#include "tm-preds.h"
#include "gt-bfin.h"
#include "basic-block.h"
+#include "cfglayout.h"
#include "timevar.h"
/* A C structure for machine-specific, per-function data.
/* Maximum size of a loop. */
#define MAX_LOOP_LENGTH 2042
+/* Maximum distance of the LSETUP instruction from the loop start. */
+#define MAX_LSETUP_DISTANCE 30
+
/* We need to keep a vector of loops */
typedef struct loop_info *loop_info;
DEF_VEC_P (loop_info);
/* loop number, for dumps */
int loop_no;
- /* Predecessor block of the loop. This is the one that falls into
- the loop and contains the initialization instruction. */
- basic_block predecessor;
+ /* All edges that jump into and out of the loop. */
+ VEC(edge,gc) *incoming;
+
+ /* We can handle two cases: all incoming edges have the same destination
+ block, or all incoming edges have the same source block. These two
+ members are set to the common source or destination we found, or NULL
+ if different blocks were found. If both are NULL the loop can't be
+ optimized. */
+ basic_block incoming_src;
+ basic_block incoming_dest;
/* First block in the loop. This is the one branched to by the loop_end
insn. */
return false;
}
+/* Estimate the length of INSN conservatively. */
+
+static int
+length_for_loop (rtx insn)
+{
+ int length = 0;
+ if (JUMP_P (insn) && any_condjump_p (insn) && !optimize_size)
+ {
+ if (TARGET_CSYNC_ANOMALY)
+ length = 8;
+ else if (TARGET_SPECLD_ANOMALY)
+ length = 6;
+ }
+ else if (LABEL_P (insn))
+ {
+ if (TARGET_CSYNC_ANOMALY)
+ length = 4;
+ }
+
+ if (INSN_P (insn))
+ length += get_attr_length (insn);
+
+ return length;
+}
+
/* Optimize LOOP. */
static void
rtx reg_lc0, reg_lc1, reg_lt0, reg_lt1, reg_lb0, reg_lb1;
rtx iter_reg;
rtx lc_reg, lt_reg, lb_reg;
- rtx seq;
+ rtx seq, seq_end;
int length;
unsigned ix;
int inner_depth = 0;
goto bad_loop;
}
+ if (loop->incoming_src)
+ {
+ /* Make sure the predecessor is before the loop start label, as required by
+ the LSETUP instruction. */
+ length = 0;
+ for (insn = BB_END (loop->incoming_src);
+ insn && insn != loop->start_label;
+ insn = NEXT_INSN (insn))
+ length += length_for_loop (insn);
+
+ if (!insn)
+ {
+ if (dump_file)
+ fprintf (dump_file, ";; loop %d lsetup not before loop_start\n",
+ loop->loop_no);
+ goto bad_loop;
+ }
+
+ if (length > MAX_LSETUP_DISTANCE)
+ {
+ if (dump_file)
+ fprintf (dump_file, ";; loop %d lsetup too far away\n", loop->loop_no);
+ goto bad_loop;
+ }
+ }
+
/* Check if start_label appears before loop_end and calculate the
offset between them. We calculate the length of instructions
conservatively. */
for (insn = loop->start_label;
insn && insn != loop->loop_end;
insn = NEXT_INSN (insn))
- {
- if (JUMP_P (insn) && any_condjump_p (insn) && !optimize_size)
- {
- if (TARGET_CSYNC_ANOMALY)
- length += 8;
- else if (TARGET_SPECLD_ANOMALY)
- length += 6;
- }
- else if (LABEL_P (insn))
- {
- if (TARGET_CSYNC_ANOMALY)
- length += 4;
- }
-
- if (INSN_P (insn))
- length += get_attr_length (insn);
- }
+ length += length_for_loop (insn);
if (!insn)
{
if (loop->init != NULL_RTX)
emit_insn (loop->init);
- emit_insn(loop->loop_init);
- emit_label (loop->start_label);
+ seq_end = emit_insn (loop->loop_init);
seq = get_insns ();
end_sequence ();
- emit_insn_after (seq, BB_END (loop->predecessor));
