/* Control flow optimization code for GNU compiler.
Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
- 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
+ Free Software Foundation, Inc.
This file is part of GCC.
#include "tree-pass.h"
#include "cfgloop.h"
#include "expr.h"
+#include "df.h"
+#include "dce.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 *, struct equiv_info *);
+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 edge thread_jump (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. */
/* 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.
+ 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
+ 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)
switch (GET_CODE (exp))
{
/* In case we do clobber the register, mark it as equal, as we know the
- value is dead so it don't have to match. */
+ value is dead so it don't have to match. */
case CLOBBER:
if (REG_P (XEXP (exp, 0)))
{
if exist, NULL otherwise. */
static edge
-thread_jump (int mode, edge e, basic_block b)
+thread_jump (edge e, basic_block b)
{
rtx set1, set2, cond1, cond2, insn;
enum rtx_code code1, code2, reversed_code2;
if (for_each_rtx (&cond2, mentions_nonequal_regs, nonequal))
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->il.rtl->global_live_at_end);
-
EXECUTE_IF_SET_IN_REG_SET (nonequal, 0, i, rsi)
goto failed_exit;
/* 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.
-
+ 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
+ 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))
int counter;
bool threaded = false;
int nthreaded_edges = 0;
- bool may_thread = first_pass | (b->flags & BB_DIRTY);
+ bool may_thread = first_pass | df_get_bb_dirty (b);
/* Skip complex edges because we don't know how to update them.
- Still handle fallthru edges, as we can succeed to forward fallthru
- edge to the same place as the branch edge of conditional branch
- and turn conditional branch to an unconditional branch. */
+ Still handle fallthru edges, as we can succeed to forward fallthru
+ 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)
{
ei_next (&ei);
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
+ 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. */
{
basic_block new_target = NULL;
bool new_target_threaded = false;
- may_thread |= target->flags & BB_DIRTY;
+ may_thread |= df_get_bb_dirty (target);
if (FORWARDER_BLOCK_P (target)
- && !(single_succ_edge (target)->flags & EDGE_CROSSING)
+ && !(single_succ_edge (target)->flags & EDGE_CROSSING)
&& single_succ (target) != EXIT_BLOCK_PTR)
{
/* Bypass trivial infinite loops. */
of probabilities. */
else if ((mode & CLEANUP_THREADING) && may_thread)
{
- edge t = thread_jump (mode, e, target);
+ edge t = thread_jump (e, target);
if (t)
{
if (!threaded_edges)
- threaded_edges = xmalloc (sizeof (*threaded_edges)
- * n_basic_blocks);
+ threaded_edges = XNEWVEC (edge, n_basic_blocks);
else
{
int i;
if (!new_target)
break;
- /* Avoid killing of loop pre-headers, as it is the place loop
- optimizer wants to hoist code to.
-
- 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) && optimize && flag_loop_optimize)
- {
- rtx insn = (EDGE_SUCC (target, 0)->flags & EDGE_FALLTHRU
- ? BB_HEAD (target) : prev_nonnote_insn (BB_END (target)));
-
- if (!NOTE_P (insn))
- insn = NEXT_INSN (insn);
-
- for (; insn && !LABEL_P (insn) && !INSN_P (insn);
- insn = NEXT_INSN (insn))
- if (NOTE_P (insn)
- && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
- break;
-
- 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 (BB_HEAD (target));
- if (insn && NOTE_P (insn)
- && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
- break;
- }
-
counter++;
target = new_target;
threaded |= new_target_threaded;
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
+ 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))
gcc_assert (BARRIER_P (barrier));
delete_insn (barrier);
- /* Move block and loop notes out of the chain so that we do not
- disturb their order.
-
- ??? A better solution would be to squeeze out all the non-nested notes
- 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. */
- only_notes = squeeze_notes (&BB_HEAD (a), &BB_END (a));
- gcc_assert (!only_notes);
-
/* Scramble the insn chain. */
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;
+ df_set_bb_dirty (a);
if (dump_file)
fprintf (dump_file, "Moved block %d before %d and merged.\n",
{
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.
-
+ 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
+ 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))
if (barrier && BARRIER_P (barrier))
delete_insn (barrier);
- /* Move block and loop notes out of the chain so that we do not
- disturb their order.
