mark some conditions as unlikely

* assertion failure
* malloc_init failure
* malloc not already initialized (in malloc_init)
* running in valgrind
* thread cache disabled at runtime

Clang and GCC already consider a comparison with NULL or -1 to be cold,
so many branches (out-of-memory) are already correctly considered as
cold and marking them is not important.

include/jemalloc/internal/util.h

@@ -41,7 +41,7 @@
  */
 #ifndef assert
 #define	assert(e) do {							\
-	if (config_debug && !(e)) {					\
+	if (unlikely(config_debug && !(e))) {				\
 		malloc_printf(						\
 		    "<jemalloc>: %s:%d: Failed assertion: \"%s\"\n",	\
 		    __FILE__, __LINE__, #e);				\
@@ -73,14 +73,14 @@
 
 #ifndef assert_not_implemented
 #define	assert_not_implemented(e) do {					\
-	if (config_debug && !(e))					\
+	if (unlikely(config_debug && !(e)))				\
 		not_implemented();					\
 } while (0)
 #endif
 
 /* Use to assert a particular configuration, e.g., cassert(config_debug). */
 #define	cassert(c) do {							\
-	if ((c) == false)						\
+	if (unlikely(!(c)))						\
 		not_reached();						\
 } while (0)