From 8d71d7cd025d5b0b62a8cb9fd99c38f1b37fcc7d Mon Sep 17 00:00:00 2001
From: Jan Hubicka <hubicka@ucw.cz>
Date: Fri, 16 Jun 2017 21:02:11 +0200
Subject: [PATCH] predict.c (force_edge_cold): Handle declaring edges
impossible more aggresively.
* predict.c (force_edge_cold): Handle declaring edges impossible
more aggresively.
From-SVN: r249276
---
gcc/ChangeLog | 5 +++++
gcc/predict.c | 33 ++++++++++++++++++++++++++++++++-
2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 44ef8579998e..b22b567358ef 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2017-06-16 Jan Hubicka <hubicka@ucw.cz>
+
+ * predict.c (force_edge_cold): Handle declaring edges impossible
+ more aggresively.
+
2017-06-16 Jan Hubicka <hubicka@ucw.cz>
* tree-ssa-loop-ivcanon.c (remove_exits_and_undefined_stmts): Update
diff --git a/gcc/predict.c b/gcc/predict.c
index 1cb7dc501036..60d1a094d106 100644
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -3968,6 +3968,7 @@ force_edge_cold (edge e, bool impossible)
profile_count old_count = e->count;
int old_probability = e->probability;
int prob_scale = REG_BR_PROB_BASE;
+ bool uninitialized_exit = false;
/* If edge is already improbably or cold, just return. */
if (e->probability <= (impossible ? PROB_VERY_UNLIKELY : 0)
@@ -3978,6 +3979,8 @@ force_edge_cold (edge e, bool impossible)
{
if (e2->count.initialized_p ())
count_sum += e2->count;
+ else
+ uninitialized_exit = true;
prob_sum += e2->probability;
}
@@ -3989,7 +3992,7 @@ force_edge_cold (edge e, bool impossible)
= MIN (e->probability, impossible ? 0 : PROB_VERY_UNLIKELY);
if (impossible)
e->count = profile_count::zero ();
- if (old_probability)
+ else if (old_probability)
e->count = e->count.apply_scale (e->probability, old_probability);
else
e->count = e->count.apply_scale (1, REG_BR_PROB_BASE);
@@ -4016,6 +4019,34 @@ force_edge_cold (edge e, bool impossible)
else
{
e->probability = REG_BR_PROB_BASE;
+ if (e->src->count == profile_count::zero ())
+ return;
+ if (count_sum == profile_count::zero () && !uninitialized_exit
+ && impossible)
+ {
+ bool found = false;
+ for (gimple_stmt_iterator gsi = gsi_start_bb (e->src);
+ !gsi_end_p (gsi); gsi_next (&gsi))
+ {
+ if (stmt_can_terminate_bb_p (gsi_stmt (gsi)))
+ {
+ found = true;
+ break;
+ }
+ }
+ if (!found)
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file,
+ "Making bb %i impossible and dropping count to 0.\n",
+ e->src->index);
+ e->count = profile_count::zero ();
+ e->src->count = profile_count::zero ();
+ FOR_EACH_EDGE (e2, ei, e->src->preds)
+ force_edge_cold (e2, impossible);
+ return;
+ }
+ }
/* If we did not adjusting, the source basic block has no likely edeges
leaving other direction. In that case force that bb cold, too.
--
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