From 92692e10db991cfabb07c62843525bdc9f56a358 Mon Sep 17 00:00:00 2001
From: Andriy Gerasika <andriy.gerasika@gmail.com>
Date: Mon, 25 Dec 2017 02:51:19 +0200
Subject: [PATCH] >2x performance increase if DLIB_DO_NOT_USE_SIMD is defined
 (#1027)

---
 dlib/simd/simd8f.h | 8 ++++----
 dlib/simd/simd8i.h | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/dlib/simd/simd8f.h b/dlib/simd/simd8f.h
index adbc28d0e..628ba74ee 100644
--- a/dlib/simd/simd8f.h
+++ b/dlib/simd/simd8f.h
@@ -125,8 +125,8 @@ namespace dlib
                 return _high[idx-4];
         }
 
-        inline simd4f low() const { return _low; }
-        inline simd4f high() const { return _high; }
+        inline const simd4f& low() const { return _low; }
+        inline const simd4f& high() const { return _high; }
 
     private:
         simd4f _low, _high;
@@ -141,8 +141,8 @@ namespace dlib
         inline simd8f_bool(const simd4f_bool& low_, const simd4f_bool& high_): _low(low_),_high(high_){}
 
 
-        inline simd4f_bool low() const { return _low; }
-        inline simd4f_bool high() const { return _high; }
+        inline const simd4f_bool& low() const { return _low; }
+        inline const simd4f_bool& high() const { return _high; }
     private:
         simd4f_bool _low,_high;
     };
diff --git a/dlib/simd/simd8i.h b/dlib/simd/simd8i.h
index 8fefa2644..18c06ec7e 100644
--- a/dlib/simd/simd8i.h
+++ b/dlib/simd/simd8i.h
@@ -91,8 +91,8 @@ namespace dlib
                 return _high[idx-4];
         }
 
-        inline simd4i low() const { return _low; }
-        inline simd4i high() const { return _high; }
+        inline const simd4i& low() const { return _low; }
+        inline const simd4i& high() const { return _high; }
 
     private:
         simd4i _low, _high;