From d40b21eebc9d41c3cb9ccbdf6338968436550621 Mon Sep 17 00:00:00 2001
From: Martin Liska <mliska@suse.cz>
Date: Tue, 26 Jan 2021 12:44:34 +0100
Subject: [PATCH] libgcov: improve profile reproducibility

libgcc/ChangeLog:

	PR gcov-profile/98739
	* libgcov.h (gcov_topn_add_value): Do not train when
	we have a merged profile with a negative number of total
	value.
---
 libgcc/libgcov.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libgcc/libgcov.h b/libgcc/libgcov.h
index df08e882dd7..ddc688509bd 100644
--- a/libgcc/libgcov.h
+++ b/libgcc/libgcov.h
@@ -443,7 +443,13 @@ gcov_topn_add_value (gcov_type *counters, gcov_type value, gcov_type count,
 		     int use_atomic, int increment_total)
 {
   if (increment_total)
-    gcov_counter_add (&counters[0], 1, use_atomic);
+    {
+      /* In the multi-threaded mode, we can have an already merged profile
+	 with a negative total value.  In that case, we should bail out.  */
+      if (counters[0] < 0)
+	return 0;
+      gcov_counter_add (&counters[0], 1, use_atomic);
+    }
 
   struct gcov_kvp *prev_node = NULL;
   struct gcov_kvp *minimal_node = NULL;