r600/sfn: handle querying the number of layers in cube arrays

This has to be loaded from a constant buffer instead of the actual
texture.

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9330>

src/gallium/drivers/r600/sfn/sfn_emitinstruction.cpp

@@ -165,6 +165,11 @@ int EmitInstruction::remap_atomic_base(int base)
 	return m_proc.remap_atomic_base(base);
 }
 
+void EmitInstruction::set_has_txs_cube_array_comp()
+{
+   m_proc.sh_info().has_txq_cube_array_z_comp = 1;
+}
+
 const std::set<AluModifiers> EmitInstruction::empty = {};
 const std::set<AluModifiers> EmitInstruction::write = {alu_write};
 const std::set<AluModifiers> EmitInstruction::last_write = {alu_write, alu_last_instr};

src/gallium/drivers/r600/sfn/sfn_emitinstruction.h

@@ -91,6 +91,8 @@ protected:
                         const PValue& reg, bool map);
 
    int remap_atomic_base(int base);
+
+   void set_has_txs_cube_array_comp();
 private:
 
    ShaderFromNirProcessor& m_proc;

src/gallium/drivers/r600/sfn/sfn_emittexinstruction.cpp

@@ -336,6 +336,15 @@ bool EmitTexInstruction::emit_tex_txs(nir_tex_instr* instr, TexInputs& tex_src,
                                    sampler.id + R600_MAX_CONST_BUFFERS, tex_src.sampler_offset);
       ir->set_dest_swizzle(dest_swz);
       emit_instruction(ir);
+
+      if (instr->is_array && instr->sampler_dim == GLSL_SAMPLER_DIM_CUBE) {
+         PValue src(new UniformValue(512 + R600_BUFFER_INFO_OFFSET / 16 + (sampler.id >> 2),
+                                     sampler.id & 3, R600_BUFFER_INFO_CONST_BUFFER));
+
+         auto alu = new AluInstruction(op1_mov, dst[2], src, {last_write});
+         emit_instruction(alu);
+         set_has_txs_cube_array_comp();
+      }
    }
 
    return true;