===================================================================
@@ -1413,6 +1413,7 @@ df_get_bb_dirty (basic_block bb)
void
df_set_bb_dirty (basic_block bb)
{
+ bb->flags |= BB_MODIFIED;
if (df)
{
int p;
===================================================================
@@ -101,7 +101,6 @@ static int noce_find_if_block (basic_blo
static int cond_exec_find_if_block (ce_if_block_t *);
static int find_if_case_1 (basic_block, edge, edge);
static int find_if_case_2 (basic_block, edge, edge);
-static int find_memory (rtx *, void *);
static int dead_or_predicable (basic_block, basic_block, basic_block,
basic_block, int);
static void noce_emit_move_insn (rtx, rtx);
@@ -3875,15 +3874,6 @@ find_if_case_2 (basic_block test_bb, edg
return TRUE;
}
-/* A subroutine of dead_or_predicable called through for_each_rtx.
- Return 1 if a memory is found. */
-
-static int
-find_memory (rtx *px, void *data ATTRIBUTE_UNUSED)
-{
- return MEM_P (*px);
-}
-
/* Used by the code above to perform the actual rtl transformations.
Return TRUE if successful.
@@ -3985,131 +3975,38 @@ dead_or_predicable (basic_block test_bb,
earliest = jump;
}
#endif
+ /* If we allocated new pseudos (e.g. in the conditional move
+ expander called from noce_emit_cmove), we must resize the
+ array first. */
+ if (max_regno < max_reg_num ())
+ max_regno = max_reg_num ();
+
/* Try the NCE path if the CE path did not result in any changes. */
if (n_validated_changes == 0)
{
+ rtx cond;
+ regset live;
+ bool success;
+
/* In the non-conditional execution case, we have to verify that there
are no trapping operations, no calls, no references to memory, and
that any registers modified are dead at the branch site. */
- rtx insn, cond, prev;
- bitmap merge_set, merge_set_noclobber, test_live, test_set;
- unsigned i, fail = 0;
- bitmap_iterator bi;
-
- /* Check for no calls or trapping operations. */
- for (insn = head; ; insn = NEXT_INSN (insn))
- {
- if (CALL_P (insn))
- return FALSE;
- if (NONDEBUG_INSN_P (insn))
- {
- if (may_trap_p (PATTERN (insn)))
- return FALSE;
-
- /* ??? Even non-trapping memories such as stack frame
- references must be avoided. For stores, we collect
- no lifetime info; for reads, we'd have to assert
- true_dependence false against every store in the
- TEST range. */
- if (for_each_rtx (&PATTERN (insn), find_memory, NULL))
- return FALSE;
- }
- if (insn == end)
- break;
- }
-
- if (! any_condjump_p (jump))
+ if (!any_condjump_p (jump))
return FALSE;
/* Find the extent of the conditional. */
cond = noce_get_condition (jump, &earliest, false);
- if (! cond)
+ if (!cond)
return FALSE;
- /* Collect:
- MERGE_SET = set of registers set in MERGE_BB
- MERGE_SET_NOCLOBBER = like MERGE_SET, but only includes registers
- that are really set, not just clobbered.
- TEST_LIVE = set of registers live at EARLIEST
- TEST_SET = set of registers set between EARLIEST and the
- end of the block. */
-
- merge_set = BITMAP_ALLOC (®_obstack);
- merge_set_noclobber = BITMAP_ALLOC (®_obstack);
- test_live = BITMAP_ALLOC (®_obstack);
- test_set = BITMAP_ALLOC (®_obstack);
-
- /* ??? bb->local_set is only valid during calculate_global_regs_live,
- so we must recompute usage for MERGE_BB. Not so bad, I suppose,
- since we've already asserted that MERGE_BB is small. */
- /* If we allocated new pseudos (e.g. in the conditional move
- expander called from noce_emit_cmove), we must resize the
- array first. */
- if (max_regno < max_reg_num ())
- max_regno = max_reg_num ();
-
- FOR_BB_INSNS (merge_bb, insn)
- {
- if (NONDEBUG_INSN_P (insn))
- {
- df_simulate_find_defs (insn, merge_set);
- df_simulate_find_noclobber_defs (insn, merge_set_noclobber);
- }
- }
-
- /* For small register class machines, don't lengthen lifetimes of
- hard registers before reload. */
- if (! reload_completed
- && targetm.small_register_classes_for_mode_p (VOIDmode))
- {
- EXECUTE_IF_SET_IN_BITMAP (merge_set_noclobber, 0, i, bi)
- {
- if (i < FIRST_PSEUDO_REGISTER
- && ! fixed_regs[i]
- && ! global_regs[i])
- fail = 1;
- }
- }
-
- /* For TEST, we're interested in a range of insns, not a whole block.
