r600g: improve inputs/interpolation handling with llvm backend

Get rid of special handling for reserved regs.
Use one intrinsic for all kinds of interpolation.

v2[Vincent Lejeune]: Rebased against current master

Reviewed-by: Tom Stellard <[email protected]>
Signed-off-by: Vadim Girlin <[email protected]>

3 files changed, 150 insertions, 207 deletions

diff --git a/src/gallium/drivers/r600/r600_llvm.c b/src/gallium/drivers/r600/r600_llvm.c
index 9f8a0954f75..913dccc53a2 100644
--- a/src/gallium/drivers/r600/r600_llvm.c
+++ b/src/gallium/drivers/r600/r600_llvm.c
@@ -83,48 +83,40 @@ static LLVMValueRef llvm_fetch_system_value(
 static LLVMValueRef
 llvm_load_input_helper(
 	struct radeon_llvm_context * ctx,
-	const char *intrinsic, unsigned idx)
+	unsigned idx, int interp, int ij_index)
 {
-	LLVMValueRef reg = lp_build_const_int32(
-		ctx->soa.bld_base.base.gallivm,
-		idx);
-	return build_intrinsic(
-		ctx->soa.bld_base.base.gallivm->builder,
-		intrinsic,
-		ctx->soa.bld_base.base.elem_type, &reg, 1,
-		LLVMReadNoneAttribute);
+	const struct lp_build_context * bb = &ctx->soa.bld_base.base;
+	LLVMValueRef arg[2];
+	int arg_count;
+	const char * intrinsic;
+
+	arg[0] = lp_build_const_int32(bb->gallivm, idx);
+
+	if (interp) {
+		intrinsic = "llvm.R600.interp.input";
+		arg[1] = lp_build_const_int32(bb->gallivm, ij_index);
+		arg_count = 2;
+	} else {
+		intrinsic = "llvm.R600.load.input";
+		arg_count = 1;
+	}
+
+	return build_intrinsic(bb->gallivm->builder, intrinsic,
+		bb->elem_type, &arg[0], arg_count, LLVMReadNoneAttribute);
 }
 
 static LLVMValueRef
 llvm_face_select_helper(
 	struct radeon_llvm_context * ctx,
-	const char *intrinsic, unsigned face_register,
-	unsigned frontcolor_register, unsigned backcolor_regiser)
+	unsigned face_loc, LLVMValueRef front_color, LLVMValueRef back_color)
 {
-
-	LLVMValueRef backcolor = llvm_load_input_helper(
-		ctx,
-		intrinsic,
-		backcolor_regiser);
-	LLVMValueRef front_color = llvm_load_input_helper(
-		ctx,
-		intrinsic,
-		frontcolor_register);
-	LLVMValueRef face = llvm_load_input_helper(
-		ctx,
-		"llvm.R600.load.input",
-		face_register);
-	LLVMValueRef is_face_positive = LLVMBuildFCmp(
-		ctx->soa.bld_base.base.gallivm->builder,
-		LLVMRealUGT, face,
-		lp_build_const_float(ctx->soa.bld_base.base.gallivm, 0.0f),
-		"");
-	return LLVMBuildSelect(
-		ctx->soa.bld_base.base.gallivm->builder,
-		is_face_positive,
-		front_color,
-		backcolor,
-		"");
+	const struct lp_build_context * bb = &ctx->soa.bld_base.base;
+	LLVMValueRef face = llvm_load_input_helper(ctx, face_loc, 0, 0);
+	LLVMValueRef is_front = LLVMBuildFCmp(
+		bb->gallivm->builder, LLVMRealUGT, face,
+		lp_build_const_float(bb->gallivm, 0.0f),	"");
+	return LLVMBuildSelect(bb->gallivm->builder, is_front,
+		front_color, back_color, "");
 }
 