-
- ??? A better solution would be to squeeze out all the non-nested notes
- 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. */
- only_notes = squeeze_notes (&BB_HEAD (b), &BB_END (b));
- gcc_assert (!only_notes);
-
/* Scramble the insn chain. */
reorder_insns_nobb (BB_HEAD (b), BB_END (b), BB_END (a));
/* 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.
-
+ 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
+ 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)
edge_iterator ei;
/* Avoid overactive code motion, as the forwarder blocks should be
- eliminated by edge redirection instead. One exception might have
+ 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))
if (! c_has_outgoing_fallthru)
{
merge_blocks_move_successor_nojumps (b, c);
- return next == ENTRY_BLOCK_PTR ? next->next_bb : next;
+ return next == ENTRY_BLOCK_PTR ? next->next_bb : next;
}
/* If B does not have an incoming fallthru, then it can be moved
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
+old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2)
+{
+ rtx p1, p2;
+
+ /* Verify that I1 and I2 are equivalent. */
+ if (GET_CODE (i1) != GET_CODE (i2))
+ return false;
+
+ p1 = PATTERN (i1);
+ p2 = PATTERN (i2);
+
+ if (GET_CODE (p1) != GET_CODE (p2))
+ return false;
+
+ /* If this is a CALL_INSN, compare register usage information.
+ If we don't check this on stack register machines, the two
+ CALL_INSNs might be merged leaving reg-stack.c with mismatching
+ numbers of stack registers in the same basic block.
+ If we don't check this on machines with delay slots, a delay slot may
+ be filled that clobbers a parameter expected by the subroutine.
+
+ ??? We take the simple route for now and assume that if they're
+ equal, they were constructed identically. */
+
+ 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)))
+ return false;
+
+#ifdef STACK_REGS
+ /* If cross_jump_death_matters is not 0, the insn's mode
+ indicates whether or not the insn contains any stack-like
+ regs. */
+
+ if ((mode & CLEANUP_POST_REGSTACK) && stack_regs_mentioned (i1))
+ {
+ /* If register stack conversion has already been done, then
+ death notes must also be compared before it is certain that
+ the two instruction streams match. */
+
+ rtx note;
+ HARD_REG_SET i1_regset, i2_regset;
+
+ CLEAR_HARD_REG_SET (i1_regset);
+ CLEAR_HARD_REG_SET (i2_regset);
+
+ for (note = REG_NOTES (i1); note; note = XEXP (note, 1))
+ if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
+ SET_HARD_REG_BIT (i1_regset, REGNO (XEXP (note, 0)));
+
+ for (note = REG_NOTES (i2); note; note = XEXP (note, 1))
+ if (REG_NOTE_KIND (note) == REG_DEAD && STACK_REG_P (XEXP (note, 0)))
+ SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0)));
+
+ if (!hard_reg_set_equal_p (i1_regset, i2_regset))
+ return false;
+ }
+#endif
+
+ if (reload_completed
+ ? 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);
+ rtx equiv2 = find_reg_equal_equiv_note (i2);
+
+ if (equiv1 && equiv2
+ /* If the equivalences are not to a constant, they may
+ reference pseudos that no longer exist, so we can't
+ use them. */
+ && (! reload_completed
+ || (CONSTANT_P (XEXP (equiv1, 0))
+ && rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))))
+ {
+ rtx s1 = single_set (i1);
+ rtx s2 = single_set (i2);
+ if (s1 != 0 && s2 != 0
+ && rtx_renumbered_equal_p (SET_DEST (s1), SET_DEST (s2)))
+ {
+ validate_change (i1, &SET_SRC (s1), XEXP (equiv1, 0), 1);
+ validate_change (i2, &SET_SRC (s2), XEXP (equiv2, 0), 1);
+ if (! rtx_renumbered_equal_p (p1, p2))
+ cancel_changes (0);
+ else if (apply_change_group ())
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+\f
+/* Look through the insns at the end of BB1 and BB2 and find the longest
+ sequence that are equivalent. Store the first insns for that sequence
+ in *F1 and *F2 and return the sequence length.
