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gimple-ssa-strength-reduction.c (MAX_INCR_VEC_LEN): New constant.

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2013-05-07  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	* gimple-ssa-strength-reduction.c (MAX_INCR_VEC_LEN): New constant.
	(incr_vec_index): Return -1 if increment not found.
	(create_add_on_incoming_edge): Assert if increment not found.
	(record_increment): Limit number of increments recorded.
	(all_phi_incrs_profitable): Return false if an increment not found.
	(replace_profitable_candidates): Don't process increments that were
	not recorded.
	(analyze_candidates_and_replace): Limit size of incr_vec.

From-SVN: r198682
This commit is contained in:
Bill Schmidt 2013-05-07 14:11:21 +00:00 committed by William Schmidt
parent 3f8825c030
commit 7bf55a70ea
2 changed files with 42 additions and 16 deletions
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11
gcc/ChangeLog
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@ -1,3 +1,14 @@
2013-05-07 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
* gimple-ssa-strength-reduction.c (MAX_INCR_VEC_LEN): New constant.
(incr_vec_index): Return -1 if increment not found.
(create_add_on_incoming_edge): Assert if increment not found.
(record_increment): Limit number of increments recorded.
(all_phi_incrs_profitable): Return false if an increment not found.
(replace_profitable_candidates): Don't process increments that were
not recorded.
(analyze_candidates_and_replace): Limit size of incr_vec.
2013-05-07 Richard Biener <rguenther@suse.de>
* calls.c (special_function_p): setjmp-like functions are leaf.

47
gcc/gimple-ssa-strength-reduction.c
View File

@ -366,9 +366,11 @@ static struct obstack chain_obstack;
/* An array INCR_VEC of incr_infos is used during analysis of related
candidates having an SSA name for a stride. INCR_VEC_LEN describes
its current length. */
its current length. MAX_INCR_VEC_LEN is used to avoid costly
pathological cases. */
static incr_info_t incr_vec;
static unsigned incr_vec_len;
const int MAX_INCR_VEC_LEN = 16;
/* For a chain of candidates with unknown stride, indicates whether or not
we must generate pointer arithmetic when replacing statements. */
@ -1960,9 +1962,11 @@ replace_unconditional_candidate (slsr_cand_t c)
replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump);
}
/* Return the index in the increment vector of the given INCREMENT. */
/* Return the index in the increment vector of the given INCREMENT,
or -1 if not found. The latter can occur if more than
MAX_INCR_VEC_LEN increments have been found. */
static inline unsigned
static inline int
incr_vec_index (double_int increment)
{
unsigned i;
@ -1970,8 +1974,10 @@ incr_vec_index (double_int increment)
for (i = 0; i < incr_vec_len && increment != incr_vec[i].incr; i++)
;
gcc_assert (i < incr_vec_len);
return i;
if (i < incr_vec_len)
return i;
else
return -1;
}
/* Create a new statement along edge E to add BASIS_NAME to the product
@ -2015,9 +2021,10 @@ create_add_on_incoming_edge (slsr_cand_t c, tree basis_name,
}
else
{
unsigned i;
int i;
bool negate_incr = (!address_arithmetic_p && increment.is_negative ());
i = incr_vec_index (negate_incr ? -increment : increment);
gcc_assert (i >= 0);
if (incr_vec[i].initializer)
{
@ -2323,7 +2330,7 @@ record_increment (slsr_cand_t c, double_int increment, bool is_phi_adjust)
}
}
if (!found)
if (!found && incr_vec_len < MAX_INCR_VEC_LEN - 1)
{
/* The first time we see an increment, create the entry for it.
If this is the root candidate which doesn't have a basis, set
@ -3025,7 +3032,7 @@ all_phi_incrs_profitable (slsr_cand_t c, gimple phi)
}
else
{
unsigned j;
int j;
slsr_cand_t arg_cand = base_cand_from_table (arg);
double_int increment = arg_cand->index - basis->index;
@ -3041,14 +3048,19 @@ all_phi_incrs_profitable (slsr_cand_t c, gimple phi)
print_gimple_stmt (dump_file, phi, 0, 0);
fputs (" increment: ", dump_file);
dump_double_int (dump_file, increment, false);
fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost);
if (profitable_increment_p (j))
fputs (" Replacing...\n", dump_file);
else
fputs (" Not replaced.\n", dump_file);
if (j < 0)
fprintf (dump_file,
"\n Not replaced; incr_vec overflow.\n");
else {
fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost);
if (profitable_increment_p (j))
fputs (" Replacing...\n", dump_file);
else
fputs (" Not replaced.\n", dump_file);
}
}
if (!profitable_increment_p (j))
if (j < 0 || !profitable_increment_p (j))
return false;
}
}
@ -3268,13 +3280,14 @@ replace_profitable_candidates (slsr_cand_t c)
{
double_int increment = cand_abs_increment (c);
enum tree_code orig_code = gimple_assign_rhs_code (c->cand_stmt);
unsigned i;
int i;
i = incr_vec_index (increment);
/* Only process profitable increments. Nothing useful can be done
to a cast or copy. */
if (profitable_increment_p (i)
if (i >= 0
&& profitable_increment_p (i)
&& orig_code != MODIFY_EXPR
&& orig_code != NOP_EXPR)
{
@ -3378,6 +3391,8 @@ analyze_candidates_and_replace (void)
length = count_candidates (c);
if (!length)
continue;
if (length > MAX_INCR_VEC_LEN)
length = MAX_INCR_VEC_LEN;
/* Construct an array of increments for this candidate chain. */
incr_vec = XNEWVEC (incr_info, length);