Added BOOST_NOINLINE, BOOST_LIKELY and BOOST_UNLIKELY macros.

[SVN r84679]

doc/macro_reference.qbk

@@ -1003,6 +1003,34 @@ Note that use of this macro can lead to cryptic error messages with some compile
 Consider defining it to `inline` before including the Boost.Config header in order to be
 able to debug errors more easily.
 ]]
+[[`BOOST_NOINLINE`][
+This macro can be used in place of the `inline` keyword to instruct the compiler
+that a function should never be inlined. One should typically use this macro
+to mark functions that are unlikely to be called, such as error handling routines.
+
+Usage example:
+``
+  BOOST_NOINLINE void handle_error(const char* descr)
+  {
+      // ...
+  }
+``
+]]
+[[`BOOST_LIKELY(X)`
+  `BOOST_UNLIKELY(X)`][
+These macros communicate to the compiler that the conditional expression `X` is likely
+or unlikely to yield a positive result. The expression should result in a boolean value.
+The result of the macro is an integer or boolean value equivalent to the result of `X`.
+
+The macros are intended to be used in branching statements. The additional hint they provide
+can be used by the compiler to arrange the compiled code of the branches more effectively.
+
+Usage example:
+``
+  if (BOOST_UNLIKELY(ptr == NULL))
+    handle_error("ptr is NULL");
+``
+]]
 ]
 
 [endsect]

include/boost/config/compiler/clang.hpp

@@ -26,6 +26,14 @@
 
 #define BOOST_HAS_NRVO
 
+// Branch prediction hints
+#if defined(__has_builtin)
+#if __has_builtin(__builtin_expect)
+#define BOOST_LIKELY(x) __builtin_expect(x, 1)
+#define BOOST_UNLIKELY(x) __builtin_expect(x, 0)
+#endif
+#endif
+
 // Clang supports "long long" in all compilation modes.
 #define BOOST_HAS_LONG_LONG
 

include/boost/config/compiler/gcc.hpp

@@ -118,6 +118,10 @@
 #define BOOST_HAS_NRVO
 #endif
 
+// Branch prediction hints
+#define BOOST_LIKELY(x) __builtin_expect(x, 1)
+#define BOOST_UNLIKELY(x) __builtin_expect(x, 0)
+
 //
 // Dynamic shared object (DSO) and dynamic-link library (DLL) support
 //
@@ -135,7 +139,7 @@
 #  endif
 #  define BOOST_SYMBOL_VISIBLE __attribute__((visibility("default")))
 #else
-// config/platform/win32.hpp will define BOOST_SYMBOL_EXPORT, etc., unless already defined  
+// config/platform/win32.hpp will define BOOST_SYMBOL_EXPORT, etc., unless already defined
 #  define BOOST_SYMBOL_EXPORT
 #endif
 
@@ -158,7 +162,7 @@
 //
 // We disable this if the compiler is really nvcc as it
 // doesn't actually support __int128 as of CUDA_VERSION=5000
-// even though it defines __SIZEOF_INT128__.  
+// even though it defines __SIZEOF_INT128__.
 // See https://svn.boost.org/trac/boost/ticket/8048
 // Only re-enable this for nvcc if you're absolutely sure
 // of the circumstances under which it's supported:

include/boost/config/compiler/intel.hpp

@@ -154,6 +154,14 @@ template<> struct assert_intrinsic_wchar_t<unsigned short> {};
 #  define BOOST_HAS_NRVO
 #endif
 
+// Branch prediction hints
+// I'm not sure 8.0 was the first version to support these builtins,
+// update the condition if the version is not accurate. (Andrey Semashev)
+#if defined(__GNUC__) && BOOST_INTEL_CXX_VERSION >= 800
+#define BOOST_LIKELY(x) __builtin_expect(x, 1)
+#define BOOST_UNLIKELY(x) __builtin_expect(x, 0)
+#endif
+
 //
 // versions check:
 // we don't support Intel prior to version 5.0:

include/boost/config/suffix.hpp

@@ -632,7 +632,7 @@ namespace std{ using ::type_info; }
 // Set some default values GPU support
 //
 #  ifndef BOOST_GPU_ENABLED
-#  define BOOST_GPU_ENABLED 
+#  define BOOST_GPU_ENABLED
 #  endif
 
 // BOOST_FORCEINLINE ---------------------------------------------//
@@ -648,6 +648,34 @@ namespace std{ using ::type_info; }
 #  endif
 #endif
 
+// BOOST_NOINLINE ---------------------------------------------//
+// Macro to use in place of 'inline' to prevent a function to be inlined
+#if !defined(BOOST_NOINLINE)
+#  if defined(_MSC_VER)
+#    define BOOST_NOINLINE __declspec(noinline)
+#  elif defined(__GNUC__) && __GNUC__ > 3
+     // Clang also defines __GNUC__ (as 4)
+#    define BOOST_NOINLINE __attribute__ ((__noinline__))
+#  else
+#    define BOOST_NOINLINE
+#  endif
+#endif
+
+// Branch prediction hints
+// These macros are intended to wrap conditional expressions that yield true or false
+//
+//  if (BOOST_LIKELY(var == 10))
+//  {
+//     // the most probable code here
+//  }
+//
+#if !defined(BOOST_LIKELY)
+#  define BOOST_LIKELY(x) x
+#endif
+#if !defined(BOOST_UNLIKELY)
+#  define BOOST_UNLIKELY(x) x
+#endif
+
 //
 // Set BOOST_NO_DECLTYPE_N3276 when BOOST_NO_DECLTYPE is defined
 //