nir: Add Mali load_output taking converison

Mali's LD_TILE instruction (mapping to NIR's load_output) requires a "conversion
descriptor" specifying how to convert from the register foramt to the tilebuffer
format. To implement framebuffer fetch on OpenGL without shader variants, we
generate these descriptors in the driver and pass them in a uniform. However, to
comply with the Ekstrand Rule, we can't have magically materialized system
values -- they should come only from the NIR where the driver can lower as it
pleases (e.g. PanVK can lower to a constant because it knows the framebuffer
format at pipeline create time). Add intrinsics to model this.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20906>

diff --git a/src/compiler/nir/nir_intrinsics.py b/src/compiler/nir/nir_intrinsics.py
index 93c5edf..74b301b 100644 (file)
--- a/src/compiler/nir/nir_intrinsics.py
+++ b/src/compiler/nir/nir_intrinsics.py
@@ -1298,6 +1298,14 @@ load("raw_output_pan", [1], [IO_SEMANTICS], [CAN_ELIMINATE, CAN_REORDER])
 # src[] = { sampler_index }
 load("sampler_lod_parameters_pan", [1], flags=[CAN_ELIMINATE, CAN_REORDER])
 
+# Like load_output but using a specified render target conversion descriptor
+load("converted_output_pan", [1], indices=[DEST_TYPE, IO_SEMANTICS], flags=[CAN_ELIMINATE])
+
+# Load the render target conversion descriptor for a given render target given
+# in the BASE index. Converts to a type with size given by the source type.
+# Valid in fragment and blend stages.
+system_value("rt_conversion_pan", 1, indices=[BASE, SRC_TYPE], bit_sizes=[32])
+
 # Loads the sample position array on Bifrost, in a packed Arm-specific format
 system_value("sample_positions_pan", 1, bit_sizes=[64])