i965: Use the tex projector lowering pass instead of hand-rolling it.

This only impacts the ARB_fp path.  We can't quite disable the GLSL-level
lowering pass, because it needs to apply before
brw_do_lower_unnormalized_offset().

total instructions in shared programs: 5667857 -> 5667847 (-0.00%)
instructions in affected programs:     1114 -> 1104 (-0.90%)
helped:                                16
HURT:                                  6

Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>

src/mesa/drivers/dri/i965/brw_fs_nir.cpp

@@ -101,6 +101,9 @@ fs_visitor::emit_nir_code()
    nir_lower_global_vars_to_local(nir);
    nir_validate_shader(nir);
 
+   nir_lower_tex_projector(nir);
+   nir_validate_shader(nir);
+
    nir_split_var_copies(nir);
    nir_validate_shader(nir);
 
@@ -1782,7 +1785,6 @@ fs_visitor::nir_emit_texture(nir_tex_instr *instr)
    int lod_components = 0, offset_components = 0;
 
    fs_reg coordinate, shadow_comparitor, lod, lod2, sample_index, mcs, tex_offset;
-   fs_reg projector;
 
    for (unsigned i = 0; i < instr->num_srcs; i++) {
       fs_reg src = get_nir_src(instr->src[i].src);
@@ -1835,8 +1837,7 @@ fs_visitor::nir_emit_texture(nir_tex_instr *instr)
             offset_components = instr->coord_components;
          break;
       case nir_tex_src_projector:
-         projector = retype(src, BRW_REGISTER_TYPE_F);
-         break;
+         unreachable("should be lowered");
 
       case nir_tex_src_sampler_offset: {
          /* Figure out the highest possible sampler index and mark it as used */
@@ -1860,13 +1861,6 @@ fs_visitor::nir_emit_texture(nir_tex_instr *instr)
       }
    }
 
-   if (projector.file != BAD_FILE) {
-      fs_reg invproj = vgrf(glsl_type::float_type);
-      emit_math(SHADER_OPCODE_RCP, invproj, projector);
-      for (int i = 0; i < 3; i++)
-         emit(MUL(offset(coordinate, i), offset(coordinate, i), invproj));
-   }
-
    if (instr->op == nir_texop_txf_ms) {
       if (brw->gen >= 7 &&
           key_tex->compressed_multisample_layout_mask & (1 << sampler)) {