ac/nir: do not reserve user SGPRs for unused descriptor sets

In theory this might lead to corruption if we bind a descriptor
set which is unused, because LLVM is smart and it can re-use
unused user SGPRs. In practice, this doesn't seem to fix
anything.

As a side effect, this will reduce the number of emitted
SH_REG packets.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index 7f0bb05862682da72c47581ebaa8ae8f2cdfd924..dc471de977362cad969596f2a1984414a3719d47 100644 (file)
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -610,7 +610,8 @@ declare_global_input_sgprs(struct radv_shader_context *ctx,
        /* 1 for each descriptor set */
        if (!user_sgpr_info->indirect_all_descriptor_sets) {
                for (unsigned i = 0; i < num_sets; ++i) {
-                       if (ctx->options->layout->set[i].layout->shader_stages & stage_mask) {
+                       if ((ctx->shader_info->info.desc_set_used_mask & (1 << i)) &&
+                           ctx->options->layout->set[i].layout->shader_stages & stage_mask) {
                                add_array_arg(args, type,
                                              &ctx->descriptor_sets[i]);
                        }
@@ -687,7 +688,8 @@ set_global_input_locs(struct radv_shader_context *ctx, gl_shader_stage stage,
 
        if (!user_sgpr_info->indirect_all_descriptor_sets) {
                for (unsigned i = 0; i < num_sets; ++i) {
-                       if (ctx->options->layout->set[i].layout->shader_stages & stage_mask) {
+                       if ((ctx->shader_info->info.desc_set_used_mask & (1 << i)) &&
+                           ctx->options->layout->set[i].layout->shader_stages & stage_mask) {
                                set_loc_desc(ctx, i, user_sgpr_idx, 0);
                        } else
                                ctx->descriptor_sets[i] = NULL;
@@ -697,7 +699,8 @@ set_global_input_locs(struct radv_shader_context *ctx, gl_shader_stage stage,
                               user_sgpr_idx, 2);
 
                for (unsigned i = 0; i < num_sets; ++i) {
-                       if (ctx->options->layout->set[i].layout->shader_stages & stage_mask) {
+                       if ((ctx->shader_info->info.desc_set_used_mask & (1 << i)) &&
+                           ctx->options->layout->set[i].layout->shader_stages & stage_mask) {
                                set_loc_desc(ctx, i, user_sgpr_idx, i * 8);
                                ctx->descriptor_sets[i] =
                                        ac_build_load_to_sgpr(&ctx->ac,