[Mesa-dev] [PATCH] radv: do not lower UBO/SSBO access to offsets

[Samuel Pitoiset]

This helps few compute shaders, mostly for F12017.

27670 shaders in 14347 tests
Totals:
SGPRS: 1231173 -> 1231173 (0.00 %)
VGPRS: 866056 -> 865928 (-0.01 %)
Spilled SGPRs: 24201 -> 24201 (0.00 %)
Code Size: 46137040 -> 46144868 (0.02 %) bytes
Max Waves: 232287 -> 232302 (0.01 %)

Totals from affected shaders:
SGPRS: 24624 -> 24624 (0.00 %)
VGPRS: 25960 -> 25832 (-0.49 %)
Spilled SGPRs: 0 -> 0 (0.00 %)
Code Size: 2922632 -> 2930460 (0.27 %) bytes
Max Waves: 1216 -> 1231 (1.23 %)

Suggested-by: <Jason Ekstrand jason at jlekstrand.net>
Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
---
 src/amd/common/ac_nir_to_llvm.c | 8 ++++++++
 src/amd/vulkan/radv_shader.c    | 5 ++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index b25cc6a0a84..c46d98e6dd9 100644
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -3275,6 +3275,14 @@ static void visit_intrinsic(struct ac_nir_context *ctx,
 	case nir_intrinsic_vulkan_resource_reindex:
 		result = visit_vulkan_resource_reindex(ctx, instr);
 		break;
+	case nir_intrinsic_load_vulkan_descriptor: {
+		LLVMValueRef values[2] = {
+			get_src(ctx, instr->src[0]),
+			ctx->ac.i32_0,
+		};
+		result = ac_build_gather_values(&ctx->ac, values, 2);
+		break;
+	}
 	case nir_intrinsic_store_ssbo:
 		visit_store_ssbo(ctx, instr);
 		break;
diff --git a/src/amd/vulkan/radv_shader.c b/src/amd/vulkan/radv_shader.c
index 19a807df199..2751302e8b9 100644
--- a/src/amd/vulkan/radv_shader.c
+++ b/src/amd/vulkan/radv_shader.c
@@ -220,7 +220,6 @@ radv_shader_compile_to_nir(struct radv_device *device,
 			}
 		}
 		const struct spirv_to_nir_options spirv_options = {
-			.lower_ubo_ssbo_access_to_offsets = true,
 			.caps = {
 				.descriptor_array_dynamic_indexing = true,
 				.device_group = true,
@@ -306,6 +305,10 @@ radv_shader_compile_to_nir(struct radv_device *device,
 		NIR_PASS_V(nir, nir_lower_system_values);
 		NIR_PASS_V(nir, nir_lower_clip_cull_distance_arrays);
 		NIR_PASS_V(nir, nir_lower_frexp);
+
+		NIR_PASS_V(nir, nir_lower_explicit_io,
+			  nir_var_mem_ubo | nir_var_mem_ssbo,
+			  nir_address_format_32bit_index_offset);
 	}
 
 	/* Vulkan uses the separate-shader linking model */
-- 
2.21.0