[x265] [PATCH] threadpool.cpp: use WIN system call for popcount

[praveen at multicorewareinc.com]

# HG changeset patch
# User Praveen Tiwari <praveen at multicorewareinc.com>
# Date 1525328839 -19800
#      Thu May 03 11:57:19 2018 +0530
# Branch stable
# Node ID 9cbb2aadcca3a2f7a308ea1dc792fb817bcc5b51
# Parent  69aafa6d70ad4e151f4590766c6b125621c5d007
threadpool.cpp: use WIN system call for popcount

diff -r 69aafa6d70ad -r 9cbb2aadcca3 source/common/threadpool.cpp
--- a/source/common/threadpool.cpp	Wed May 02 15:15:05 2018 +0530
+++ b/source/common/threadpool.cpp	Thu May 03 11:57:19 2018 +0530
@@ -71,21 +71,6 @@
 # define strcasecmp _stricmp
 #endif
 
-#if defined(_WIN32_WINNT) && _WIN32_WINNT >= _WIN32_WINNT_WIN7
-const uint64_t m1 = 0x5555555555555555; //binary: 0101...
-const uint64_t m2 = 0x3333333333333333; //binary: 00110011..
-const uint64_t m3 = 0x0f0f0f0f0f0f0f0f; //binary:  4 zeros,  4 ones ...
-const uint64_t h01 = 0x0101010101010101; //the sum of 256 to the power of 0,1,2,3...
-
-static int popCount(uint64_t x)
-{
-    x -= (x >> 1) & m1;
-    x = (x & m2) + ((x >> 2) & m2);
-    x = (x + (x >> 4)) & m3;
-    return (x * h01) >> 56;
-}
-#endif
-
 namespace X265_NS {
 // x265 private namespace
 
@@ -274,7 +259,7 @@
     for (int i = 0; i < numNumaNodes; i++)
     {
         GetNumaNodeProcessorMaskEx((UCHAR)i, groupAffinityPointer);
-        cpusPerNode[i] = popCount(groupAffinityPointer->Mask);
+        cpusPerNode[i] = __popcnt(static_cast<unsigned int>(groupAffinityPointer->Mask));
     }
     delete groupAffinityPointer;
 #elif HAVE_LIBNUMA
@@ -623,7 +608,7 @@
     for (int i = 0; i < numNumaNodes; i++)
     {
         GetNumaNodeProcessorMaskEx((UCHAR)i, &groupAffinity);
-        cpus += popCount(groupAffinity.Mask);
+        cpus += __popcnt(static_cast<unsigned int>(groupAffinity.Mask));
     }
     return cpus;
 #elif _WIN32