From 76ef6d0ab0ea0937e8bb92c3a11a6445504d720f Mon Sep 17 00:00:00 2001
From: Alex Deymo <deymo@google.com>
Date: Fri, 28 Jul 2017 16:33:43 +0200
Subject: [PATCH] Allow to predefine FORCE_INLINE macro.

FORCE_INLINE macro is defined based on the compiler used. When using
gcc, it will include "__attribute__((always_inline))" forcing gcc to
always inline all the functions marked as FORCE_INLINE. However, this
can cause a performance degradation of about 15%.

This patch allows to set the FORCE_INLINE macro from the compiler
command line to either "static" or "static inline" giving allowing it
to inline functions as needed when performing optimizations.
---
 lib/lz4.c    | 25 ++++++++++++++++---------
 lib/xxhash.c | 27 ++++++++++++++++-----------
 2 files changed, 32 insertions(+), 20 deletions(-)

diff --git a/lib/lz4.c b/lib/lz4.c
index 87ec6ab..62e4dc2 100644
--- a/lib/lz4.c
+++ b/lib/lz4.c
@@ -96,20 +96,27 @@
 *  Compiler Options
 **************************************/
 #ifdef _MSC_VER    /* Visual Studio */
-#  define FORCE_INLINE static __forceinline
 #  include <intrin.h>
 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
 #  pragma warning(disable : 4293)        /* disable: C4293: too large shift (32-bits) */
-#else
-#  if defined(__GNUC__) || defined(__clang__)
-#    define FORCE_INLINE static inline __attribute__((always_inline))
-#  elif defined(__cplusplus) || (defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
-#    define FORCE_INLINE static inline
-#  else
-#    define FORCE_INLINE static
-#  endif
 #endif  /* _MSC_VER */
 
+#ifndef FORCE_INLINE
+#  ifdef _MSC_VER    /* Visual Studio */
+#    define FORCE_INLINE static __forceinline
+#  else
+#    if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
+#      ifdef __GNUC__
+#        define FORCE_INLINE static inline __attribute__((always_inline))
+#      else
+#        define FORCE_INLINE static inline
+#      endif
+#    else
+#      define FORCE_INLINE static
+#    endif /* __STDC_VERSION__ */
+#  endif  /* _MSC_VER */
+#endif /* FORCE_INLINE */
+
 #if (defined(__GNUC__) && (__GNUC__ >= 3)) || (defined(__INTEL_COMPILER) && (__INTEL_COMPILER >= 800)) || defined(__clang__)
 #  define expect(expr,value)    (__builtin_expect ((expr),(value)) )
 #else
diff --git a/lib/xxhash.c b/lib/xxhash.c
index e9ff2d4..a532358 100644
--- a/lib/xxhash.c
+++ b/lib/xxhash.c
@@ -113,19 +113,24 @@ static void* XXH_memcpy(void* dest, const void* src, size_t size) { return memcp
 ***************************************/
 #ifdef _MSC_VER    /* Visual Studio */
 #  pragma warning(disable : 4127)      /* disable: C4127: conditional expression is constant */
-#  define FORCE_INLINE static __forceinline
-#else
-#  if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
-#    ifdef __GNUC__
-#      define FORCE_INLINE static inline __attribute__((always_inline))
-#    else
-#      define FORCE_INLINE static inline
-#    endif
-#  else
-#    define FORCE_INLINE static
-#  endif /* __STDC_VERSION__ */
 #endif
 
+#ifndef FORCE_INLINE
+#  ifdef _MSC_VER    /* Visual Studio */
+#    define FORCE_INLINE static __forceinline
+#  else
+#    if defined (__cplusplus) || defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L   /* C99 */
+#      ifdef __GNUC__
+#        define FORCE_INLINE static inline __attribute__((always_inline))
+#      else
+#        define FORCE_INLINE static inline
+#      endif
+#    else
+#      define FORCE_INLINE static
+#    endif /* __STDC_VERSION__ */
+#  endif  /* _MSC_VER */
+#endif /* FORCE_INLINE */
+
 
 /* *************************************
 *  Basic Types