[Mesa-dev] [PATCH 1/5] nir: Make nir_block_{first, last}_instr return NULL for empty blocks.

[Kenneth Graunke]

This is a lot more reasonable than returning an offset from NULL.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/glsl/nir/nir.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 40871f7..12ddeb2 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1219,14 +1219,14 @@ static inline nir_instr *
 nir_block_first_instr(nir_block *block)
 {
    struct exec_node *head = exec_list_get_head(&block->instr_list);
-   return exec_node_data(nir_instr, head, node);
+   return head ? exec_node_data(nir_instr, head, node) : NULL;
 }
 
 static inline nir_instr *
 nir_block_last_instr(nir_block *block)
 {
    struct exec_node *tail = exec_list_get_tail(&block->instr_list);
-   return exec_node_data(nir_instr, tail, node);
+   return tail ? exec_node_data(nir_instr, tail, node) : NULL;
 }
 
 #define nir_foreach_instr(block, instr) \
-- 
2.5.0