 static void llvm_load_input(
@@ -132,110 +124,59 @@ static void llvm_load_input(
 	unsigned input_index,
 	const struct tgsi_full_declaration *decl)
 {
+	const struct r600_shader_io * input = &ctx->r600_inputs[input_index];
 	unsigned chan;
-
-	const char *intrinsics = "llvm.R600.load.input";
-	unsigned offset = 4 * ctx->reserved_reg_count;
-
-	if (ctx->type == TGSI_PROCESSOR_FRAGMENT && ctx->chip_class >= EVERGREEN) {
-		switch (decl->Interp.Interpolate) {
-		case TGSI_INTERPOLATE_COLOR:
-		case TGSI_INTERPOLATE_PERSPECTIVE:
-			offset = 0;
-			intrinsics = "llvm.R600.load.input.perspective";
-			break;
-		case TGSI_INTERPOLATE_LINEAR:
-			offset = 0;
-			intrinsics = "llvm.R600.load.input.linear";
-			break;
-		case TGSI_INTERPOLATE_CONSTANT:
-			offset = 0;
-			intrinsics = "llvm.R600.load.input.constant";
-			break;
-		default:
-			assert(0 && "Unknow Interpolate mode");
-		}
+	unsigned interp = 0;
+	int ij_index;
+	int two_side = (ctx->two_side && input->name == TGSI_SEMANTIC_COLOR);
+	LLVMValueRef v;
+
+	if (ctx->chip_class >= EVERGREEN && ctx->type == TGSI_PROCESSOR_FRAGMENT &&
+			input->spi_sid) {
+		interp = 1;
+		ij_index = (input->interpolate > 0) ? input->ij_index : -1;
 	}
 
 	for (chan = 0; chan < 4; chan++) {
-		unsigned soa_index = radeon_llvm_reg_index_soa(input_index,
-								chan);
-
-		switch (decl->Semantic.Name) {
-		case TGSI_SEMANTIC_FACE:
-			ctx->inputs[soa_index] = llvm_load_input_helper(ctx,
-				"llvm.R600.load.input",
-				4 * ctx->face_input);
-			break;
-		case TGSI_SEMANTIC_POSITION:
-			if (ctx->type != TGSI_PROCESSOR_FRAGMENT || chan != 3) {
-				ctx->inputs[soa_index] = llvm_load_input_helper(ctx,
-					"llvm.R600.load.input",
-					soa_index + (ctx->reserved_reg_count * 4));
-			} else {
-				LLVMValueRef w_coord = llvm_load_input_helper(ctx,
-				"llvm.R600.load.input",
-				soa_index + (ctx->reserved_reg_count * 4));
-				ctx->inputs[soa_index] = LLVMBuildFDiv(ctx->gallivm.builder,
-				lp_build_const_float(&(ctx->gallivm), 1.0f), w_coord, "");
-			}
-			break;
-		case TGSI_SEMANTIC_COLOR:
-			if (ctx->two_side) {
-				unsigned front_location, back_location;
-				unsigned back_reg = ctx->r600_inputs[input_index]
-					.potential_back_facing_reg;
-				if (ctx->chip_class >= EVERGREEN) {
-					front_location = 4 * ctx->r600_inputs[input_index].lds_pos + chan;
-					back_location = 4 * ctx->r600_inputs[back_reg].lds_pos + chan;
-				} else {
-					front_location = soa_index + 4 * ctx->reserved_reg_count;
-					back_location = radeon_llvm_reg_index_soa(
-						ctx->r600_inputs[back_reg].gpr,
-						chan);
-				}
-				ctx->inputs[soa_index] = llvm_face_select_helper(ctx,
-					intrinsics,
-					4 * ctx->face_input, front_location, back_location);
-				break;
-			}
-		default:
-			{
-				unsigned location;
-				if (ctx->chip_class >= EVERGREEN) {
-					location = 4 * ctx->r600_inputs[input_index].lds_pos + chan;
-				} else {
-					location = soa_index + 4 * ctx->reserved_reg_count;
-				}
-				/* The * 4 is assuming that we are in soa mode. */
-				ctx->inputs[soa_index] = llvm_load_input_helper(ctx,
-					intrinsics, location);
-					
-			break;
-			}
+		unsigned soa_index = radeon_llvm_reg_index_soa(input_index, chan);
+		int loc;
+
+		if (interp) {
+			loc = 4 * input->lds_pos + chan;
+		} else {
+			if (input->name == TGSI_SEMANTIC_FACE)
+				loc = 4 * ctx->face_gpr;
+			else
+				loc = 4 * input->gpr + chan;
+		}
+
+		v = llvm_load_input_helper(ctx, loc, interp, ij_index);
+
+		if (two_side) {
+			struct r600_shader_io * back_input =
+					&ctx->r600_inputs[input->back_color_input];
+			int back_loc = interp ? back_input->lds_pos : back_input->gpr;
+			LLVMValueRef v2;
+
+			back_loc = 4 * back_loc + chan;
+			v2 = llvm_load_input_helper(ctx, back_loc, interp, ij_index);
+			v = llvm_face_select_helper(ctx, 4 * ctx->face_gpr, v, v2);
+		} else if (input->name == TGSI_SEMANTIC_POSITION &&
+				ctx->type == TGSI_PROCESSOR_FRAGMENT && chan == 3) {
+			/* RCP for fragcoord.w */
+			v = LLVMBuildFDiv(ctx->gallivm.builder,
+					lp_build_const_float(&(ctx->gallivm), 1.0f),
+					v, "");
 		}
+
+		ctx->inputs[soa_index] = v;
 	}
 }
 
 static void llvm_emit_prologue(struct lp_build_tgsi_context * bld_base)
 {
 	struct radeon_llvm_context * ctx = radeon_llvm_context(bld_base);
-	struct lp_build_context * base = &bld_base->base;
-	unsigned i;
 
