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Re: PATCH(v. 3) : insn-attrtab vs. VM usage
> Robert
>
> My example was obviously wrong, forgot to remove the visited parameter.
>
> Here's the corrected example.
Good catch!
I expanded on your corrected example and wrapped another function that
should have been wrapped. Since it had multiple exit points, my earlier
version would have leaked.
* gcse.c (expr_reaches_here_p): Use xcalloc and explit free instead
of alloca.
(pre_gcse): Likewise.
(hoist_expr_reaches_here_p): Likewise.
(hoist_code): Likewise.
(pre_expr_reaches_here_p): Replace alloca with xcalloc. Move core
code to ...
(pre_expr_reaches_here_p_work): ... here.
(expr_reaches_here_p): Replace alloca with xcalloc. Move core code to ...
(expr_reaches_here_p_work): ... here.
Index: gcse.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/gcse.c,v
retrieving revision 1.58
diff -u -p -r1.58 gcse.c
--- gcse.c 1999/10/24 19:23:11 1.58
+++ gcse.c 1999/10/26 02:19:55
@@ -585,7 +585,7 @@ static void alloc_pre_mem PROTO ((i
static void free_pre_mem PROTO ((void));
static void compute_pre_data PROTO ((void));
static int pre_expr_reaches_here_p PROTO ((int, struct expr *,
- int, int, char *));
+ int, int));
static void insert_insn_end_bb PROTO ((struct expr *, int, int));
static void pre_insert_copy_insn PROTO ((struct expr *, rtx));
static void pre_insert_copies PROTO ((void));
@@ -614,7 +614,7 @@ static void compute_ae_gen PROTO ((v
static int expr_killed_p PROTO ((rtx, int));
static void compute_ae_kill PROTO ((sbitmap *, sbitmap *));
static int expr_reaches_here_p PROTO ((struct occr *, struct expr *,
- int, int, char *));
+ int, int));
static rtx computing_insn PROTO ((struct expr *, rtx));
static int def_reaches_here_p PROTO ((rtx, rtx));
static int can_disregard_other_sets PROTO ((struct reg_set **, rtx, int));
@@ -2881,7 +2881,7 @@ compute_ae_kill (ae_gen, ae_kill)
the closest such expression. */
static int
-expr_reaches_here_p (occr, expr, bb, check_self_loop, visited)
+expr_reaches_here_p_work (occr, expr, bb, check_self_loop, visited)
struct occr *occr;
struct expr *expr;
int bb;
@@ -2890,12 +2890,6 @@ expr_reaches_here_p (occr, expr, bb, che
{
edge pred;
- if (visited == NULL)
- {
- visited = (char *) alloca (n_basic_blocks);
- bzero (visited, n_basic_blocks);
- }
-
for (pred = BASIC_BLOCK(bb)->pred; pred != NULL; pred = pred->pred_next)
{
int pred_bb = pred->src->index;
@@ -2932,7 +2926,8 @@ expr_reaches_here_p (occr, expr, bb, che
else
{
visited[pred_bb] = 1;
- if (expr_reaches_here_p (occr, expr, pred_bb, check_self_loop, visited))
+ if (expr_reaches_here_p_work (occr, expr, pred_bb, check_self_loop,
+ visited))
return 1;
}
}
@@ -2941,6 +2936,26 @@ expr_reaches_here_p (occr, expr, bb, che
return 0;
}
+/* This wrapper for expr_reaches_here_p_work() is to ensure that any
+ memory allocated for that function is returned. */
+
+static int
+expr_reaches_here_p (occr, expr, bb, check_self_loop)
+ struct occr *occr;
+ struct expr *expr;
+ int bb;
+ int check_self_loop;
+{
+ int rval;
+ char * visited = (char *) xcalloc (n_basic_blocks, 1);
+
+ rval = expr_reaches_here_p_work(occr, expr, bb, check_self_loop, visited);
+
+ free (visited);
+
+ return (rval);
+}
+
/* Return the instruction that computes EXPR that reaches INSN's basic block.
If there is more than one such instruction, return NULL.