- Moreover, we're interested in the insns live from OTHER_BB. */
-
- /* The loop below takes the set of live registers
- after JUMP, and calculates the live set before EARLIEST. */
- bitmap_copy (test_live, df_get_live_in (other_bb));
- df_simulate_initialize_backwards (test_bb, test_live);
- for (insn = jump; ; insn = prev)
- {
- if (INSN_P (insn))
- {
- df_simulate_find_defs (insn, test_set);
- df_simulate_one_insn_backwards (test_bb, insn, test_live);
- }
- prev = PREV_INSN (insn);
- if (insn == earliest)
- break;
- }
-
- /* We can perform the transformation if
- MERGE_SET_NOCLOBBER & TEST_SET
- and
- MERGE_SET & TEST_LIVE)
- and
- TEST_SET & DF_LIVE_IN (merge_bb)
- are empty. */
-
- if (bitmap_intersect_p (test_set, merge_set_noclobber)
- || bitmap_intersect_p (test_live, merge_set)
- || bitmap_intersect_p (test_set, df_get_live_in (merge_bb)))
- fail = 1;
-
- BITMAP_FREE (merge_set_noclobber);
- BITMAP_FREE (merge_set);
- BITMAP_FREE (test_live);
- BITMAP_FREE (test_set);
-
- if (fail)
+ live = BITMAP_ALLOC (®_obstack);
+ simulate_backwards_to_point (merge_bb, live, end);
+ success = can_move_insns_across (head, end, earliest, jump,
+ merge_bb, live,
+ df_get_live_in (other_bb), NULL);
+ BITMAP_FREE (live);
+ if (!success)
return FALSE;
}
===================================================================
@@ -985,7 +985,9 @@ extern void df_simulate_one_insn_backwar
extern void df_simulate_finalize_backwards (basic_block, bitmap);
extern void df_simulate_initialize_forwards (basic_block, bitmap);
extern void df_simulate_one_insn_forwards (basic_block, rtx, bitmap);
-
+extern void simulate_backwards_to_point (basic_block, regset, rtx);
+extern bool can_move_insns_across (rtx, rtx, rtx, rtx, basic_block, regset,
+ regset, rtx *);
/* Functions defined in df-scan.c. */
extern void df_scan_alloc (bitmap);
===================================================================
@@ -66,6 +66,10 @@ static bool first_pass;
/* Set to true if crossjumps occured in the latest run of try_optimize_cfg. */
static bool crossjumps_occured;
+/* Set to true if we couldn't run an optimization due to stale liveness
+ information; we should run df_analyze to enable more opportunities. */
+static bool block_was_dirty;
+
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);
@@ -432,7 +436,7 @@ try_forward_edges (int mode, basic_block
int counter, goto_locus;
bool threaded = false;
int nthreaded_edges = 0;
- bool may_thread = first_pass | df_get_bb_dirty (b);
+ bool may_thread = first_pass || (b->flags & BB_MODIFIED) != 0;
/* Skip complex edges because we don't know how to update them.
