lima/ppir: fix lod bias src

ppir has some code that operates on all ppir_src variables, and for that
uses ppir_node_get_src.
lod bias support introduced a separate ppir_src that is inaccessible by
that function, causing it to be missed by the compiler in some routines.
Ultimately this caused, in some cases, a bug in const lowering:

  .../pp/lower.c:42: ppir_lower_const: Assertion `src != NULL' failed.

This fix moves the ppir_srcs in ppir_load_texture_node together so they
don't get missed.

Fixes: 721d82cf06 lima/ppir: add lod-bias support

Signed-off-by: Erico Nunes <nunes.erico@gmail.com>
Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3185>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3185>

src/gallium/drivers/lima/ir/pp/codegen.c

@@ -130,7 +130,7 @@ static void ppir_codegen_encode_texld(ppir_node *node, void *code)
    f->lod_bias_en = ldtex->lod_bias_en;
    f->explicit_lod = ldtex->explicit_lod;
    if (ldtex->lod_bias_en)
-      ppir_target_get_src_reg_index(&ldtex->lod_bias);
+      ppir_target_get_src_reg_index(&ldtex->src[1]);
 
    switch (ldtex->sampler_dim) {
    case GLSL_SAMPLER_DIM_2D:

src/gallium/drivers/lima/ir/pp/lower.c

@@ -168,7 +168,7 @@ static bool ppir_lower_texture(ppir_block *block, ppir_node *node)
          return false;
       list_addtail(&load->node.list, &node->list);
 
-      load->src = load_tex->src_coords;
+      load->src = load_tex->src[0];
       load->num_src = 1;
       if (load_tex->sampler_dim == GLSL_SAMPLER_DIM_CUBE)
          load->num_components = 3;
@@ -187,8 +187,8 @@ static bool ppir_lower_texture(ppir_block *block, ppir_node *node)
    }
 
    assert(load);
-   load_tex->src_coords.type = load->dest.type = ppir_target_pipeline;
-   load_tex->src_coords.pipeline = load->dest.pipeline = ppir_pipeline_reg_discard;
+   load_tex->src[0].type = load->dest.type = ppir_target_pipeline;
+   load_tex->src[0].pipeline = load->dest.pipeline = ppir_pipeline_reg_discard;
 
    if (ppir_node_has_single_src_succ(node)) {
       ppir_node *succ = ppir_node_first_succ(node);

src/gallium/drivers/lima/ir/pp/nir.c

@@ -486,19 +486,21 @@ static ppir_node *ppir_emit_tex(ppir_block *block, nir_instr *ni)
    node->sampler_dim = instr->sampler_dim;
 
    for (int i = 0; i < instr->coord_components; i++)
-         node->src_coords.swizzle[i] = i;
+         node->src[0].swizzle[i] = i;
 
    for (int i = 0; i < instr->num_srcs; i++) {
       switch (instr->src[i].src_type) {
       case nir_tex_src_coord:
-         ppir_node_add_src(block->comp, &node->node, &node->src_coords, &instr->src[i].src,
+         ppir_node_add_src(block->comp, &node->node, &node->src[0], &instr->src[i].src,
                            u_bit_consecutive(0, instr->coord_components));
+         node->num_src++;
          break;
       case nir_tex_src_bias:
       case nir_tex_src_lod:
          node->lod_bias_en = true;
          node->explicit_lod = (instr->src[i].src_type == nir_tex_src_lod);
-         ppir_node_add_src(block->comp, &node->node, &node->lod_bias, &instr->src[i].src, 1);
+         ppir_node_add_src(block->comp, &node->node, &node->src[1], &instr->src[i].src, 1);
+         node->num_src++;
          break;
       default:
          ppir_error("unsupported texture source type\n");

src/gallium/drivers/lima/ir/pp/node.c

@@ -456,7 +456,8 @@ void ppir_node_replace_child(ppir_node *parent, ppir_node *old_child, ppir_node
    case ppir_node_type_load_texture:
    {
       ppir_load_texture_node *load_texture = ppir_node_to_load_texture(parent);
-      _ppir_node_replace_child(&load_texture->src_coords, old_child, new_child);
+      for (int i = 0; i < load_texture->num_src; i++)
+         _ppir_node_replace_child(ppir_node_get_src(parent, i), old_child, new_child);
       break;
    }
    case ppir_node_type_store:

src/gallium/drivers/lima/ir/pp/ppir.h

@@ -270,12 +270,13 @@ typedef struct {
 typedef struct {
    ppir_node node;
    ppir_dest dest;
-   ppir_src src_coords; /* not to be used after lowering */
+   ppir_src src[2]; /* src[0] temporarily stores src_coords,
+                       not to be used after lowering */
+   int num_src;
    int sampler;
    int sampler_dim;
    bool lod_bias_en;
    bool explicit_lod;
-   ppir_src lod_bias;
 } ppir_load_texture_node;
 
 typedef struct {
@@ -475,6 +476,7 @@ static inline int ppir_node_get_src_num(ppir_node *node)
    case ppir_node_type_load:
       return ppir_node_to_load(node)->num_src;
    case ppir_node_type_load_texture:
+      return ppir_node_to_load_texture(node)->num_src;
    case ppir_node_type_store:
       return 1;
    default:
@@ -495,7 +497,7 @@ static inline ppir_src *ppir_node_get_src(ppir_node *node, int idx)
    case ppir_node_type_branch:
       return &ppir_node_to_branch(node)->src[idx];
    case ppir_node_type_load_texture:
-      return &ppir_node_to_load_texture(node)->src_coords;
+      return &ppir_node_to_load_texture(node)->src[idx];
    case ppir_node_type_load:
       return &ppir_node_to_load(node)->src;
    case ppir_node_type_store: