zink: use Offset param for txf ops

there's an image operand for handling offsets, so we can use this when it
hasn't previously been lowered away

Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8151>

src/gallium/drivers/zink/nir_to_spirv/nir_to_spirv.c

@@ -2095,29 +2095,6 @@ tex_instr_is_lod_allowed(nir_tex_instr *tex)
            tex->sampler_dim == GLSL_SAMPLER_DIM_CUBE);
 }
 
-static SpvId
-pad_coord_vector(struct ntv_context *ctx, SpvId orig, unsigned old_size, unsigned new_size)
-{
-    SpvId int_type = spirv_builder_type_int(&ctx->builder, 32);
-    SpvId type = get_ivec_type(ctx, 32, new_size);
-    SpvId constituents[NIR_MAX_VEC_COMPONENTS] = {0};
-    SpvId zero = emit_int_const(ctx, 32, 0);
-    assert(new_size < NIR_MAX_VEC_COMPONENTS);
-
-    if (old_size == 1)
-       constituents[0] = orig;
-    else {
-       for (unsigned i = 0; i < old_size; i++)
-          constituents[i] = spirv_builder_emit_vector_extract(&ctx->builder, int_type, orig, i);
-    }
-
-    for (unsigned i = old_size; i < new_size; i++)
-       constituents[i] = zero;
-
-    return spirv_builder_emit_composite_construct(&ctx->builder, type,
-                                                  constituents, new_size);
-}
-
 static void
 emit_tex(struct ntv_context *ctx, nir_tex_instr *tex)
 {
@@ -2133,7 +2110,7 @@ emit_tex(struct ntv_context *ctx, nir_tex_instr *tex)
 
    SpvId coord = 0, proj = 0, bias = 0, lod = 0, dref = 0, dx = 0, dy = 0,
          offset = 0, sample = 0, tex_offset = 0;
-   unsigned coord_components = 0, coord_bitsize = 0, offset_components = 0;
+   unsigned coord_components = 0;
    for (unsigned i = 0; i < tex->num_srcs; i++) {
       switch (tex->src[i].src_type) {
       case nir_tex_src_coord:
@@ -2143,7 +2120,6 @@ emit_tex(struct ntv_context *ctx, nir_tex_instr *tex)
          else
             coord = get_src_float(ctx, &tex->src[i].src);
          coord_components = nir_src_num_components(tex->src[i].src);
-         coord_bitsize = nir_src_bit_size(tex->src[i].src);
          break;
 
       case nir_tex_src_projector:
@@ -2154,7 +2130,6 @@ emit_tex(struct ntv_context *ctx, nir_tex_instr *tex)
 
       case nir_tex_src_offset:
          offset = get_src_int(ctx, &tex->src[i].src);
-         offset_components = nir_src_num_components(tex->src[i].src);
          break;
 
       case nir_tex_src_bias:
@@ -2294,21 +2269,10 @@ emit_tex(struct ntv_context *ctx, nir_tex_instr *tex)
    if (tex->op == nir_texop_txf ||
        tex->op == nir_texop_txf_ms) {
       SpvId image = spirv_builder_emit_image(&ctx->builder, image_type, load);
-      if (offset) {
-         /* SPIRV requires matched length vectors for OpIAdd, so if a shader
-          * uses vecs of differing sizes we need to make a new vec padded with zeroes
-          * to mimic how GLSL does this implicitly
-          */
-         if (offset_components > coord_components)
-            coord = pad_coord_vector(ctx, coord, coord_components, offset_components);
-         else if (coord_components > offset_components)
-            offset = pad_coord_vector(ctx, offset, offset_components, coord_components);
-         coord = emit_binop(ctx, SpvOpIAdd,
-                            get_ivec_type(ctx, coord_bitsize, coord_components),
-                            coord, offset);
-      }
+      if (offset)
+         spirv_builder_emit_cap(&ctx->builder, SpvCapabilityImageGatherExtended);
       result = spirv_builder_emit_image_fetch(&ctx->builder, dest_type,
-                                              image, coord, lod, sample);
+                                              image, coord, lod, sample, offset);
    } else {
       result = spirv_builder_emit_image_sample(&ctx->builder,
                                                actual_dest_type, load,

src/gallium/drivers/zink/nir_to_spirv/spirv_builder.c

@@ -716,12 +716,13 @@ spirv_builder_emit_image_fetch(struct spirv_builder *b,
                                SpvId image,
                                SpvId coordinate,
                                SpvId lod,
-                               SpvId sample)
+                               SpvId sample,
+                               SpvId offset)
 {
    SpvId result = spirv_builder_new_id(b);
 
    SpvImageOperandsMask operand_mask = SpvImageOperandsMaskNone;
-   SpvId extra_operands[3];
+   SpvId extra_operands[4];
    int num_extra_operands = 0;
    if (lod) {
       extra_operands[++num_extra_operands] = lod;
@@ -731,6 +732,10 @@ spirv_builder_emit_image_fetch(struct spirv_builder *b,
       extra_operands[++num_extra_operands] = sample;
       operand_mask |= SpvImageOperandsSampleMask;
    }
+   if (offset) {
+      extra_operands[++num_extra_operands] = offset;
+      operand_mask |= SpvImageOperandsOffsetMask;
+   }
 
    /* finalize num_extra_operands / extra_operands */
    if (num_extra_operands > 0) {

src/gallium/drivers/zink/nir_to_spirv/spirv_builder.h

@@ -263,8 +263,8 @@ spirv_builder_emit_image_fetch(struct spirv_builder *b,
                                SpvId image,
                                SpvId coordinate,
                                SpvId lod,
-                               SpvId sample);
-
+                               SpvId sample,
+                               SpvId offset);
 SpvId
 spirv_builder_emit_image_query_size(struct spirv_builder *b,
                                     SpvId result_type,