@@ -467,7 +471,7 @@ try_forward_edges (int mode, basic_block
{
basic_block new_target = NULL;
bool new_target_threaded = false;
- may_thread |= df_get_bb_dirty (target);
+ may_thread |= (target->flags & BB_MODIFIED) != 0;
if (FORWARDER_BLOCK_P (target)
&& !(single_succ_edge (target)->flags & EDGE_CROSSING)
@@ -1857,8 +1861,8 @@ try_crossjump_bb (int mode, basic_block
/* If nothing changed since the last attempt, there is nothing
we can do. */
if (!first_pass
- && (!(df_get_bb_dirty (e->src))
- && !(df_get_bb_dirty (fallthru->src))))
+ && !((e->src->flags & BB_MODIFIED)
+ || (fallthru->src->flags & BB_MODIFIED)))
continue;
if (try_crossjump_to_edge (mode, e, fallthru))
@@ -1907,8 +1911,8 @@ try_crossjump_bb (int mode, basic_block
/* If nothing changed since the last attempt, there is nothing
we can do. */
if (!first_pass
- && (!(df_get_bb_dirty (e->src))
- && !(df_get_bb_dirty (e2->src))))
+ && !((e->src->flags & BB_MODIFIED)
+ || (e2->src->flags & BB_MODIFIED)))
continue;
if (try_crossjump_to_edge (mode, e, e2))
@@ -1927,6 +1931,265 @@ try_crossjump_bb (int mode, basic_block
return changed;
}
+/* Search the successors of BB for common insn sequences. When found,
+ share code between them by moving it across the basic block
+ boundary. Return true if any changes made. */
+
+static bool
+try_head_merge_bb (basic_block bb)
+{
+ basic_block final_dest_bb = NULL;
+ int max_match = INT_MAX;
+ edge e0;
+ rtx *headptr, *currptr;
+ bool changed, moveall;
+ unsigned ix;
+ rtx e0_last_head, cond, move_before;
+ unsigned nedges = EDGE_COUNT (bb->succs);
+ rtx jump = BB_END (bb);
+ regset live, live_union;
+
+ /* Nothing to do if there is not at least two outgoing edges. */
+ if (nedges < 2)
+ return false;
+
+ /* Don't crossjump if this block ends in a computed jump,
+ unless we are optimizing for size. */
+ if (optimize_bb_for_size_p (bb)
+ && bb != EXIT_BLOCK_PTR
+ && computed_jump_p (BB_END (bb)))
+ return false;
+
+ cond = get_condition (jump, &move_before, true, false);
+ if (cond == NULL_RTX)
+ move_before = jump;
+
+ for (ix = 0; ix < nedges; ix++)
+ if (EDGE_SUCC (bb, ix)->dest == EXIT_BLOCK_PTR)
+ return false;
+
+ for (ix = 0; ix < nedges; ix++)
+ {
+ edge e = EDGE_SUCC (bb, ix);
+ basic_block other_bb = e->dest;
+
+ if (df_get_bb_dirty (other_bb))
+ {
+ block_was_dirty = true;
+ return false;
+ }
+
+ if (e->flags & EDGE_ABNORMAL)
+ return false;
+
+ /* Normally, all destination blocks must only be reachable from this
+ block, i.e. they must have one incoming edge.
+
+ There is one special case we can handle, that of multiple consecutive
+ jumps where the first jumps to one of the targets of the second jump.
+ This happens frequently in switch statements for default labels.
+ The structure is as follows:
+ FINAL_DEST_BB
+ ....
+ if (cond) jump A;
+ fall through
+ BB
+ jump with targets A, B, C, D...
