From e61e4883464370fc31296ca7b38c9f4122fa2cd9 Mon Sep 17 00:00:00 2001
From: heckflosse <heckflosse67@gmx.de>
Date: Sat, 23 Apr 2016 22:45:40 +0200
Subject: [PATCH] small speedup for lut += operator

---
 rtengine/LUT.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/rtengine/LUT.h b/rtengine/LUT.h
index b128d89b8..76bcf0ccd 100644
--- a/rtengine/LUT.h
+++ b/rtengine/LUT.h
@@ -258,14 +258,19 @@ public:
         return *this;
     }
 
-    // handy to sum up per thread histograms
+    // handy to sum up per thread histograms. #pragma omp simd speeds up the loop by about factor 3 for LUTu (unsigned int).
     LUT<T> & operator+=(LUT<T> &rhs)
     {
         if (rhs.size == this->size) {
+#ifdef _OPENMP
+            #pragma omp simd
+#endif
+
             for(unsigned int i = 0; i < this->size; i++) {
                 data[i] += rhs.data[i];
             }
         }
+
         return *this;
     }