From patchwork Wed Nov  7 12:47:28 2012
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Subject: : Update bb->count to avoid erroneous partitioning decisions
Date: Wed, 07 Nov 2012 02:47:28 -0000
From: Christian Bruel <christian.bruel@st.com>
X-Patchwork-Id: 197657
Message-Id: <509A5860.3060503@st.com>
To: Jan Hubicka <hubicka@ucw.cz>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>

> OK,
> is bb1 going to die?  If not, probably bb1->count = 0 should be there, if so,
> then the bb1->frequency = 0 is redundant.

Agree, we do 'delete_basic_block (bb1)' and the frequency is not used in
between, so the setting to 0 seems unnecessary.

testing it:


OK when validation completes ?

thanks

Christian


Index: tree-ssa-tail-merge.c
===================================================================
--- tree-ssa-tail-merge.c       (revision 193283)
+++ tree-ssa-tail-merge.c       (working copy)
@@ -1488,8 +1488,9 @@ replace_block_by (basic_block bb1, basic_block bb2
   bb2->frequency += bb1->frequency;
   if (bb2->frequency > BB_FREQ_MAX)
     bb2->frequency = BB_FREQ_MAX;
-  bb1->frequency = 0;

+  bb2->count += bb1->count;
+
   /* Do updates that use bb1, before deleting bb1.  */
   release_last_vdef (bb1);
   same_succ_flush_bb (bb1);