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re PR tree-optimization/18800 (ivopt missed)

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PR tree-optimization/18800
        * params.def (PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND): New parameter.
        * tree-ssa-loop-ivopts.c (struct iv_ca): Add n_cands field.
        (ALWAYS_PRUNE_CAND_SET_BOUND): New macro.
        (iv_ca_set_no_cp, iv_ca_set_cp, iv_ca_new): Update n_cands field.
        (iv_ca_delta_join, iv_ca_delta_reverse, iv_ca_n_cands, iv_ca_prune):
        New functions.
        (iv_ca_extend): Return number of candidates in the set.
        (try_add_cand_for): Add argument to iv_ca_extend calls.
        (try_improve_iv_set): Use iv_ca_prune.
        * doc/invoke.texi (iv-always-prune-cand-set-bound): Document.

From-SVN: r92363
This commit is contained in:
Zdenek Dvorak 2004-12-18 21:22:52 +01:00 committed by Zdenek Dvorak
parent f54ff90037
commit 36f5ada19a
4 changed files with 187 additions and 27 deletions
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14
gcc/ChangeLog
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@ -2,6 +2,20 @@
* stor-layout.c (layout_decl): Use unshare_expr, not unsave_expr.
2004-12-18 Zdenek Dvorak <dvorakz@suse.cz>
PR tree-optimization/18800
* params.def (PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND): New parameter.
* tree-ssa-loop-ivopts.c (struct iv_ca): Add n_cands field.
(ALWAYS_PRUNE_CAND_SET_BOUND): New macro.
(iv_ca_set_no_cp, iv_ca_set_cp, iv_ca_new): Update n_cands field.
(iv_ca_delta_join, iv_ca_delta_reverse, iv_ca_n_cands, iv_ca_prune):
New functions.
(iv_ca_extend): Return number of candidates in the set.
(try_add_cand_for): Add argument to iv_ca_extend calls.
(try_improve_iv_set): Use iv_ca_prune.
* doc/invoke.texi (iv-always-prune-cand-set-bound): Document.
2004-12-18 Zdenek Dvorak <dvorakz@suse.cz>
PR rtl-optimization/19001

5
gcc/doc/invoke.texi
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@ -5478,6 +5478,11 @@ if there are more candidates, to avoid quadratic time complexity.
The induction variable optimizations give up on loops that contain more
induction variable uses.
@item iv-always-prune-cand-set-bound
If number of candidates in the set is smaller than this value,
we always try to remove unnecessary ivs from the set during its
optimization when a new iv is added to the set.
@item max-iterations-to-track
The maximum number of iterations of a loop the brute force algorithm

8
gcc/params.def
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@ -347,6 +347,14 @@ DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
"Bound on number of iv uses in loop optimized in iv optimizations",
250, 0, 0)
/* If there are at most this number of ivs in the set, try removing unnecessary
ivs from the set always. */
DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
"iv-always-prune-cand-set-bound",
"If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
10, 0, 0)
/* The product of the next two is used to decide whether or not to
use .GLOBAL_VAR. See tree-dfa.c. */
DEFPARAM(PARAM_GLOBAL_VAR_THRESHOLD,

