_init (false);
/* First process all values computed in the source basic block. */
- for (insn = NEXT_INSN (e->src->head); insn != NEXT_INSN (e->src->end);
+ for (insn = NEXT_INSN (BB_HEAD (e->src));
+ insn != NEXT_INSN (BB_END (e->src));
insn = NEXT_INSN (insn))
if (INSN_P (insn))
cselib_process_insn (insn);
- nonequal = BITMAP_XMALLOC();
+ nonequal = BITMAP_ALLOC (NULL);
CLEAR_REG_SET (nonequal);
/* Now assume that we've continued by the edge E to B and continue
processing as if it were same basic block.
Our goal is to prove that whole block is an NOOP. */
- for (insn = NEXT_INSN (b->head); insn != NEXT_INSN (b->end) && !failed;
+ for (insn = NEXT_INSN (BB_HEAD (b));
+ insn != NEXT_INSN (BB_END (b)) && !failed;
insn = NEXT_INSN (insn))
{
if (INSN_P (insn))
if (GET_CODE (pat) == PARALLEL)
{
- for (i = 0; i < XVECLEN (pat, 0); i++)
+ for (i = 0; i < (unsigned)XVECLEN (pat, 0); i++)
failed |= mark_effect (XVECEXP (pat, 0, i), nonequal);
}
else
have life information in cfg_cleanup. */
if (failed)
{
- BB_SET_FLAG (b, BB_NONTHREADABLE_BLOCK);
+ b->flags |= BB_NONTHREADABLE_BLOCK;
goto failed_exit;
}
/* In case liveness information is available, we need to prove equivalence
only of the live values. */
if (mode & CLEANUP_UPDATE_LIFE)
- AND_REG_SET (nonequal, b->global_live_at_end);
+ AND_REG_SET (nonequal, b->il.rtl->global_live_at_end);
- EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, goto failed_exit;);
+ EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, rsi)
+ goto failed_exit;
- BITMAP_XFREE (nonequal);
+ BITMAP_FREE (nonequal);
cselib_finish ();
if ((comparison_dominates_p (code1, code2) != 0)
!= (XEXP (SET_SRC (set2), 1) == pc_rtx))
return FALLTHRU_EDGE (b);
failed_exit:
- BITMAP_XFREE (nonequal);
+ BITMAP_FREE (nonequal);
cselib_finish ();
return NULL;
}
Return true if successful. */
static bool
-try_forward_edges (mode, b)
- basic_block b;
- int mode;
+try_forward_edges (int mode, basic_block b)
{
bool changed = false;
- edge e, next, *threaded_edges = NULL;
+ edge_iterator ei;
+ edge e, *threaded_edges = NULL;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really m
+ ust be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX))
+ return false;
- for (e = b->succ; e; e = next)
+ for (ei = ei_start (b->succs); (e = ei_safe_edge (ei)); )
{
basic_block target, first;
int counter;
bool threaded = false;
int nthreaded_edges = 0;
-
- next = e->succ_next;
+ bool may_thread = first_pass | (b->flags & BB_DIRTY);
/* Skip complex edges because we don't know how to update them.
edge to the same place as the branch edge of conditional branch
and turn conditional branch to an unconditional branch. */
if (e->flags & EDGE_COMPLEX)
- continue;
+ {
+ ei_next (&ei);
+ continue;
+ }
target = first = e->dest;
- counter = 0;
+ counter = NUM_FIXED_BLOCKS;
+
+ /* If we are partitioning hot/cold basic_blocks, we don't want to mess
+ up jumps that cross between hot/cold sections.
+
+ Basic block partitioning may result in some jumps that appear
+ to be optimizable (or blocks that appear to be mergeable), but which
+ really must be left untouched (they are required to make it safely
+ across partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete
+ details. */
+
+ if (first != EXIT_BLOCK_PTR
+ && find_reg_note (BB_END (first), REG_CROSSING_JUMP, NULL_RTX))
+ return false;
while (counter < n_basic_blocks)
{
basic_block new_target = NULL;
bool new_target_threaded = false;
+ may_thread |= target->flags & BB_DIRTY;
if (FORWARDER_BLOCK_P (target)
- && target->succ->dest != EXIT_BLOCK_PTR)
+ && !(single_succ_edge (target)->flags & EDGE_CROSSING)
+ && single_succ (target) != EXIT_BLOCK_PTR)
{
/* Bypass trivial infinite loops. */
- if (target == target->succ->dest)
+ new_target = single_succ (target);
+ if (target == new_target)
counter = n_basic_blocks;
- new_target = target->succ->dest;
}
/* Allow to thread only over one edge at time to simplify updating
of probabilities. */
- else if (mode & CLEANUP_THREADING)
+ else if ((mode & CLEANUP_THREADING) && may_thread)
{
edge t = thread_jump (mode, e, target);
if (t)
if (t->dest == b)
break;
- if (nthreaded_edges >= n_basic_blocks)
- abort ();
+ gcc_assert (nthreaded_edges < n_basic_blocks - NUM_FIXED_BLOCKS);
threaded_edges[nthreaded_edges++] = t;
new_target = t->dest;
For fallthru forwarders, the LOOP_BEG note must appear between
the header of block and CODE_LABEL of the loop, for non forwarders
it must appear before the JUMP_INSN. */
- if (mode & CLEANUP_PRE_LOOP)
+ if ((mode & CLEANUP_PRE_LOOP) && optimize && flag_loop_optimize)
{
- rtx insn = (target->succ->flags & EDGE_FALLTHRU
- ? target->head : prev_nonnote_insn (target->end));
+ rtx insn = (EDGE_SUCC (target, 0)->flags & EDGE_FALLTHRU
+ ? BB_HEAD (target) : prev_nonnote_insn (BB_END (target)));
- if (GET_CODE (insn) != NOTE)
+ if (!NOTE_P (insn))
insn = NEXT_INSN (insn);
- for (; insn && GET_CODE (insn) != CODE_LABEL && !INSN_P (insn);
+ for (; insn && !LABEL_P (insn) && !INSN_P (insn);
insn = NEXT_INSN (insn))
- if (GET_CODE (insn) == NOTE
+ if (NOTE_P (insn)
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
break;
- if (GET_CODE (insn) == NOTE)
+ if (insn && NOTE_P (insn))
break;
/* Do not clean up branches to just past the end of a loop
at this time; it can mess up the loop optimizer's
recognition of some patterns. */
- insn = PREV_INSN (target->head);
- if (insn && GET_CODE (insn) == NOTE
+ insn = PREV_INSN (BB_HEAD (target));
+ if (insn && NOTE_P (insn)
&& NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
break;
}
if (counter >= n_basic_blocks)
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Infinite loop in BB %i.\n",
+ if (dump_file)
+ fprintf (dump_file, "Infinite loop in BB %i.\n",
target->index);
}
else if (target == first)
if (threaded && target != EXIT_BLOCK_PTR)
{
notice_new_block (redirect_edge_and_branch_force (e, target));
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Conditionals threaded.\n");
+ if (dump_file)
+ fprintf (dump_file, "Conditionals threaded.\n");
}
else if (!redirect_edge_and_branch (e, target))
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Forwarding edge %i->%i to %i failed.\n",
b->index, e->dest->index, target->index);
+ ei_next (&ei);
continue;
}
/ REG_BR_PROB_BASE);
if (!FORWARDER_BLOCK_P (b) && forwarder_block_p (b))
- BB_SET_FLAG (b, BB_FORWARDER_BLOCK);
+ b->flags |= BB_FORWARDER_BLOCK;
do
{
edge t;
- first->count -= edge_count;
- if (first->count < 0)
- first->count = 0;
- first->frequency -= edge_frequency;
- if (first->frequency < 0)
- first->frequency = 0;
- if (first->succ->succ_next)
+ if (!single_succ_p (first))
{
- edge e;
- int prob;
- if (n >= nthreaded_edges)
- abort ();
+ gcc_assert (n < nthreaded_edges);
t = threaded_edges [n++];
