[Mesa-dev] [PATCH] nir: Pick just the channels we want for bitmap and drawpixels lowering.

[Eric Anholt]

One of the quirks of NIR is that it has allowed SSA references where the
reference uses fewer channels than exist in the SSA value, which surprises
new developers and makes some analysis harder.  Jason is about to remove
that quirk and validate that reference num_components == value
num_components, so fix up these passes in preparation.

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>
---
 src/compiler/nir/nir_lower_bitmap.c     | 4 +++-
 src/compiler/nir/nir_lower_drawpixels.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/compiler/nir/nir_lower_bitmap.c b/src/compiler/nir/nir_lower_bitmap.c
index f08fb9b9c346..a1b4a32a5d4b 100644
--- a/src/compiler/nir/nir_lower_bitmap.c
+++ b/src/compiler/nir/nir_lower_bitmap.c
@@ -96,7 +96,9 @@ lower_bitmap(nir_shader *shader, nir_builder *b,
    tex->texture_index = options->sampler;
    tex->dest_type = nir_type_float;
    tex->src[0].src_type = nir_tex_src_coord;
-   tex->src[0].src = nir_src_for_ssa(texcoord);
+   tex->src[0].src =
+      nir_src_for_ssa(nir_channels(b, texcoord,
+                                   (1 << tex->coord_components) - 1));
 
    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
    nir_builder_instr_insert(b, &tex->instr);
diff --git a/src/compiler/nir/nir_lower_drawpixels.c b/src/compiler/nir/nir_lower_drawpixels.c
index 51c52d038c7e..891f89a45a20 100644
--- a/src/compiler/nir/nir_lower_drawpixels.c
+++ b/src/compiler/nir/nir_lower_drawpixels.c
@@ -135,7 +135,9 @@ lower_color(lower_drawpixels_state *state, nir_intrinsic_instr *intr)
    tex->texture_index = state->options->drawpix_sampler;
    tex->dest_type = nir_type_float;
    tex->src[0].src_type = nir_tex_src_coord;
-   tex->src[0].src = nir_src_for_ssa(texcoord);
+   tex->src[0].src =
+      nir_src_for_ssa(nir_channels(b, texcoord,
+                                   (1 << tex->coord_components) - 1));
 
    nir_ssa_dest_init(&tex->instr, &tex->dest, 4, 32, NULL);
    nir_builder_instr_insert(b, &tex->instr);
-- 
2.11.0