Don't interfere with the __builtin_foo namespace under MSVC
This patch follows up on feedback received in the review for D32988. Specifically that libc++ should not mess with the __builtin namespace, and that libc++ should use __popcnt to implement __pop_count under MSVC. llvm-svn: 302731
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3c5e4237c6
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@ -645,7 +645,7 @@ template <class BidirectionalIterator, class Compare>
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#include "support/ibm/support.h"
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#endif
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#if defined(_LIBCPP_COMPILER_MSVC)
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#include "support/win32/msvc_builtin_support.h"
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#include <intrin.h>
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#endif
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#include <__undef_min_max>
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@ -783,51 +783,132 @@ struct __debug_less
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// Precondition: __x != 0
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inline _LIBCPP_INLINE_VISIBILITY
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unsigned
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__ctz(unsigned __x)
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{
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unsigned __ctz(unsigned __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return static_cast<unsigned>(__builtin_ctz(__x));
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#else
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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static_assert(sizeof(unsigned long) == 4, "");
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unsigned long where;
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// Search from LSB to MSB for first set bit.
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// Returns zero if no set bit is found.
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if (_BitScanForward(&where, mask))
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return where;
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return 32;
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#endif
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}
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inline _LIBCPP_INLINE_VISIBILITY
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unsigned long
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__ctz(unsigned long __x)
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{
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unsigned long __ctz(unsigned long __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return static_cast<unsigned long>(__builtin_ctzl(__x));
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#else
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static_assert(sizeof(unsigned long) == sizeof(unsigned), "");
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return __ctz(static_cast<unsigned>(__x));
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#endif
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}
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inline _LIBCPP_INLINE_VISIBILITY
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unsigned long long
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__ctz(unsigned long long __x)
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{
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unsigned long long __ctz(unsigned long long __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return static_cast<unsigned long long>(__builtin_ctzll(__x));
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#else
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unsigned long where;
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// Search from LSB to MSB for first set bit.
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// Returns zero if no set bit is found.
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#if defined(_LIBCPP_HAS_BITSCAN64)
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(defined(_M_AMD64) || defined(__x86_64__))
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if (_BitScanForward64(&where, mask))
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return static_cast<int>(where);
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#else
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// Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
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// Scan the Low Word.
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if (_BitScanForward(&where, static_cast<unsigned long>(mask)))
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return where;
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// Scan the High Word.
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if (_BitScanForward(&where, static_cast<unsigned long>(mask >> 32)))
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return where + 32; // Create a bit offset from the LSB.
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#endif
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return 64;
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#endif // _LIBCPP_COMPILER_MSVC
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}
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// Precondition: __x != 0
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inline _LIBCPP_INLINE_VISIBILITY
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unsigned
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__clz(unsigned __x)
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{
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unsigned __clz(unsigned __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return static_cast<unsigned>(__builtin_clz(__x));
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#else
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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static_assert(sizeof(unsigned long) == 4, "");
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unsigned long where;
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// Search from LSB to MSB for first set bit.
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// Returns zero if no set bit is found.
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if (_BitScanReverse(&where, mask))
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return 31 - where;
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return 32; // Undefined Behavior.
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#endif
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}
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inline _LIBCPP_INLINE_VISIBILITY
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unsigned long
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__clz(unsigned long __x)
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{
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unsigned long __clz(unsigned long __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return static_cast<unsigned long>(__builtin_clzl (__x));
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#else
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static_assert(sizeof(unsigned) == sizeof(unsigned long), "");
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return __clz(static_cast<unsigned>(__x));
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#endif
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}
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inline _LIBCPP_INLINE_VISIBILITY
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unsigned long long
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__clz(unsigned long long __x)
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{
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unsigned long long __clz(unsigned long long __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return static_cast<unsigned long long>(__builtin_clzll(__x));
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#else
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unsigned long where;
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// BitScanReverse scans from MSB to LSB for first set bit.
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// Returns 0 if no set bit is found.
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#if defined(_LIBCPP_HAS_BITSCAN64)
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if (_BitScanReverse64(&where, mask))
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return static_cast<int>(63 - where);
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#else
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// Scan the high 32 bits.
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if (_BitScanReverse(&where, static_cast<unsigned long>(mask >> 32)))
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return 63 - (where + 32); // Create a bit offset from the MSB.
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// Scan the low 32 bits.
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if (_BitScanReverse(&where, static_cast<unsigned long>(mask)))
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return 63 - where;
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#endif
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return 64; // Undefined Behavior.
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#endif // _LIBCPP_COMPILER_MSVC
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}
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inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned __x) {return __builtin_popcount (__x);}
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inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long __x) {return __builtin_popcountl (__x);}
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inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {return __builtin_popcountll(__x);}
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inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return __builtin_popcount (__x);
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#else
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static_assert(sizeof(unsigned) == 4, "");
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return __popcnt(__x);
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#endif
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}
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inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return __builtin_popcountl (__x);
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#else
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static_assert(sizeof(unsigned long) == 4, "");
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return __popcnt(__x);
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#endif
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}
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inline _LIBCPP_INLINE_VISIBILITY int __pop_count(unsigned long long __x) {
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#ifndef _LIBCPP_COMPILER_MSVC
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return __builtin_popcountll(__x);
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#else
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static_assert(sizeof(unsigned long long) == 8, "");
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return __popcnt64(__x);
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#endif
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}
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// all_of
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@ -1,156 +0,0 @@
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// -*- C++ -*-
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//===----------------------- support/win32/support.h ----------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP_SUPPORT_WIN32_MSVC_BUILTIN_SUPPORT_H
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#define _LIBCPP_SUPPORT_WIN32_MSVC_BUILTIN_SUPPORT_H
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#ifndef _LIBCPP_COMPILER_MSVC
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#error "This header can only be included when using Microsoft's C1XX frontend"
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#endif
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#ifndef NOMINMAX
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#define NOMINMAX
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#endif
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// "builtins" not implemented here for Clang or GCC as they provide
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// implementations. Assuming required for elsewhere else, certainly MSVC.