187
gcc/tree-ssa-loop-ivopts.c
View File

@ -244,6 +244,9 @@ struct iv_ca
/* The candidates used. */
bitmap cands;
/* The number of candidates in the set. */
unsigned n_cands;
/* Total number of registers needed. */
unsigned n_regs;
@ -288,6 +291,12 @@ struct iv_ca_delta
#define MAX_CONSIDERED_USES \
((unsigned) PARAM_VALUE (PARAM_IV_MAX_CONSIDERED_USES))
/* If there are at most this number of ivs in the set, try removing unnecessary
ivs from the set always. */
#define ALWAYS_PRUNE_CAND_SET_BOUND \
((unsigned) PARAM_VALUE (PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND))
/* The list of trees for that the decl_rtl field must be reset is stored
here. */
@ -3661,6 +3670,7 @@ iv_ca_set_no_cp (struct ivopts_data *data, struct iv_ca *ivs,
/* Do not count the pseudocandidates. */
if (cp->cand->iv)
ivs->n_regs--;
ivs->n_cands--;
ivs->cand_cost -= cp->cand->cost;
}
@ -3710,6 +3720,7 @@ iv_ca_set_cp (struct ivopts_data *data, struct iv_ca *ivs,
/* Do not count the pseudocandidates. */
if (cp->cand->iv)
ivs->n_regs++;
ivs->n_cands++;
ivs->cand_cost += cp->cand->cost;
}
@ -3806,6 +3817,27 @@ iv_ca_delta_add (struct iv_use *use, struct cost_pair *old_cp,
return change;
}
/* Joins two lists of changes L1 and L2. Destructive -- old lists
are rewritten. */
static struct iv_ca_delta *
iv_ca_delta_join (struct iv_ca_delta *l1, struct iv_ca_delta *l2)
{
struct iv_ca_delta *last;
if (!l2)
return l1;
if (!l1)
return l2;
for (last = l1; last->next_change; last = last->next_change)
continue;
last->next_change = l2;
return l1;
}
/* Returns candidate by that USE is expressed in IVS. */
static struct cost_pair *
@ -3814,6 +3846,28 @@ iv_ca_cand_for_use (struct iv_ca *ivs, struct iv_use *use)
return ivs->cand_for_use[use->id];
}
/* Reverse the list of changes DELTA, forming the inverse to it. */
static struct iv_ca_delta *
iv_ca_delta_reverse (struct iv_ca_delta *delta)
{
struct iv_ca_delta *act, *next, *prev = NULL;
struct cost_pair *tmp;
for (act = delta; act; act = next)
{
next = act->next_change;
act->next_change = prev;
prev = act;
tmp = act->old_cp;
act->old_cp = act->new_cp;
act->new_cp = tmp;
}
return prev;
}
/* Commit changes in DELTA to IVS. If FORWARD is false, the changes are
reverted instead. */
@ -3822,23 +3876,21 @@ iv_ca_delta_commit (struct ivopts_data *data, struct iv_ca *ivs,
struct iv_ca_delta *delta, bool forward)
{
struct cost_pair *from, *to;
struct iv_ca_delta *act;
for (; delta; delta = delta->next_change)
if (!forward)
delta = iv_ca_delta_reverse (delta);
for (act = delta; act; act = act->next_change)
{
if (forward)
{
from = delta->old_cp;
to = delta->new_cp;
}
else
{
from = delta->new_cp;
to = delta->old_cp;
}
gcc_assert (iv_ca_cand_for_use (ivs, delta->use) == from);
iv_ca_set_cp (data, ivs, delta->use, to);
from = act->old_cp;
to = act->new_cp;
gcc_assert (iv_ca_cand_for_use (ivs, act->use) == from);
iv_ca_set_cp (data, ivs, act->use, to);
}
if (!forward)
iv_ca_delta_reverse (delta);
}
/* Returns true if CAND is used in IVS. */
@ -3849,6 +3901,14 @@ iv_ca_cand_used_p (struct iv_ca *ivs, struct iv_cand *cand)
return ivs->n_cand_uses[cand->id] > 0;
}
/* Returns number of induction variable candidates in the set IVS. */
static unsigned
iv_ca_n_cands (struct iv_ca *ivs)
{
return ivs->n_cands;
}
/* Free the list of changes DELTA. */
static void
@ -3877,6 +3937,7 @@ iv_ca_new (struct ivopts_data *data)
nw->cand_for_use = xcalloc (n_iv_uses (data), sizeof (struct cost_pair *));
nw->n_cand_uses = xcalloc (n_iv_cands (data), sizeof (unsigned));
nw->cands = BITMAP_XMALLOC ();
nw->n_cands = 0;
nw->n_regs = 0;
nw->cand_use_cost = 0;
nw->cand_cost = 0;
@ -3920,11 +3981,13 @@ iv_ca_dump (struct ivopts_data *data, FILE *file, struct iv_ca *ivs)
}
/* Try changing candidate in IVS to CAND for each use. Return cost of the
new set, and store differences in DELTA. */
new set, and store differences in DELTA. Number of induction variables
in the new set is stored to N_IVS. */
static unsigned
iv_ca_extend (struct ivopts_data *data, struct iv_ca *ivs,
struct iv_cand *cand, struct iv_ca_delta **delta)
struct iv_cand *cand, struct iv_ca_delta **delta,
