From 9302169bd5ad8380ebe95f50986d2b32eb486901 Mon Sep 17 00:00:00 2001
From: Nikolai Kosjar <nikolai.kosjar@digia.com>
Date: Fri, 29 Nov 2013 14:06:50 +0100
Subject: QtConcurrent: Workaround GCC bug 58800 in median calculation

1) Revert 880b614 for libstdc++ <= 4.7.3 || (4.8.0 >= ... <= 4.8.2)
2) Fix off-by-one error in reverted code for Median::_bufferSize <= 2.

Task-number: QTBUG-35058
Change-Id: I9d226c2806c1cf06c3d5b9c9f371262d2d69bf2b
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
---
 src/concurrent/qtconcurrentmedian.h | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'src/concurrent')

diff --git a/src/concurrent/qtconcurrentmedian.h b/src/concurrent/qtconcurrentmedian.h
index b39b3ed32b..ce2afb9c28 100644
--- a/src/concurrent/qtconcurrentmedian.h
+++ b/src/concurrent/qtconcurrentmedian.h
@@ -102,10 +102,19 @@ public:
     {
         if (dirty) {
             dirty = false;
+
+// This is a workaround for http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58800
+// Avoid using std::nth_element for stdlibc++ <= 4.7.3 || (>= 4.8.0 && <= 4.8.2)
+#if defined(__GLIBCXX__) && (__GLIBCXX__ <= 20130411 || (__GLIBCXX__ >= 20130322 && __GLIBCXX__ <= 20131016))
+            QVector<T> sorted = values;
+            std::sort(sorted.begin(), sorted.end());
+            currentMedian = sorted.at(bufferSize / 2);
+#else
             QVector<T> copy = values;
             typename QVector<T>::iterator begin = copy.begin(), mid = copy.begin() + bufferSize/2, end = copy.end();
             std::nth_element(begin, mid, end);
             currentMedian = *mid;
+#endif
         }
         return currentMedian;
     }
-- 
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