nir: Add a function to detect if a block is immediately followed by an if

Since we don't actually have an "if" instruction, this is a very common
pattern when iterating over instructions.  This adds a helper function for
it to make things a little less painful.

Reviewed-by: Connor Abbott <[email protected]>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 2ea7542d313..84be1d65f0a 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1277,6 +1277,11 @@ bool nir_foreach_block(nir_function_impl *impl, nir_foreach_block_cb cb,
 bool nir_foreach_block_reverse(nir_function_impl *impl, nir_foreach_block_cb cb,
                                void *state);
 
+/* If the following CF node is an if, this function returns that if.
+ * Otherwise, it returns NULL.
+ */
+nir_if *nir_block_following_if(nir_block *block);
+
 void nir_index_local_regs(nir_function_impl *impl);
 void nir_index_global_regs(nir_shader *shader);
 void nir_index_ssa_defs(nir_function_impl *impl);