T.3_5 = <blah>
a_1 = T.3_5
- If this copy couldn't be copy propagated, it could possibly remain in the
- program throughout the optimization phases. After SSA->normal, it would
+ If this copy couldn't be copy propagated, it could possibly remain in the
+ program throughout the optimization phases. After SSA->normal, it would
become:
T.3 = <blah>
a = T.3
-
- Since T.3_5 is distinct from all other SSA versions of T.3, there is no
- fundamental reason why the base variable needs to be T.3, subject to
- certain restrictions. This optimization attempts to determine if we can
+
+ Since T.3_5 is distinct from all other SSA versions of T.3, there is no
+ fundamental reason why the base variable needs to be T.3, subject to
+ certain restrictions. This optimization attempts to determine if we can
change the base variable on copies like this, and result in code such as:
a_5 = <blah>
a_1 = a_5
- This gives the SSA->normal pass a shot at coalescing a_1 and a_5. If it is
+ This gives the SSA->normal pass a shot at coalescing a_1 and a_5. If it is
possible, the copy goes away completely. If it isn't possible, a new temp
will be created for a_5, and you will end up with the exact same code:
a_1 = <blah>
<blah2> = a_1
- get turned into
-
+ get turned into
+
T.3_5 = <blah>
a_1 = T.3_5
<blah2> = a_1
<blah2> = a_1
which copy propagation would then turn into:
-
+
a_5 = <blah>
<blah2> = a_5
int p1, p2, p3;
tree root1, root2;
tree rep1, rep2;
- var_ann_t ann1, ann2, ann3;
bool ign1, ign2, abnorm;
gcc_assert (TREE_CODE (var1) == SSA_NAME);
root1 = SSA_NAME_VAR (rep1);
root2 = SSA_NAME_VAR (rep2);
- ann1 = var_ann (root1);
- ann2 = var_ann (root2);
-
if (p1 == p2)
{
if (debug)
ign1 = TREE_CODE (root1) == VAR_DECL && DECL_IGNORED_P (root1);
ign2 = TREE_CODE (root2) == VAR_DECL && DECL_IGNORED_P (root2);
- /* Never attempt to coalesce 2 user variables unless one is an inline
+ /* Never attempt to coalesce 2 user variables unless one is an inline
variable. */
if (!ign1 && !ign2)
{
ign2 = true;
else if (DECL_FROM_INLINE (root1))
ign1 = true;
- else
+ else
{
if (debug)
fprintf (debug, " : 2 different USER vars. No coalesce.\n");
}
}
- /* Don't coalesce if there are two different memory tags. */
- if (ann1->symbol_mem_tag
- && ann2->symbol_mem_tag
- && ann1->symbol_mem_tag != ann2->symbol_mem_tag)
- {
- if (debug)
- fprintf (debug, " : 2 memory tags. No coalesce.\n");
- return false;
- }
-
- /* If both values have default defs, we can't coalesce. If only one has a
+ /* If both values have default defs, we can't coalesce. If only one has a
tag, make sure that variable is the new root partition. */
if (gimple_default_def (cfun, root1))
{
return false;
}
- /* Don't coalesce if the aliasing sets of the types are different. */
- if (POINTER_TYPE_P (TREE_TYPE (root1))
- && POINTER_TYPE_P (TREE_TYPE (root2))
- && ((get_alias_set (TREE_TYPE (TREE_TYPE (root1)))
- != get_alias_set (TREE_TYPE (TREE_TYPE (root2))))
- || ((DECL_P (root1) && !MTAG_P (root1))
- && (DECL_P (root2) && !MTAG_P (root2))
- && DECL_NO_TBAA_P (root1) != DECL_NO_TBAA_P (root2))))
- {
- if (debug)
- fprintf (debug, " : 2 different aliasing sets. No coalesce.\n");
- return false;
- }
-
-
/* Merge the two partitions. */
p3 = partition_union (map->var_partition, p1, p2);
- /* Set the root variable of the partition to the better choice, if there is
+ /* Set the root variable of the partition to the better choice, if there is
one. */
if (!ign2)
replace_ssa_name_symbol (partition_to_var (map, p3), root2);
else if (!ign1)
replace_ssa_name_symbol (partition_to_var (map, p3), root1);
- /* Update the various flag widgitry of the current base representative. */
- ann3 = var_ann (SSA_NAME_VAR (partition_to_var (map, p3)));
- if (ann1->symbol_mem_tag)
- ann3->symbol_mem_tag = ann1->symbol_mem_tag;
- else
- ann3->symbol_mem_tag = ann2->symbol_mem_tag;
-
if (debug)
{
fprintf (debug, " --> P%d ", p3);
- print_generic_expr (debug, SSA_NAME_VAR (partition_to_var (map, p3)),
+ print_generic_expr (debug, SSA_NAME_VAR (partition_to_var (map, p3)),
TDF_SLIM);
fprintf (debug, "\n");
}
/* This function will make a pass through the IL, and attempt to coalesce any
SSA versions which occur in PHI's or copies. Coalescing is accomplished by
- changing the underlying root variable of all coalesced version. This will
- then cause the SSA->normal pass to attempt to coalesce them all to the same
+ changing the underlying root variable of all coalesced version. This will
+ then cause the SSA->normal pass to attempt to coalesce them all to the same
variable. */
static unsigned int
else
debug = NULL;
- map = init_var_map (num_ssa_names + 1);
+ map = init_var_map (num_ssa_names);
FOR_EACH_BB (bb)
{
/* Now one more pass to make all elements of a partition share the same
root variable. */
-
- for (x = 1; x <= num_ssa_names; x++)
+
+ for (x = 1; x < num_ssa_names; x++)
{
part_var = partition_to_var (map, x);
if (!part_var)
continue;
- var = map->partition_to_var[x];
+ var = ssa_name (x);
if (debug)
{
if (SSA_NAME_VAR (var) != SSA_NAME_VAR (part_var))
return flag_tree_copyrename != 0;
}
-struct gimple_opt_pass pass_rename_ssa_copies =
+struct gimple_opt_pass pass_rename_ssa_copies =
{
{
GIMPLE_PASS,
PROP_cfg | PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
- 0, /* todo_flags_start */
+ 0, /* todo_flags_start */
TODO_dump_func | TODO_verify_ssa /* todo_flags_finish */
}
-};
+};
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