/* Control flow optimization code for GNU compiler.
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of GCC.
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, 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 "params.h"
#include "tm_p.h"
#include "target.h"
+#include "regs.h"
+#include "cfglayout.h"
+#include "emit-rtl.h"
/* cleanup_cfg maintains following flags for each basic block. */
#define FORWARDER_BLOCK_P(BB) (BB_FLAGS (BB) & 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 insns_match_p (int, rtx, rtx);
-static bool label_is_jump_target_p (rtx, rtx);
-static bool tail_recursion_label_p (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 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. */
basic_block jump_block, jump_dest_block, cbranch_dest_block;
edge cbranch_jump_edge, cbranch_fallthru_edge;
rtx cbranch_insn;
- rtx insn, next;
- rtx end;
/* Verify that there are exactly two successors. */
if (!cbranch_block->succ
/* 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;
return false;
jump_dest_block = jump_block->succ->dest;
+ /* 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 (flag_reorder_blocks_and_partition
+ && (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
cbranch_fallthru_edge->flags &= ~EDGE_FALLTHRU;
update_br_prob_note (cbranch_block);
- end = jump_block->end;
- /* Deleting a block may produce unreachable code warning even when we are
- not deleting anything live. Supress it by moving all the line number
- notes out of the block. */
- for (insn = jump_block->head; insn != NEXT_INSN (jump_block->end);
- insn = next)
- {
- next = NEXT_INSN (insn);
- if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) > 0)
- {
- if (insn == jump_block->end)
- {
- jump_block->end = PREV_INSN (insn);
- if (insn == end)
- break;
- }
- reorder_insns_nobb (insn, insn, end);
- end = insn;
- }
- }
/* Delete the block with the unconditional jump, and clean up the mess. */
- 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;
}
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 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;
}
/* 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);
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)))
{
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);
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))
bool changed = false;
edge e, next, *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 (flag_reorder_blocks_and_partition
+ && find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX))
+ return false;
+
for (e = b->succ; e; e = next)
{
basic_block target, first;
int counter;
bool threaded = false;
int nthreaded_edges = 0;
+ bool may_thread = first_pass | (b->flags & BB_DIRTY);
next = e->succ_next;
target = first = e->dest;
counter = 0;
+ /* 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 (flag_reorder_blocks_and_partition
+ && 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->flags & EDGE_CROSSING)
&& target->succ->dest != EXIT_BLOCK_PTR)
{
/* Bypass trivial infinite loops. */
/* 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 ((mode & CLEANUP_PRE_LOOP) && optimize)
{
rtx insn = (target->succ->flags & EDGE_FALLTHRU
- ? target->head : prev_nonnote_insn (target->end));
+ ? 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 (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);
continue;
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 (rtx label, rtx jump_insn)
-{
- rtx tmp = JUMP_LABEL (jump_insn);
-
- if (label == tmp)
- return true;
-
- if (tablejump_p (jump_insn, NULL, &tmp))
- {
- 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 (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
{
rtx barrier;
- barrier = next_nonnote_insn (a->end);
- if (GET_CODE (barrier) != BARRIER)
+ /* 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 (flag_reorder_blocks_and_partition
+ && (BB_PARTITION (a) != BB_PARTITION (b)
+ || find_reg_note (BB_END (a), REG_CROSSING_JUMP, NULL_RTX)))
+ return;
+
+ barrier = next_nonnote_insn (BB_END (a));
+ if (!BARRIER_P (barrier))
abort ();
delete_insn (barrier);
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))
+ if (squeeze_notes (&BB_HEAD (a), &BB_END (a)))
abort ();
/* 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. */
rtx barrier, real_b_end;
rtx label, table;
- real_b_end = b->end;
+ /* 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 (flag_reorder_blocks_and_partition