+
+ To simplify callers of this function, if the blocks match exactly,
+ store the head of the blocks in *F1 and *F2. */
+
+static int
+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 = BB_END (bb1);
+ last1 = afterlast1 = last2 = afterlast2 = NULL_RTX;
+ if (onlyjump_p (i1)
+ || (returnjump_p (i1) && !side_effects_p (PATTERN (i1))))
+ {
+ last1 = i1;
+ i1 = PREV_INSN (i1);
+ }
+
+ i2 = BB_END (bb2);
+ if (onlyjump_p (i2)
+ || (returnjump_p (i2) && !side_effects_p (PATTERN (i2))))
+ {
+ last2 = i2;
+ /* Count everything except for unconditional jump as insn. */
+ if (!simplejump_p (i2) && !returnjump_p (i2) && last1)
+ ninsns++;
+ i2 = PREV_INSN (i2);
+ }
+
+ while (true)
+ {
+ /* Ignore notes. */
+ while (!INSN_P (i1) && i1 != BB_HEAD (bb1))
+ i1 = PREV_INSN (i1);
+
+ while (!INSN_P (i2) && i2 != BB_HEAD (bb2))
+ i2 = PREV_INSN (i2);
+
+ if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2))
+ break;
+
+ if (!old_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))
+ {
+ /* If the merged insns have different REG_EQUAL notes, then
+ remove them. */
+ rtx equiv1 = find_reg_equal_equiv_note (i1);
+ rtx equiv2 = find_reg_equal_equiv_note (i2);
+
+ if (equiv1 && !equiv2)
+ remove_note (i1, equiv1);
+ else if (!equiv1 && equiv2)
+ remove_note (i2, equiv2);
+ else if (equiv1 && equiv2
+ && !rtx_equal_p (XEXP (equiv1, 0), XEXP (equiv2, 0)))
+ {
+ remove_note (i1, equiv1);
+ remove_note (i2, equiv2);
+ }
+
+ afterlast1 = last1, afterlast2 = last2;
+ last1 = i1, last2 = i2;
+ ninsns++;
+ }
+
+ i1 = PREV_INSN (i1);
+ i2 = PREV_INSN (i2);
+ }
+
+#ifdef HAVE_cc0
+ /* Don't allow the insn after a compare to be shared by
+ cross-jumping unless the compare is also shared. */
+ if (ninsns && reg_mentioned_p (cc0_rtx, last1) && ! sets_cc0_p (last1))
+ last1 = afterlast1, last2 = afterlast2, ninsns--;
+#endif
+
+ /* Include preceding notes and labels in the cross-jump. One,
+ this may bring us to the head of the blocks as requested above.
+ Two, it keeps line number notes as matched as may be. */
+ if (ninsns)
+ {
+ while (last1 != BB_HEAD (bb1) && !INSN_P (PREV_INSN (last1)))
+ last1 = PREV_INSN (last1);
+
+ if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1)))
+ last1 = PREV_INSN (last1);
+
+ while (last2 != BB_HEAD (bb2) && !INSN_P (PREV_INSN (last2)))
+ last2 = PREV_INSN (last2);
+
+ if (last2 != BB_HEAD (bb2) && LABEL_P (PREV_INSN (last2)))
+ last2 = PREV_INSN (last2);
+
+ *f1 = last1;
+ *f2 = last2;
+ }
+
+ 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)
return match;
}
-/* Return true iff outgoing edges of INFO->y_block and INFO->x_block 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.
- If we need to compare jumps, we set STRUCT_EQUIV_MATCH_JUMPS in *MODE,
- and pass *MODE to struct_equiv_init or assign it to INFO->mode, as
- appropriate.
