pan/midgard: Use type-appropriate swizzle for texture coordinate

The texture coordinate for a 2D texture could be a vec2 or a vec3,
depending if it's an array texture or not. If it's vec2 (non-array
texture), we should not reference the z component; otherwise, liveness
analysis will get very confused when z is never written.

v2: Fix typo (Ilia).

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
diff --git a/src/panfrost/midgard/midgard_compile.c b/src/panfrost/midgard/midgard_compile.c
index 67c5c84..2b454a9 100644
--- a/src/panfrost/midgard/midgard_compile.c
+++ b/src/panfrost/midgard/midgard_compile.c
@@ -1753,6 +1753,7 @@
         for (unsigned i = 0; i < instr->num_srcs; ++i) {
                 int index = nir_src_index(ctx, &instr->src[i].src);
                 midgard_vector_alu_src alu_src = blank_alu_src;
+                unsigned nr_components = nir_src_num_components(instr->src[i].src);
 
                 switch (instr->src[i].src_type) {
                 case nir_tex_src_coord: {
@@ -1804,7 +1805,12 @@
 
                         if (instr->sampler_dim == GLSL_SAMPLER_DIM_2D) {
                                 /* Array component in w but NIR wants it in z */
-                                ins.texture.in_reg_swizzle = SWIZZLE_XYZZ;
+                                if (nr_components == 3)
+                                        ins.texture.in_reg_swizzle = SWIZZLE_XYZZ;
+                                else if (nr_components == 2)
+                                        ins.texture.in_reg_swizzle = SWIZZLE_XYXX;
+                                else
+                                        unreachable("Invalid texture 2D components");
                         }
 
                         break;