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basic-block.h (merge_blocks_nomove): Declare.

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* basic-block.h (merge_blocks_nomove): Declare.
        (tidy_fallthru_edge): Declare.
        * flow.c (merge_blocks_nomove): Document as merging into previous
        blocks.  Remove cruft from between blocks; remove all edges out of A.
        (tidy_fallthru_edge): Export.

From-SVN: r32994
This commit is contained in:
Richard Henderson 2000-04-07 02:22:10 -07:00 committed by Richard Henderson
parent 1e143002cb
commit dc108b7a75
3 changed files with 115 additions and 93 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2000-04-07 Richard Henderson <rth@cygnus.com>
* basic-block.h (merge_blocks_nomove): Declare.
(tidy_fallthru_edge): Declare.
* flow.c (merge_blocks_nomove): Document as merging into previous
blocks. Remove cruft from between blocks; remove all edges out of A.
(tidy_fallthru_edge): Export.
2000-04-06 Alex Samuel <samuel@codesourcery.com>
* ssa.c (compute_conservative_reg_partition): Declare with

4
gcc/basic-block.h
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@ -231,7 +231,9 @@ extern void make_edge PARAMS ((sbitmap *, basic_block,
basic_block, int));
extern void remove_edge PARAMS ((edge));
extern void create_basic_block PARAMS ((int, rtx, rtx, rtx));
extern void merge_blocks_nomove PARAMS ((basic_block, basic_block));
extern void tidy_fallthru_edge PARAMS ((edge, basic_block,
basic_block));
/* Structure to hold information for each natural loop. */
struct loop

