nir/builder: Add a load_system_value helper

While we're at it, go ahead and make nir_lower_clip use it.

Reviewed-by: Eric Anholt <[email protected]>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/glsl/nir/nir_builder.h b/src/glsl/nir/nir_builder.h
index b909f483579..332bb0246df 100644
--- a/src/glsl/nir/nir_builder.h
+++ b/src/glsl/nir/nir_builder.h
@@ -322,4 +322,16 @@ nir_store_var(nir_builder *build, nir_variable *var, nir_ssa_def *value)
    nir_builder_instr_insert(build, &store->instr);
 }
 
+static inline nir_ssa_def *
+nir_load_system_value(nir_builder *build, nir_intrinsic_op op, int index)
+{
+   nir_intrinsic_instr *load = nir_intrinsic_instr_create(build->shader, op);
+   load->num_components = nir_intrinsic_infos[op].dest_components;
+   load->const_index[0] = index;
+   nir_ssa_dest_init(&load->instr, &load->dest,
+                     nir_intrinsic_infos[op].dest_components, NULL);
+   nir_builder_instr_insert(build, &load->instr);
+   return &load->dest.ssa;
+}
+
 #endif /* NIR_BUILDER_H */