Mesa (master): aco: Only store TCS outputs to VMEM when they are read by TES.

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Module: Mesa
Branch: master
Commit: 25775d346c5bd91c8def493ee6e76d1c8e44b059
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=25775d346c5bd91c8def493ee6e76d1c8e44b059

Author: Timur Kristóf <timur.kristof at gmail.com>
Date:   Mon Apr 13 19:03:55 2020 +0200

aco: Only store TCS outputs to VMEM when they are read by TES.

Totals from affected shaders (GFX10):
Code Size: 10832 -> 10736 (-0.89 %) bytes

Signed-off-by: Timur Kristóf <timur.kristof at gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02 at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4536>

---

 src/amd/compiler/aco_instruction_selection.cpp | 38 ++++++++++++++++++--------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/src/amd/compiler/aco_instruction_selection.cpp b/src/amd/compiler/aco_instruction_selection.cpp
index acf8b36912a..6673f41b961 100644
--- a/src/amd/compiler/aco_instruction_selection.cpp
+++ b/src/amd/compiler/aco_instruction_selection.cpp
@@ -3698,6 +3698,9 @@ std::pair<Temp, unsigned> get_tcs_per_patch_output_vmem_offset(isel_context *ctx
 
 bool tcs_driver_location_matches_api_mask(isel_context *ctx, nir_intrinsic_instr *instr, bool per_vertex, uint64_t mask, bool *indirect)
 {
+   if (mask == 0)
+      return false;
+
    unsigned off = nir_intrinsic_base(instr) * 4u;
    nir_src *off_src = nir_get_io_offset_src(instr);
 
@@ -3822,23 +3825,35 @@ void visit_store_ls_or_es_output(isel_context *ctx, nir_intrinsic_instr *instr)
    }
 }
 
-bool should_write_tcs_patch_output_to_vmem(isel_context *ctx, nir_intrinsic_instr *instr)
+bool tcs_output_is_tess_factor(isel_context *ctx, nir_intrinsic_instr *instr, bool per_vertex)
 {
+   if (per_vertex)
+      return false;
+
    unsigned off = nir_intrinsic_base(instr) * 4u;
-   return off != ctx->tcs_tess_lvl_out_loc &&
-          off != ctx->tcs_tess_lvl_in_loc;
+   return off == ctx->tcs_tess_lvl_out_loc ||
+          off == ctx->tcs_tess_lvl_in_loc;
+
 }
 
-bool should_write_tcs_output_to_lds(isel_context *ctx, nir_intrinsic_instr *instr, bool per_vertex)
+bool tcs_output_is_read_by_tes(isel_context *ctx, nir_intrinsic_instr *instr, bool per_vertex)
 {
-   /* When none of the appropriate outputs are read, we are OK to never write to LDS */
-   if (per_vertex ? ctx->shader->info.outputs_read == 0U : ctx->shader->info.patch_outputs_read == 0u)
-      return false;
+   uint64_t mask = per_vertex
+                   ? ctx->program->info->tcs.tes_inputs_read
+                   : ctx->program->info->tcs.tes_patch_inputs_read;
+
+   bool indirect_write = false;
+   bool output_read_by_tes = tcs_driver_location_matches_api_mask(ctx, instr, per_vertex, mask, &indirect_write);
+   return indirect_write || output_read_by_tes;
+}
 
+bool tcs_output_is_read_by_tcs(isel_context *ctx, nir_intrinsic_instr *instr, bool per_vertex)
+{
    uint64_t mask = per_vertex
                    ? ctx->shader->info.outputs_read
                    : ctx->shader->info.patch_outputs_read;
-   bool indirect_write;
+
+   bool indirect_write = false;
    bool output_read = tcs_driver_location_matches_api_mask(ctx, instr, per_vertex, mask, &indirect_write);
    return indirect_write || output_read;
 }
@@ -3854,10 +3869,9 @@ void visit_store_tcs_output(isel_context *ctx, nir_intrinsic_instr *instr, bool
    unsigned elem_size_bytes = instr->src[0].ssa->bit_size / 8;
    unsigned write_mask = nir_intrinsic_write_mask(instr);
 
-   /* Only write to VMEM if the output is per-vertex or it's per-patch non tess factor */
-   bool write_to_vmem = per_vertex || should_write_tcs_patch_output_to_vmem(ctx, instr);
-   /* Only write to LDS if the output is read by the shader, or it's per-patch tess factor */
-   bool write_to_lds = !write_to_vmem || should_write_tcs_output_to_lds(ctx, instr, per_vertex);
+   bool is_tess_factor = tcs_output_is_tess_factor(ctx, instr, per_vertex);
+   bool write_to_vmem = !is_tess_factor && tcs_output_is_read_by_tes(ctx, instr, per_vertex);
+   bool write_to_lds = is_tess_factor || tcs_output_is_read_by_tcs(ctx, instr, per_vertex);
 
    if (write_to_vmem) {
       std::pair<Temp, unsigned> vmem_offs = per_vertex