Re-land: 178586 Avoid fragmenting address space on small windows systems.

Source/wtf/CPU.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007-2009 Torch Mobile, Inc.
  * Copyright (C) 2010, 2011 Research In Motion Limited. All rights reserved.
  * Copyright (C) 2013 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 19 matching lines @@
 #define WTF_CPU_h
 
 #include "wtf/Compiler.h"
 
 /* CPU() - the target CPU architecture */
 #define CPU(WTF_FEATURE) (defined WTF_CPU_##WTF_FEATURE  && WTF_CPU_##WTF_FEATURE)
 
 /* ==== CPU() - the target CPU architecture ==== */
 
 /* This defines CPU(BIG_ENDIAN) or nothing, as appropriate. */
-/* This defines CPU(32BIT) or CPU(64BIT), as appropriate. */
+/* This defines CPU(64BIT) or nothing, as appropriate. */
 
 /* CPU(X86) - i386 / x86 32-bit */
 #if   defined(__i386__) \
     || defined(i386)     \
     || defined(_M_IX86)  \
     || defined(_X86_)    \
     || defined(__THW_INTEL)
 #define WTF_CPU_X86 1
 #endif
 
@@ skipping 110 matching lines @@
 
 #if CPU(ARM_NEON) && (!COMPILER(GCC) || GCC_VERSION_AT_LEAST(4, 7, 0))
 // All NEON intrinsics usage can be disabled by this macro.
 #define HAVE_ARM_NEON_INTRINSICS 1
 #endif
 
 #if defined(__ARM_ARCH_7S__)
 #define WTF_CPU_APPLE_ARMV7S 1
 #endif
 
-#if !defined(WTF_CPU_64BIT)
-#define WTF_CPU_32BIT 1
-#endif
-
 #endif /* ARM */
 
 /* CPU(ARM64) - AArch64 64-bit */
 #if defined(__aarch64__)
 #define WTF_CPU_ARM64 1
 #define WTF_CPU_64BIT 1
 #endif
 
 /* This defines CPU(64BIT). */
 #if defined(__mips__) && (_MIPS_SIM == _ABI64)
 #define WTF_CPU_64BIT 1
 #endif
 
 #endif /* WTF_CPU_h */