- if (t->src != first)
- abort ();
- if (first->frequency)
- prob = edge_frequency * REG_BR_PROB_BASE / first->frequency;
- else
- prob = 0;
- if (prob > t->probability)
- prob = t->probability;
- t->probability -= prob;
- prob = REG_BR_PROB_BASE - prob;
- if (prob <= 0)
- {
- first->succ->probability = REG_BR_PROB_BASE;
- first->succ->succ_next->probability = 0;
- }
- else
- for (e = first->succ; e; e = e->succ_next)
- e->probability = ((e->probability * REG_BR_PROB_BASE)
- / (double) prob);
+ gcc_assert (t->src == first);
+ update_bb_profile_for_threading (first, edge_frequency,
+ edge_count, t);
update_br_prob_note (first);
}
else
{
+ first->count -= edge_count;
+ if (first->count < 0)
+ first->count = 0;
+ first->frequency -= edge_frequency;
+ if (first->frequency < 0)
+ first->frequency = 0;
/* It is possible that as the result of
threading we've removed edge as it is
threaded to the fallthru edge. Avoid
if (n < nthreaded_edges
&& first == threaded_edges [n]->src)
n++;
- t = first->succ;
+ t = single_succ_edge (first);
}
t->count -= edge_count;
while (first != target);
changed = true;
+ continue;
}
+ ei_next (&ei);
}
if (threaded_edges)
return changed;
}
\f
-/* Return true if LABEL is a target of JUMP_INSN. This applies only
- to non-complex jumps. That is, direct unconditional, conditional,
- and tablejumps, but not computed jumps or returns. It also does
- not apply to the fallthru case of a conditional jump. */
-
-static bool
-label_is_jump_target_p (label, jump_insn)
- rtx label, jump_insn;
-{
- rtx tmp = JUMP_LABEL (jump_insn);
-
- if (label == tmp)
- return true;
-
- if (tmp != NULL_RTX
- && (tmp = NEXT_INSN (tmp)) != NULL_RTX
- && GET_CODE (tmp) == JUMP_INSN
- && (tmp = PATTERN (tmp),
- GET_CODE (tmp) == ADDR_VEC
- || GET_CODE (tmp) == ADDR_DIFF_VEC))
- {
- rtvec vec = XVEC (tmp, GET_CODE (tmp) == ADDR_DIFF_VEC);
- int i, veclen = GET_NUM_ELEM (vec);
-
- for (i = 0; i < veclen; ++i)
- if (XEXP (RTVEC_ELT (vec, i), 0) == label)
- return true;
- }
-
- return false;
-}
-
-/* Return true if LABEL is used for tail recursion. */
-
-static bool
-tail_recursion_label_p (label)
- rtx label;
-{
- rtx x;
-
- for (x = tail_recursion_label_list; x; x = XEXP (x, 1))
- if (label == XEXP (x, 0))
- return true;
-
- return false;
-}
/* Blocks A and B are to be merged into a single block. A has no incoming
fallthru edge, so it can be moved before B without adding or modifying
any jumps (aside from the jump from A to B). */
static void
-merge_blocks_move_predecessor_nojumps (a, b)
- basic_block a, b;
+merge_blocks_move_predecessor_nojumps (basic_block a, basic_block b)
{
rtx barrier;
+ bool only_notes;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (a) != BB_PARTITION (b))
+ return;
- barrier = next_nonnote_insn (a->end);
- if (GET_CODE (barrier) != BARRIER)
- abort ();
+ barrier = next_nonnote_insn (BB_END (a));
+ gcc_assert (BARRIER_P (barrier));
delete_insn (barrier);
/* Move block and loop notes out of the chain so that we do not
and adjust the block trees appropriately. Even better would be to have
a tighter connection between block trees and rtl so that this is not
necessary. */
- if (squeeze_notes (&a->head, &a->end))
- abort ();
+ only_notes = squeeze_notes (&BB_HEAD (a), &BB_END (a));
+ gcc_assert (!only_notes);
/* Scramble the insn chain. */
- if (a->end != PREV_INSN (b->head))
- reorder_insns_nobb (a->head, a->end, PREV_INSN (b->head));
+ if (BB_END (a) != PREV_INSN (BB_HEAD (b)))
+ reorder_insns_nobb (BB_HEAD (a), BB_END (a), PREV_INSN (BB_HEAD (b)));
a->flags |= BB_DIRTY;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Moved block %d before %d and merged.\n",
+ if (dump_file)
+ fprintf (dump_file, "Moved block %d before %d and merged.\n",
a->index, b->index);
/* Swap the records for the two blocks around. */
link_block (a, b->prev_bb);
/* Now blocks A and B are contiguous. Merge them. */
- merge_blocks_nomove (a, b);
+ merge_blocks (a, b);
}
/* Blocks A and B are to be merged into a single block. B has no outgoing
any jumps (aside from the jump from A to B). */
static void
-merge_blocks_move_successor_nojumps (a, b)
- basic_block a, b;
+merge_blocks_move_successor_nojumps (basic_block a, basic_block b)
{
rtx barrier, real_b_end;
+ rtx label, table;
+ bool only_notes;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (a) != BB_PARTITION (b))
+ return;
- real_b_end = b->end;
- barrier = NEXT_INSN (b->end);
+ real_b_end = BB_END (b);
- /* Recognize a jump table following block B. */
- if (barrier
- && GET_CODE (barrier) == CODE_LABEL
- && NEXT_INSN (barrier)
- && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN
- && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC
- || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC))
+ /* If there is a jump table following block B temporarily add the jump table
+ to block B so that it will also be moved to the correct location. */
+ if (tablejump_p (BB_END (b), &label, &table)
+ && prev_active_insn (label) == BB_END (b))
{
- /* Temporarily add the table jump insn to b, so that it will also
- be moved to the correct location. */
- b->end = NEXT_INSN (barrier);
- barrier = NEXT_INSN (b->end);
+ BB_END (b) = table;
}
/* There had better have been a barrier there. Delete it. */
- if (barrier && GET_CODE (barrier) == BARRIER)
+ barrier = NEXT_INSN (BB_END (b));
+ if (barrier && BARRIER_P (barrier))
delete_insn (barrier);
/* Move block and loop notes out of the chain so that we do not
and adjust the block trees appropriately. Even better would be to have
a tighter connection between block trees and rtl so that this is not
necessary. */
- if (squeeze_notes (&b->head, &b->end))
- abort ();
+ only_notes = squeeze_notes (&BB_HEAD (b), &BB_END (b));
+ gcc_assert (!only_notes);
+
/* Scramble the insn chain. */
- reorder_insns_nobb (b->head, b->end, a->end);
+ reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a));
/* Restore the real end of b. */
- b->end = real_b_end;
+ BB_END (b) = real_b_end;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Moved block %d after %d and merged.\n",
+ if (dump_file)
+ fprintf (dump_file, "Moved block %d after %d and merged.\n",
b->index, a->index);
/* Now blocks A and B are contiguous. Merge them. */
- merge_blocks_nomove (a, b);
+ merge_blocks (a, b);
}
/* Attempt to merge basic blocks that are potentially non-adjacent.
- Return true iff the attempt succeeded. */
-
-static bool
-merge_blocks (e, b, c, mode)
- edge e;
- basic_block b, c;
- int mode;
+ Return NULL iff the attempt failed, otherwise return basic block
+ where cleanup_cfg should continue. Because the merging commonly
+ moves basic block away or introduces another optimization
+ possibility, return basic block just before B so cleanup_cfg don't
+ need to iterate.