- delete_insn (loop->loop_end);
+ if (loop->incoming_src)
+ {
+ rtx prev = BB_END (loop->incoming_src);
+ if (VEC_length (edge, loop->incoming) > 1
+ || !(VEC_last (edge, loop->incoming)->flags & EDGE_FALLTHRU))
+ {
+ gcc_assert (JUMP_P (prev));
+ prev = PREV_INSN (prev);
+ }
+ emit_insn_after (seq, prev);
+ }
+ else
+ {
+ basic_block new_bb;
+ edge e;
+ edge_iterator ei;
+
+ if (loop->head != loop->incoming_dest)
+ {
+ FOR_EACH_EDGE (e, ei, loop->head->preds)
+ {
+ if (e->flags & EDGE_FALLTHRU)
+ {
+ rtx newjump = gen_jump (loop->start_label);
+ emit_insn_before (newjump, BB_HEAD (loop->head));
+ new_bb = create_basic_block (newjump, newjump, loop->head->prev_bb);
+ gcc_assert (new_bb = loop->head->prev_bb);
+ break;
+ }
+ }
+ }
+
+ emit_insn_before (seq, BB_HEAD (loop->head));
+ seq = emit_label_before (gen_label_rtx (), seq);
+ new_bb = create_basic_block (seq, seq_end, loop->head->prev_bb);
+ FOR_EACH_EDGE (e, ei, loop->incoming)
+ {
+ if (!(e->flags & EDGE_FALLTHRU)
+ || e->dest != loop->head)
+ redirect_edge_and_branch_force (e, new_bb);
+ else
+ redirect_edge_succ (e, new_bb);
+ }
+ }
+
+ delete_insn (loop->loop_end);
/* Insert the loop end label before the last instruction of the loop. */
emit_label_before (loop->end_label, loop->last_insn);
return;
-bad_loop:
+ bad_loop:
if (dump_file)
fprintf (dump_file, ";; loop %d is bad\n", loop->loop_no);
loop->tail = tail_bb;
loop->head = BRANCH_EDGE (tail_bb)->dest;
loop->successor = FALLTHRU_EDGE (tail_bb)->dest;
- loop->predecessor = NULL;
loop->loop_end = tail_insn;
loop->last_insn = NULL_RTX;
loop->iter_reg = SET_DEST (XVECEXP (PATTERN (tail_insn), 0, 1));
loop->clobber_loop0 = loop->clobber_loop1 = 0;
loop->outer = NULL;
loop->loops = NULL;
-
+ loop->incoming = VEC_alloc (edge, gc, 2);
loop->init = loop->loop_init = NULL_RTX;
loop->start_label = XEXP (XEXP (SET_SRC (XVECEXP (PATTERN (tail_insn), 0, 0)), 1), 0);
loop->end_label = NULL_RTX;
}
}
+ /* Find the predecessor, and make sure nothing else jumps into this loop. */
if (!loop->bad)
{
- /* Make sure we only have one entry point. */
- if (EDGE_COUNT (loop->head->preds) == 2)
+ int pass, retry;
+ for (dwork = 0; VEC_iterate (basic_block, loop->blocks, dwork, bb); dwork++)
{
- loop->predecessor = EDGE_PRED (loop->head, 0)->src;
- if (loop->predecessor == loop->tail)
- /* We wanted the other predecessor. */
- loop->predecessor = EDGE_PRED (loop->head, 1)->src;
-
- /* We can only place a loop insn on a fall through edge of a
- single exit block. */
- if (EDGE_COUNT (loop->predecessor->succs) != 1
- || !(EDGE_SUCC (loop->predecessor, 0)->flags & EDGE_FALLTHRU)
- /* If loop->predecessor is in loop, loop->head is not really
- the head of the loop. */
- || bfin_bb_in_loop (loop, loop->predecessor))
- loop->predecessor = NULL;
+ edge e;
+ edge_iterator ei;
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ basic_block pred = e->src;
+
+ if (!bfin_bb_in_loop (loop, pred))
+ {
+ if (dump_file)
+ fprintf (dump_file, ";; Loop %d: incoming edge %d -> %d\n",
+ loop->loop_no, pred->index,
+ e->dest->index);
+ VEC_safe_push (edge, gc, loop->incoming, e);
+ }
+ }
}
- if (loop->predecessor == NULL)
+ for (pass = 0, retry = 1; retry && pass < 2; pass++)
{
- if (dump_file)