+ A
+ has two incoming edges, from FINAL_DEST_BB and BB
+
+ In this case, we can try to move the insns through BB and into
+ FINAL_DEST_BB. */
+ if (EDGE_COUNT (other_bb->preds) != 1)
+ {
+ edge incoming_edge, incoming_bb_other_edge;
+ edge_iterator ei;
+
+ if (final_dest_bb != NULL
+ || EDGE_COUNT (other_bb->preds) != 2)
+ return false;
+
+ /* We must be able to move the insns across the whole block. */
+ move_before = BB_HEAD (bb);
+ while (!NONDEBUG_INSN_P (move_before))
+ move_before = NEXT_INSN (move_before);
+
+ FOR_EACH_EDGE (incoming_edge, ei, bb->preds)
+ if (incoming_edge->dest == bb)
+ break;
+ final_dest_bb = incoming_edge->src;
+ if (EDGE_COUNT (final_dest_bb->succs) != 2)
+ return false;
+ FOR_EACH_EDGE (incoming_bb_other_edge, ei, final_dest_bb->succs)
+ if (incoming_bb_other_edge != incoming_edge)
+ break;
+ if (incoming_bb_other_edge->dest != other_bb)
+ return false;
+ }
+ }
+
+ e0 = EDGE_SUCC (bb, 0);
+ e0_last_head = NULL_RTX;
+ changed = false;
+
+ for (ix = 1; ix < nedges; ix++)
+ {
+ edge e = EDGE_SUCC (bb, ix);
+ rtx e0_last, e_last;
+ int nmatch;
+
+ nmatch = flow_find_head_matching_sequence (e0->dest, e->dest,
+ &e0_last, &e_last, 0);
+ if (nmatch == 0)
+ return false;
+
+ if (nmatch < max_match)
+ {
+ max_match = nmatch;
+ e0_last_head = e0_last;
+ }
+ }
+
+ /* If we matched an entire block, we probably have to avoid moving the
+ last insn. */
+ if (max_match > 0
+ && e0_last_head == BB_END (e0->dest)
+ && (find_reg_note (e0_last_head, REG_EH_REGION, 0)
+ || control_flow_insn_p (e0_last_head)))
+ {
+ max_match--;
+ if (max_match == 0)
+ return false;
+ do
+ e0_last_head = prev_real_insn (e0_last_head);
+ while (DEBUG_INSN_P (e0_last_head));
+ }
+
+ if (max_match == 0)
+ return false;
+
+ /* We must find a union of the live registers at each of the end points. */
+ live = BITMAP_ALLOC (NULL);
+ live_union = BITMAP_ALLOC (NULL);
+
+ currptr = XNEWVEC (rtx, nedges);
+ headptr = XNEWVEC (rtx, nedges);
+
+ for (ix = 0; ix < nedges; ix++)
+ {
+ int j;
+ basic_block merge_bb = EDGE_SUCC (bb, ix)->dest;
+ rtx head = BB_HEAD (merge_bb);
+
+ while (!NONDEBUG_INSN_P (head))
+ head = NEXT_INSN (head);
+ headptr[ix] = head;
+ currptr[ix] = head;
+
+ /* Compute the end point and live information */
+ for (j = 1; j < max_match; j++)
+ do
+ head = NEXT_INSN (head);
+ while (!NONDEBUG_INSN_P (head));
+ simulate_backwards_to_point (merge_bb, live, head);
+ IOR_REG_SET (live_union, live);
+ }
+
+ /* If we're moving across two blocks, verify the validity of the
+ first move, then adjust the target and let the loop below deal
+ with the final move. */
+ if (final_dest_bb != NULL)
+ {
+ rtx move_upto;
+
+ moveall = can_move_insns_across (currptr[0], e0_last_head, move_before,
+ jump, e0->dest, live_union,
+ NULL, &move_upto);
+ if (!moveall)
+ e0_last_head = move_upto;
+ if (e0_last_head == NULL_RTX)
+ goto out;
+
+ jump = BB_END (final_dest_bb);
+ cond = get_condition (jump, &move_before, true, false);
+ if (cond == NULL_RTX)
+ move_before = jump;
+ }
+
+ do
+ {
+ rtx move_upto;
+ moveall = can_move_insns_across (currptr[0], e0_last_head,
+ move_before, jump, e0->dest, live_union,
+ NULL, &move_upto);
+ if (!moveall && move_upto == NULL_RTX)
+ {
+ if (jump == move_before)
+ break;
+
+ /* Try again, using a different insertion point. */
+ move_before = jump;
+ continue;
+ }
+
+ if (final_dest_bb && !moveall)
+ /* We haven't checked whether a partial move would be OK for the first
+ move, so we have to fail this case. */
+ break;