+
+ It may be good idea to return basic block before C in the case
+ C has been moved after B and originally appeared earlier in the
+ insn sequence, but we have no information available about the
+ relative ordering of these two. Hopefully it is not too common. */
+
+static basic_block
+merge_blocks_move (edge e, basic_block b, basic_block c, int mode)
{
- /* If C has a tail recursion label, do not merge. There is no
- edge recorded from the call_placeholder back to this label, as
- that would make optimize_sibling_and_tail_recursive_calls more
- complex for no gain. */
- if ((mode & CLEANUP_PRE_SIBCALL)
- && GET_CODE (c->head) == CODE_LABEL
- && tail_recursion_label_p (c->head))
- return false;
+ basic_block next;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (b) != BB_PARTITION (c))
+ return NULL;
+
+
/* If B has a fallthru edge to C, no need to move anything. */
if (e->flags & EDGE_FALLTHRU)
{
int b_index = b->index, c_index = c->index;
- merge_blocks_nomove (b, c);
+ merge_blocks (b, c);
update_forwarder_flag (b);
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Merged %d and %d without moving.\n",
+ if (dump_file)
+ fprintf (dump_file, "Merged %d and %d without moving.\n",
b_index, c_index);
- return true;
+ return b->prev_bb == ENTRY_BLOCK_PTR ? b : b->prev_bb;
}
/* Otherwise we will need to move code around. Do that only if expensive
edge tmp_edge, b_fallthru_edge;
bool c_has_outgoing_fallthru;
bool b_has_incoming_fallthru;
+ edge_iterator ei;
/* Avoid overactive code motion, as the forwarder blocks should be
eliminated by edge redirection instead. One exception might have
been if B is a forwarder block and C has no fallthru edge, but
that should be cleaned up by bb-reorder instead. */
if (FORWARDER_BLOCK_P (b) || FORWARDER_BLOCK_P (c))
- return false;
+ return NULL;
/* We must make sure to not munge nesting of lexical blocks,
and loop notes. This is done by squeezing out all the notes
and leaving them there to lie. Not ideal, but functional. */
- for (tmp_edge = c->succ; tmp_edge; tmp_edge = tmp_edge->succ_next)
+ FOR_EACH_EDGE (tmp_edge, ei, c->succs)
if (tmp_edge->flags & EDGE_FALLTHRU)
break;
c_has_outgoing_fallthru = (tmp_edge != NULL);
- for (tmp_edge = b->pred; tmp_edge; tmp_edge = tmp_edge->pred_next)
+ FOR_EACH_EDGE (tmp_edge, ei, b->preds)
if (tmp_edge->flags & EDGE_FALLTHRU)
break;
b_has_incoming_fallthru = (tmp_edge != NULL);
b_fallthru_edge = tmp_edge;
+ next = b->prev_bb;
+ if (next == c)
+ next = next->prev_bb;
/* Otherwise, we're going to try to move C after B. If C does
not have an outgoing fallthru, then it can be moved
if (! c_has_outgoing_fallthru)
{
merge_blocks_move_successor_nojumps (b, c);
- return true;
+ return next == ENTRY_BLOCK_PTR ? next->next_bb : next;
}
/* If B does not have an incoming fallthru, then it can be moved
basic_block bb;
if (b_fallthru_edge->src == ENTRY_BLOCK_PTR)
- return false;
+ return NULL;
bb = force_nonfallthru (b_fallthru_edge);
if (bb)
notice_new_block (bb);
}
merge_blocks_move_predecessor_nojumps (b, c);
- return true;
+ return next == ENTRY_BLOCK_PTR ? next->next_bb : next;
}
- return false;
+ return NULL;
}
\f
+/* Removes the memory attributes of MEM expression
+ if they are not equal. */
+
+void
+merge_memattrs (rtx x, rtx y)
+{
+ int i;
+ int j;
+ enum rtx_code code;
+ const char *fmt;
+
+ if (x == y)
+ return;
+ if (x == 0 || y == 0)
+ return;
+
+ code = GET_CODE (x);
+
+ if (code != GET_CODE (y))
+ return;
+
+ if (GET_MODE (x) != GET_MODE (y))
+ return;
+
+ if (code == MEM && MEM_ATTRS (x) != MEM_ATTRS (y))
+ {
+ if (! MEM_ATTRS (x))
+ MEM_ATTRS (y) = 0;
+ else if (! MEM_ATTRS (y))
+ MEM_ATTRS (x) = 0;
+ else
+ {
+ rtx mem_size;
+
+ if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y))
+ {
+ set_mem_alias_set (x, 0);
+ set_mem_alias_set (y, 0);
+ }
+
+ if (! mem_expr_equal_p (MEM_EXPR (x), MEM_EXPR (y)))
+ {
+ set_mem_expr (x, 0);
+ set_mem_expr (y, 0);
+ set_mem_offset (x, 0);
+ set_mem_offset (y, 0);
+ }
+ else if (MEM_OFFSET (x) != MEM_OFFSET (y))
+ {
+ set_mem_offset (x, 0);
+ set_mem_offset (y, 0);
+ }
+
+ if (!MEM_SIZE (x))
+ mem_size = NULL_RTX;
+ else if (!MEM_SIZE (y))
+ mem_size = NULL_RTX;
+ else
+ mem_size = GEN_INT (MAX (INTVAL (MEM_SIZE (x)),
+ INTVAL (MEM_SIZE (y))));
+ set_mem_size (x, mem_size);
+ set_mem_size (y, mem_size);
+
+ set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y)));
+ set_mem_align (y, MEM_ALIGN (x));
+ }
+ }
+
+ fmt = GET_RTX_FORMAT (code);
+ for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
+ {
+ switch (fmt[i])
+ {
+ case 'E':
+ /* Two vectors must have the same length. */
+ if (XVECLEN (x, i) != XVECLEN (y, i))
+ return;
+
+ for (j = 0; j < XVECLEN (x, i); j++)
+ merge_memattrs (XVECEXP (x, i, j), XVECEXP (y, i, j));
+
+ break;
+
+ case 'e':
+ merge_memattrs (XEXP (x, i), XEXP (y, i));
+ }
+ }
+ return;
+}
+
+
/* Return true if I1 and I2 are equivalent and thus can be crossjumped. */
static bool
-insns_match_p (mode, i1, i2)
- int mode ATTRIBUTE_UNUSED;
- rtx i1, i2;
+old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2)
{
rtx p1, p2;
??? We take the simple route for now and assume that if they're
equal, they were constructed identically. */
- if (GET_CODE (i1) == CALL_INSN
+ if (CALL_P (i1)
&& (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1),
CALL_INSN_FUNCTION_USAGE (i2))
|| SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)))
#endif
if (reload_completed
- ? ! rtx_renumbered_equal_p (p1, p2) : ! rtx_equal_p (p1, p2))
+ ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2))
+ return true;
+
+ /* Do not do EQUIV substitution after reload. First, we're undoing the
+ work of reload_cse. Second, we may be undoing the work of the post-
+ reload splitting pass. */
+ /* ??? Possibly add a new phase switch variable that can be used by
+ targets to disallow the troublesome insns after splitting. */
+ if (!reload_completed)
{
/* The following code helps take care of G++ cleanups. */
rtx equiv1 = find_reg_equal_equiv_note (i1);
return true;
}
}
-
- return false;
}
- return true;
+ return false;
}
\f
/* Look through the insns at the end of BB1 and BB2 and find the longest
store the head of the blocks in *F1 and *F2. */
