intel/rt: Add a pass to lower the new ray-tracing intrinsics

The new intrinsics we added for doing address calculations are all
things we fetch from the RT_DISPATCH_GLOBALS struct.  We could emit an
RT_DISPATCH_GLOBALS load at every point we want it and trust NIR to CSE
it for us but it's easier to use intermediate intrinsics.

Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7356>

src/intel/compiler/brw_nir_rt.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2020 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef BRW_NIR_RT_H
+#define BRW_NIR_RT_H
+
+#include "brw_nir.h"
+#include "brw_rt.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void brw_nir_lower_rt_intrinsics(nir_shader *shader,
+                                 const struct gen_device_info *devinfo);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* BRW_NIR_RT_H */