+
+ changed = true;
+ for (;;)
+ {
+ if (currptr[0] == move_upto)
+ break;
+ for (ix = 0; ix < nedges; ix++)
+ {
+ rtx curr = currptr[ix];
+ do
+ curr = NEXT_INSN (curr);
+ while (!NONDEBUG_INSN_P (curr));
+ currptr[ix] = curr;
+ }
+ }
+
+ reorder_insns (headptr[0], currptr[0], PREV_INSN (move_before));
+ df_set_bb_dirty (EDGE_SUCC (bb, 0)->dest);
+ if (final_dest_bb != NULL)
+ df_set_bb_dirty (final_dest_bb);
+ df_set_bb_dirty (bb);
+ for (ix = 1; ix < nedges; ix++)
+ {
+ df_set_bb_dirty (EDGE_SUCC (bb, ix)->dest);
+ delete_insn_chain (headptr[ix], currptr[ix], false);
+ }
+ if (!moveall)
+ {
+ if (jump == move_before)
+ break;
+
+ /* Try again, using a different insertion point. */
+ move_before = jump;
+ for (ix = 0; ix < nedges; ix++)
+ {
+ rtx curr = currptr[ix];
+ do
+ curr = NEXT_INSN (curr);
+ while (!NONDEBUG_INSN_P (curr));
+ currptr[ix] = headptr[ix] = curr;
+ }
+ }
+ }
+ while (!moveall);
+
+ out:
+ free (currptr);
+ free (headptr);
+
+ crossjumps_occured |= changed;
+
+ return changed;
+}
+
/* Return true if BB contains just bb note, or bb note followed
by only DEBUG_INSNs. */
@@ -1972,6 +2235,7 @@ try_optimize_cfg (int mode)
one predecessor, they may be combined. */
do
{
+ block_was_dirty = false;
changed = false;
iterations++;
@@ -2170,6 +2434,13 @@ try_optimize_cfg (int mode)
&& try_crossjump_bb (mode, b))
changed_here = true;
+ if ((mode & CLEANUP_CROSSJUMP)
+ /* This can lengthen register lifetimes. Do it only after
+ reload. */
+ && reload_completed
+ && try_head_merge_bb (b))
+ changed_here = true;
+
/* Don't get confused by the index shift caused by
deleting blocks. */
if (!changed_here)
@@ -2182,6 +2453,13 @@ try_optimize_cfg (int mode)
&& try_crossjump_bb (mode, EXIT_BLOCK_PTR))
changed = true;
+ if (block_was_dirty)
+ {
+ /* This should only be set by head-merging. */
+ gcc_assert (mode & CLEANUP_CROSSJUMP);
+ df_analyze ();
+ }
+
#ifdef ENABLE_CHECKING
if (changed)
verify_flow_info ();
@@ -2366,8 +2644,7 @@ cleanup_cfg (int mode)
if ((mode & CLEANUP_EXPENSIVE) && !reload_completed
&& !delete_trivially_dead_insns (get_insns (), max_reg_num ()))
break;
- else if ((mode & CLEANUP_CROSSJUMP)
- && crossjumps_occured)
+ if ((mode & CLEANUP_CROSSJUMP) && crossjumps_occured)
run_fast_dce ();
}
else
===================================================================
@@ -39,6 +39,7 @@ along with GCC; see the file COPYING3.
#include "basic-block.h"
#include "sbitmap.h"
#include "bitmap.h"
+#include "target.h"
#include "timevar.h"
#include "df.h"
#include "except.h"
@@ -3500,6 +3501,27 @@ df_simulate_find_defs (rtx insn, bitmap
}
}
+/* Find the set of uses for INSN. This includes partial defs. */
+
+static void
+df_simulate_find_uses (rtx insn, bitmap uses)
+{
+ df_ref *rec;
+ unsigned int uid = INSN_UID (insn);
+
+ for (rec = DF_INSN_UID_DEFS (uid); *rec; rec++)
+ {
+ df_ref def = *rec;
+ if (DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))
+ bitmap_set_bit (uses, DF_REF_REGNO (def));
+ }
+ for (rec = DF_INSN_UID_USES (uid); *rec; rec++)
+ {
+ df_ref use = *rec;
+ bitmap_set_bit (uses, DF_REF_REGNO (use));
+ }
+}
+
/* Find the set of real DEFs, which are not clobbers, for INSN. */
void
@@ -3727,7 +3749,301 @@ df_simulate_one_insn_forwards (basic_blo
}
df_simulate_fixup_sets (bb, live);
}
+
+/* Used by the next two functions to encode information about the
+ memory references we found. */
+#define MEMREF_NORMAL 1
+#define MEMREF_VOLATILE 2
+
+/* A subroutine of can_move_insns_across_p called through for_each_rtx.
