--- deliantra/server/include/compiler.h	2009/11/07 18:30:05	1.1
+++ deliantra/server/include/compiler.h	2009/11/08 15:11:23	1.2
@@ -23,13 +23,15 @@
 #ifndef COMPILER_H
 #define COMPILER_H
 
-#if __GNUC__ >= 3
+#define GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
+
+#if GCC_VERSION(3,0)
 # define attribute(attrlist) __attribute__(attrlist)
 #else
 # define attribute(attrlist)
 #endif
 
-#if __GNUC__ >= 3
+#if GCC_VERSION(3,0)
 # define is_constant(c)             __builtin_constant_p (c)
 # define expect(expr,value)         __builtin_expect ((expr),(value))
 # define prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
@@ -41,15 +43,26 @@
 # define noinline
 #endif
 
-#if __GNUC__ < 4 || (__GNUC__ == 4 || __GNUC_MINOR__ < 4)
+#if !GCC_VERSION(4,4)
 # define decltype(x) typeof(x)
 #endif
 
+#if GCC_VERSION(4,5)
+# define unreachable() __builtin_unreachable ()
+#else
+ // this seems to work fine, but gcc always emits a warning for it :/
+ static inline void unreachable () attribute ((noreturn));
+ static inline void unreachable () { }
+#endif
+
 // put into ifs if you are very sure that the expression
 // is mostly true or mosty false. note that these return
 // booleans, not the expression.
 #define expect_false(expr) expect ((expr) ? 1 : 0, 0)
 #define expect_true(expr)  expect ((expr) ? 1 : 0, 1)
 
+// try to tell the compiler tat some condition is definitely true
+#define assume(cond) do { if (!(cond)) unreachable (); } while (0)
+
 #endif