From 6732eb9eb5db7b4496c4421a5866476a8aefd981 Mon Sep 17 00:00:00 2001
From: Stefan Weil <sw@weilnetz.de>
Date: Wed, 20 May 2020 20:06:23 +0200
Subject: [PATCH] Clean code for NEON support

Include it only for NEON and remove unneeded code.

Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 src/api/tesseractmain.cpp      | 5 ++++-
 src/arch/intsimdmatrix.h       | 5 +++--
 src/arch/intsimdmatrixneon.cpp | 6 ++----
 src/arch/simddetect.cpp        | 9 +++++----
 4 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/api/tesseractmain.cpp b/src/api/tesseractmain.cpp
index bbfc3b7e..8e5513e5 100644
--- a/src/api/tesseractmain.cpp
+++ b/src/api/tesseractmain.cpp
@@ -135,13 +135,16 @@ static void PrintVersionInfo() {
     }
   }
 #endif
+#if defined(HAVE_NEON)
+  if (tesseract::SIMDDetect::IsNEONAvailable()) printf(" Found NEON\n");
+#else
   if (tesseract::SIMDDetect::IsAVX512BWAvailable()) printf(" Found AVX512BW\n");
   if (tesseract::SIMDDetect::IsAVX512FAvailable()) printf(" Found AVX512F\n");
   if (tesseract::SIMDDetect::IsAVX2Available()) printf(" Found AVX2\n");
   if (tesseract::SIMDDetect::IsAVXAvailable()) printf(" Found AVX\n");
   if (tesseract::SIMDDetect::IsFMAAvailable()) printf(" Found FMA\n");
   if (tesseract::SIMDDetect::IsSSEAvailable()) printf(" Found SSE\n");
-  if (tesseract::SIMDDetect::IsNEONAvailable()) printf(" Found NEON\n");
+#endif
 #ifdef _OPENMP
   printf(" Found OpenMP %d\n", _OPENMP);
 #endif
diff --git a/src/arch/intsimdmatrix.h b/src/arch/intsimdmatrix.h
index 41e78447..7f208aba 100644
--- a/src/arch/intsimdmatrix.h
+++ b/src/arch/intsimdmatrix.h
@@ -2,7 +2,6 @@
 // File:        intsimdmatrix.h
 // Description: Base class for 8-bit int SIMD matrix multipliers.
 // Author:      Ray Smith
-// Created:     Tue Aug 15 07:37:20 PST 2017
 //
 // (C) Copyright 2017, Google Inc.
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -114,9 +113,11 @@ struct IntSimdMatrix {
   // num_input_groups_ = num_inputs_per_register_ / num_inputs_per_group_
 
   static const IntSimdMatrix* intSimdMatrix;
+  // Only available with NEON.
+  static const IntSimdMatrix intSimdMatrixNEON;
+  // Only available with AVX2 / SSE.
   static const IntSimdMatrix intSimdMatrixAVX2;
   static const IntSimdMatrix intSimdMatrixSSE;
-  static const IntSimdMatrix intSimdMatrixNEON;
 };
 
 }  // namespace tesseract
diff --git a/src/arch/intsimdmatrixneon.cpp b/src/arch/intsimdmatrixneon.cpp
index 220e1b7a..d1b6b8a3 100644
--- a/src/arch/intsimdmatrixneon.cpp
+++ b/src/arch/intsimdmatrixneon.cpp
@@ -16,9 +16,7 @@
 // limitations under the License.
 ///////////////////////////////////////////////////////////////////////
 
-#if !defined(__ARM_NEON)
-//#error Implementation only for NEON capable architectures
-#else
+#if defined(__ARM_NEON)
 
 #include "intsimdmatrix.h"
 
@@ -158,4 +156,4 @@ const IntSimdMatrix IntSimdMatrix::intSimdMatrixNEON = {
 
 }  // namespace tesseract.
 
-#endif
+#endif /* __ARM_NEON */
diff --git a/src/arch/simddetect.cpp b/src/arch/simddetect.cpp
index 22acd237..74919acf 100644
--- a/src/arch/simddetect.cpp
+++ b/src/arch/simddetect.cpp
@@ -66,6 +66,10 @@ static STRING_VAR(dotproduct, "auto",
 
 SIMDDetect SIMDDetect::detector;
 
+#if defined(HAVE_NEON)
+// If true, then Neon has been detected.
+bool SIMDDetect::neon_available_;
+#else
 // If true, then AVX has been detected.
 bool SIMDDetect::avx_available_;
 bool SIMDDetect::avx2_available_;
@@ -75,8 +79,7 @@ bool SIMDDetect::avx512BW_available_;
 bool SIMDDetect::fma_available_;
 // If true, then SSe4.1 has been detected.
 bool SIMDDetect::sse_available_;
-// If true, then Neon has been detected.
-bool SIMDDetect::neon_available_;
+#endif
 
 // Computes and returns the dot product of the two n-vectors u and v.
 static double DotProductGeneric(const double* u, const double* v, int n) {
@@ -188,8 +191,6 @@ SIMDDetect::SIMDDetect() {
       neon_available_ = (android_getCpuFeatures() &
                          ANDROID_CPU_ARM64_FEATURE_ASIMD);
 #endif
-    else
-      neon_available_ = false;
   }
 #else
   /* Assume linux */