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aco: Only write TCS outputs to LDS when they are read by the TCS.

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Note that tess factors are always read at the end of the shader,
so those are still always saved to LDS.

Totals from affected shaders:
VGPRS: 25244 -> 25164 (-0.32 %)
Code Size: 1768268 -> 1690804 (-4.38 %) bytes
Max Waves: 4947 -> 4953 (0.12 %)

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3964>
This commit is contained in:
Timur Kristóf
2020-03-07 01:51:39 +01:00
committed by Marge Bot
parent 4dcca26945
commit 9b36d8c23a
1 changed files with 25 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/amd/compiler/aco_instruction_selection.cpp
+25 -2
View File
@@ -3334,6 +3334,29 @@ bool should_write_tcs_patch_output_to_vmem(isel_context *ctx, nir_intrinsic_inst
(off != (tess_index_outer * 16u));
}
bool should_write_tcs_patch_output_to_lds(isel_context *ctx, nir_intrinsic_instr *instr, bool per_vertex)
{
unsigned off = nir_intrinsic_base(instr) * 4u;
nir_src *off_src = nir_get_io_offset_src(instr);
/* Indirect offset, we can't be sure if this is read or not, always write to LDS */
if (!nir_src_is_const(*off_src))
return true;
off += nir_src_as_uint(*off_src) * 16u;
uint64_t out_rd = per_vertex
? ctx->shader->info.outputs_read
: ctx->shader->info.patch_outputs_read;
while (out_rd) {
unsigned slot = u_bit_scan64(&out_rd) + (per_vertex ? 0 : VARYING_SLOT_PATCH0);
if (off == shader_io_get_unique_index((gl_varying_slot) slot) * 16u)
return true;
}
return false;
}
void visit_store_tcs_output(isel_context *ctx, nir_intrinsic_instr *instr, bool per_vertex)
{
assert(ctx->stage == tess_control_hs || ctx->stage == vertex_tess_control_hs);
@@ -3347,8 +3370,8 @@ void visit_store_tcs_output(isel_context *ctx, nir_intrinsic_instr *instr, bool
/* 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);
/* TODO: Only write to LDS if the output is read by the shader, or it's per-patch tess factor */
bool write_to_lds = true;
/* 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_patch_output_to_lds(ctx, instr, per_vertex);
if (write_to_vmem) {
std::pair<Temp, unsigned> vmem_offs = per_vertex