- fprintf (dump_file, ";; loop has bad predecessor\n");
- loop->bad = 1;
+ edge e;
+ edge_iterator ei;
+ bool first = true;
+ retry = 0;
+
+ FOR_EACH_EDGE (e, ei, loop->incoming)
+ {
+ if (first)
+ {
+ loop->incoming_src = e->src;
+ loop->incoming_dest = e->dest;
+ first = false;
+ }
+ else
+ {
+ if (e->dest != loop->incoming_dest)
+ loop->incoming_dest = NULL;
+ if (e->src != loop->incoming_src)
+ loop->incoming_src = NULL;
+ }
+ if (loop->incoming_src == NULL && loop->incoming_dest == NULL)
+ {
+ if (pass == 0)
+ {
+ if (dump_file)
+ fprintf (dump_file,
+ ";; retrying loop %d with forwarder blocks\n",
+ loop->loop_no);
+ retry = 1;
+ break;
+ }
+ loop->bad = 1;
+ if (dump_file)
+ fprintf (dump_file,
+ ";; can't find suitable entry for loop %d\n",
+ loop->loop_no);
+ goto out;
+ }
+ }
+ if (retry)
+ {
+ retry = 0;
+ FOR_EACH_EDGE (e, ei, loop->incoming)
+ {
+ if (forwarder_block_p (e->src))
+ {
+ edge e2;
+ edge_iterator ei2;
+
+ if (dump_file)
+ fprintf (dump_file,
+ ";; Adding forwarder block %d to loop %d and retrying\n",
+ e->src->index, loop->loop_no);
+ VEC_safe_push (basic_block, heap, loop->blocks, e->src);
+ bitmap_set_bit (loop->block_bitmap, e->src->index);
+ FOR_EACH_EDGE (e2, ei2, e->src->preds)
+ VEC_safe_push (edge, gc, loop->incoming, e2);
+ VEC_unordered_remove (edge, loop->incoming, ei.index);
+ retry = 1;
+ break;
+ }
+ }
+ }
}
}
-#ifdef ENABLE_CHECKING
- /* Make sure nothing jumps into this loop. This shouldn't happen as we
- wouldn't have generated the counted loop patterns in such a case.
- However, this test must be done after the test above to detect loops
- with invalid headers. */
- if (!loop->bad)
- for (dwork = 0; VEC_iterate (basic_block, loop->blocks, dwork, bb); dwork++)
- {
- edge e;
- edge_iterator ei;
- if (bb == loop->head)
- continue;
- FOR_EACH_EDGE (e, ei, bb->preds)
- {
- basic_block pred = EDGE_PRED (bb, ei.index)->src;
- if (!bfin_bb_in_loop (loop, pred))
- abort ();
- }
- }
-#endif
+ out:
VEC_free (basic_block, heap, works);
}
-static void
-bfin_reorg_loops (FILE *dump_file)
+/* Analyze the structure of the loops in the current function. Use STACK
+ for bitmap allocations. Returns all the valid candidates for hardware
+ loops found in this function. */
+static loop_info
+bfin_discover_loops (bitmap_obstack *stack, FILE *dump_file)
{
- bitmap_obstack stack;
- bitmap tmp_bitmap;
- basic_block bb;
loop_info loops = NULL;
loop_info loop;
+ basic_block bb;
+ bitmap tmp_bitmap;
int nloops = 0;
- bitmap_obstack_initialize (&stack);
-
/* Find all the possible loop tails. This means searching for every
loop_end instruction. For each one found, create a loop_info
structure and add the head block to the work list. */
loops = loop;
loop->loop_no = nloops++;
loop->blocks = VEC_alloc (basic_block, heap, 20);
- loop->block_bitmap = BITMAP_ALLOC (&stack);
+ loop->block_bitmap = BITMAP_ALLOC (stack);
bb->aux = loop;
if (dump_file)
}
}
- tmp_bitmap = BITMAP_ALLOC (&stack);
+ tmp_bitmap = BITMAP_ALLOC (stack);
/* Compute loop nestings. */
for (loop = loops; loop; loop = loop->next)
{
}
else
{
+ if (dump_file)
+ fprintf (dump_file,
+ ";; can't find suitable nesting for loops %d and %d\n",
+ loop->loop_no, other->loop_no);
loop->bad = other->bad = 1;
}
}