+/* 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 (int *mode, struct equiv_info *info)
+outgoing_edges_match (int mode, basic_block bb1, basic_block bb2)
{
- basic_block bb1 = info->y_block;
- basic_block bb2 = info->x_block;
int nehedges1 = 0, nehedges2 = 0;
edge fallthru1 = 0, fallthru2 = 0;
edge e1, e2;
& (EDGE_COMPLEX | EDGE_FAKE)) == 0
&& (!JUMP_P (BB_END (bb2)) || simplejump_p (BB_END (bb2))));
- *mode |= STRUCT_EQUIV_MATCH_JUMPS;
/* Match conditional jumps - this may get tricky when fallthru and branch
edges are crossed. */
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 (EDGE_COUNT (bb2->succs) != 2
|| !any_condjump_p (BB_END (bb2))
|| !onlyjump_p (BB_END (bb2)))
return false;
- info->mode = *mode;
- return condjump_equiv_p (info, true);
+
+ b1 = BRANCH_EDGE (bb1);
+ b2 = BRANCH_EDGE (bb2);
+ f1 = FALLTHRU_EDGE (bb1);
+ f2 = FALLTHRU_EDGE (bb2);
+
+ /* 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;
+
+ cond1 = XEXP (SET_SRC (set1), 0);
+ cond2 = XEXP (SET_SRC (set2), 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;
+
+ /* Verify codes and operands match. */
+ match = ((code1 == code2
+ && rtx_renumbered_equal_p (XEXP (cond1, 0), XEXP (cond2, 0))
+ && rtx_renumbered_equal_p (XEXP (cond1, 1), XEXP (cond2, 1)))
+ || (code1 == swap_condition (code2)
+ && rtx_renumbered_equal_p (XEXP (cond1, 1),
+ XEXP (cond2, 0))
+ && rtx_renumbered_equal_p (XEXP (cond1, 0),
+ XEXP (cond2, 1))));
+
+ /* 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);
+
+ return false;
+ }
+ }
+
+ 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
identical = false;
}
- if (identical
- && struct_equiv_init (STRUCT_EQUIV_START | *mode, info))
+ if (identical)
{
+ replace_label_data rr;
bool match;
- /* Indicate that LABEL1 is to be replaced with LABEL2
+ /* Temporarily replace references to LABEL1 with LABEL2
in BB1->END so that we could compare the instructions. */
- info->y_label = label1;
- info->x_label = label2;
+ rr.r1 = label1;
+ rr.r2 = label2;
+ rr.update_label_nuses = false;
+ for_each_rtx (&BB_END (bb1), replace_label, &rr);
- match = insns_match_p (BB_END (bb1), BB_END (bb2), info);
+ 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;
}
}
/* First ensure that the instructions match. There may be many outgoing
edges so this test is generally cheaper. */
- if (!struct_equiv_init (STRUCT_EQUIV_START | *mode, info)
- || !insns_match_p (BB_END (bb1), BB_END (bb2), info))
+ 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
FOR_EACH_EDGE (e1, ei, bb1->succs)
{
e2 = EDGE_SUCC (bb2, ei.index);
-
+
if (e1->flags & EDGE_EH)
nehedges1++;
return false;
}
- /* We don't need to match the rest of edges as above checks should be enough
- to ensure that they are equivalent. */
+ /* The same checks as in try_crossjump_to_edge. It is required for RTL
+ version of sequence abstraction. */
+ FOR_EACH_EDGE (e1, ei, bb2->succs)
+ {
+ edge e2;
+ edge_iterator ei;
+ basic_block d1 = e1->dest;
+
+ if (FORWARDER_BLOCK_P (d1))
+ d1 = EDGE_SUCC (d1, 0)->dest;
+
+ FOR_EACH_EDGE (e2, ei, bb1->succs)
+ {
+ basic_block d2 = e2->dest;
+ if (FORWARDER_BLOCK_P (d2))
+ d2 = EDGE_SUCC (d2, 0)->dest;
+ if (d1 == d2)
+ break;
+ }
+
+ if (!e2)
+ return false;
+ }
+
return true;
}
+/* Returns true if BB basic block has a preserve label. */
+
+static bool
+block_has_preserve_label (basic_block bb)
+{
+ return (bb
+ && block_label (bb)
+ && LABEL_PRESERVE_P (block_label (bb)));
+}
+
/* E1 and E2 are edges with the same destination block. Search their
predecessors for common code. If found, redirect control flow from
(maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC. */
static bool
try_crossjump_to_edge (int mode, edge e1, edge e2)
{
- int nmatch, i;
+ 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;
- struct equiv_info info;
- rtx x_active, y_active;
+
+ newpos1 = newpos2 = NULL_RTX;
/* If we have partitioned hot/cold basic blocks, it is a bad idea
to try this optimization.
