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

1 files changed, 0 insertions, 156 deletions

diff --git a/libcxx/include/support/win32/msvc_builtin_support.h b/libcxx/include/support/win32/msvc_builtin_support.h
deleted file mode 100644
index 0ef63203b63..00000000000
--- a/libcxx/include/support/win32/msvc_builtin_support.h
+++ /dev/null
@@ -1,156 +0,0 @@
-// -*- C++ -*-
-//===----------------------- support/win32/support.h ----------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_SUPPORT_WIN32_MSVC_BUILTIN_SUPPORT_H
-#define _LIBCPP_SUPPORT_WIN32_MSVC_BUILTIN_SUPPORT_H
-
-#ifndef _LIBCPP_COMPILER_MSVC
-#error "This header can only be included when using Microsoft's C1XX frontend"
-#endif
-
-#ifndef NOMINMAX
-#define NOMINMAX
-#endif
-
-// "builtins" not implemented here for Clang or GCC as they provide
-// implementations. Assuming required for elsewhere else, certainly MSVC.
-#include <intrin.h>
-
-// Bit builtin's make these assumptions when calling _BitScanForward/Reverse
-// etc. These assumptions are expected to be true for Win32/Win64 which this
-// file supports.
-static_assert(sizeof(unsigned long long) == 8, "");
-static_assert(sizeof(unsigned long) == 4, "");
-static_assert(sizeof(unsigned int) == 4, "");
-
-_LIBCPP_ALWAYS_INLINE int __builtin_popcount(unsigned int x)
-{
-  // Binary: 0101...
-  static const unsigned int m1 = 0x55555555;
-  // Binary: 00110011..
-  static const unsigned int m2 = 0x33333333;
-  // Binary:  4 zeros,  4 ones ...
-  static const unsigned int m4 = 0x0f0f0f0f;
-  // The sum of 256 to the power of 0,1,2,3...
-  static const unsigned int h01 = 0x01010101;
-  // Put count of each 2 bits into those 2 bits.
-  x -= (x >> 1) & m1;
-  // Put count of each 4 bits into those 4 bits.
-  x = (x & m2) + ((x >> 2) & m2);
-  // Put count of each 8 bits into those 8 bits.
-  x = (x + (x >> 4)) & m4;
-  // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24).
-  return (x * h01) >> 24;
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_popcountl(unsigned long x)
-{
-  return __builtin_popcount(static_cast<int>(x));
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_popcountll(unsigned long long x)
-{
-  // Binary: 0101...
-  static const unsigned long long m1 = 0x5555555555555555;
-  // Binary: 00110011..
-  static const unsigned long long m2 = 0x3333333333333333;
-  // Binary:  4 zeros,  4 ones ...
-  static const unsigned long long m4 = 0x0f0f0f0f0f0f0f0f;
-  // The sum of 256 to the power of 0,1,2,3...
-  static const unsigned long long h01 = 0x0101010101010101;
-  // Put count of each 2 bits into those 2 bits.
-  x -= (x >> 1) & m1;
-  // Put count of each 4 bits into those 4 bits.
-  x = (x & m2) + ((x >> 2) & m2);
-  // Put count of each 8 bits into those 8 bits.
-  x = (x + (x >> 4)) & m4;
-  // Returns left 8 bits of x + (x<<8) + (x<<16) + (x<<24) + ...
-  return static_cast<int>((x * h01) >> 56);
-}
-
-// Returns the number of trailing 0-bits in x, starting at the least significant
-// bit position. If x is 0, the result is undefined.
-_LIBCPP_ALWAYS_INLINE int __builtin_ctzll(unsigned long long mask)
-{
-  unsigned long where;
-// Search from LSB to MSB for first set bit.
-// Returns zero if no set bit is found.
-#if defined(_LIBCPP_HAS_BITSCAN64)
-    (defined(_M_AMD64) || defined(__x86_64__))
-  if (_BitScanForward64(&where, mask))
-    return static_cast<int>(where);
-#else
-  // Win32 doesn't have _BitScanForward64 so emulate it with two 32 bit calls.
-  // Scan the Low Word.
-  if (_BitScanForward(&where, static_cast<unsigned long>(mask)))
-    return static_cast<int>(where);
-  // Scan the High Word.
-  if (_BitScanForward(&where, static_cast<unsigned long>(mask >> 32)))
-    return static_cast<int>(where + 32); // Create a bit offset from the LSB.
-#endif
-  return 64;
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_ctzl(unsigned long mask)
-{
-  unsigned long where;
-  // Search from LSB to MSB for first set bit.
-  // Returns zero if no set bit is found.
-  if (_BitScanForward(&where, mask))
-    return static_cast<int>(where);
-  return 32;
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_ctz(unsigned int mask)
-{
-  // Win32 and Win64 expectations.
-  static_assert(sizeof(mask) == 4, "");
-  static_assert(sizeof(unsigned long) == 4, "");
-  return __builtin_ctzl(static_cast<unsigned long>(mask));
-}
-
-// Returns the number of leading 0-bits in x, starting at the most significant
-// bit position. If x is 0, the result is undefined.
-_LIBCPP_ALWAYS_INLINE int __builtin_clzll(unsigned long long mask)
-{
-  unsigned long where;
-// BitScanReverse scans from MSB to LSB for first set bit.
-// Returns 0 if no set bit is found.
-#if defined(_LIBCPP_HAS_BITSCAN64)
-  if (_BitScanReverse64(&where, mask))
-    return static_cast<int>(63 - where);
-#else
-  // Scan the high 32 bits.
-  if (_BitScanReverse(&where, static_cast<unsigned long>(mask >> 32)))
-    return static_cast<int>(63 -
-                            (where + 32)); // Create a bit offset from the MSB.
-  // Scan the low 32 bits.
-  if (_BitScanReverse(&where, static_cast<unsigned long>(mask)))
-    return static_cast<int>(63 - where);
-#endif
-  return 64; // Undefined Behavior.
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_clzl(unsigned long mask)
-{
-  unsigned long where;
-  // Search from LSB to MSB for first set bit.
-  // Returns zero if no set bit is found.
-  if (_BitScanReverse(&where, mask))
-    return static_cast<int>(31 - where);
-  return 32; // Undefined Behavior.
-}
-
-_LIBCPP_ALWAYS_INLINE int __builtin_clz(unsigned int x)
-{
-  return __builtin_clzl(x);
-}
-
-#endif // _LIBCPP_SUPPORT_WIN32_MSVC_BUILTIN_SUPPORT_H