}
BITMAP_FREE (tmp_bitmap);
+ return loops;
+}
+
+/* Free up the loop structures in LOOPS. */
+static void
+free_loops (loop_info loops)
+{
+ while (loops)
+ {
+ loop_info loop = loops;
+ loops = loop->next;
+ VEC_free (loop_info, heap, loop->loops);
+ VEC_free (basic_block, heap, loop->blocks);
+ BITMAP_FREE (loop->block_bitmap);
+ XDELETE (loop);
+ }
+}
+
+#define BB_AUX_INDEX(BB) ((unsigned)(BB)->aux)
+
+/* The taken-branch edge from the loop end can actually go forward. Since the
+ Blackfin's LSETUP instruction requires that the loop end be after the loop
+ start, try to reorder a loop's basic blocks when we find such a case. */
+static void
+bfin_reorder_loops (loop_info loops, FILE *dump_file)
+{
+ basic_block bb;
+ loop_info loop;
+
+ FOR_EACH_BB (bb)
+ bb->aux = NULL;
+ cfg_layout_initialize (CLEANUP_UPDATE_LIFE);
+
+ for (loop = loops; loop; loop = loop->next)
+ {
+ unsigned index;
+ basic_block bb;
+ edge e;
+ edge_iterator ei;
+
+ if (loop->bad)
+ continue;
+
+ /* Recreate an index for basic blocks that represents their order. */
+ for (bb = ENTRY_BLOCK_PTR->next_bb, index = 0;
+ bb != EXIT_BLOCK_PTR;
+ bb = bb->next_bb, index++)
+ bb->aux = (PTR) index;
+
+ if (BB_AUX_INDEX (loop->head) < BB_AUX_INDEX (loop->tail))
+ continue;
+
+ FOR_EACH_EDGE (e, ei, loop->head->succs)
+ {
+ if (bitmap_bit_p (loop->block_bitmap, e->dest->index)
+ && BB_AUX_INDEX (e->dest) < BB_AUX_INDEX (loop->tail))
+ {
+ basic_block start_bb = e->dest;
+ basic_block start_prev_bb = start_bb->prev_bb;
+
+ if (dump_file)
+ fprintf (dump_file, ";; Moving block %d before block %d\n",
+ loop->head->index, start_bb->index);
+ loop->head->prev_bb->next_bb = loop->head->next_bb;
+ loop->head->next_bb->prev_bb = loop->head->prev_bb;
+
+ loop->head->prev_bb = start_prev_bb;
+ loop->head->next_bb = start_bb;
+ start_prev_bb->next_bb = start_bb->prev_bb = loop->head;
+ break;
+ }
+ }
+ loops = loops->next;
+ }
+
+ FOR_EACH_BB (bb)
+ {
+ if (bb->next_bb != EXIT_BLOCK_PTR)
+ bb->aux = bb->next_bb;
+ else
+ bb->aux = NULL;
+ }
+ cfg_layout_finalize ();
+}
+
+/* Run from machine_dependent_reorg, this pass looks for doloop_end insns
+ and tries to rewrite the RTL of these loops so that proper Blackfin
+ hardware loops are generated. */
+
+static void
+bfin_reorg_loops (FILE *dump_file)
+{
+ loop_info loops = NULL;
+ loop_info loop;
+ basic_block bb;
+ bitmap_obstack stack;
+
+ bitmap_obstack_initialize (&stack);
+
+ if (dump_file)
+ fprintf (dump_file, ";; Find loops, first pass\n\n");
+
+ loops = bfin_discover_loops (&stack, dump_file);
+
+ if (dump_file)
+ bfin_dump_loops (loops);
+
+ bfin_reorder_loops (loops, dump_file);
+ free_loops (loops);
+
+ if (dump_file)
+ fprintf (dump_file, ";; Find loops, second pass\n\n");
+
+ loops = bfin_discover_loops (&stack, dump_file);
if (dump_file)
{
fprintf (dump_file, ";; All loops found:\n\n");
bfin_dump_loops (loops);
}
- /* Free up the loop structures */
- while (loops)
- {
- loop = loops;
- loops = loop->next;
- VEC_free (loop_info, heap, loop->loops);
- VEC_free (basic_block, heap, loop->blocks);
- BITMAP_FREE (loop->block_bitmap);
- XDELETE (loop);
- }
+ free_loops (loops);
if (dump_file)
print_rtl (dump_file, get_insns ());
projects / thirdparty / gcc.git / commitdiff