196
gcc/flow.c
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@ -302,10 +302,8 @@ static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block,
basic_block));
static int merge_blocks_move_successor_nojumps PARAMS ((basic_block,
basic_block));
static void merge_blocks_nomove PARAMS ((basic_block, basic_block));
static int merge_blocks PARAMS ((edge,basic_block,basic_block));
static void try_merge_blocks PARAMS ((void));
static void tidy_fallthru_edge PARAMS ((edge,basic_block,basic_block));
static void tidy_fallthru_edges PARAMS ((void));
static int verify_wide_reg_1 PARAMS ((rtx *, void *));
static void verify_wide_reg PARAMS ((int, rtx, rtx));
@ -2032,6 +2030,109 @@ can_delete_label_p (label)
return 1;
}
/* Blocks A and B are to be merged into a single block A. The insns
are already contiguous, hence `nomove'. */
void
merge_blocks_nomove (a, b)
basic_block a, b;
{
edge e;
rtx b_head, b_end, a_end;
rtx del_first = NULL_RTX, del_last = NULL_RTX;
int b_empty = 0;
/* If there was a CODE_LABEL beginning B, delete it. */
b_head = b->head;
b_end = b->end;
if (GET_CODE (b_head) == CODE_LABEL)
{
/* Detect basic blocks with nothing but a label. This can happen
in particular at the end of a function. */
if (b_head == b_end)
b_empty = 1;
del_first = del_last = b_head;
b_head = NEXT_INSN (b_head);
}
/* Delete the basic block note. */
if (GET_CODE (b_head) == NOTE
&& NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK)
{
if (b_head == b_end)
b_empty = 1;
if (! del_last)
del_first = b_head;
del_last = b_head;
b_head = NEXT_INSN (b_head);
}
/* If there was a jump out of A, delete it. */
a_end = a->end;
if (GET_CODE (a_end) == JUMP_INSN)
{
rtx prev;
prev = prev_nonnote_insn (a_end);
if (!prev)
prev = a->head;
del_first = a_end;
#ifdef HAVE_cc0
/* If this was a conditional jump, we need to also delete
the insn that set cc0. */
if (prev && sets_cc0_p (prev))
{
rtx tmp = prev;
prev = prev_nonnote_insn (prev);
if (!prev)
prev = a->head;
del_first = tmp;
}
#endif
a_end = prev;
}
/* Delete everything marked above as well as crap that might be
hanging out between the two blocks. */
flow_delete_insn_chain (del_first, del_last);
/* Normally there should only be one successor of A and that is B, but
partway though the merge of blocks for conditional_execution we'll
be merging a TEST block with THEN and ELSE successors. Free the
whole lot of them and hope the caller knows what they're doing. */
while (a->succ)
remove_edge (a->succ);
/* Adjust the edges out of B for the new owner. */
for (e = b->succ; e ; e = e->succ_next)
e->src = a;
a->succ = b->succ;
/* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */
b->pred = b->succ = NULL;
/* Reassociate the insns of B with A. */
if (!b_empty)
{
if (basic_block_for_insn)
{
BLOCK_FOR_INSN (b_head) = a;
while (b_head != b_end)
{
b_head = NEXT_INSN (b_head);
BLOCK_FOR_INSN (b_head) = a;
}
}
a_end = b_end;
}
a->end = a_end;
expunge_block (b);
}
/* Blocks A and B are to be merged into a single block. A has no incoming
fallthru edge, so it can be moved before B without adding or modifying
any jumps (aside from the jump from A to B). */
@ -2145,95 +2246,6 @@ merge_blocks_move_successor_nojumps (a, b)
return 1;
}
/* Blocks A and B are to be merged into a single block. The insns
are already contiguous, hence `nomove'. */
static void
merge_blocks_nomove (a, b)
basic_block a, b;
{
edge e;
rtx b_head, b_end, a_end;
int b_empty = 0;
/* If there was a CODE_LABEL beginning B, delete it. */
b_head = b->head;
b_end = b->end;
if (GET_CODE (b_head) == CODE_LABEL)
{
/* Detect basic blocks with nothing but a label. This can happen
in particular at the end of a function. */
if (b_head == b_end)
b_empty = 1;
b_head = flow_delete_insn (b_head);
}
/* Delete the basic block note. */
if (GET_CODE (b_head) == NOTE
&& NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK)
{
if (b_head == b_end)
b_empty = 1;
b_head = flow_delete_insn (b_head);
}
/* If there was a jump out of A, delete it. */
a_end = a->end;
if (GET_CODE (a_end) == JUMP_INSN)
{
rtx prev;
prev = prev_nonnote_insn (a_end);
if (!prev)
prev = a->head;
#ifdef HAVE_cc0
/* If this was a conditional jump, we need to also delete
the insn that set cc0. */
if (prev && sets_cc0_p (prev))
{
rtx tmp = prev;
prev = prev_nonnote_insn (prev);
if (!prev)
prev = a->head;
flow_delete_insn (tmp);
}
#endif
/* Note that a->head != a->end, since we should have at least a
bb note plus the jump, so prev != insn. */
flow_delete_insn (a_end);
a_end = prev;
}
/* By definition, there should only be one successor of A, and that is
B. Free that edge struct. */
n_edges--;
free (a->succ);
/* Adjust the edges out of B for the new owner. */
for (e = b->succ; e ; e = e->succ_next)
e->src = a;
a->succ = b->succ;
/* Reassociate the insns of B with A. */
if (!b_empty)
{
BLOCK_FOR_INSN (b_head) = a;
while (b_head != b_end)
{
b_head = NEXT_INSN (b_head);
BLOCK_FOR_INSN (b_head) = a;
}
a_end = b_head;
}
a->end = a_end;
/* Compact the basic block array. */
expunge_block (b);
}
/* Attempt to merge basic blocks that are potentially non-adjacent.
Return true iff the attempt succeeded. */
@ -2366,7 +2378,7 @@ try_merge_blocks ()
/* The given edge should potentially be a fallthru edge. If that is in
fact true, delete the jump and barriers that are in the way. */
static void
void
tidy_fallthru_edge (e, b, c)
edge e;
basic_block b, c;