+ && (find_reg_note (BB_END (a), REG_CROSSING_JUMP, NULL_RTX)
+ || BB_PARTITION (a) != BB_PARTITION (b)))
+ return;
+
+ real_b_end = BB_END (b);
/* 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 (b->end, &label, &table)
- && prev_active_insn (label) == b->end)
+ if (tablejump_p (BB_END (b), &label, &table)
+ && prev_active_insn (label) == BB_END (b))
{
- b->end = table;
+ BB_END (b) = table;
}
/* There had better have been a barrier there. Delete it. */
- barrier = NEXT_INSN (b->end);
- 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))
+ if (squeeze_notes (&BB_HEAD (b), &BB_END (b)))
abort ();
/* 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_move (edge e, basic_block b, basic_block c, int mode)
{
basic_block next;
- /* 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))
+
+ /* 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 (flag_reorder_blocks_and_partition
+ && (find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX)
+ || find_reg_note (BB_END (c), REG_CROSSING_JUMP, NULL_RTX)
+ || 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)
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 b->prev_bb == ENTRY_BLOCK_PTR ? b : b->prev_bb;
}
\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
+ {
+ 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);
+ }
+
+ set_mem_size (x, MAX (MEM_SIZE (x), MEM_SIZE (y)));
+ set_mem_size (y, MEM_SIZE (x));
+
+ 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
??? 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)))
/* 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 (!INSN_P (i1) && i1 != bb1->head)
+ while (!INSN_P (i1) && i1 != BB_HEAD (bb1))
i1 = PREV_INSN (i1);
- while (!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))
break;
+ merge_memattrs (i1, i2);
+
/* Don't begin a cross-jump with a NOTE insn. */
if (INSN_P (i1))
{
Two, it keeps line number notes as matched as may be. */
if (ninsns)
{
- while (last1 != bb1->head && !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 && !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;
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)))
+ && (!JUMP_P (BB_END (bb1)) || simplejump_p (BB_END (bb1))))
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)));
+ && (!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))
+ && any_condjump_p (BB_END (bb1))
+ && onlyjump_p (BB_END (bb1)))
{
edge b1, f1, b2, f2;
bool reverse, match;
if (!bb2->succ
|| !bb2->succ->succ_next
|| bb2->succ->succ_next->succ_next
- || !any_condjump_p (bb2->end)
- || !onlyjump_p (bb2->end))
+ || !any_condjump_p (BB_END (bb2))
+ || !onlyjump_p (BB_END (bb2)))
return false;
b1 = BRANCH_EDGE (bb1);
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,
+ if (dump_file)
+ fprintf (dump_file,
"Outcomes of branch in bb %i and %i differs to much (%i %i)\n",
bb1->index, bb2->index, b1->probability, prob2);
}
}
- 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;
rtx label1, label2;
rtx table1, table2;
- if (tablejump_p (bb1->end, &label1, &table1)
- && tablejump_p (bb2->end, &label2, &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_block () the jump table would be deleted too. */
+ 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, bb1->end))
+ if (label1 != label2 && !rtx_referenced_p (label2, BB_END (bb1)))
{
/* Set IDENTICAL to true when the tables are identical. */
bool identical = false;
rr.r1 = label1;
rr.r2 = label2;
rr.update_label_nuses = false;
- for_each_rtx (&bb1->end, replace_label, &rr);
+ for_each_rtx (&BB_END (bb1), replace_label, &rr);
- match = insns_match_p (mode, bb1->end, bb2->end);
- if (rtl_dump_file && match)
- fprintf (rtl_dump_file,
+ match = 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);
from the instruction is deleted too. */
rr.r1 = label2;
rr.r2 = label1;
- for_each_rtx (&bb1->end, replace_label, &rr);
+ for_each_rtx (&BB_END (bb1), replace_label, &rr);
return match;
}
/* First ensure that the instructions match. There may be many outgoing
edges so this test is generally cheaper. */
- if (!insns_match_p (mode, bb1->end, bb2->end))
+ if (!insns_match_p (mode, BB_END (bb1), BB_END (bb2)))
return false;
/* Search the outgoing edges, ensure that the counts do match, find possible
/* Ensure the same EH region. */
{
- rtx n1 = find_reg_note (bb1->end, REG_EH_REGION, 0);
- rtx n2 = find_reg_note (bb2->end, REG_EH_REGION, 0);
+ 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 (!n1 && n2)
return false;
rtx newpos1, newpos2;
