Hi Jeff,
Test case has been added. With the patch, both x86_64-unknown-linux-gnu
and aarch64-none-elf compile the test case successfully.
Okay to commit?
On 04/11/14 21:59, Jeff Law wrote:
On 11/03/14 08:29, Renlin Li wrote:
On 29/10/14 12:42, Teresa Johnson wrote:
Hi Renlin,
Are the incoming edge counts or probabilities insane in this case? I
guess the patch is ok if we need to do this to handle those incoming
insanitiles. But I can't approve patches myself.
Not really, it's just a little bigger than the limit.
For this particular test case, ABC is a threaded path.
B is the fallthrough basic block of A, D is a basic block split from B
(used to be a self loop). A, B and D have roughly the same frequency (
8281, 9100, 8281).
When calculating the path_in_freq, frequencies from AB and DB edges are
accumulated, and the final result is large than BB_FREQ_MAX.
A
100% |
| 9%
------>B---------->C
| |
|100%| 91%
| |
--------D
There are 2 suspicious points:
1, The BD edge is not correctly guessed at the profile stage. However,
anyway it's heuristic, so I don't think, it's here the problem starts.
2, The BD edge is not eliminated before jump threading. But the jump
threading pass will analysis the condition jump statement in B block (In
this particular case, the BD probability should be zero), and makes the
decision to thread it.
Later in the dom pass, the BD edge is indeed removed.
Can you add a testcase please? With a testcase, this patch is OK for
the trunk.
jeff
x86_64-unknown-linux-gnu bootstrap and regression test have been done,
no new issue.
aarch64-none-elf toolchain has been test on the model. No new regression.
gcc/ChangeLog:
2014-11-06 Renlin Li <renlin...@arm.com>
PR middle-end/61529
* tree-ssa-threadupdate.c (compute_path_counts): Bound path_in_freq.
gcc/testsuite/ChangeLog:
2014-11-06 Renlin Li <renlin...@arm.com>
PR middle-end/61529
* gcc.dg/pr61529.c: New.commit fead29d30b2985a1ba338759054f99d71d81f3c0
Author: Renlin Li <renlin...@arm.com>
Date: Tue Oct 28 16:30:42 2014 +0000
fix pr61529
diff --git a/gcc/testsuite/gcc.dg/pr61529.c b/gcc/testsuite/gcc.dg/pr61529.c
new file mode 100644
index 0000000..9ae2e06
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr61529.c
@@ -0,0 +1,26 @@
+/* PR middle-end/61529 */
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+unsigned int a, b, c;
+
+int
+main ()
+{
+ unsigned int d;
+ int e[5];
+
+ for (; b < 1; b++)
+ d = 0;
+ for (; d < 1; d++)
+ a = 0;
+ for (; a < 1; a++)
+ ;
+
+ for (c = 0; c < 5; c++)
+ e[c] = 1;
+ if (e[0])
+ c = 0;
+
+ return 0;
+}
diff --git a/gcc/tree-ssa-threadupdate.c b/gcc/tree-ssa-threadupdate.c
index d2cf4de..e3077a1 100644
--- a/gcc/tree-ssa-threadupdate.c
+++ b/gcc/tree-ssa-threadupdate.c
@@ -730,6 +730,10 @@ compute_path_counts (struct redirection_data *rd,
nonpath_count += ein->count;
}
}
+
+ if (path_in_freq > BB_FREQ_MAX)
+ path_in_freq = BB_FREQ_MAX;
+
BITMAP_FREE (in_edge_srcs);
/* Now compute the fraction of the total count coming into the first