+ Return either MEMREF_NORMAL or MEMREF_VOLATILE if a memory is found. */
+
+static int
+find_memory (rtx *px, void *data ATTRIBUTE_UNUSED)
+{
+ rtx x = *px;
+
+ if (GET_CODE (x) == ASM_OPERANDS && MEM_VOLATILE_P (x))
+ return MEMREF_VOLATILE;
+
+ if (!MEM_P (x))
+ return 0;
+ if (MEM_VOLATILE_P (x))
+ return MEMREF_VOLATILE;
+ if (MEM_READONLY_P (x))
+ return 0;
+
+ return MEMREF_NORMAL;
+}
+
+/* A subroutine of can_move_insns_across_p called through note_stores.
+ DATA points to an integer in which we set either the bit for
+ MEMREF_NORMAL or the bit for MEMREF_VOLATILE if we find a MEM
+ of either kind. */
+
+static void
+find_memory_stores (rtx x, const_rtx pat ATTRIBUTE_UNUSED,
+ void *data ATTRIBUTE_UNUSED)
+{
+ int *pflags = (int *)data;
+ if (GET_CODE (x) == SUBREG)
+ x = XEXP (x, 0);
+ /* Treat stores to SP as stores to memory, this will prevent problems
+ when there are references to the stack frame. */
+ if (x == stack_pointer_rtx)
+ *pflags |= MEMREF_VOLATILE;
+ if (!MEM_P (x))
+ return;
+ *pflags |= MEM_VOLATILE_P (x) ? MEMREF_VOLATILE : MEMREF_NORMAL;
+}
+
+/* Scan BB backwards, using df_simulate functions to keep track of
+ lifetimes, up to insn POINT. The result is stored in LIVE. */
+
+void
+simulate_backwards_to_point (basic_block bb, regset live, rtx point)
+{
+ rtx insn;
+ bitmap_copy (live, df_get_live_out (bb));
+ df_simulate_initialize_backwards (bb, live);
+
+ /* Scan and update life information until we reach the point we're
+ interested in. */
+ for (insn = BB_END (bb); insn != point; insn = PREV_INSN (insn))
+ df_simulate_one_insn_backwards (bb, insn, live);
+}
+
+/* Return true if it is safe to move a group of insns, described by
+ the range FROM to TO, backwards across another group of insns,
+ described by ACROSS_FROM to ACROSS_TO. It is assumed that there
+ are no insns between ACROSS_TO and FROM, but they may be in
+ different basic blocks; MERGE_BB is the block from which the
+ insns will be moved. The caller must pass in a regset MERGE_LIVE
+ which specifies the registers live after TO.
+
+ This function may be called in one of two cases: either we try to
+ move identical instructions from all successor blocks into their
+ predecessor, or we try to move from only one successor block. If
+ OTHER_BRANCH_LIVE is nonnull, it indicates that we're dealing with
+ the second case. It should contain a set of registers live at the
+ end of ACROSS_TO which must not be clobbered by moving the insns.
+ In that case, we're also more careful about moving memory references
+ and trapping insns.
+
+ We return false if it is not safe to move the entire group, but it
+ may still be possible to move a subgroup. PMOVE_UPTO, if nonnull,
+ is set to point at the last moveable insn in such a case. */
+
+bool
+can_move_insns_across (rtx from, rtx to, rtx across_from, rtx across_to,
+ basic_block merge_bb, regset merge_live,
+ regset other_branch_live, rtx *pmove_upto)
+{
+ rtx insn, next, max_to;
+ bitmap merge_set, merge_use, local_merge_live;
+ bitmap test_set, test_use;
+ unsigned i, fail = 0;
+ bitmap_iterator bi;
+ int memrefs_in_across = 0;
+ int mem_sets_in_across = 0;
+ bool trapping_insns_in_across = false;
+
+ if (pmove_upto != NULL)
+ *pmove_upto = NULL_RTX;
+
+ /* Find real bounds, ignoring debug insns. */
+ while (!NONDEBUG_INSN_P (from) && from != to)
+ from = NEXT_INSN (from);
+ while (!NONDEBUG_INSN_P (to) && from != to)
+ to = PREV_INSN (to);
+
+ for (insn = across_to; ; insn = next)
+ {
+ if (NONDEBUG_INSN_P (insn))
+ {
+ memrefs_in_across |= for_each_rtx (&PATTERN (insn), find_memory,
+ NULL);
+ note_stores (PATTERN (insn), find_memory_stores,
+ &mem_sets_in_across);
+ /* This is used just to find sets of the stack pointer. */
+ memrefs_in_across |= mem_sets_in_across;
+ trapping_insns_in_across |= may_trap_p (PATTERN (insn));
+ }
+ next = PREV_INSN (insn);
+ if (insn == across_from)
+ break;
+ }
+
+ /* Collect:
+ MERGE_SET = set of registers set in MERGE_BB
+ MERGE_USE = set of registers used in MERGE_BB and live at its top
+ MERGE_LIVE = set of registers live at the point inside the MERGE
+ range that we've reached during scanning
+ TEST_SET = set of registers set between ACROSS_FROM and ACROSS_END.