return false;
/* Look for the common insn sequence, part the first ... */
- info.x_block = src2;
- info.y_block = src1;
- if (!outgoing_edges_match (&mode, &info))
+ if (!outgoing_edges_match (mode, src1, src2))
return false;
/* ... and part the second. */
- info.input_cost = optimize_size ? COSTS_N_INSNS (1) : -1;
- nmatch = struct_equiv_block_eq (STRUCT_EQUIV_START | mode, &info);
+ nmatch = flow_find_cross_jump (mode, src1, src2, &newpos1, &newpos2);
/* 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)
- return false;
- if ((nmatch -info.cur.input_count < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
- && (info.cur.y_start != BB_HEAD (src1)))
+ if ((nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
+ && (newpos1 != BB_HEAD (src1)))
return false;
- while (info.need_rerun)
- {
- nmatch = struct_equiv_block_eq (STRUCT_EQUIV_RERUN | mode, &info);
- if (!nmatch)
- return false;
- if ((nmatch -info.cur.input_count < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
- && (info.cur.y_start != BB_HEAD (src1)))
- return false;
- }
- nmatch = struct_equiv_block_eq (STRUCT_EQUIV_FINAL | mode, &info);
- if ((nmatch -info.cur.input_count < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS))
- && (info.cur.y_start != BB_HEAD (src1)))
- return false;
-
- /* Skip possible basic block header. */
- x_active = info.cur.x_start;
- if (LABEL_P (x_active))
- x_active = NEXT_INSN (x_active);
- if (NOTE_P (x_active))
- x_active = NEXT_INSN (x_active);
-
- y_active = info.cur.y_start;
- if (LABEL_P (y_active))
- y_active = NEXT_INSN (y_active);
- if (NOTE_P (y_active))
- y_active = NEXT_INSN (y_active);
-
- /* In order for this code to become active, either we have to be called
- before reload, or struct_equiv_block_eq needs to add register scavenging
- code to allocate input_reg after reload. */
- if (info.input_reg)
- {
- emit_insn_before (gen_move_insn (info.input_reg, info.x_input),
- x_active);
- emit_insn_before (gen_move_insn (info.input_reg, info.y_input),
- y_active);
- }
- for (i = 0; i < info.cur.local_count; i++)
- if (info.local_rvalue[i])
- emit_insn_before (gen_move_insn (info.x_local[i], info.y_local[i]),
- y_active);
+ /* Avoid deleting preserve label when redirecting ABNORMAL edges. */
+ if (block_has_preserve_label (e1->dest)
+ && (e1->flags & EDGE_ABNORMAL))
+ return false;
/* Here we know that the insns in the end of SRC1 which are common with SRC2
will be deleted.
/* 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 (info.cur.x_start == BB_HEAD (src2)
+ if (newpos2 == BB_HEAD (src2)
&& !(EDGE_PRED (src2, 0)->flags & EDGE_EH))
redirect_to = src2;
else
{
- if (info.cur.x_start == BB_HEAD (src2))
+ if (newpos2 == BB_HEAD (src2))
{
/* Skip possible basic block header. */
- if (LABEL_P (info.cur.x_start))
- info.cur.x_start = NEXT_INSN (info.cur.x_start);
- if (NOTE_P (info.cur.x_start))
- info.cur.x_start = NEXT_INSN (info.cur.x_start);
+ 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 (info.cur.x_start))->dest;
- COPY_REG_SET (info.y_block->il.rtl->global_live_at_end,
- info.x_block->il.rtl->global_live_at_end);
+ redirect_to = split_block (src2, PREV_INSN (newpos2))->dest;
}
if (dump_file)
- {
- fprintf (dump_file, "Cross jumping from bb %i to bb %i; %i common insns",
- src1->index, src2->index, nmatch);
- if (info.cur.local_count)
- fprintf (dump_file, ", %i local registers", info.cur.local_count);
- fprintf (dump_file, "\n");
- }
+ fprintf (dump_file,
+ "Cross jumping from bb %i to bb %i; %i common insns\n",
+ src1->index, src2->index, nmatch);
redirect_to->count += src1->count;
redirect_to->frequency += src1->frequency;
- /* We may have some registers visible trought the block. */
- redirect_to->flags |= BB_DIRTY;
+ /* We may have some registers visible through the block. */
+ df_set_bb_dirty (redirect_to);
/* Recompute the frequencies and counts of outgoing edges. */
FOR_EACH_EDGE (s, ei, redirect_to->succs)
s->count += s2->count;
/* Take care to update possible forwarder blocks. We verified
- that there is no more than one in the chain, so we can't run
- into infinite loop. */
+ that there is no more than one in the chain, so we can't run
+ into infinite loop. */
if (FORWARDER_BLOCK_P (s->dest))
{
single_succ_edge (s->dest)->count += s2->count;
/* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */
- redirect_from = split_block (src1, PREV_INSN (y_active))->src;
+ /* Skip possible basic block header. */
+ if (LABEL_P (newpos1))
+ newpos1 = NEXT_INSN (newpos1);
+
+ if (NOTE_P (newpos1))
+ newpos1 = NEXT_INSN (newpos1);
+
+ redirect_from = split_block (src1, PREV_INSN (newpos1))->src;
to_remove = single_succ (redirect_from);
redirect_edge_and_branch_force (single_succ_edge (redirect_from), redirect_to);
/* 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.