static int
-flow_find_cross_jump (mode, bb1, bb2, f1, f2)
- int mode ATTRIBUTE_UNUSED;
- basic_block bb1, bb2;
- rtx *f1, *f2;
+flow_find_cross_jump (int mode ATTRIBUTE_UNUSED, basic_block bb1,
+ basic_block bb2, rtx *f1, rtx *f2)
{
rtx i1, i2, last1, last2, afterlast1, afterlast2;
int ninsns = 0;
/* Skip simple jumps at the end of the blocks. Complex jumps still
need to be compared for equivalence, which we'll do below. */
- i1 = bb1->end;
+ i1 = BB_END (bb1);
last1 = afterlast1 = last2 = afterlast2 = NULL_RTX;
if (onlyjump_p (i1)
|| (returnjump_p (i1) && !side_effects_p (PATTERN (i1))))
i1 = PREV_INSN (i1);
}
- i2 = bb2->end;
+ i2 = BB_END (bb2);
if (onlyjump_p (i2)
|| (returnjump_p (i2) && !side_effects_p (PATTERN (i2))))
{
while (true)
{
/* Ignore notes. */
- while (!active_insn_p (i1) && i1 != bb1->head)
+ while (!INSN_P (i1) && i1 != BB_HEAD (bb1))
i1 = PREV_INSN (i1);
- while (!active_insn_p (i2) && i2 != bb2->head)
+ while (!INSN_P (i2) && i2 != BB_HEAD (bb2))
i2 = PREV_INSN (i2);
- if (i1 == bb1->head || i2 == bb2->head)
+ if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2))
break;
- if (!insns_match_p (mode, i1, i2))
+ if (!old_insns_match_p (mode, i1, i2))
break;
- /* Don't begin a cross-jump with a USE or CLOBBER insn. */
- if (active_insn_p (i1))
+ merge_memattrs (i1, i2);
+
+ /* Don't begin a cross-jump with a NOTE insn. */
+ if (INSN_P (i1))
{
/* If the merged insns have different REG_EQUAL notes, then
remove them. */
Two, it keeps line number notes as matched as may be. */
if (ninsns)
{
- while (last1 != bb1->head && !active_insn_p (PREV_INSN (last1)))
+ while (last1 != BB_HEAD (bb1) && !INSN_P (PREV_INSN (last1)))
last1 = PREV_INSN (last1);
- if (last1 != bb1->head && GET_CODE (PREV_INSN (last1)) == CODE_LABEL)
+ if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1)))
last1 = PREV_INSN (last1);
- while (last2 != bb2->head && !active_insn_p (PREV_INSN (last2)))
+ while (last2 != BB_HEAD (bb2) && !INSN_P (PREV_INSN (last2)))
last2 = PREV_INSN (last2);
- if (last2 != bb2->head && GET_CODE (PREV_INSN (last2)) == CODE_LABEL)
+ if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2)))
last2 = PREV_INSN (last2);
*f1 = last1;
return ninsns;
}
+/* Return true iff the condbranches at the end of BB1 and BB2 match. */
+bool
+condjump_equiv_p (struct equiv_info *info, bool call_init)
+{
+ basic_block bb1 = info->x_block;
+ basic_block bb2 = info->y_block;
+ edge b1 = BRANCH_EDGE (bb1);
+ edge b2 = BRANCH_EDGE (bb2);
+ edge f1 = FALLTHRU_EDGE (bb1);
+ edge f2 = FALLTHRU_EDGE (bb2);
+ bool reverse, match;
+ rtx set1, set2, cond1, cond2;
+ rtx src1, src2;
+ enum rtx_code code1, code2;
+
+ /* Get around possible forwarders on fallthru edges. Other cases
+ should be optimized out already. */
+ if (FORWARDER_BLOCK_P (f1->dest))
+ f1 = single_succ_edge (f1->dest);
+
+ if (FORWARDER_BLOCK_P (f2->dest))
+ f2 = single_succ_edge (f2->dest);
+
+ /* To simplify use of this function, return false if there are
+ unneeded forwarder blocks. These will get eliminated later
+ during cleanup_cfg. */
+ if (FORWARDER_BLOCK_P (f1->dest)
+ || FORWARDER_BLOCK_P (f2->dest)
+ || FORWARDER_BLOCK_P (b1->dest)
+ || FORWARDER_BLOCK_P (b2->dest))
+ return false;
+
+ if (f1->dest == f2->dest && b1->dest == b2->dest)
+ reverse = false;
+ else if (f1->dest == b2->dest && b1->dest == f2->dest)
+ reverse = true;
+ else
+ return false;
+
+ set1 = pc_set (BB_END (bb1));
+ set2 = pc_set (BB_END (bb2));
+ if ((XEXP (SET_SRC (set1), 1) == pc_rtx)
+ != (XEXP (SET_SRC (set2), 1) == pc_rtx))
+ reverse = !reverse;
+
+ src1 = SET_SRC (set1);
+ src2 = SET_SRC (set2);
+ cond1 = XEXP (src1, 0);
+ cond2 = XEXP (src2, 0);
+ code1 = GET_CODE (cond1);
+ if (reverse)
+ code2 = reversed_comparison_code (cond2, BB_END (bb2));
+ else
+ code2 = GET_CODE (cond2);
+
+ if (code2 == UNKNOWN)
+ return false;
+
+ if (call_init && !struct_equiv_init (STRUCT_EQUIV_START | info->mode, info))
+ gcc_unreachable ();
+ /* Make the sources of the pc sets unreadable so that when we call
+ insns_match_p it won't process them.
+ The death_notes_match_p from insns_match_p won't see the local registers
+ used for the pc set, but that could only cause missed optimizations when
+ there are actually condjumps that use stack registers. */
+ SET_SRC (set1) = pc_rtx;
+ SET_SRC (set2) = pc_rtx;
+ /* Verify codes and operands match. */
+ if (code1 == code2)
+ {
+ match = (insns_match_p (BB_END (bb1), BB_END (bb2), info)
+ && rtx_equiv_p (&XEXP (cond1, 0), XEXP (cond2, 0), 1, info)
+ && rtx_equiv_p (&XEXP (cond1, 1), XEXP (cond2, 1), 1, info));
+
+ }
+ else if (code1 == swap_condition (code2))
+ {
+ match = (insns_match_p (BB_END (bb1), BB_END (bb2), info)
+ && rtx_equiv_p (&XEXP (cond1, 1), XEXP (cond2, 0), 1, info)
+ && rtx_equiv_p (&XEXP (cond1, 0), XEXP (cond2, 1), 1, info));
+
+ }
+ else
+ match = false;
+ SET_SRC (set1) = src1;
+ SET_SRC (set2) = src2;
+ match &= verify_changes (0);
+
+ /* If we return true, we will join the blocks. Which means that
+ we will only have one branch prediction bit to work with. Thus
+ we require the existing branches to have probabilities that are
+ roughly similar. */
+ if (match
+ && !optimize_size
+ && maybe_hot_bb_p (bb1)
+ && maybe_hot_bb_p (bb2))
+ {
+ int prob2;
+
+ if (b1->dest == b2->dest)
+ prob2 = b2->probability;
+ else
+ /* Do not use f2 probability as f2 may be forwarded. */
+ prob2 = REG_BR_PROB_BASE - b2->probability;
+
+ /* Fail if the difference in probabilities is greater than 50%.
+ This rules out two well-predicted branches with opposite
+ outcomes. */
+ if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2)
+ {
+ if (dump_file)
+ fprintf (dump_file,
+ "Outcomes of branch in bb %i and %i differ too much (%i %i)\n",
+ bb1->index, bb2->index, b1->probability, prob2);
+
+ match = false;
+ }
+ }
+
+ if (dump_file && match)
+ fprintf (dump_file, "Conditionals in bb %i and %i match.\n",
+ bb1->index, bb2->index);
+
+ if (!match)
+ cancel_changes (0);
+ return match;
+}
+
/* Return true iff outgoing edges of BB1 and BB2 match, together with
the branch instruction. This means that if we commonize the control
flow before end of the basic block, the semantic remains unchanged.
