nir/builder: Add a build_deref_array_imm helper

Unlike most of the cases in which we do this by hand, the new helper
properly handles non-32-bit pointers.

Reviewed-by: Karol Herbst <kherbst@redhat.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>

src/compiler/nir/nir_builder.h

@@ -843,6 +843,17 @@ nir_build_deref_array(nir_builder *build, nir_deref_instr *parent,
    return deref;
 }
 
+static inline nir_deref_instr *
+nir_build_deref_array_imm(nir_builder *build, nir_deref_instr *parent,
+                          int64_t index)
+{
+   assert(parent->dest.is_ssa);
+   nir_ssa_def *idx_ssa = nir_imm_intN_t(build, index,
+                                         parent->dest.ssa.bit_size);
+
+   return nir_build_deref_array(build, parent, idx_ssa);
+}
+
 static inline nir_deref_instr *
 nir_build_deref_ptr_as_array(nir_builder *build, nir_deref_instr *parent,
                              nir_ssa_def *index)