glsl: Add lowering pass for ir_triop_vector_insert

This will eventually replace do_vec_index_to_cond_assign.  This lowering
pass is called in all the places where do_vec_index_to_cond_assign or
do_vec_index_to_swizzle is called.

v2: Use WRITEMASK_* instead of integer literals.  Use a more concise
method of generating broadcast_index.  Both suggested by Eric.

v3: Use a series of scalar compares instead of a single vector compare.
Suggested by Eric and Ken.  It still uses 'if (cond) v.x = y;' instead
of conditional assignments because ir_builder doesn't do conditional
assignments, and I'd rather keep the code simple.

Signed-off-by: Ian Romanick <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/glsl/ir_optimization.h b/src/glsl/ir_optimization.h
index 28093cfe1a1..1c3bc60088f 100644
--- a/src/glsl/ir_optimization.h
+++ b/src/glsl/ir_optimization.h
@@ -109,6 +109,7 @@ void lower_ubo_reference(struct gl_shader *shader, exec_list *instructions);
 void lower_packed_varyings(void *mem_ctx, unsigned location_base,
                            unsigned locations_used, ir_variable_mode mode,
                            gl_shader *shader);
+bool lower_vector_insert(exec_list *instructions, bool lower_nonconstant_index);
 bool optimize_redundant_jumps(exec_list *instructions);
 bool optimize_split_arrays(exec_list *instructions, bool linked);