We may assume that there exists one edge with a common destination. */
static bool
-outgoing_edges_match (mode, bb1, bb2)
- int mode;
- basic_block bb1;
- basic_block bb2;
+outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
{
int nehedges1 = 0, nehedges2 = 0;
edge fallthru1 = 0, fallthru2 = 0;
edge e1, e2;
+ edge_iterator ei;
/* If BB1 has only one successor, we may be looking at either an
unconditional jump, or a fake edge to exit. */
- if (bb1->succ && !bb1->succ->succ_next
- && (bb1->succ->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0
- && (GET_CODE (bb1->end) != JUMP_INSN || simplejump_p (bb1->end)))
- return (bb2->succ && !bb2->succ->succ_next
- && (bb2->succ->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0
- && (GET_CODE (bb2->end) != JUMP_INSN || simplejump_p (bb2->end)));
+ if (single_succ_p (bb1)
+ && (single_succ_edge (bb1)->flags & (EDGE_COMPLEX | EDGE_FAKE)) == 0
+ && (!JUMP_P (BB_END (bb1)) || simplejump_p (BB_END (bb1))))
+ return (single_succ_p (bb2)
+ && (single_succ_edge (bb2)->flags
+ & (EDGE_COMPLEX | EDGE_FAKE)) == 0
+ && (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2))));
/* Match conditional jumps - this may get tricky when fallthru and branch
edges are crossed. */
- if (bb1->succ
- && bb1->succ->succ_next
- && !bb1->succ->succ_next->succ_next
- && any_condjump_p (bb1->end)
- && onlyjump_p (bb1->end))
+ if (EDGE_COUNT (bb1->succs) == 2
+ && any_condjump_p (BB_END (bb1))
+ && onlyjump_p (BB_END (bb1)))
{
edge b1, f1, b2, f2;
bool reverse, match;
rtx set1, set2, cond1, cond2;
enum rtx_code code1, code2;
- if (!bb2->succ
- || !bb2->succ->succ_next
- || bb2->succ->succ_next->succ_next
- || !any_condjump_p (bb2->end)
- || !onlyjump_p (bb2->end))
+ if (EDGE_COUNT (bb2->succs) != 2
+ || !any_condjump_p (BB_END (bb2))
+ || !onlyjump_p (BB_END (bb2)))
return false;
b1 = BRANCH_EDGE (bb1);
/* Get around possible forwarders on fallthru edges. Other cases
should be optimized out already. */
if (FORWARDER_BLOCK_P (f1->dest))
- f1 = f1->dest->succ;
+ f1 = single_succ_edge (f1->dest);
if (FORWARDER_BLOCK_P (f2->dest))
- f2 = f2->dest->succ;
+ f2 = single_succ_edge (f2->dest);
/* To simplify use of this function, return false if there are
unneeded forwarder blocks. These will get eliminated later
else
return false;
- set1 = pc_set (bb1->end);
- set2 = pc_set (bb2->end);
+ set1 = pc_set (BB_END (bb1));
+ set2 = pc_set (BB_END (bb2));
if ((XEXP (SET_SRC (set1), 1) == pc_rtx)
!= (XEXP (SET_SRC (set2), 1) == pc_rtx))
reverse = !reverse;
cond2 = XEXP (SET_SRC (set2), 0);
code1 = GET_CODE (cond1);
if (reverse)
- code2 = reversed_comparison_code (cond2, bb2->end);
+ code2 = reversed_comparison_code (cond2, BB_END (bb2));
else
code2 = GET_CODE (cond2);
outcomes. */
if (abs (b1->probability - prob2) > REG_BR_PROB_BASE / 2)
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
- "Outcomes of branch in bb %i and %i differs to much (%i %i)\n",
+ if (dump_file)
+ fprintf (dump_file,
+ "Outcomes of branch in bb %i and %i differ too much (%i %i)\n",
bb1->index, bb2->index, b1->probability, prob2);
return false;
}
}
- if (rtl_dump_file && match)
- fprintf (rtl_dump_file, "Conditionals in bb %i and %i match.\n",
+ if (dump_file && match)
+ fprintf (dump_file, "Conditionals in bb %i and %i match.\n",
bb1->index, bb2->index);
return match;
/* Generic case - we are seeing a computed jump, table jump or trapping
instruction. */
+ /* Check whether there are tablejumps in the end of BB1 and BB2.
+ Return true if they are identical. */
+ {
+ rtx label1, label2;
+ rtx table1, table2;
+
+ if (tablejump_p (BB_END (bb1), &label1, &table1)
+ && tablejump_p (BB_END (bb2), &label2, &table2)
+ && GET_CODE (PATTERN (table1)) == GET_CODE (PATTERN (table2)))
+ {
+ /* The labels should never be the same rtx. If they really are same
+ the jump tables are same too. So disable crossjumping of blocks BB1
+ and BB2 because when deleting the common insns in the end of BB1
+ by delete_basic_block () the jump table would be deleted too. */
+ /* If LABEL2 is referenced in BB1->END do not do anything
+ because we would loose information when replacing
+ LABEL1 by LABEL2 and then LABEL2 by LABEL1 in BB1->END. */
+ if (label1 != label2 && !rtx_referenced_p (label2, BB_END (bb1)))
+ {
+ /* Set IDENTICAL to true when the tables are identical. */
+ bool identical = false;
+ rtx p1, p2;
+
+ p1 = PATTERN (table1);
+ p2 = PATTERN (table2);
+ if (GET_CODE (p1) == ADDR_VEC && rtx_equal_p (p1, p2))
+ {
+ identical = true;
+ }
+ else if (GET_CODE (p1) == ADDR_DIFF_VEC
+ && (XVECLEN (p1, 1) == XVECLEN (p2, 1))
+ && rtx_equal_p (XEXP (p1, 2), XEXP (p2, 2))
+ && rtx_equal_p (XEXP (p1, 3), XEXP (p2, 3)))
+ {
+ int i;
+
+ identical = true;
+ for (i = XVECLEN (p1, 1) - 1; i >= 0 && identical; i--)
+ if (!rtx_equal_p (XVECEXP (p1, 1, i), XVECEXP (p2, 1, i)))
+ identical = false;
+ }
+
+ if (identical)
+ {
+ replace_label_data rr;
+ bool match;
+
+ /* Temporarily replace references to LABEL1 with LABEL2
+ in BB1->END so that we could compare the instructions. */
+ rr.r1 = label1;
+ rr.r2 = label2;
+ rr.update_label_nuses = false;
+ for_each_rtx (&BB_END (bb1), replace_label, &rr);
+
+ match = old_insns_match_p (mode, BB_END (bb1), BB_END (bb2));
+ if (dump_file && match)
+ fprintf (dump_file,
+ "Tablejumps in bb %i and %i match.\n",
+ bb1->index, bb2->index);
+
+ /* Set the original label in BB1->END because when deleting
+ a block whose end is a tablejump, the tablejump referenced
+ from the instruction is deleted too. */
+ rr.r1 = label2;
+ rr.r2 = label1;
+ for_each_rtx (&BB_END (bb1), replace_label, &rr);
+
+ return match;
+ }
+ }
+ return false;
+ }
+ }
+
/* First ensure that the instructions match. There may be many outgoing
- edges so this test is generally cheaper.
- ??? Currently the tablejumps will never match, as they do have
- different tables. */
- if (!insns_match_p (mode, bb1->end, bb2->end))
+ edges so this test is generally cheaper. */
+ if (!old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)))
return false;
/* Search the outgoing edges, ensure that the counts do match, find possible
fallthru and exception handling edges since these needs more
validation. */
- for (e1 = bb1->succ, e2 = bb2->succ; e1 && e2;
- e1 = e1->succ_next, e2 = e2->succ_next)
+ if (EDGE_COUNT (bb1->succs) != EDGE_COUNT (bb2->succs))
+ return false;
+
+ FOR_EACH_EDGE (e1, ei, bb1->succs)
{
+ e2 = EDGE_SUCC (bb2, ei.index);
+
if (e1->flags & EDGE_EH)
nehedges1++;
}
/* If number of edges of various types does not match, fail. */
- if (e1 || e2
- || nehedges1 != nehedges2
+ if (nehedges1 != nehedges2
|| (fallthru1 != 0) != (fallthru2 != 0))
return false;
if (fallthru1)
{
basic_block d1 = (forwarder_block_p (fallthru1->dest)
- ? fallthru1->dest->succ->dest: fallthru1->dest);
+ ? single_succ (fallthru1->dest): fallthru1->dest);
basic_block d2 = (forwarder_block_p (fallthru2->dest)
- ? fallthru2->dest->succ->dest: fallthru2->dest);
+ ? single_succ (fallthru2->dest): fallthru2->dest);
if (d1 != d2)
return false;
}
- /* In case we do have EH edges, ensure we are in the same region. */
- if (nehedges1)
- {
- rtx n1 = find_reg_note (bb1->end, REG_EH_REGION, 0);
- rtx n2 = find_reg_note (bb2->end, REG_EH_REGION, 0);
+ /* Ensure the same EH region. */
+ {
+ rtx n1 = find_reg_note (BB_END (bb1), REG_EH_REGION, 0);
+ rtx n2 = find_reg_note (BB_END (bb2), REG_EH_REGION, 0);
- if (XEXP (n1, 0) != XEXP (n2, 0))