-
+ 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
+ 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)
+ if (BB_PARTITION (EDGE_PRED (bb, 0)->src) !=
+ BB_PARTITION (EDGE_PRED (bb, 1)->src)
|| (EDGE_PRED (bb, 0)->flags & EDGE_CROSSING))
return false;
FOR_EACH_EDGE (e, ei, bb->preds)
{
if (e->flags & EDGE_FALLTHRU)
- fallthru = e;
+ fallthru = e;
}
changed = false;
/* 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)))
+ && (!(df_get_bb_dirty (e->src))
+ && !(df_get_bb_dirty (fallthru->src))))
continue;
if (try_crossjump_to_edge (mode, e, fallthru))
/* 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)))
+ && (!(df_get_bb_dirty (e->src))
+ && !(df_get_bb_dirty (e2->src))))
continue;
if (try_crossjump_to_edge (mode, e, e2))
if (mode & CLEANUP_CROSSJUMP)
add_noreturn_fake_exit_edges ();
- if (mode & (CLEANUP_UPDATE_LIFE | CLEANUP_CROSSJUMP | CLEANUP_THREADING))
+ if (mode & (CLEANUP_CROSSJUMP | CLEANUP_THREADING))
clear_bb_flags ();
FOR_EACH_BB (bb)
bool changed_here = false;
/* Delete trivially dead basic blocks. */
- while (EDGE_COUNT (b->preds) == 0)
+ if (EDGE_COUNT (b->preds) == 0)
{
c = b->prev_bb;
if (dump_file)
delete_basic_block (b);
if (!(mode & CLEANUP_CFGLAYOUT))
changed = true;
- b = c;
+ /* Avoid trying to remove ENTRY_BLOCK_PTR. */
+ b = (c == ENTRY_BLOCK_PTR ? c->next_bb : c);
+ continue;
}
/* Remove code labels no longer used. */
{
rtx label = BB_HEAD (b);
- delete_insn_chain (label, label);
- /* In the case label is undeletable, move it after the
+ delete_insn_chain (label, label, false);
+ /* If the case label is undeletable, move it after the
BASIC_BLOCK note. */
- if (NOTE_LINE_NUMBER (BB_HEAD (b)) == NOTE_INSN_DELETED_LABEL)
+ if (NOTE_KIND (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 (BB_END (b) == bb_note)
+ BB_END (b) = label;
}
if (dump_file)
fprintf (dump_file, "Deleted label in block %i.\n",
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))
{
return changed;
}
-/* Merges sequential blocks if possible. */
-
-bool
-merge_seq_blocks (void)
+/* Delete any jump tables never referenced. We can't delete them at the
+ time of removing tablejump insn as they are referenced by the preceding
+ insns computing the destination, so we delay deleting and garbagecollect
+ them once life information is computed. */
+void
+delete_dead_jumptables (void)
{
basic_block bb;
- bool changed = false;
- for (bb = ENTRY_BLOCK_PTR->next_bb; bb != EXIT_BLOCK_PTR; )
+ /* A dead jump table does not belong to any basic block. Scan insns
+ between two adjacent basic blocks. */
+ FOR_EACH_BB (bb)
{
- if (single_succ_p (bb)
- && can_merge_blocks_p (bb, single_succ (bb)))
+ rtx insn, next;
+
+ for (insn = NEXT_INSN (BB_END (bb));
+ insn && !NOTE_INSN_BASIC_BLOCK_P (insn);
+ insn = next)
{
- /* Merge the blocks and retry. */
- merge_blocks (bb, single_succ (bb));
- changed = true;
- continue;
- }
+ next = NEXT_INSN (insn);
+ if (LABEL_P (insn)
+ && LABEL_NUSES (insn) == LABEL_PRESERVE_P (insn)
+ && JUMP_P (next)
+ && (GET_CODE (PATTERN (next)) == ADDR_VEC
+ || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC))
