intel/compiler: Move logical-send lowering to a separate file

brw_fs.cpp was 10kloc.  Now it's only 7.5kloc.  Ugh.

v2: Rebase on 9680e0e4a2.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17379>

src/intel/compiler/brw_fs.h

@@ -658,4 +658,11 @@ void brw_compute_urb_setup_index(struct brw_wm_prog_data *wm_prog_data);
 
 void brw_nir_lower_simd(nir_shader *nir, unsigned dispatch_width);
 
+namespace brw {
+   class fs_builder;
+}
+
+fs_reg brw_sample_mask_reg(const brw::fs_builder &bld);
+void brw_emit_predicate_on_sample_mask(const brw::fs_builder &bld, fs_inst *inst);
+
 #endif /* BRW_FS_H */