1 files changed, 1 insertions, 58 deletions
diff --git a/base/bits.h b/base/bits.h
index d101cb731a..a3a59d1dfa 100644
--- a/base/bits.h
+++ b/base/bits.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -10,13 +10,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
-#include "base/compiler_specific.h"
 #include "base/logging.h"
 
-#if defined(COMPILER_MSVC)
-#include <intrin.h>
-#endif
-
 namespace base {
 namespace bits {
 
@@ -54,58 +49,6 @@ inline size_t Align(size_t size, size_t alignment) {
   return (size + alignment - 1) & ~(alignment - 1);
 }
 
-// These functions count the number of leading zeros in a binary value, starting
-// with the most significant bit. C does not have an operator to do this, but
-// fortunately the various compilers have built-ins that map to fast underlying
-// processor instructions.
-#if defined(COMPILER_MSVC)
-
-ALWAYS_INLINE uint32_t CountLeadingZeroBits32(uint32_t x) {
-  unsigned long index;
-  return LIKELY(_BitScanReverse(&index, x)) ? (31 - index) : 32;
-}
-
-#if defined(ARCH_CPU_64_BITS)
-
-// MSVC only supplies _BitScanForward64 when building for a 64-bit target.
-ALWAYS_INLINE uint64_t CountLeadingZeroBits64(uint64_t x) {
-  unsigned long index;
-  return LIKELY(_BitScanReverse64(&index, x)) ? (63 - index) : 64;
-}
-
-#endif
-
-#elif defined(COMPILER_GCC)
-
-// This is very annoying. __builtin_clz has undefined behaviour for an input of
-// 0, even though there's clearly a return value that makes sense, and even
-// though some processor clz instructions have defined behaviour for 0. We could
-// drop to raw __asm__ to do better, but we'll avoid doing that unless we see
-// proof that we need to.
-ALWAYS_INLINE uint32_t CountLeadingZeroBits32(uint32_t x) {
-  return LIKELY(x) ? __builtin_clz(x) : 32;
-}
-
-ALWAYS_INLINE uint64_t CountLeadingZeroBits64(uint64_t x) {
-  return LIKELY(x) ? __builtin_clzll(x) : 64;
-}
-
-#endif
-
-#if defined(ARCH_CPU_64_BITS)
-
-ALWAYS_INLINE size_t CountLeadingZeroBitsSizeT(size_t x) {
-  return CountLeadingZeroBits64(x);
-}
-
-#else
-
-ALWAYS_INLINE size_t CountLeadingZeroBitsSizeT(size_t x) {
-  return CountLeadingZeroBits32(x);
-}
-
-#endif
-
 }  // namespace bits
 }  // namespace base