nir/builder: Use nir_after_instr to advance the cursor

This *should* ensure that the cursor gets properly advanced in all cases.
We had a problem before where, if the cursor was created using
nir_after_cf_node on a non-block cf_node, that would call nir_before_block
on the block following the cf node.  Instructions would then get inserted
in backwards order at the top of the block which is not at all what you
would expect from nir_after_cf_node.  By just resetting to after_instr, we
avoid all these problems.

diff --git a/src/glsl/nir/nir_builder.h b/src/glsl/nir/nir_builder.h
index 3aa0efded3c90817bce9fad806e23847922dc34a..295a209b4e653972009a3d457a66a739f22153ae 100644 (file)
--- a/src/glsl/nir/nir_builder.h
+++ b/src/glsl/nir/nir_builder.h
@@ -49,8 +49,7 @@ nir_builder_instr_insert(nir_builder *build, nir_instr *instr)
    nir_instr_insert(build->cursor, instr);
 
    /* Move the cursor forward. */
-   if (build->cursor.option == nir_cursor_after_instr)
-      build->cursor.instr = instr;
+   build->cursor = nir_after_instr(instr);
 }
 
 static inline void