-	/* Reserve special input registers */
-	for (i = 0; i < ctx->reserved_reg_count; i++) {
-		unsigned chan;
-		for (chan = 0; chan < TGSI_NUM_CHANNELS; chan++) {
-			LLVMValueRef reg_index = lp_build_const_int32(
-					base->gallivm,
-					radeon_llvm_reg_index_soa(i, chan));
-			lp_build_intrinsic_unary(base->gallivm->builder,
-				"llvm.AMDGPU.reserve.reg",
-				LLVMVoidTypeInContext(base->gallivm->context),
-				reg_index);
-		}
-	}
 }
 
 static void llvm_emit_epilogue(struct lp_build_tgsi_context * bld_base)
diff --git a/src/gallium/drivers/r600/r600_shader.c b/src/gallium/drivers/r600/r600_shader.c
index c16e467c853..e8992ba5bed 100644
--- a/src/gallium/drivers/r600/r600_shader.c
+++ b/src/gallium/drivers/r600/r600_shader.c
@@ -650,19 +650,15 @@ static int tgsi_is_supported(struct r600_shader_ctx *ctx)
 	return 0;
 }
 
-static int evergreen_interp_alu(struct r600_shader_ctx *ctx, int input)
+static void evergreen_interp_assign_ij_index(struct r600_shader_ctx *ctx,
+		int input)
 {
-	int i, r;
-	struct r600_bytecode_alu alu;
-	int gpr = 0, base_chan = 0;
 	int ij_index = 0;
 
 	if (ctx->shader->input[input].interpolate == TGSI_INTERPOLATE_PERSPECTIVE) {
-		ij_index = 0;
 		if (ctx->shader->input[input].centroid)
 			ij_index++;
 	} else if (ctx->shader->input[input].interpolate == TGSI_INTERPOLATE_LINEAR) {
-		ij_index = 0;
 		/* if we have perspective add one */
 		if (ctx->input_perspective)  {
 			ij_index++;
@@ -674,6 +670,16 @@ static int evergreen_interp_alu(struct r600_shader_ctx *ctx, int input)
 			ij_index++;
 	}
 
+	ctx->shader->input[input].ij_index = ij_index;
+}
+
+static int evergreen_interp_alu(struct r600_shader_ctx *ctx, int input)
+{
+	int i, r;
+	struct r600_bytecode_alu alu;
+	int gpr = 0, base_chan = 0;
+	int ij_index = ctx->shader->input[input].ij_index;
+
 	/* work out gpr and base_chan from index */
 	gpr = ij_index / 2;
 	base_chan = (2 * (ij_index % 2)) + 1;
@@ -806,12 +812,13 @@ static int evergreen_interp_input(struct r600_shader_ctx *ctx, int index)
 
