[Mesa-dev] [PATCH] util: Implement assume() for clang.

[Matt Turner]

---
 src/util/macros.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/util/macros.h b/src/util/macros.h
index da5daff..b67596d 100644
--- a/src/util/macros.h
+++ b/src/util/macros.h
@@ -29,6 +29,10 @@
 #  define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
 #endif
 
+/* For compatibility with Clang's __has_builtin() */
+#ifndef __has_builtin
+#  define __has_builtin(x) 0
+#endif
 
 /**
  * __builtin_expect macros
@@ -85,7 +89,13 @@ do {                        \
  * Assume macro. Useful for expressing our assumptions to the compiler,
  * typically for purposes of silencing warnings.
  */
-#ifdef HAVE___BUILTIN_UNREACHABLE
+#if __has_builtin(__builtin_assume)
+#define assume(expr)             \
+do {                             \
+   assert(!"assumption failed"); \
+   __builtin_assume(expr);       \
+} while (0)
+#elif defined HAVE___BUILTIN_UNREACHABLE
 #define assume(expr) ((expr) ? ((void) 0) \
                              : (assert(!"assumption failed"), \
                                 __builtin_unreachable()))
-- 
2.0.4