+ TEST_USE = set of registers used between ACROSS_FROM and ACROSS_END,
+ and live before ACROSS_FROM. */
+
+ merge_set = BITMAP_ALLOC (®_obstack);
+ merge_use = BITMAP_ALLOC (®_obstack);
+ local_merge_live = BITMAP_ALLOC (®_obstack);
+ test_set = BITMAP_ALLOC (®_obstack);
+ test_use = BITMAP_ALLOC (®_obstack);
+
+ /* Compute the set of registers set and used in the ACROSS range. */
+ if (other_branch_live != NULL)
+ bitmap_copy (test_use, other_branch_live);
+ df_simulate_initialize_backwards (merge_bb, test_use);
+ for (insn = across_to; ; insn = next)
+ {
+ if (NONDEBUG_INSN_P (insn))
+ {
+ df_simulate_find_defs (insn, test_set);
+ df_simulate_defs (insn, test_use);
+ df_simulate_uses (insn, test_use);
+ }
+ next = PREV_INSN (insn);
+ if (insn == across_from)
+ break;
+ }
+
+ /* Compute an upper bound for the amount of insns moved, by finding
+ the first insn in MERGE that sets a register in TEST_USE, or uses
+ a register in TEST_SET. We also check for calls, trapping operations,
+ and memory references. */
+ max_to = NULL_RTX;
+ for (insn = from; ; insn = next)
+ {
+ if (CALL_P (insn))
+ break;
+ if (NONDEBUG_INSN_P (insn))
+ {
+ if (may_trap_p (PATTERN (insn))
+ && (trapping_insns_in_across || other_branch_live != NULL))
+ break;
+
+ /* We cannot move memory stores past each other, or move memory
+ reads past stores, at least not without tracking them and
+ calling true_dependence on every pair.
+
+ If there is no other branch and no memory references or
+ sets in the ACROSS range, we can move memory references
+ freely, even volatile ones.
+
+ Otherwise, the rules are as follows: volatile memory
+ references and stores can't be moved at all, and any type
+ of memory reference can't be moved if there are volatile
+ accesses or stores in the ACROSS range. That leaves
+ normal reads, which can be moved, as the trapping case is
+ dealt with elsewhere. */
+ if (other_branch_live != NULL || memrefs_in_across != 0)
+ {
+ int mem_ref_flags = 0;
+ int mem_set_flags = 0;
+ note_stores (PATTERN (insn), find_memory_stores, &mem_set_flags);
+ mem_ref_flags = for_each_rtx (&PATTERN (insn), find_memory,
+ NULL);
+ /* Catch sets of the stack pointer. */
+ mem_ref_flags |= mem_set_flags;
+
+ if ((mem_ref_flags | mem_set_flags) & MEMREF_VOLATILE)
+ break;
+ if ((memrefs_in_across & MEMREF_VOLATILE) && mem_ref_flags != 0)
+ break;
+ if (mem_set_flags != 0
+ || (mem_sets_in_across != 0 && mem_ref_flags != 0))
+ break;
+ }
+ df_simulate_find_uses (insn, merge_use);
+ /* We're only interested in uses which use a value live at
+ the top, not one previously set in this block. */
+ bitmap_and_compl_into (merge_use, merge_set);
+ df_simulate_find_defs (insn, merge_set);
+ if (bitmap_intersect_p (merge_set, test_use)
+ || bitmap_intersect_p (merge_use, test_set))
+ break;
+ max_to = insn;
+ }
+ next = NEXT_INSN (insn);
+ if (insn == to)
+ break;
+ }
+ if (max_to != to)
+ fail = 1;
+
+ if (max_to == NULL_RTX || (fail && pmove_upto == NULL))
+ goto out;
+
+ /* Now, lower this upper bound by also taking into account that
+ a range of insns moved across ACROSS must not leave a register
+ live at the end that will be clobbered in ACROSS. We need to
+ find a point where TEST_SET & LIVE == 0.
