[Mesa-dev] [RFC 1/4] nir: Add a new intrinsic 'load_image_stride'

[Eduardo Lima Mitev]

This is an internal intrinsic intended to be injected by a
(freedreno-specific) 'lower_sampler_io' pass that will be introduced
later in this series; and consumed by ir3_compiler_nir.

The intrinsic will load in SSA values for various constants
for images (image_dims), namely the format's bytes-per-pixel,
y-stride and z-stride; for which the backend compiler will emit
the corresponding uniforms.

const_index[0] is the image index, and const_index[1] is the index
into image_dims' register file for a given image: 0 for bpp, 1 to
y-stride and 2 for z-stride.
---
 src/compiler/nir/nir_intrinsics.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/compiler/nir/nir_intrinsics.py b/src/compiler/nir/nir_intrinsics.py
index a5cc3f7401c..169c835d746 100644
--- a/src/compiler/nir/nir_intrinsics.py
+++ b/src/compiler/nir/nir_intrinsics.py
@@ -590,6 +590,8 @@ load("shared", 1, [BASE, ALIGN_MUL, ALIGN_OFFSET], [CAN_ELIMINATE])
 load("push_constant", 1, [BASE, RANGE], [CAN_ELIMINATE, CAN_REORDER])
 # src[] = { offset }. const_index[] = { base, range }
 load("constant", 1, [BASE, RANGE], [CAN_ELIMINATE, CAN_REORDER])
+# src[] = { offset }. const_index[] = { image_idx, dim_idx }
+load("image_stride", 1, [], [CAN_REORDER])
 
 # Stores work the same way as loads, except now the first source is the value
 # to store and the second (and possibly third) source specify where to store
-- 
2.20.1