unsigned *n_ivs)
{
unsigned i, cost;
struct iv_use *use;
@ -3955,6 +4018,8 @@ iv_ca_extend (struct ivopts_data *data, struct iv_ca *ivs,
iv_ca_delta_commit (data, ivs, *delta, true);
cost = iv_ca_cost (ivs);
if (n_ivs)
*n_ivs = iv_ca_n_cands (ivs);
iv_ca_delta_commit (data, ivs, *delta, false);
return cost;
@ -4044,6 +4109,55 @@ iv_ca_narrow (struct ivopts_data *data, struct iv_ca *ivs,
return cost;
}
/* Try optimizing the set of candidates IVS by removing candidates different
from to EXCEPT_CAND from it. Return cost of the new set, and store
differences in DELTA. */
static unsigned
iv_ca_prune (struct ivopts_data *data, struct iv_ca *ivs,
struct iv_cand *except_cand, struct iv_ca_delta **delta)
{
bitmap_iterator bi;
struct iv_ca_delta *act_delta, *best_delta;
unsigned i, best_cost, acost;
struct iv_cand *cand;
best_delta = NULL;
best_cost = iv_ca_cost (ivs);
EXECUTE_IF_SET_IN_BITMAP (ivs->cands, 0, i, bi)
{
cand = iv_cand (data, i);
if (cand == except_cand)
continue;
acost = iv_ca_narrow (data, ivs, cand, &act_delta);
if (acost < best_cost)
{
best_cost = acost;
iv_ca_delta_free (&best_delta);
best_delta = act_delta;
}
else
iv_ca_delta_free (&act_delta);
}
if (!best_delta)
{
*delta = NULL;
return best_cost;
}
/* Recurse to possibly remove other unnecessary ivs. */
iv_ca_delta_commit (data, ivs, best_delta, true);
best_cost = iv_ca_prune (data, ivs, except_cand, delta);
iv_ca_delta_commit (data, ivs, best_delta, false);
*delta = iv_ca_delta_join (best_delta, *delta);
return best_cost;
}
/* Tries to extend the sets IVS in the best possible way in order
to express the USE. */
@ -4088,7 +4202,7 @@ try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs,
continue;
iv_ca_set_cp (data, ivs, use, cp);
act_cost = iv_ca_extend (data, ivs, cand, &act_delta);
act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL);
iv_ca_set_no_cp (data, ivs, use);
act_delta = iv_ca_delta_add (use, NULL, cp, act_delta);
@ -4121,7 +4235,7 @@ try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs,
act_delta = NULL;
iv_ca_set_cp (data, ivs, use, cp);
act_cost = iv_ca_extend (data, ivs, cand, &act_delta);
act_cost = iv_ca_extend (data, ivs, cand, &act_delta, NULL);
iv_ca_set_no_cp (data, ivs, use);
act_delta = iv_ca_delta_add (use, iv_ca_cand_for_use (ivs, use),
cp, act_delta);
@ -4168,25 +4282,36 @@ get_initial_solution (struct ivopts_data *data)
static bool
try_improve_iv_set (struct ivopts_data *data, struct iv_ca *ivs)
{
unsigned i, acost, best_cost = iv_ca_cost (ivs);
struct iv_ca_delta *best_delta = NULL, *act_delta;
unsigned i, acost, best_cost = iv_ca_cost (ivs), n_ivs;
struct iv_ca_delta *best_delta = NULL, *act_delta, *tmp_delta;
struct iv_cand *cand;
/* Try altering the set of induction variables by one. */
/* Try extending the set of induction variables by one. */
for (i = 0; i < n_iv_cands (data); i++)
{
cand = iv_cand (data, i);
if (iv_ca_cand_used_p (ivs, cand))
acost = iv_ca_narrow (data, ivs, cand, &act_delta);
else
acost = iv_ca_extend (data, ivs, cand, &act_delta);
continue;
acost = iv_ca_extend (data, ivs, cand, &act_delta, &n_ivs);
if (!act_delta)
continue;
/* If we successfully added the candidate and the set is small enough,
try optimizing it by removing other candidates. */
if (n_ivs <= ALWAYS_PRUNE_CAND_SET_BOUND)
{
iv_ca_delta_commit (data, ivs, act_delta, true);
acost = iv_ca_prune (data, ivs, cand, &tmp_delta);
iv_ca_delta_commit (data, ivs, act_delta, false);
act_delta = iv_ca_delta_join (act_delta, tmp_delta);
}
if (acost < best_cost)
{
best_cost = acost;
if (best_delta)
iv_ca_delta_free (&best_delta);
iv_ca_delta_free (&best_delta);
best_delta = act_delta;
}
else
@ -4194,9 +4319,17 @@ try_improve_iv_set (struct ivopts_data *data, struct iv_ca *ivs)
}
if (!best_delta)
return false;
{
/* Try removing the candidates from the set instead. */
best_cost = iv_ca_prune (data, ivs, NULL, &best_delta);
/* Nothing more we can do. */
if (!best_delta)
return false;
}
iv_ca_delta_commit (data, ivs, best_delta, true);
gcc_assert (best_cost == iv_ca_cost (ivs));
iv_ca_delta_free (&best_delta);
return true;
}