+
+ Insns in the MERGE range that set registers which are also set
+ in the ACROSS range may still be moved as long as we also move
+ later insns which use the results of the set, and make the
+ register dead again. This is verified by the condition stated
+ above. We only need to test it for registers that are set in
+ the moved region.
+ MERGE_LIVE is provided by the caller and holds live registers after
+ TO. */
+ bitmap_copy (local_merge_live, merge_live);
+ for (insn = to; insn != max_to; insn = PREV_INSN (insn))
+ df_simulate_one_insn_backwards (merge_bb, insn, local_merge_live);
+
+ /* We're not interested in registers that aren't set in the moved
+ region at all. */
+ bitmap_and_into (local_merge_live, merge_set);
+ for (;;)
+ {
+ if (NONDEBUG_INSN_P (insn))
+ {
+ if (!bitmap_intersect_p (test_set, local_merge_live))
+ {
+ max_to = insn;
+ break;
+ }
+
+ df_simulate_one_insn_backwards (merge_bb, insn,
+ local_merge_live);
+ }
+ if (insn == from)
+ {
+ fail = 1;
+ goto out;
+ }
+ insn = PREV_INSN (insn);
+ }
+
+ if (max_to != to)
+ fail = 1;
+
+ if (pmove_upto)
+ *pmove_upto = max_to;
+
+ /* For small register class machines, don't lengthen lifetimes of
+ hard registers before reload. */
+ if (! reload_completed
+ && targetm.small_register_classes_for_mode_p (VOIDmode))
+ {
+ EXECUTE_IF_SET_IN_BITMAP (merge_set, 0, i, bi)
+ {
+ if (i < FIRST_PSEUDO_REGISTER
+ && ! fixed_regs[i]
+ && ! global_regs[i])
+ fail = 1;
+ }
+ }
+
+ out:
+ BITMAP_FREE (merge_set);
+ BITMAP_FREE (merge_use);
+ BITMAP_FREE (local_merge_live);
+ BITMAP_FREE (test_set);
+ BITMAP_FREE (test_use);
+
+ return !fail;
+}
/*----------------------------------------------------------------------------
===================================================================
@@ -3160,7 +3160,7 @@ df-core.o : df-core.c $(CONFIG_H) $(SYST
df-problems.o : df-problems.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
$(RTL_H) insn-config.h $(RECOG_H) $(FUNCTION_H) $(REGS_H) alloc-pool.h \
hard-reg-set.h $(BASIC_BLOCK_H) $(DF_H) $(BITMAP_H) sbitmap.h $(TIMEVAR_H) \
- $(TM_P_H) $(FLAGS_H) output.h $(EXCEPT_H) dce.h vecprim.h
+ $(TM_P_H) $(TARGET_H) $(FLAGS_H) output.h $(EXCEPT_H) dce.h vecprim.h
df-scan.o : df-scan.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
insn-config.h $(RECOG_H) $(FUNCTION_H) $(REGS_H) alloc-pool.h \
hard-reg-set.h $(BASIC_BLOCK_H) $(DF_H) $(BITMAP_H) sbitmap.h $(TIMEVAR_H) \
===================================================================
@@ -246,7 +246,12 @@ enum bb_flags
/* Set on blocks that cannot be threaded through.
Only used in cfgcleanup.c. */
- BB_NONTHREADABLE_BLOCK = 1 << 11
+ BB_NONTHREADABLE_BLOCK = 1 << 11,
+
+ /* Set on blocks that were modified in some way. Used during
+ try_optimize_cfg to determine when to retry optimizations during
+ the second and later passes. It is set in df_set_bb_dirty. */
+ BB_MODIFIED = 1 << 12
};
/* Dummy flag for convenience in the hot/cold partitioning code. */