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https://github.com/GPUOpen-LibrariesAndSDKs/VulkanMemoryAllocator
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Optimized VmaCountBitsSets to use std::popcount when C++20 is enabled
Closes #251
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@ -2574,6 +2574,9 @@ VMA_CALL_PRE void VMA_CALL_POST vmaFreeStatsString(
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#ifdef _MSC_VER
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#include <intrin.h> // For functions like __popcnt, _BitScanForward etc.
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#endif
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#if __cplusplus >= 202002L || _MSVC_LANG >= 202002L // C++20
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#include <bit> // For std::popcount
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#endif
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/*******************************************************************************
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CONFIGURATION SECTION
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@ -3176,12 +3179,16 @@ But you need to check in runtime whether user's CPU supports these, as some old
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*/
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static inline uint32_t VmaCountBitsSet(uint32_t v)
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{
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#if __cplusplus >= 202002L || _MSVC_LANG >= 202002L // C++20
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return std::popcount(v);
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#else
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uint32_t c = v - ((v >> 1) & 0x55555555);
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c = ((c >> 2) & 0x33333333) + (c & 0x33333333);
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c = ((c >> 4) + c) & 0x0F0F0F0F;
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c = ((c >> 8) + c) & 0x00FF00FF;
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c = ((c >> 16) + c) & 0x0000FFFF;
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return c;
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#endif
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}
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static inline uint8_t VmaBitScanLSB(uint64_t mask)
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