+ {
+ rtx label = insn, jump = next;
- bb = bb->next_bb;
- }
+ if (dump_file)
+ fprintf (dump_file, "Dead jumptable %i removed\n",
+ INSN_UID (insn));
- return changed;
+ next = NEXT_INSN (next);
+ delete_insn (jump);
+ delete_insn (label);
+ }
+ }
+ }
}
+
\f
/* Tidy the CFG by deleting unreachable code and whatnot. */
{
bool changed = false;
+ /* Set the cfglayout mode flag here. We could update all the callers
+ but that is just inconvenient, especially given that we eventually
+ want to have cfglayout mode as the default. */
+ if (current_ir_type () == IR_RTL_CFGLAYOUT)
+ mode |= CLEANUP_CFGLAYOUT;
+
timevar_push (TV_CLEANUP_CFG);
if (delete_unreachable_blocks ())
{
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))
+ if (!(mode & (CLEANUP_NO_INSN_DEL))
&& !reload_completed)
- delete_trivially_dead_insns (get_insns(), max_reg_num ());
+ delete_trivially_dead_insns (get_insns (), max_reg_num ());
}
compact_blocks ();
while (try_optimize_cfg (mode))
{
delete_unreachable_blocks (), changed = true;
- if (mode & CLEANUP_UPDATE_LIFE)
- {
- /* Cleaning up CFG introduces more opportunities for dead code
- removal that in turn may introduce more opportunities for
- cleaning up the CFG. */
- if (!update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
- PROP_DEATH_NOTES
- | PROP_SCAN_DEAD_CODE
- | PROP_KILL_DEAD_CODE
- | ((mode & CLEANUP_LOG_LINKS)
- ? PROP_LOG_LINKS : 0)))
- break;
- }
- else if (!(mode & CLEANUP_NO_INSN_DEL)
- && (mode & CLEANUP_EXPENSIVE)
- && !reload_completed)
+ if (!(mode & CLEANUP_NO_INSN_DEL)
+ && (mode & CLEANUP_EXPENSIVE)
+ && !reload_completed)
{
- if (!delete_trivially_dead_insns (get_insns(), max_reg_num ()))
+ if (!delete_trivially_dead_insns (get_insns (), max_reg_num ()))
break;
}
else
break;
- delete_dead_jumptables ();
}
+ /* Don't call delete_dead_jumptables in cfglayout mode, because
+ that function assumes that jump tables are in the insns stream.
+ But we also don't _have_ to delete dead jumptables in cfglayout
+ mode because we shouldn't even be looking at things that are
+ not in a basic block. Dead jumptables are cleaned up when
+ going out of cfglayout mode. */
+ if (!(mode & CLEANUP_CFGLAYOUT))
+ delete_dead_jumptables ();
+
timevar_pop (TV_CLEANUP_CFG);
return changed;
}
\f
-static void
+static unsigned int
rest_of_handle_jump (void)
{
delete_unreachable_blocks ();
if (cfun->tail_call_emit)
fixup_tail_calls ();
+ return 0;
}
struct tree_opt_pass pass_jump =
{
"sibling", /* name */
- NULL, /* gate */
- rest_of_handle_jump, /* execute */
+ NULL, /* gate */
+ rest_of_handle_jump, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
};
-static void
+static unsigned int
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);
+ dump_flow_info (dump_file, dump_flags);
+ cleanup_cfg ((optimize ? CLEANUP_EXPENSIVE : 0)
+ | (flag_thread_jumps ? CLEANUP_THREADING : 0));
+ return 0;
}
struct tree_opt_pass pass_jump2 =
{
"jump", /* name */
- NULL, /* gate */
- rest_of_handle_jump2, /* execute */
+ NULL, /* gate */
+ rest_of_handle_jump2, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */