From d9614b5796da09247398f21affe38eeb27f1709e Mon Sep 17 00:00:00 2001
From: Shin <Tom.Cernik@gmail.com>
Date: Tue, 23 Feb 2016 14:08:46 +0100
Subject: [PATCH] AVX fix for non-FMA CPU

---
 CMakeLists.txt                             |  1 -
 cmake/CPUFeatures                          | 14 ++++++++++++++
 src/NeuralNetwork/BasisFunction/Linear.cpp | 13 +++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5ca0f94..1871444 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -18,7 +18,6 @@ if(CPU_SSE3_AVAILABLE)
 
 endif(CPU_SSE3_AVAILABLE)
 
-
 OPTION(USE_AVX "If AVX instruction set should be used." OFF)
 OPTION(USE_SSE "If SSE instruction set should be used." OFF)
 OPTION(USE_SSE2 "If SSE 2 instruction set should be used." ON)
diff --git a/cmake/CPUFeatures b/cmake/CPUFeatures
index 2172282..8b2334e 100644
--- a/cmake/CPUFeatures
+++ b/cmake/CPUFeatures
@@ -10,6 +10,7 @@ macro(CHECK_CPU)
 		  MESSAGE("-- -- Found SSE2")
 		  set(CPU_SSE2_AVAILABLE "true" INTERNAL BOOL "SSE2 available on host")
 	   ELSE ()
+		  MESSAGE("-- -- Not found SSE2")
 	   ENDIF (SSE2_TRUE)
 
 	   STRING(REGEX REPLACE "^.*(sse3).*$" "\\1" SSE_THERE ${CPUINFO})
@@ -18,6 +19,7 @@ macro(CHECK_CPU)
 		  MESSAGE("-- -- Found SSE3")
 		  set(CPU_SSE3_AVAILABLE "true" INTERNAL BOOL "SSE3 available on host")
 	   ELSE ()
+		  MESSAGE("-- -- Not found SSE3")
 	   ENDIF (SSE3_TRUE)
 
 	   STRING(REGEX REPLACE "^.*(sse4_2).*$" "\\1" SSE_THERE ${CPUINFO})
@@ -26,6 +28,7 @@ macro(CHECK_CPU)
 		  MESSAGE("-- -- Found SSE4.2")
 		  set(CPU_SSE4.2_AVAILABLE "true" INTERNAL BOOL "SSE4.2 available on host")
 	   ELSE ()
+		  MESSAGE("-- -- Not found SSE4.2")
 	   ENDIF (SSE4.2_TRUE)
 
 	   STRING(REGEX REPLACE "^.*(avx).*$" "\\1" SSE_THERE ${CPUINFO})
@@ -34,7 +37,18 @@ macro(CHECK_CPU)
 		  MESSAGE("-- -- Found AVX")
 		  set(CPU_AVX_AVAILABLE "TRUE" INTERNAL BOOL "AVX available on host")
 	   ELSE ()
+		  MESSAGE("-- -- Not found AVX")
 	   ENDIF (AVX_TRUE)
+
+	   STRING(REGEX REPLACE "^.*(fma).*$" "\\1" SSE_THERE ${CPUINFO})
+	   STRING(COMPARE EQUAL "fma" "${SSE_THERE}" FMA_TRUE)
+	   IF (FMA_TRUE)
+		  MESSAGE("-- -- Found FMA")
+		  set(CPU_FMA_AVAILABLE "TRUE" INTERNAL BOOL "FMA available on host")
+	   ELSE ()
+		  MESSAGE("-- -- Not found FMA")
+	   ENDIF (FMA_TRUE)
+
 	else()
 		MESSAGE("Error detecting CPU features")
 	endif(CMAKE_SYSTEM_NAME MATCHES "Linux")
diff --git a/src/NeuralNetwork/BasisFunction/Linear.cpp b/src/NeuralNetwork/BasisFunction/Linear.cpp
index c676375..5d74def 100644
--- a/src/NeuralNetwork/BasisFunction/Linear.cpp
+++ b/src/NeuralNetwork/BasisFunction/Linear.cpp
@@ -18,13 +18,26 @@ float NeuralNetwork::BasisFunction::Linear::operator()(const std::vector<float>
 
 	partialSolution.avx=_mm256_setzero_ps();
 
+#ifndef USE_FMA
+	__m256 tmp;
+#endif
 	for(size_t k=0;k<alignedPrev;k+=8) {
 		//TODO: assignement!! -- possible speedup
+#ifdef USE_FMA
 		partialSolution.avx=_mm256_fmadd_ps(_mm256_loadu_ps(weightsData+k),_mm256_loadu_ps(inputData+k),partialSolution.avx);
+#else
+		tmp=_mm256_mul_ps(_mm256_loadu_ps(weightsData+k),_mm256_loadu_ps(inputData+k));
+		partialSolution.avx=_mm256_add_ps(tmp,partialSolution.avx);
+#endif
 	}
 
 	for(size_t k=alignedPrev;k<inputSize;k++) {
+#ifdef USE_FMA
 		partialSolution.avx=_mm256_fmadd_ps(_mm256_set_ps(weightsData[k],0,0,0,0,0,0,0),_mm256_set_ps(inputData[k],0,0,0,0,0,0,0),partialSolution.avx);
+#else
+		tmp=_mm256_mul_ps(_mm256_set_ps(weightsData[k],0,0,0,0,0,0,0),_mm256_set_ps(inputData[k],0,0,0,0,0,0,0));
+		partialSolution.avx=_mm256_add_ps(tmp,partialSolution.avx);
+#endif
 	}
 
 	partialSolution.avx = _mm256_add_ps(partialSolution.avx,  _mm256_permute2f128_ps(partialSolution.avx , partialSolution.avx , 1));