edge s;
+ 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
/* ... 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;
#ifndef CASE_DROPS_THROUGH
rtx label1, label2;
rtx table1, table2;
- if (tablejump_p (src1->end, &label1, &table1)
- && tablejump_p (src2->end, &label2, &table2)
+ if (tablejump_p (BB_END (src1), &label1, &table1)
+ && tablejump_p (BB_END (src2), &label2, &table2)
&& label1 != label2)
{
replace_label_data rr;
/* 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 != src1->end)
+ if (insn != BB_END (src1))
for_each_rtx (&insn, replace_label, &rr);
}
}
#endif
/* Avoid splitting if possible. */
- if (newpos2 == src2->head)
+ if (newpos2 == BB_HEAD (src2))
redirect_to = src2;
else
{
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Splitting bb %i before %i insns\n",
+ 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);
/* 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;
redirect_edge_and_branch_force (redirect_from->succ, redirect_to);
- delete_block (to_remove);
+ delete_basic_block (to_remove);
update_forwarder_flag (redirect_from);
if (!bb->pred || !bb->pred->pred_next)
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 (flag_reorder_blocks_and_partition
+ && (BB_PARTITION (bb->pred->src) != BB_PARTITION (bb->pred->pred_next->src)
+ || (bb->pred->flags & EDGE_CROSSING)))
+ return false;
+
/* It is always cheapest to redirect a block that ends in a branch to
a block that falls through into BB, as that adds no branches to the
program. We'll try that combination first. */
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))
{
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;
FOR_EACH_BB (bb)
update_forwarder_flag (bb);
- if (mode & CLEANUP_UPDATE_LIFE)
+ if (mode & (CLEANUP_UPDATE_LIFE | CLEANUP_CROSSJUMP | CLEANUP_THREADING))
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);
while (b->pred == NULL)
{
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);
- delete_block (b);
+ 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. */
+ /* Remove code labels no longer used. */
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))
+ && 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
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)))
+ || !JUMP_P (BB_END (b->pred->src))
+ || ! label_is_jump_target_p (BB_HEAD (b),
+ BB_END (b->pred->src))))
{
- rtx label = b->head;
+ rtx label = BB_HEAD (b);
delete_insn_chain (label, label);
/* In the case label is undeletable, move it after the
BASIC_BLOCK note. */
- if (NOTE_LINE_NUMBER (b->head) == NOTE_INSN_DELETED_LABEL)
+ if (NOTE_LINE_NUMBER (BB_HEAD (b)) == NOTE_INSN_DELETED_LABEL)
{
- rtx bb_note = NEXT_INSN (b->head);
+ rtx bb_note = NEXT_INSN (BB_HEAD (b));
reorder_insns_nobb (label, label, bb_note);
- b->head = bb_note;
+ BB_HEAD (b) = bb_note;
}
- if (rtl_dump_file)
- fprintf (rtl_dump_file, "Deleted label in block %i.\n",
+ if (dump_file)
+ fprintf (dump_file, "Deleted label in block %i.\n",
b->index);
}
if (!(mode & CLEANUP_CFGLAYOUT)
&& b->pred->pred_next == NULL
&& (b->pred->flags & EDGE_FALLTHRU)
- && GET_CODE (b->head) != CODE_LABEL
+ && !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)
{
- 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);
- delete_block (b);
+ delete_basic_block (b);
changed = true;
b = c;
}
else if (!(mode & CLEANUP_CFGLAYOUT)
/* If the jump insn has side effects,
we can't kill the edge. */
- && (GET_CODE (b->end) != JUMP_INSN
- || (flow2_completed
- ? simplejump_p (b->end)
- : onlyjump_p (b->end)))
+ && (!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;
/* 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. */
+ with a simple unconditional jump. */
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))
+ && onlyjump_p (BB_END (b))
+ && !find_reg_note (BB_END (b), REG_CROSSING_JUMP, NULL_RTX)
+ && try_redirect_by_replacing_jump (b->succ, b->succ->dest,
+ (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 ();
if (!(b->flags & BB_REACHABLE))
{
- 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 (bb->succ
+ && !bb->succ->succ_next
+ && can_merge_blocks_p (bb, bb->succ->dest))
+ {
+ /* Merge the blocks and retry. */
+ merge_blocks (bb, bb->succ->dest);
+ changed = true;
+ continue;
+ }
+
+ bb = bb->next_bb;
+ }
+
+ return changed;
+}
\f
/* Tidy the CFG by deleting unreachable code and whatnot. */
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)
{
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