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[google] [4.6] fix a bug in capping bb count scaling (issue5786054)
- From: xur at google dot com (Rong Xu)
- To: reply at codereview dot appspotmail dot com,davidxl at google dot com,gcc-patches at gcc dot gnu dot org
- Date: Thu, 8 Mar 2012 10:04:20 -0800 (PST)
- Subject: [google] [4.6] fix a bug in capping bb count scaling (issue5786054)
Hi,
This patch is for google-4_6 branch only.
It fixes a bug in r184378 which makes some capping escape (like
stale max_bb_count in cgraph node).
Tested with the internal benchmark that exposes this issue.
Tested with gcc bootstrap.
-Rong
2012-03-08 Rong Xu <xur@google.com>
* gcc/tree-inline.c (copy_cfg_body): fix the bug in r184378.
Google ref b/6105259.
Index: gcc/tree-inline.c
===================================================================
--- gcc/tree-inline.c (revision 185095)
+++ gcc/tree-inline.c (working copy)
@@ -2210,7 +2210,7 @@
struct cgraph_node *node = cgraph_node (callee_fndecl);
double f_max;
gcov_type max_count_scale;
- gcov_type max_src_bb_cnt;
+ gcov_type max_src_bb_cnt = 0;
gcov_type max_value = ((gcov_type) 1 << ((sizeof(gcov_type) * 8) - 1));
max_value = ~max_value;
count_scale = (REG_BR_PROB_BASE * (double)count
@@ -2220,14 +2220,13 @@
This can happen for comdat functions where the counters are split.
It's more likely for recursive inlines. */
gcc_assert (node);
- max_src_bb_cnt = node->max_bb_count;
/* Find the maximum count value to that will be copied. */
FOR_EACH_BB_FN (bb, cfun_to_copy)
if (!blocks_to_copy || bitmap_bit_p (blocks_to_copy, bb->index))
{
- if (bb->count > node->max_bb_count)
- max_src_bb_cnt = node->max_bb_count;
+ if (bb->count > max_src_bb_cnt)
+ max_src_bb_cnt = bb->count;
}
f_max = (double) max_value * REG_BR_PROB_BASE / max_src_bb_cnt - 1;
--
This patch is available for review at http://codereview.appspot.com/5786054