@@ -2984,7 +2999,7 @@ computing_insn (expr, insn)
We let the normal cse pass handle the other cases. */
if (INSN_CUID (insn) < INSN_CUID (occr->insn))
{
- if (expr_reaches_here_p (occr, expr, bb, 1, NULL))
+ if (expr_reaches_here_p (occr, expr, bb, 1))
{
can_reach++;
if (can_reach > 1)
@@ -2995,7 +3010,7 @@ computing_insn (expr, insn)
}
else /* Computation of the pattern outside this block. */
{
- if (expr_reaches_here_p (occr, expr, bb, 0, NULL))
+ if (expr_reaches_here_p (occr, expr, bb, 0))
{
can_reach++;
if (can_reach > 1)
@@ -4178,7 +4193,7 @@ compute_pre_data ()
the closest such expression. */
static int
-pre_expr_reaches_here_p (occr_bb, expr, bb, check_pre_comp, visited)
+pre_expr_reaches_here_p_work (occr_bb, expr, bb, check_pre_comp, visited)
int occr_bb;
struct expr *expr;
int bb;
@@ -4187,12 +4202,6 @@ pre_expr_reaches_here_p (occr_bb, expr,
{
edge pred;
- if (visited == NULL)
- {
- visited = (char *) alloca (n_basic_blocks);
- bzero (visited, n_basic_blocks);
- }
-
for (pred = BASIC_BLOCK (bb)->pred; pred != NULL; pred = pred->pred_next)
{
int pred_bb = pred->src->index;
@@ -4221,8 +4230,8 @@ pre_expr_reaches_here_p (occr_bb, expr,
else
{
visited[pred_bb] = 1;
- if (pre_expr_reaches_here_p (occr_bb, expr, pred_bb,
- check_pre_comp, visited))
+ if (pre_expr_reaches_here_p_work (occr_bb, expr, pred_bb,
+ check_pre_comp, visited))
return 1;
}
}
@@ -4230,6 +4239,27 @@ pre_expr_reaches_here_p (occr_bb, expr,
/* All paths have been checked. */
return 0;
}
+
+/* The wrapper for pre_expr_reaches_here_work that ensures that any
+ memory allocated for that function is returned. */
+
+static int
+pre_expr_reaches_here_p (occr_bb, expr, bb, check_pre_comp)
+ int occr_bb;
+ struct expr *expr;
+ int bb;
+ int check_pre_comp;
+{
+ int rval;
+ char * visited = (char *) xcalloc (n_basic_blocks, 1);
+
+ rval = pre_expr_reaches_here_p_work(occr_bb, expr, bb, check_pre_comp,
+ visited);
+
+ free (visited);
+
+ return (rval);
+}
/* Given an expr, generate RTL which we can insert at the end of a BB,
@@ -4472,8 +4502,7 @@ pre_edge_insert (edge_list, index_map)
if (!TEST_BIT (inserted[e], j)
&& (bb == ENTRY_BLOCK
|| pre_expr_reaches_here_p (bb, expr,
- BLOCK_NUM (occr->insn), 0,
- NULL)))
+ BLOCK_NUM (occr->insn), 0)))
{
rtx insn;
edge eg = INDEX_EDGE (edge_list, e);
@@ -4597,8 +4626,7 @@ pre_insert_copies ()
continue;
/* Or if the expression doesn't reach the deleted one. */
if (! pre_expr_reaches_here_p (BLOCK_NUM (avail->insn), expr,
- BLOCK_NUM (occr->insn),
- 1, NULL))
+ BLOCK_NUM (occr->insn),1))
continue;
/* Copy the result of avail to reaching_reg. */
@@ -4719,8 +4747,7 @@ pre_gcse ()
/* Compute a mapping from expression number (`bitmap_index') to
hash table entry. */
- index_map = (struct expr **) alloca (n_exprs * sizeof (struct expr *));
- bzero ((char *) index_map, n_exprs * sizeof (struct expr *));
+ index_map = xcalloc (n_exprs, sizeof (struct expr *));
for (i = 0; i < expr_hash_table_size; i++)
{
struct expr *expr;
@@ -4749,6 +4776,7 @@ pre_gcse ()
changed = 1;
}
+ free (index_map);
free (pre_redundant_insns);
return changed;
@@ -4985,10 +5013,10 @@ delete_null_pointer_checks (f)
/* We need predecessor/successor lists as well as pred/succ counts for
each basic block. */
- s_preds = (int_list_ptr *) alloca (n_basic_blocks * sizeof (int_list_ptr));
- s_succs = (int_list_ptr *) alloca (n_basic_blocks * sizeof (int_list_ptr));
- num_preds = (int *) alloca (n_basic_blocks * sizeof (int));
- num_succs = (int *) alloca (n_basic_blocks * sizeof (int));
+ s_preds = (int_list_ptr *) gmalloc (n_basic_blocks * sizeof (int_list_ptr));
+ s_succs = (int_list_ptr *) gmalloc (n_basic_blocks * sizeof (int_list_ptr));
+ num_preds = (int *) gmalloc (n_basic_blocks * sizeof (int));
+ num_succs = (int *) gmalloc (n_basic_blocks * sizeof (int));
compute_preds_succs (s_preds, s_succs, num_preds, num_succs);
/* Allocate bitmaps to hold local and global properties. */
@@ -5141,6 +5169,12 @@ delete_null_pointer_checks (f)
/* Free storage allocated by find_basic_blocks. */
free_basic_block_vars (0);
+ /* Free our local predecessor/successor lists. */
+ free (s_preds);
+ free (s_succs);
+ free (num_preds);
+ free (num_succs);
+
/* Free bitmaps. */
free (nonnull_local);
free (nonnull_killed);
@@ -5273,11 +5307,13 @@ hoist_expr_reaches_here_p (expr_bb, expr
char *visited;
{
edge pred;
+ int visited_allocated_locally = 0;
+
if (visited == NULL)
{
- visited = (char *) alloca (n_basic_blocks);
- bzero (visited, n_basic_blocks);
+ visited_allocated_locally = 1;
+ visited = xcalloc (n_basic_blocks, 1);
}
visited[expr_bb] = 1;
@@ -5303,7 +5339,8 @@ hoist_expr_reaches_here_p (expr_bb, expr
break;
}
}
-
+ if (visited_allocated_locally)
+ free (visited);
return (pred == NULL);
}
@@ -5319,8 +5356,7 @@ hoist_code ()
/* Compute a mapping from expression number (`bitmap_index') to
hash table entry. */
- index_map = (struct expr **) alloca (n_exprs * sizeof (struct expr *));
- bzero ((char *) index_map, n_exprs * sizeof (struct expr *));
+ index_map = xcalloc (n_exprs, sizeof (struct expr *));
for (i = 0; i < expr_hash_table_size; i++)
{
struct expr *expr;
@@ -5473,6 +5509,7 @@ hoist_code ()
}
}
}
+ free (index_map);
}
/* Top level routine to perform one code hoisting (aka unification) pass