From 2c5123744bae39d080ca33d9463a517417ebafbe Mon Sep 17 00:00:00 2001
From: Jan Hubicka <hubicka@ucw.cz>
Date: Sun, 1 Jan 2017 16:40:29 +0100
Subject: [PATCH] re PR middle-end/77484 (Static branch predictor causes ~6-8%
regression of SPEC2000 GAP)
PR middle-end/77484
* predict.def (PRED_CALL): Update hitrate.
(PRED_INDIR_CALL, PRED_POLYMORPHIC_CALL): New predictors.
* predict.c (tree_estimate_probability_bb): Split CALL predictor
into direct/indirect/polymorphic variants.
From-SVN: r243995
---
gcc/ChangeLog | 8 ++++++++
gcc/predict.c | 7 ++++++-
gcc/predict.def | 8 +++++++-
3 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 07e5c3e592a3..a5767870bcab 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2017-01-01 Jan Hubicka <hubicka@ucw.cz>
+
+ PR middle-end/77484
+ * predict.def (PRED_CALL): Update hitrate.
+ (PRED_INDIR_CALL, PRED_POLYMORPHIC_CALL): New predictors.
+ * predict.c (tree_estimate_probability_bb): Split CALL predictor
+ into direct/indirect/polymorphic variants.
+
2017-01-01 Jakub Jelinek <jakub@redhat.com>
Update copyright years.
diff --git a/gcc/predict.c b/gcc/predict.c
index 82177abeb891..e85573bc51dd 100644
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -2786,7 +2786,12 @@ tree_estimate_probability_bb (basic_block bb)
something exceptional. */
&& gimple_has_side_effects (stmt))
{
- predict_edge_def (e, PRED_CALL, NOT_TAKEN);
+ if (gimple_call_fndecl (stmt))
+ predict_edge_def (e, PRED_CALL, NOT_TAKEN);
+ else if (virtual_method_call_p (gimple_call_fn (stmt)))
+ predict_edge_def (e, PRED_POLYMORPHIC_CALL, TAKEN);
+ else
+ predict_edge_def (e, PRED_INDIR_CALL, TAKEN);
break;
}
}
diff --git a/gcc/predict.def b/gcc/predict.def
index c151ce2104fc..b6b2a402b22e 100644
--- a/gcc/predict.def
+++ b/gcc/predict.def
@@ -116,7 +116,13 @@ DEF_PREDICTOR (PRED_TREE_OPCODE_NONEQUAL, "opcode values nonequal (on trees)",
DEF_PREDICTOR (PRED_TREE_FPOPCODE, "fp_opcode (on trees)", HITRATE (90), 0)
/* Branch guarding call is probably taken. */
-DEF_PREDICTOR (PRED_CALL, "call", HITRATE (67), 0)
+DEF_PREDICTOR (PRED_CALL, "call", HITRATE (55), 0)
+
+/* PRED_CALL is not very reliable predictor and it turns out to be even
+ less reliable for indirect calls and polymorphic calls. For spec2k6
+ the predictio nis slightly in the direction of taking the call. */
+DEF_PREDICTOR (PRED_INDIR_CALL, "indirect call", HITRATE (51), 0)
+DEF_PREDICTOR (PRED_POLYMORPHIC_CALL, "polymorphic call", HITRATE (58), 0)
/* Recursive calls are usually not taken or the function will recurse
indefinitely. */
--
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