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profile.c (compute_branch_probabilites): Compute probabilities for entry/exit edges; estimate probabilities for zero counts. 

* profile.c (compute_branch_probabilites):  Compute probabilities
	for entry/exit edges; estimate probabilities for zero counts.

From-SVN: r47242
This commit is contained in:
Jan Hubicka 2001-11-21 11:47:02 +00:00
parent 1258ee8070
commit b9224c9422
2 changed files with 52 additions and 25 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Wed Nov 21 12:38:37 CET 2001 Jan Hubicka
* profile.c (compute_branch_probabilites): Compute probabilities
for entry/exit edges; estimate probabilities for zero counts.
2001-11-21 Jakub Jelinek <jakub@redhat.com>
* explow.c (probe_stack_range): Use LCT_NORMAL as second argument

72
gcc/profile.c
View File

@ -411,38 +411,32 @@ compute_branch_probabilities ()
num_never_executed = 0;
num_branches = 0;
for (i = 0; i < n_basic_blocks; i++)
for (i = 0; i <= n_basic_blocks + 1; i++)
{
basic_block bb = BASIC_BLOCK (i);
basic_block bb = GCOV_INDEX_TO_BB (i);
edge e;
gcov_type total;
rtx note;
total = bb->count;
if (total)
for (e = bb->succ; e; e = e->succ_next)
{
e->probability = (e->count * REG_BR_PROB_BASE + total / 2) / total;
if (e->probability < 0 || e->probability > REG_BR_PROB_BASE)
{
error ("Corrupted profile info: prob for %d-%d thought to be %d",
e->src->index, e->dest->index, e->probability);
e->probability = REG_BR_PROB_BASE / 2;
}
}
if (any_condjump_p (bb->end)
&& bb->succ->succ_next)
{
int prob;
edge e;
if (total == 0)
prob = -1;
else
if (total == -1)
num_never_executed++;
else
for (e = bb->succ; e; e = e->succ_next)
{
e->probability = (e->count * REG_BR_PROB_BASE + total / 2) / total;
if (e->probability < 0 || e->probability > REG_BR_PROB_BASE)
{
error ("Corrupted profile info: prob for %d-%d thought to be %d",
e->src->index, e->dest->index, e->probability);
e->probability = REG_BR_PROB_BASE / 2;
}
}
if (bb->index >= 0
&& any_condjump_p (bb->end)
&& bb->succ->succ_next)
{
int prob;
edge e;
int index;
/* Find the branch edge. It is possible that we do have fake
@ -467,9 +461,37 @@ compute_branch_probabilities ()
REG_NOTES (bb->end)
= gen_rtx_EXPR_LIST (REG_BR_PROB, GEN_INT (prob),
REG_NOTES (bb->end));
num_branches++;
}
num_branches++;
}
/* Otherwise distribute the probabilities evenly so we get sane sum.
Use simple heuristics that if there are normal edges, give all abnormals
frequency of 0, otherwise distribute the frequency over abnormals
(this is the case of noreturn calls). */
else
{
for (e = bb->succ; e; e = e->succ_next)
if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
total ++;
if (total)
{
for (e = bb->succ; e; e = e->succ_next)
if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
e->probability = REG_BR_PROB_BASE / total;
else
e->probability = 0;
}
else
{
for (e = bb->succ; e; e = e->succ_next)
total ++;
for (e = bb->succ; e; e = e->succ_next)
e->probability = REG_BR_PROB_BASE / total;
}
if (bb->index >= 0
&& any_condjump_p (bb->end)
&& bb->succ->succ_next)
num_branches++, num_never_executed;
}
}