Hi,
GCC avoids multi-pointers/dangling-pointers of struct iv by allocating
multiple copies of the structure. This patch is an obvious fix to the issue
by managing iv structures in obstack.
Bootstrap on x86_64, will apply to trunk if no objection.
Thanks,
bin
2015-06-26 Bin Cheng <[email protected]>
* tree-ssa-loop-ivopts.c (struct ivopts_data): New field iv_obstack.
(tree_ssa_iv_optimize_init): Initialize iv_obstack.
(alloc_iv): New parameter. Allocate struct iv using obstack_alloc.
(set_iv, find_interesting_uses_address, add_candidate_1): New
argument.
(find_interesting_uses_op): Don't duplicate struct iv.
(free_loop_data): Don't free iv structure explicitly.
(tree_ssa_iv_optimize_finalize): Free iv_obstack.
Index: gcc/tree-ssa-loop-ivopts.c
===================================================================
--- gcc/tree-ssa-loop-ivopts.c (revision 224930)
+++ gcc/tree-ssa-loop-ivopts.c (working copy)
@@ -352,6 +352,9 @@ struct ivopts_data
/* The maximum invariant id. */
unsigned max_inv_id;
+ /* Obstack for iv structure. */
+ struct obstack iv_obstack;
+
/* Whether to consider just related and important candidates when replacing a
use. */
bool consider_all_candidates;
@@ -912,6 +915,7 @@ tree_ssa_iv_optimize_init (struct ivopts_data *dat
data->inv_expr_id = 0;
data->name_expansion_cache = NULL;
decl_rtl_to_reset.create (20);
+ gcc_obstack_init (&data->iv_obstack);
}
/* Returns a memory object to that EXPR points. In case we are able to
@@ -995,10 +999,12 @@ contain_complex_addr_expr (tree expr)
for loop LOOP. NO_OVERFLOW implies the iv doesn't overflow. */
static struct iv *
-alloc_iv (tree base, tree step, bool no_overflow = false)
+alloc_iv (struct ivopts_data *data, tree base, tree step,
+ bool no_overflow = false)
{
tree expr = base;
- struct iv *iv = XCNEW (struct iv);
+ struct iv *iv = (struct iv*) obstack_alloc (&data->iv_obstack,
+ sizeof (struct iv));
gcc_assert (step != NULL_TREE);
/* Lower address expression in base except ones with DECL_P as operand.
@@ -1039,7 +1045,7 @@ set_iv (struct ivopts_data *data, tree iv, tree ba
gcc_assert (!info->iv);
bitmap_set_bit (data->relevant, SSA_NAME_VERSION (iv));
- info->iv = alloc_iv (base, step, no_overflow);
+ info->iv = alloc_iv (data, base, step, no_overflow);
info->iv->ssa_name = iv;
}
@@ -1430,7 +1432,6 @@ static struct iv_use *
find_interesting_uses_op (struct ivopts_data *data, tree op)
{
struct iv *iv;
- struct iv *civ;
gimple stmt;
struct iv_use *use;
@@ -1456,14 +1457,11 @@ find_interesting_uses_op (struct ivopts_data *data
}
iv->have_use_for = true;
- civ = XNEW (struct iv);
- *civ = *iv;
-
stmt = SSA_NAME_DEF_STMT (op);
gcc_assert (gimple_code (stmt) == GIMPLE_PHI
|| is_gimple_assign (stmt));
- use = record_use (data, NULL, civ, stmt, USE_NONLINEAR_EXPR);
+ use = record_use (data, NULL, iv, stmt, USE_NONLINEAR_EXPR);
iv->use_id = use->id;
return use;
@@ -2038,7 +2036,7 @@ find_interesting_uses_address (struct ivopts_data
}
}
- civ = alloc_iv (base, step);
+ civ = alloc_iv (data, base, step);
record_group_use (data, op_p, civ, stmt, USE_ADDRESS);
return;
@@ -2681,7 +2679,7 @@ add_candidate_1 (struct ivopts_data *data,
if (!base && !step)
cand->iv = NULL;
else
- cand->iv = alloc_iv (base, step);
+ cand->iv = alloc_iv (data, base, step);
cand->pos = pos;
if (pos != IP_ORIGINAL && cand->iv)
@@ -7188,7 +7186,6 @@ free_loop_data (struct ivopts_data *data)
struct version_info *info;
info = ver_info (data, i);
- free (info->iv);
info->iv = NULL;
info->has_nonlin_use = false;
info->preserve_biv = false;
@@ -7207,13 +7204,11 @@ free_loop_data (struct ivopts_data *data)
gcc_assert (sub->related_cands == NULL);
gcc_assert (sub->n_map_members == 0 && sub->cost_map == NULL);
- free (sub->iv);
pre = sub;
sub = sub->next;
free (pre);
}
- free (use->iv);
BITMAP_FREE (use->related_cands);
for (j = 0; j < use->n_map_members; j++)
if (use->cost_map[j].depends_on)
@@ -7227,7 +7222,6 @@ free_loop_data (struct ivopts_data *data)
{
struct iv_cand *cand = iv_cand (data, i);
- free (cand->iv);
if (cand->depends_on)
BITMAP_FREE (cand->depends_on);
free (cand);
@@ -7269,6 +7263,7 @@ tree_ssa_iv_optimize_finalize (struct ivopts_data
delete data->inv_expr_tab;
data->inv_expr_tab = NULL;
free_affine_expand_cache (&data->name_expansion_cache);
+ obstack_free (&data->iv_obstack, NULL);
}
/* Returns true if the loop body BODY includes any function calls. */