- return false;
- }
+ if (!n1 && n2)
+ return false;
- /* We don't need to match the rest of edges as above checks should be enought
+ if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0)))
+ return false;
+ }
+
+ /* We don't need to match the rest of edges as above checks should be enough
to ensure that they are equivalent. */
return true;
}
(maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC. */
static bool
-try_crossjump_to_edge (mode, e1, e2)
- int mode;
- edge e1, e2;
+try_crossjump_to_edge (int mode, edge e1, edge e2)
{
int nmatch;
basic_block src1 = e1->src, src2 = e2->src;
basic_block redirect_to, redirect_from, to_remove;
rtx newpos1, newpos2;
edge s;
+ edge_iterator ei;
+
+ newpos1 = newpos2 = NULL_RTX;
+
+ /* If we have partitioned hot/cold basic blocks, it is a bad idea
+ to try this optimization.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (flag_reorder_blocks_and_partition && no_new_pseudos)
+ return false;
/* Search backward through forwarder blocks. We don't need to worry
about multiple entry or chained forwarders, as they will be optimized
away. We do this to look past the unconditional jump following a
conditional jump that is required due to the current CFG shape. */
- if (src1->pred
- && !src1->pred->pred_next
+ if (single_pred_p (src1)
&& FORWARDER_BLOCK_P (src1))
- e1 = src1->pred, src1 = e1->src;
+ e1 = single_pred_edge (src1), src1 = e1->src;
- if (src2->pred
- && !src2->pred->pred_next
+ if (single_pred_p (src2)
&& FORWARDER_BLOCK_P (src2))
- e2 = src2->pred, src2 = e2->src;
+ e2 = single_pred_edge (src2), src2 = e2->src;
/* Nothing to do if we reach ENTRY, or a common source block. */
if (src1 == ENTRY_BLOCK_PTR || src2 == ENTRY_BLOCK_PTR)
/* Seeing more than 1 forwarder blocks would confuse us later... */
if (FORWARDER_BLOCK_P (e1->dest)
- && FORWARDER_BLOCK_P (e1->dest->succ->dest))
+ && FORWARDER_BLOCK_P (single_succ (e1->dest)))
return false;
if (FORWARDER_BLOCK_P (e2->dest)
- && FORWARDER_BLOCK_P (e2->dest->succ->dest))
+ && FORWARDER_BLOCK_P (single_succ (e2->dest)))
return false;
/* Likewise with dead code (possibly newly created by the other optimizations
of cfg_cleanup). */
- if (!src1->pred || !src2->pred)
+ if (EDGE_COUNT (src1->preds) == 0 || EDGE_COUNT (src2->preds) == 0)
return false;
/* Look for the common insn sequence, part the first ... */
/* ... and part the second. */
nmatch = flow_find_cross_jump (mode, src1, src2, &newpos1, &newpos2);
- if (!nmatch)
+
+ /* Don't proceed with the crossjump unless we found a sufficient number
+ of matching instructions or the 'from' block was totally matched
+ (such that its predecessors will hopefully be redirected and the
+ block removed). */
+ if ((nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
+ && (newpos1 != BB_HEAD (src1)))
return false;
- /* Avoid splitting if possible. */
- if (newpos2 == src2->head)
+ /* Here we know that the insns in the end of SRC1 which are common with SRC2
+ will be deleted.
+ If we have tablejumps in the end of SRC1 and SRC2
+ they have been already compared for equivalence in outgoing_edges_match ()
+ so replace the references to TABLE1 by references to TABLE2. */
+ {
+ rtx label1, label2;
+ rtx table1, table2;
+
+ if (tablejump_p (BB_END (src1), &label1, &table1)
+ && tablejump_p (BB_END (src2), &label2, &table2)
+ && label1 != label2)
+ {
+ replace_label_data rr;
+ rtx insn;
+
+ /* Replace references to LABEL1 with LABEL2. */
+ rr.r1 = label1;
+ rr.r2 = label2;
+ rr.update_label_nuses = true;
+ for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
+ {
+ /* Do not replace the label in SRC1->END because when deleting
+ a block whose end is a tablejump, the tablejump referenced
+ from the instruction is deleted too. */
+ if (insn != BB_END (src1))
+ for_each_rtx (&insn, replace_label, &rr);
+ }
+ }
+ }
+
+ /* Avoid splitting if possible. We must always split when SRC2 has
+ EH predecessor edges, or we may end up with basic blocks with both
+ normal and EH predecessor edges. */
+ if (newpos2 == BB_HEAD (src2)
+ && !(EDGE_PRED (src2, 0)->flags & EDGE_EH))
redirect_to = src2;
else
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Splitting bb %i before %i insns\n",
+ if (newpos2 == BB_HEAD (src2))
+ {
+ /* Skip possible basic block header. */
+ if (LABEL_P (newpos2))
+ newpos2 = NEXT_INSN (newpos2);
+ if (NOTE_P (newpos2))
+ newpos2 = NEXT_INSN (newpos2);
+ }
+
+ if (dump_file)
+ fprintf (dump_file, "Splitting bb %i before %i insns\n",
src2->index, nmatch);
redirect_to = split_block (src2, PREV_INSN (newpos2))->dest;
}
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Cross jumping from bb %i to bb %i; %i common insns\n",
src1->index, src2->index, nmatch);
redirect_to->flags |= BB_DIRTY;
/* Recompute the frequencies and counts of outgoing edges. */
- for (s = redirect_to->succ; s; s = s->succ_next)
+ FOR_EACH_EDGE (s, ei, redirect_to->succs)
{
edge s2;
+ edge_iterator ei;
basic_block d = s->dest;
if (FORWARDER_BLOCK_P (d))
- d = d->succ->dest;
+ d = single_succ (d);
- for (s2 = src1->succ; ; s2 = s2->succ_next)
+ FOR_EACH_EDGE (s2, ei, src1->succs)
{
basic_block d2 = s2->dest;
if (FORWARDER_BLOCK_P (d2))
- d2 = d2->succ->dest;
+ d2 = single_succ (d2);
if (d == d2)
break;
}
into infinite loop. */
if (FORWARDER_BLOCK_P (s->dest))
{
- s->dest->succ->count += s2->count;
+ single_succ_edge (s->dest)->count += s2->count;
s->dest->count += s2->count;
s->dest->frequency += EDGE_FREQUENCY (s);
}
if (FORWARDER_BLOCK_P (s2->dest))
{
- s2->dest->succ->count -= s2->count;
- if (s2->dest->succ->count < 0)
- s2->dest->succ->count = 0;
+ single_succ_edge (s2->dest)->count -= s2->count;
+ if (single_succ_edge (s2->dest)->count < 0)
+ single_succ_edge (s2->dest)->count = 0;
s2->dest->count -= s2->count;
s2->dest->frequency -= EDGE_FREQUENCY (s);
if (s2->dest->frequency < 0)
/* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */
/* Skip possible basic block header. */
- if (GET_CODE (newpos1) == CODE_LABEL)
+ if (LABEL_P (newpos1))
newpos1 = NEXT_INSN (newpos1);
- if (GET_CODE (newpos1) == NOTE)
+ if (NOTE_P (newpos1))
newpos1 = NEXT_INSN (newpos1);
redirect_from = split_block (src1, PREV_INSN (newpos1))->src;
- to_remove = redirect_from->succ->dest;
+ to_remove = single_succ (redirect_from);
- redirect_edge_and_branch_force (redirect_from->succ, redirect_to);
- flow_delete_block (to_remove);
+ redirect_edge_and_branch_force (single_succ_edge (redirect_from), redirect_to);
+ delete_basic_block (to_remove);
update_forwarder_flag (redirect_from);
+ if (redirect_to != src2)
+ update_forwarder_flag (src2);
return true;
}
any changes made. */
static bool
-try_crossjump_bb (mode, bb)
- int mode;
- basic_block bb;
+try_crossjump_bb (int mode, basic_block bb)
{
- edge e, e2, nexte2, nexte, fallthru;
+ edge e, e2, fallthru;
bool changed;
- int n = 0, max;
+ unsigned max, ix, ix2;
+ basic_block ev, ev2;
+ edge_iterator ei;
/* Nothing to do if there is not at least two incoming edges. */
- if (!bb->pred || !bb->pred->pred_next)
+ if (EDGE_COUNT (bb->preds) < 2)
+ return false;
+
+ /* Don't crossjump if this block ends in a computed jump,
+ unless we are optimizing for size. */
+ if (!optimize_size
+ && bb != EXIT_BLOCK_PTR
+ && computed_jump_p (BB_END (bb)))
+ return false;
+
+ /* If we are partitioning hot/cold basic blocks, we don't want to
+ mess up unconditional or indirect jumps that cross between hot
+ and cold sections.