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#include <intrin.h>
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// Bit builtin's make these assumptions when calling _BitScanForward/Reverse
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// etc. These assumptions are expected to be true for Win32/Win64 which this
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// file supports.
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static_assert(sizeof(unsigned long long) == 8, "");
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static_assert(sizeof(unsigned long) == 4, "");
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static_assert(sizeof(unsigned int) == 4, "");
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_LIBCPP_ALWAYS_INLINE int __builtin_popcount(unsigned int x)
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{
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// Binary: 0101...
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static const unsigned int m1 = 0x55555555;
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// Binary: 00110011..
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static const unsigned int m2 = 0x33333333;
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// Binary: 4 zeros, 4 ones ...
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static const unsigned int m4 = 0x0f0f0f0f;
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// The sum of 256 to the power of 0,1,2,3...
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static const unsigned int h01 = 0x01010101;
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// Put count of each 2 bits into those 2 bits.
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x -= (x >> 1) & m1;
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// Put count of each 4 bits into those 4 bits.
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x = (x & m2) + ((x >> 2) & m2);
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// Put count of each 8 bits into those 8 bits.
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x = (x + (x >> 4)) & m4;
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// Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24).
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return (x * h01) >> 24;
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}
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_LIBCPP_ALWAYS_INLINE int __builtin_popcountl(unsigned long x)
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{
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return __builtin_popcount(static_cast<int>(x));
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}
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_LIBCPP_ALWAYS_INLINE int __builtin_popcountll(unsigned long long x)
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{
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// Binary: 0101...
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static const unsigned long long m1 = 0x5555555555555555;
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// Binary: 00110011..
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static const unsigned long long m2 = 0x3333333333333333;
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// Binary: 4 zeros, 4 ones ...
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static const unsigned long long m4 = 0x0f0f0f0f0f0f0f0f;
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// The sum of 256 to the power of 0,1,2,3...
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static const unsigned long long h01 = 0x0101010101010101;
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// Put count of each 2 bits into those 2 bits.
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x -= (x >> 1) & m1;
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// Put count of each 4 bits into those 4 bits.
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x = (x & m2) + ((x >> 2) & m2);
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// Put count of each 8 bits into those 8 bits.
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x = (x + (x >> 4)) & m4;
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// Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ...
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return static_cast<int>((x * h01) >> 56);
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}
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// Returns the number of trailing 0-bits in x, starting at the least significant
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// bit position. If x is 0, the result is undefined.
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_LIBCPP_ALWAYS_INLINE int __builtin_ctzll(unsigned long long mask)
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{
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unsigned long where;
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// Search from LSB to MSB for first set bit.
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// Returns zero if no set bit is found.
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#if defined(_LIBCPP_HAS_BITSCAN64)
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(defined(_M_AMD64) || defined(__x86_64__))
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if (_BitScanForward64(&where, mask))
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return static_cast<int>(where);
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#else
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// Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
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// Scan the Low Word.
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if (_BitScanForward(&where, static_cast<unsigned long>(mask)))
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return static_cast<int>(where);
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// Scan the High Word.
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if (_BitScanForward(&where, static_cast<unsigned long>(mask >> 32)))
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return static_cast<int>(where + 32); // Create a bit offset from the LSB.
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#endif
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return 64;
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}
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_LIBCPP_ALWAYS_INLINE int __builtin_ctzl(unsigned long mask)
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{
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unsigned long where;
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// Search from LSB to MSB for first set bit.
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// Returns zero if no set bit is found.
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if (_BitScanForward(&where, mask))
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return static_cast<int>(where);
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return 32;
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}
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_LIBCPP_ALWAYS_INLINE int __builtin_ctz(unsigned int mask)
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{
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// Win32 and Win64 expectations.
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static_assert(sizeof(mask) == 4, "");
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static_assert(sizeof(unsigned long) == 4, "");
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return __builtin_ctzl(static_cast<unsigned long>(mask));
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}
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// Returns the number of leading 0-bits in x, starting at the most significant
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// bit position. If x is 0, the result is undefined.
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_LIBCPP_ALWAYS_INLINE int __builtin_clzll(unsigned long long mask)
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{
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unsigned long where;
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// BitScanReverse scans from MSB to LSB for first set bit.
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// Returns 0 if no set bit is found.
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#if defined(_LIBCPP_HAS_BITSCAN64)
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if (_BitScanReverse64(&where, mask))
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return static_cast<int>(63 - where);
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#else
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// Scan the high 32 bits.
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if (_BitScanReverse(&where, static_cast<unsigned long>(mask >> 32)))
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return static_cast<int>(63 -
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(where + 32)); // Create a bit offset from the MSB.
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// Scan the low 32 bits.
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if (_BitScanReverse(&where, static_cast<unsigned long>(mask)))
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return static_cast<int>(63 - where);
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#endif
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return 64; // Undefined Behavior.
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}
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_LIBCPP_ALWAYS_INLINE int __builtin_clzl(unsigned long mask)
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{
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unsigned long where;
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// Search from LSB to MSB for first set bit.
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// Returns zero if no set bit is found.
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if (_BitScanReverse(&where, mask))
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return static_cast<int>(31 - where);
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return 32; // Undefined Behavior.
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}
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_LIBCPP_ALWAYS_INLINE int __builtin_clz(unsigned int x)
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{
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return __builtin_clzl(x);
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}
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#endif // _LIBCPP_SUPPORT_WIN32_MSVC_BUILTIN_SUPPORT_H
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