This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
[PATCH] cap frequency in make_forwarder_block PR64326
- From: tbsaunde+gcc at tbsaunde dot org
- To: gcc-patches at gcc dot gnu dot org
- Cc: hubicka at ucw dot cz
- Date: Tue, 10 Feb 2015 09:51:08 -0500
- Subject: [PATCH] cap frequency in make_forwarder_block PR64326
- Authentication-results: sourceware.org; auth=none
From: tbsaunde <tbsaunde@138bc75d-0d04-0410-961f-82ee72b054a4>
In the testcase the block with problematic frequency has to incoming
edges. Each edge has probability 1. The first edge's source bb has
frequency 873/10000, and the second has a frequency of 9409/10000. So
at least one of those is slightly high probably from some sort of rounding
issue related to fixed point, but in any case make_forwarder_block
should not create basic blocks with frequency greater than BB_FREQ_MAX.
bootstrapped + regtested x86_64-linux-gnu, checked test only passes with patch.
pre approved by Honza on irc so committed.
Trev
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 72fbdd7..50fa380 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2015-02-10 Trevor Saunders <tsaunders@mozilla.com>
+
+ PR tree-optimization/64326
+ * cfghooks.c (make_forwarder_block): Cap frequency of created block.
+
2015-02-10 Rainer Emrich <rainer@emrich-ebersheim.de>
PR gcov-profile/61889
diff --git a/gcc/cfghooks.c b/gcc/cfghooks.c
index 4b57280..abeab8c 100644
--- a/gcc/cfghooks.c
+++ b/gcc/cfghooks.c
@@ -863,6 +863,9 @@ make_forwarder_block (basic_block bb, bool (*redirect_edge_p) (edge),
if (redirect_edge_p (e))
{
dummy->frequency += EDGE_FREQUENCY (e);
+ if (dummy->frequency > BB_FREQ_MAX)
+ dummy->frequency = BB_FREQ_MAX;
+
dummy->count += e->count;
fallthru->count += e->count;
ei_next (&ei);
diff --git a/gcc/testsuite/gcc.dg/torture/pr64326.c b/gcc/testsuite/gcc.dg/torture/pr64326.c
new file mode 100644
index 0000000..88ebf35
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr64326.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+
+int a, b, c, d, e, f[5][2];
+char g;
+
+int
+fn1 ()
+{
+ return d && c ? 0 : 1;
+}
+
+int
+fn2 ()
+{
+ int h;
+ for (;;)
+ for (; e;)
+ {
+ int i, j;
+ h = a ? 1 : b;
+ if (h || fn1 () ^ g - 682)
+ {
+ for (i = 0; i < 5; i++)
+ for (j = 0; j < 2; j++)
+ f[i][j] = 0;
+ return 0;
+ }
+ }
+}
+
--
2.1.4