From b0d2af20ae7f15545524c8ba813dcc14faefe524 Mon Sep 17 00:00:00 2001
From: TimQu <tim.quatmann@rwth-aachen.de>
Date: Sat, 28 May 2016 17:24:19 +0200
Subject: [PATCH] added check for existence of __builtin_popcountll (reverted
 from commit 30bcfcad0eb4041f954e4d893d5b0c3bd4f8d4f6 [formerly
 65f94a6d6e9536398b4921953d00304af26514e5])

Former-commit-id: 6aaa503f580c3f460fe707e5a13d9282e5e0ba90
---
 CMakeLists.txt            |  4 ----
 src/storage/BitVector.cpp | 16 ++++++----------
 storm-config.h.in         |  3 ---
 3 files changed, 6 insertions(+), 17 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 42525ae36..f2621cf4d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,7 +13,6 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/resources/cmak
 
 
 include(ExternalProject)
-include(CheckFunctionExists) 
 #############################################################
 ##
 ##	CMake options of StoRM
@@ -106,9 +105,6 @@ message(STATUS "Assuming extension for static libraries: ${STATIC_EXT}")
 ##	Compiler specific settings and definitions
 ##
 #############################################################
-
-CHECK_FUNCTION_EXISTS(__builtin_popcountll, STORM_HAS_BUILTIN_POPCOUNT)
-
 # Path to the no-strict-aliasing target
 set(CONVERSIONHELPER_TARGET "${PROJECT_SOURCE_DIR}/src/utility/ConversionHelper.cpp")
 
diff --git a/src/storage/BitVector.cpp b/src/storage/BitVector.cpp
index a40c89a2d..a60b8c10c 100644
--- a/src/storage/BitVector.cpp
+++ b/src/storage/BitVector.cpp
@@ -549,13 +549,13 @@ namespace storm {
             // First, count all full buckets.
             uint_fast64_t bucket = index >> 6;
             for (uint_fast64_t i = 0; i < bucket; ++i) {
-                // Check how to determine the number of set bits in a bucket
-#ifdef WINDOWS
+                // Check if we are using g++ or clang++ and, if so, use the built-in function
+#if (defined (__GNUG__) || defined(__clang__))
+                result += __builtin_popcountll(buckets[i]);
+#elif defined WINDOWS
 #include <nmmintrin.h>
                 // If the target machine does not support SSE4, this will fail.
                 result += _mm_popcnt_u64(bucketVector[i]);
-#elif defined STORM_HAS_BUILTIN_POPCOUNT
-                result += __builtin_popcountll(buckets[i]);
 #else
                 uint_fast32_t cnt;
                 uint_fast64_t bitset = buckets[i];
@@ -571,12 +571,8 @@ namespace storm {
             if (tmp != 0) {
                 tmp = ~((1ll << (64 - (tmp & mod64mask))) - 1ll);
                 tmp &= buckets[bucket];
-                // Check how to determine the number of set bits in a bucket
-#ifdef WINDOWS
-#include <nmmintrin.h>
-                // If the target machine does not support SSE4, this will fail.
-                result += _mm_popcnt_u64(tmp);
-#elif defined STORM_HAS_BUILTIN_POPCOUNT
+                // Check if we are using g++ or clang++ and, if so, use the built-in function
+#if (defined (__GNUG__) || defined(__clang__))
                 result += __builtin_popcountll(tmp);
 #else
                 uint_fast32_t cnt;
diff --git a/storm-config.h.in b/storm-config.h.in
index 539d75a55..1bc2eac7d 100644
--- a/storm-config.h.in
+++ b/storm-config.h.in
@@ -51,7 +51,4 @@
 
 #cmakedefine STORM_LOG_DISABLE_DEBUG
 
-// Check whether machine supports builtin_popcount
-#cmakedefine STORM_HAS_BUILTIN_POPCOUNT
-
 #endif // STORM_GENERATED_STORMCONFIG_H_