Mesa (master): glsl: Add a foreach_in_list_reverse_safe macro.

[Matt Turner]

Module: Mesa
Branch: master
Commit: 579157e6c1a30fbe11af4b936c23f2e3a784c5da
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=579157e6c1a30fbe11af4b936c23f2e3a784c5da

Author: Matt Turner <mattst88 at gmail.com>
Date:   Tue Dec 30 16:14:25 2014 -0800

glsl: Add a foreach_in_list_reverse_safe macro.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/glsl/list.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/glsl/list.h b/src/glsl/list.h
index 330c17e..85368a4 100644
--- a/src/glsl/list.h
+++ b/src/glsl/list.h
@@ -636,6 +636,12 @@ inline void exec_node::insert_before(exec_list *before)
         __next != NULL;                              \
         __node = __next, __next = (__type *)__next->next)
 
+#define foreach_in_list_reverse_safe(__type, __node, __list) \
+   for (__type *__node = (__type *)(__list)->tail_pred,      \
+               *__prev = (__type *)__node->prev;             \
+        __prev != NULL;                                      \
+        __node = __prev, __prev = (__type *)__prev->prev)
+
 #define foreach_in_list_use_after(__type, __inst, __list) \
    __type *(__inst);                                      \
    for ((__inst) = (__type *)(__list)->head;              \