[PATCH] Remove wrong assert about gcov_type (PR lto/79587).

[PATCH] Remove wrong assert about gcov_type (PR lto/79587).

[Martin Liška]

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Hello.

As described in the PR, we represent unsigned long types as gcov_type in compiler.
That can lead to a negative value in context of GCOV_SINGLE_VALUE (coming from DIV/MOV expression).
Thus, we have to relax the assert.

Patch can bootstrap on ppc64le-redhat-linux and survives regression tests. And Python can be bootstrapped
with the patch.

Ready to be installed?
Martin

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From ccee30401dc59b41f962330b5f5390075813be14 Mon Sep 17 00:00:00 2001
From: marxin <mliska@suse.cz>
Date: Mon, 20 Feb 2017 15:55:08 +0100
Subject: [PATCH] Remove wrong assert about gcov_type (PR lto/79587).

gcc/ChangeLog:

2017-02-20  Martin Liska  <mliska@suse.cz>

	PR lto/79587
	* data-streamer-in.c (streamer_read_gcov_count): Remove assert.
	* data-streamer-out.c (streamer_write_gcov_count_stream):
	Likewise.
	* value-prof.c (stream_out_histogram_value): Make assert more
	precise based on type of counter.

gcc/testsuite/ChangeLog:

2017-02-20  Martin Liska  <mliska@suse.cz>

	PR lto/79587
	* gcc.dg/tree-prof/pr79587.c: New test.
---
 gcc/data-streamer-in.c                   |  1 -
 gcc/data-streamer-out.c                  |  1 -
 gcc/testsuite/gcc.dg/tree-prof/pr79587.c | 26 ++++++++++++++++++++++++++
 gcc/value-prof.c                         | 12 +++++++++++-
 4 files changed, 37 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/tree-prof/pr79587.c

diff --git a/gcc/data-streamer-in.c b/gcc/data-streamer-in.c
index b38d91353fc..ad32ce1e99a 100644
--- a/gcc/data-streamer-in.c
+++ b/gcc/data-streamer-in.c
@@ -181,7 +181,6 @@ gcov_type
 streamer_read_gcov_count (struct lto_input_block *ib)
 {
   gcov_type ret = streamer_read_hwi (ib);
-  gcc_assert (ret >= 0);
   return ret;
 }
 
diff --git a/gcc/data-streamer-out.c b/gcc/data-streamer-out.c
index 1ee8c9f53af..1e8feb1e74a 100644
--- a/gcc/data-streamer-out.c
+++ b/gcc/data-streamer-out.c
@@ -340,7 +340,6 @@ streamer_write_hwi_stream (struct lto_output_stream *obs, HOST_WIDE_INT work)
 void
 streamer_write_gcov_count_stream (struct lto_output_stream *obs, gcov_type work)
 {
-  gcc_assert (work >= 0);
   gcc_assert ((HOST_WIDE_INT) work == work);
   streamer_write_hwi_stream (obs, work);
 }
diff --git a/gcc/testsuite/gcc.dg/tree-prof/pr79587.c b/gcc/testsuite/gcc.dg/tree-prof/pr79587.c
new file mode 100644
index 00000000000..517e0819919
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-prof/pr79587.c
@@ -0,0 +1,26 @@
+/* { dg-require-effective-target lto } */
+/* { dg-options "-O2 -flto" } */
+
+unsigned long global = -12345;
+
+unsigned long
+__attribute__((noinline))
+test(unsigned long v, unsigned long v2)
+{
+  unsigned long x = v % v2;
+
+  return x;
+}
+
+int main(int argc, char **argv)
+{
+  unsigned long r = 0;
+
+  for (int i = 0; i < 100; i++)
+    r += test(argc, global);
+
+  if (r != 100)
+    __builtin_abort ();
+
+  return 0;
+}
diff --git a/gcc/value-prof.c b/gcc/value-prof.c
index 097e4094095..22dc2c9e257 100644
--- a/gcc/value-prof.c
+++ b/gcc/value-prof.c
@@ -365,7 +365,17 @@ stream_out_histogram_value (struct output_block *ob, histogram_value hist)
       break;
     }
   for (i = 0; i < hist->n_counters; i++)
-    streamer_write_gcov_count (ob, hist->hvalue.counters[i]);
+    {
+      /* When user uses an unsigned type with a big value, constant converted
+	 to gcov_type (a signed type) can be negative.  */
+      gcov_type value = hist->hvalue.counters[i];
+      if (hist->type == HIST_TYPE_SINGLE_VALUE && i == 0)
+	;
+      else
+	gcc_assert (value >= 0);
+
+      streamer_write_gcov_count (ob, value);
+    }
   if (hist->hvalue.next)
     stream_out_histogram_value (ob, hist->hvalue.next);
 }
-- 
2.11.0

Re: [PATCH] Remove wrong assert about gcov_type (PR lto/79587).

[Jan Hubicka]

> Hello.
> 
> As described in the PR, we represent unsigned long types as gcov_type in compiler.
> That can lead to a negative value in context of GCOV_SINGLE_VALUE (coming from DIV/MOV expression).
> Thus, we have to relax the assert.
> 
> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests. And Python can be bootstrapped
> with the patch.
> 
> Ready to be installed?
OK,
thanks!
Honza