+
+ Basic block partitioning may result in some jumps that appear to
+ be optimizable (or blocks that appear to be mergeable), but which really
+ must be left untouched (they are required to make it safely across
+ partition boundaries). See the comments at the top of
+ bb-reorder.c:partition_hot_cold_basic_blocks for complete details. */
+
+ if (BB_PARTITION (EDGE_PRED (bb, 0)->src) !=
+ BB_PARTITION (EDGE_PRED (bb, 1)->src)
+ || (EDGE_PRED (bb, 0)->flags & EDGE_CROSSING))
return false;
/* It is always cheapest to redirect a block that ends in a branch to
program. We'll try that combination first. */
fallthru = NULL;
max = PARAM_VALUE (PARAM_MAX_CROSSJUMP_EDGES);
- for (e = bb->pred; e ; e = e->pred_next, n++)
+
+ if (EDGE_COUNT (bb->preds) > max)
+ return false;
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
{
if (e->flags & EDGE_FALLTHRU)
- fallthru = e;
- if (n > max)
- return false;
+ fallthru = e;
}
changed = false;
- for (e = bb->pred; e; e = nexte)
+ for (ix = 0, ev = bb; ix < EDGE_COUNT (ev->preds); )
{
- nexte = e->pred_next;
+ e = EDGE_PRED (ev, ix);
+ ix++;
/* As noted above, first try with the fallthru predecessor. */
if (fallthru)
If there is a match, we'll do it the other way around. */
if (e == fallthru)
continue;
+ /* If nothing changed since the last attempt, there is nothing
+ we can do. */
+ if (!first_pass
+ && (!(e->src->flags & BB_DIRTY)
+ && !(fallthru->src->flags & BB_DIRTY)))
+ continue;
if (try_crossjump_to_edge (mode, e, fallthru))
{
changed = true;
- nexte = bb->pred;
+ ix = 0;
+ ev = bb;
continue;
}
}
can eliminate redundant checks of crossjump(A,B) by arbitrarily
choosing to do the check from the block for which the edge
in question is the first successor of A. */
- if (e->src->succ != e)
+ if (EDGE_SUCC (e->src, 0) != e)
continue;
- for (e2 = bb->pred; e2; e2 = nexte2)
+ for (ix2 = 0, ev2 = bb; ix2 < EDGE_COUNT (ev2->preds); )
{
- nexte2 = e2->pred_next;
+ e2 = EDGE_PRED (ev2, ix2);
+ ix2++;
if (e2 == e)
continue;
if (e->src->index > e2->src->index)
continue;
+ /* If nothing changed since the last attempt, there is nothing
+ we can do. */
+ if (!first_pass
+ && (!(e->src->flags & BB_DIRTY)
+ && !(e2->src->flags & BB_DIRTY)))
+ continue;
+
if (try_crossjump_to_edge (mode, e, e2))
{
changed = true;
- nexte = bb->pred;
+ ev2 = bb;
+ ix = 0;
break;
}
}
instructions etc. Return nonzero if changes were made. */
static bool
-try_optimize_cfg (mode)
- int mode;
+try_optimize_cfg (int mode)
{
bool changed_overall = false;
bool changed;
int iterations = 0;
- basic_block bb, b;
+ basic_block bb, b, next;
if (mode & CLEANUP_CROSSJUMP)
add_noreturn_fake_exit_edges ();
+ if (mode & (CLEANUP_UPDATE_LIFE | CLEANUP_CROSSJUMP | CLEANUP_THREADING))
+ clear_bb_flags ();
+
FOR_EACH_BB (bb)
update_forwarder_flag (bb);
- if (mode & CLEANUP_UPDATE_LIFE)
- clear_bb_flags ();
-
- if (! (* targetm.cannot_modify_jumps_p) ())
+ if (! targetm.cannot_modify_jumps_p ())
{
+ first_pass = true;
/* Attempt to merge blocks as made possible by edge removal. If
a block has only one successor, and the successor has only
one predecessor, they may be combined. */
changed = false;
iterations++;
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"\n\ntry_optimize_cfg iteration %i\n\n",
iterations);
bool changed_here = false;
/* Delete trivially dead basic blocks. */
- while (b->pred == NULL)
+ while (EDGE_COUNT (b->preds) == 0)
{
c = b->prev_bb;
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Deleting block %i.\n",
+ if (dump_file)
+ fprintf (dump_file, "Deleting block %i.\n",
b->index);
- flow_delete_block (b);
- changed = true;
+ delete_basic_block (b);
+ if (!(mode & CLEANUP_CFGLAYOUT))
+ changed = true;
b = c;
}
- /* Remove code labels no longer used. Don't do this
- before CALL_PLACEHOLDER is removed, as some branches
- may be hidden within. */
- if (b->pred->pred_next == NULL
- && (b->pred->flags & EDGE_FALLTHRU)
- && !(b->pred->flags & EDGE_COMPLEX)
- && GET_CODE (b->head) == CODE_LABEL
- && (!(mode & CLEANUP_PRE_SIBCALL)
- || !tail_recursion_label_p (b->head))
+ /* Remove code labels no longer used. */
+ if (single_pred_p (b)
+ && (single_pred_edge (b)->flags & EDGE_FALLTHRU)
+ && !(single_pred_edge (b)->flags & EDGE_COMPLEX)
+ && LABEL_P (BB_HEAD (b))
/* If the previous block ends with a branch to this
block, we can't delete the label. Normally this
is a condjump that is yet to be simplified, but
if CASE_DROPS_THRU, this can be a tablejump with
some element going to the same place as the
default (fallthru). */
- && (b->pred->src == ENTRY_BLOCK_PTR
- || GET_CODE (b->pred->src->end) != JUMP_INSN
- || ! label_is_jump_target_p (b->head,
- b->pred->src->end)))
+ && (single_pred (b) == ENTRY_BLOCK_PTR
+ || !JUMP_P (BB_END (single_pred (b)))
+ || ! label_is_jump_target_p (BB_HEAD (b),
+ BB_END (single_pred (b)))))
{
- rtx label = b->head;
+ rtx label = BB_HEAD (b);
- b->head = NEXT_INSN (b->head);
delete_insn_chain (label, label);
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Deleted label in block %i.\n",
+ /* In the case label is undeletable, move it after the
+ BASIC_BLOCK note. */
+ if (NOTE_LINE_NUMBER (BB_HEAD (b)) == NOTE_INSN_DELETED_LABEL)
+ {
+ rtx bb_note = NEXT_INSN (BB_HEAD (b));
+
+ reorder_insns_nobb (label, label, bb_note);
+ BB_HEAD (b) = bb_note;
+ }
+ if (dump_file)
+ fprintf (dump_file, "Deleted label in block %i.\n",
b->index);
}
/* If we fall through an empty block, we can remove it. */
- if (b->pred->pred_next == NULL
- && (b->pred->flags & EDGE_FALLTHRU)
- && GET_CODE (b->head) != CODE_LABEL
+ if (!(mode & CLEANUP_CFGLAYOUT)
+ && single_pred_p (b)
+ && (single_pred_edge (b)->flags & EDGE_FALLTHRU)
+ && !LABEL_P (BB_HEAD (b))
&& FORWARDER_BLOCK_P (b)
/* Note that forwarder_block_p true ensures that
there is a successor for this block. */
- && (b->succ->flags & EDGE_FALLTHRU)
- && n_basic_blocks > 1)
+ && (single_succ_edge (b)->flags & EDGE_FALLTHRU)
+ && n_basic_blocks > NUM_FIXED_BLOCKS + 1)
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file,
+ if (dump_file)
+ fprintf (dump_file,
"Deleting fallthru block %i.\n",
b->index);
c = b->prev_bb == ENTRY_BLOCK_PTR ? b->next_bb : b->prev_bb;
- redirect_edge_succ_nodup (b->pred, b->succ->dest);
- flow_delete_block (b);
+ redirect_edge_succ_nodup (single_pred_edge (b),
+ single_succ (b));
+ delete_basic_block (b);
