[Mesa-dev] [PATCH 3/3] radv/ac: handle gs->copy shader clip distances.

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

This fixes up the clip distance passing between the geometry
shader and the copy shader. It packs the clip and cull distances
into one or two consecutive slots, and avoids wasting space and
make sure the gs output and copy shader input agree on where
things are stored.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/amd/common/ac_nir_to_llvm.c | 81 ++++++++++++++++++++++++++++++++++-------
 1 file changed, 68 insertions(+), 13 deletions(-)

diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
index 43d5295..a74b906 100644
--- a/src/amd/common/ac_nir_to_llvm.c
+++ b/src/amd/common/ac_nir_to_llvm.c
@@ -2980,7 +2980,7 @@ visit_emit_vertex(struct nir_to_llvm_context *ctx,
 	LLVMValueRef gs_next_vertex;
 	LLVMValueRef can_emit, kill;
 	int idx;
-
+	int clip_cull_slot = -1;
 	assert(instr->const_index[0] == 0);
 	/* Write vertex attribute values to GSVS ring */
 	gs_next_vertex = LLVMBuildLoad(ctx->builder,
@@ -3005,13 +3005,40 @@ visit_emit_vertex(struct nir_to_llvm_context *ctx,
 	idx = 0;
 	for (unsigned i = 0; i < RADEON_LLVM_MAX_OUTPUTS; ++i) {
 		LLVMValueRef *out_ptr = &ctx->outputs[i * 4];
+		int length = 4;
+		int start = 0;
+		int slot = idx;
+		int slot_inc = 1;
+
 		if (!(ctx->output_mask & (1ull << i)))
 			continue;
 
-		for (unsigned j = 0; j < 4; j++) {
+		if (i == VARYING_SLOT_CLIP_DIST1 ||
+		    i == VARYING_SLOT_CULL_DIST1)
+			continue;
+
+		if (i == VARYING_SLOT_CLIP_DIST0 ||
+		    i == VARYING_SLOT_CULL_DIST0) {
+			/* pack clip and cull into a single set of slots */
+			if (clip_cull_slot == -1) {
+				clip_cull_slot = idx;
+				if (ctx->num_output_clips + ctx->num_output_culls > 4)
+					slot_inc = 2;
+			} else {
+				slot = clip_cull_slot;
+				slot_inc = 0;
+			}
+			if (i == VARYING_SLOT_CLIP_DIST0)
+				length = ctx->num_output_clips;
+			if (i == VARYING_SLOT_CULL_DIST0) {
+				start = ctx->num_output_clips;
+				length = ctx->num_output_culls;
+			}
+		}
+		for (unsigned j = 0; j < length; j++) {
 			LLVMValueRef out_val = LLVMBuildLoad(ctx->builder,
 							     out_ptr[j], "");
-			LLVMValueRef voffset = LLVMConstInt(ctx->i32, (idx * 4 + j) * ctx->gs_max_out_vertices, false);
+			LLVMValueRef voffset = LLVMConstInt(ctx->i32, (slot * 4 + j + start) * ctx->gs_max_out_vertices, false);
 			voffset = LLVMBuildAdd(ctx->builder, voffset, gs_next_vertex, "");
 			voffset = LLVMBuildMul(ctx->builder, voffset, LLVMConstInt(ctx->i32, 4, false), "");
 
@@ -3024,7 +3051,7 @@ visit_emit_vertex(struct nir_to_llvm_context *ctx,
 					       V_008F0C_BUF_NUM_FORMAT_UINT,
 					       1, 0, 1, 1, 0);
 		}
-		idx++;
+		idx += slot_inc;
 	}
 
 	gs_next_vertex = LLVMBuildAdd(ctx->builder, gs_next_vertex,
@@ -4155,14 +4182,14 @@ handle_shader_output_decl(struct nir_to_llvm_context *ctx,
 		if (idx == VARYING_SLOT_CLIP_DIST0 ||
 		    idx == VARYING_SLOT_CULL_DIST0) {
 			int length = glsl_get_length(variable->type);
-			if (ctx->stage == MESA_SHADER_VERTEX) {
-				if (idx == VARYING_SLOT_CLIP_DIST0) {
+			if (idx == VARYING_SLOT_CLIP_DIST0) {
+				if (ctx->stage == MESA_SHADER_VERTEX)
 					ctx->shader_info->vs.clip_dist_mask = (1 << length) - 1;
-					ctx->num_output_clips = length;
-				} else if (idx == VARYING_SLOT_CULL_DIST0) {
+				ctx->num_output_clips = length;
+			} else if (idx == VARYING_SLOT_CULL_DIST0) {
+				if (ctx->stage == MESA_SHADER_VERTEX)
 					ctx->shader_info->vs.cull_dist_mask = (1 << length) - 1;
-					ctx->num_output_culls = length;
-				}
+				ctx->num_output_culls = length;
 			}
 			if (length > 4)
 				attrib_count = 2;
@@ -5049,14 +5076,42 @@ ac_gs_copy_shader_emit(struct nir_to_llvm_context *ctx)
 	args[8] = ctx->i32zero; /* TFE */
 
 	int idx = 0;
+	int clip_cull_slot = -1;
 	for (unsigned i = 0; i < RADEON_LLVM_MAX_OUTPUTS; ++i) {
+		int length = 4;
+		int start = 0;
+		int slot = idx;
+		int slot_inc = 1;
 		if (!(ctx->output_mask & (1ull << i)))
 			continue;
 
-		for (unsigned j = 0; j < 4; j++) {
+		if (i == VARYING_SLOT_CLIP_DIST1 ||
+		    i == VARYING_SLOT_CULL_DIST1)
+			continue;
+
+		if (i == VARYING_SLOT_CLIP_DIST0 ||
+		    i == VARYING_SLOT_CULL_DIST0) {
+			/* unpack clip and cull from a single set of slots */
+			if (clip_cull_slot == -1) {
+				clip_cull_slot = idx;
+				if (ctx->num_output_clips + ctx->num_output_culls > 4)
+					slot_inc = 2;
+			} else {
+				slot = clip_cull_slot;
+				slot_inc = 0;
+			}
+			if (i == VARYING_SLOT_CLIP_DIST0)
+				length = ctx->num_output_clips;
+			if (i == VARYING_SLOT_CULL_DIST0) {
+				start = ctx->num_output_clips;
+				length = ctx->num_output_culls;
+			}
+		}
+
+		for (unsigned j = 0; j < length; j++) {
 			LLVMValueRef value;
 			args[2] = LLVMConstInt(ctx->i32,
-					       (idx * 4 + j) *
+					       (slot * 4 + j + start) *
 					       ctx->gs_max_out_vertices * 16 * 4, false);
 
 			value = ac_emit_llvm_intrinsic(&ctx->ac,
@@ -5067,7 +5122,7 @@ ac_gs_copy_shader_emit(struct nir_to_llvm_context *ctx)
 			LLVMBuildStore(ctx->builder,
 				       to_float(ctx, value), ctx->outputs[radeon_llvm_reg_index_soa(i, j)]);
 		}
-		idx++;
+		idx += slot_inc;
 	}
 	handle_vs_outputs_post(ctx);
 }
-- 
2.9.3