changed = true;
b = c;
}
- /* Merge blocks. Loop because chains of blocks might be
- combineable. */
- while ((s = b->succ) != NULL
- && s->succ_next == NULL
- && !(s->flags & EDGE_COMPLEX)
- && (c = s->dest) != EXIT_BLOCK_PTR
- && c->pred->pred_next == NULL
- && b != c
- /* If the jump insn has side effects,
- we can't kill the edge. */
- && (GET_CODE (b->end) != JUMP_INSN
- || simplejump_p (b->end))
- && merge_blocks (s, b, c, mode))
- changed_here = true;
+ if (single_succ_p (b)
+ && (s = single_succ_edge (b))
+ && !(s->flags & EDGE_COMPLEX)
+ && (c = s->dest) != EXIT_BLOCK_PTR
+ && single_pred_p (c)
+ && b != c)
+ {
+ /* When not in cfg_layout mode use code aware of reordering
+ INSN. This code possibly creates new basic blocks so it
+ does not fit merge_blocks interface and is kept here in
+ hope that it will become useless once more of compiler
+ is transformed to use cfg_layout mode. */
+
+ if ((mode & CLEANUP_CFGLAYOUT)
+ && can_merge_blocks_p (b, c))
+ {
+ merge_blocks (b, c);
+ update_forwarder_flag (b);
+ changed_here = true;
+ }
+ else if (!(mode & CLEANUP_CFGLAYOUT)
+ /* If the jump insn has side effects,
+ we can't kill the edge. */
+ && (!JUMP_P (BB_END (b))
+ || (reload_completed
+ ? simplejump_p (BB_END (b))
+ : (onlyjump_p (BB_END (b))
+ && !tablejump_p (BB_END (b),
+ NULL, NULL))))
+ && (next = merge_blocks_move (s, b, c, mode)))
+ {
+ b = next;
+ changed_here = true;
+ }
+ }
/* Simplify branch over branch. */
- if ((mode & CLEANUP_EXPENSIVE) && try_simplify_condjump (b))
+ if ((mode & CLEANUP_EXPENSIVE)
+ && !(mode & CLEANUP_CFGLAYOUT)
+ && try_simplify_condjump (b))
changed_here = true;
/* If B has a single outgoing edge, but uses a
non-trivial jump instruction without side-effects, we
can either delete the jump entirely, or replace it
- with a simple unconditional jump. Use
- redirect_edge_and_branch to do the dirty work. */
- if (b->succ
- && ! b->succ->succ_next
- && b->succ->dest != EXIT_BLOCK_PTR
- && onlyjump_p (b->end)
- && redirect_edge_and_branch (b->succ, b->succ->dest))
+ with a simple unconditional jump. */
+ if (single_succ_p (b)
+ && single_succ (b) != EXIT_BLOCK_PTR
+ && onlyjump_p (BB_END (b))
+ && !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX)
+ && try_redirect_by_replacing_jump (single_succ_edge (b),
+ single_succ (b),
+ (mode & CLEANUP_CFGLAYOUT) != 0))
{
update_forwarder_flag (b);
changed_here = true;
#endif
changed_overall |= changed;
+ first_pass = false;
}
while (changed);
}
if (mode & CLEANUP_CROSSJUMP)
- remove_fake_edges ();
+ remove_fake_exit_edges ();
- clear_aux_for_blocks ();
+ FOR_ALL_BB (b)
+ b->flags &= ~(BB_FORWARDER_BLOCK | BB_NONTHREADABLE_BLOCK);
return changed_overall;
}
/* Delete all unreachable basic blocks. */
bool
-delete_unreachable_blocks ()
+delete_unreachable_blocks (void)
{
bool changed = false;
basic_block b, next_bb;
if (!(b->flags & BB_REACHABLE))
{
- flow_delete_block (b);
+ delete_basic_block (b);
changed = true;
}
}
tidy_fallthru_edges ();
return changed;
}
+
+/* Merges sequential blocks if possible. */
+
+bool
+merge_seq_blocks (void)
+{
+ basic_block bb;
+ bool changed = false;
+
+ for (bb = ENTRY_BLOCK_PTR->next_bb; bb != EXIT_BLOCK_PTR; )
+ {
+ if (single_succ_p (bb)
+ && can_merge_blocks_p (bb, single_succ (bb)))
+ {
+ /* Merge the blocks and retry. */
+ merge_blocks (bb, single_succ (bb));
+ changed = true;
+ continue;
+ }
+
+ bb = bb->next_bb;
+ }
+
+ return changed;
+}
\f
/* Tidy the CFG by deleting unreachable code and whatnot. */
bool
-cleanup_cfg (mode)
- int mode;
+cleanup_cfg (int mode)
{
bool changed = false;
changed = true;
/* We've possibly created trivially dead code. Cleanup it right
now to introduce more opportunities for try_optimize_cfg. */
- if (!(mode & (CLEANUP_NO_INSN_DEL
- | CLEANUP_UPDATE_LIFE | CLEANUP_PRE_SIBCALL))
+ if (!(mode & (CLEANUP_NO_INSN_DEL | CLEANUP_UPDATE_LIFE))
&& !reload_completed)
delete_trivially_dead_insns (get_insns(), max_reg_num ());
}
PROP_DEATH_NOTES
| PROP_SCAN_DEAD_CODE
| PROP_KILL_DEAD_CODE
- | PROP_LOG_LINKS))
+ | ((mode & CLEANUP_LOG_LINKS)
+ ? PROP_LOG_LINKS : 0)))
break;
}
- else if (!(mode & (CLEANUP_NO_INSN_DEL | CLEANUP_PRE_SIBCALL))
+ else if (!(mode & CLEANUP_NO_INSN_DEL)
+ && (mode & CLEANUP_EXPENSIVE)
&& !reload_completed)
{
if (!delete_trivially_dead_insns (get_insns(), max_reg_num ()))
delete_dead_jumptables ();
}
- /* Kill the data we won't maintain. */
- free_EXPR_LIST_list (&label_value_list);
timevar_pop (TV_CLEANUP_CFG);
return changed;
}
+\f
+static void
+rest_of_handle_jump (void)
+{
+ delete_unreachable_blocks ();
+
+ if (cfun->tail_call_emit)
+ fixup_tail_calls ();
+}
+
+struct tree_opt_pass pass_jump =
+{
+ "sibling", /* name */
+ NULL, /* gate */
+ rest_of_handle_jump, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_JUMP, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ TODO_ggc_collect, /* todo_flags_start */
+ TODO_dump_func |
+ TODO_verify_flow, /* todo_flags_finish */
+ 'i' /* letter */
+};
+
+
+static void
+rest_of_handle_jump2 (void)
+{
+ /* Turn NOTE_INSN_EXPECTED_VALUE into REG_BR_PROB. Do this
+ before jump optimization switches branch directions. */
+ if (flag_guess_branch_prob)
+ expected_value_to_br_prob ();
+
+ delete_trivially_dead_insns (get_insns (), max_reg_num ());
+ reg_scan (get_insns (), max_reg_num ());
+ if (dump_file)
+ dump_flow_info (dump_file);
+ cleanup_cfg ((optimize ? CLEANUP_EXPENSIVE : 0) | CLEANUP_PRE_LOOP
+ | (flag_thread_jumps ? CLEANUP_THREADING : 0));
+
+ create_loop_notes ();
+
+ purge_line_number_notes ();
+
+ if (optimize)
+ cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_PRE_LOOP);
+
+ /* Jump optimization, and the removal of NULL pointer checks, may
+ have reduced the number of instructions substantially. CSE, and
+ future passes, allocate arrays whose dimensions involve the
+ maximum instruction UID, so if we can reduce the maximum UID
+ we'll save big on memory. */
+ renumber_insns (dump_file);
+}
+
+
+struct tree_opt_pass pass_jump2 =
+{
+ "jump", /* name */
+ NULL, /* gate */
+ rest_of_handle_jump2, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_JUMP, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ TODO_ggc_collect, /* todo_flags_start */
+ TODO_dump_func, /* todo_flags_finish */
+ 'j' /* letter */
+};
+
+
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