 	if (ctx->shader->input[index].spi_sid) {
 		ctx->shader->input[index].lds_pos = ctx->shader->nlds++;
-		if (!ctx->use_llvm) {
-			if (ctx->shader->input[index].interpolate > 0) {
+		if (ctx->shader->input[index].interpolate > 0) {
+			evergreen_interp_assign_ij_index(ctx, index);
+			if (!ctx->use_llvm)
 				r = evergreen_interp_alu(ctx, index);
-			} else {
+		} else {
+			if (!ctx->use_llvm)
 				r = evergreen_interp_flat(ctx, index);
-			}
 		}
 	}
 	return r;
@@ -857,11 +864,11 @@ static int tgsi_declaration(struct r600_shader_ctx *ctx)
 		i = ctx->shader->ninput++;
 		ctx->shader->input[i].name = d->Semantic.Name;
 		ctx->shader->input[i].sid = d->Semantic.Index;
-		ctx->shader->input[i].spi_sid = r600_spi_sid(&ctx->shader->input[i]);
 		ctx->shader->input[i].interpolate = d->Interp.Interpolate;
 		ctx->shader->input[i].centroid = d->Interp.Centroid;
 		ctx->shader->input[i].gpr = ctx->file_offset[TGSI_FILE_INPUT] + d->Range.First;
 		if (ctx->type == TGSI_PROCESSOR_FRAGMENT) {
+			ctx->shader->input[i].spi_sid = r600_spi_sid(&ctx->shader->input[i]);
 			switch (ctx->shader->input[i].name) {
 			case TGSI_SEMANTIC_FACE:
 				ctx->face_gpr = ctx->shader->input[i].gpr;
@@ -883,11 +890,11 @@ static int tgsi_declaration(struct r600_shader_ctx *ctx)
 		i = ctx->shader->noutput++;
 		ctx->shader->output[i].name = d->Semantic.Name;
 		ctx->shader->output[i].sid = d->Semantic.Index;
-		ctx->shader->output[i].spi_sid = r600_spi_sid(&ctx->shader->output[i]);
 		ctx->shader->output[i].gpr = ctx->file_offset[TGSI_FILE_OUTPUT] + d->Range.First;
 		ctx->shader->output[i].interpolate = d->Interp.Interpolate;
 		ctx->shader->output[i].write_mask = d->Declaration.UsageMask;
 		if (ctx->type == TGSI_PROCESSOR_VERTEX) {
+			ctx->shader->output[i].spi_sid = r600_spi_sid(&ctx->shader->output[i]);
 			switch (d->Semantic.Name) {
 			case TGSI_SEMANTIC_CLIPDIST:
 				ctx->shader->clip_dist_write |= d->Declaration.UsageMask << (d->Semantic.Index << 2);
@@ -1193,17 +1200,9 @@ static int process_twoside_color_inputs(struct r600_shader_ctx *ctx)
 
 	for (i = 0; i < count; i++) {
 		if (ctx->shader->input[i].name == TGSI_SEMANTIC_COLOR) {
-			unsigned back_facing_reg = ctx->shader->input[i].potential_back_facing_reg;
-			if (ctx->bc->chip_class >= EVERGREEN) {
-				if ((r = evergreen_interp_input(ctx, back_facing_reg)))
-					return r;
-			}
-			
-			if (!ctx->use_llvm) {
-				r = select_twoside_color(ctx, i, back_facing_reg);
-				if (r)
-					return r;
-			}
+			r = select_twoside_color(ctx, i, ctx->shader->input[i].back_color_input);
+			if (r)
+				return r;
 		}
 	}
 	return 0;
@@ -1396,7 +1395,11 @@ static int r600_shader_from_tgsi(struct r600_screen *rscreen,
 				// TGSI to LLVM needs to know the lds position of inputs.
 				// Non LLVM path computes it later (in process_twoside_color)
 				ctx.shader->input[ni].lds_pos = next_lds_loc++;
-				ctx.shader->input[i].potential_back_facing_reg = ni;
+				ctx.shader->input[i].back_color_input = ni;
+				if (ctx.bc->chip_class >= EVERGREEN) {
+					if ((r = evergreen_interp_input(&ctx, ni)))
+						return r;
+				}
 			}
 		}
 	}
@@ -1408,10 +1411,9 @@ static int r600_shader_from_tgsi(struct r600_screen *rscreen,
 		LLVMModuleRef mod;
 		unsigned dump = 0;
 		memset(&radeon_llvm_ctx, 0, sizeof(radeon_llvm_ctx));
-		radeon_llvm_ctx.reserved_reg_count = ctx.file_offset[TGSI_FILE_INPUT];
 		radeon_llvm_ctx.type = ctx.type;
 		radeon_llvm_ctx.two_side = shader->two_side;
-		radeon_llvm_ctx.face_input = ctx.face_gpr;
+		radeon_llvm_ctx.face_gpr = ctx.face_gpr;
 		radeon_llvm_ctx.r600_inputs = ctx.shader->input;
 		radeon_llvm_ctx.r600_outputs = ctx.shader->output;
 		radeon_llvm_ctx.color_buffer_count = MAX2(key.nr_cbufs , 1);
@@ -1442,9 +1444,24 @@ static int r600_shader_from_tgsi(struct r600_screen *rscreen,
 	if (shader->fs_write_all && rscreen->chip_class >= EVERGREEN)
 		shader->nr_ps_max_color_exports = 8;
 
-	if (ctx.fragcoord_input >= 0 && !use_llvm) {
-		if (ctx.bc->chip_class == CAYMAN) {
-			for (j = 0 ; j < 4; j++) {
+	if (!use_llvm) {
+		if (ctx.fragcoord_input >= 0) {
+			if (ctx.bc->chip_class == CAYMAN) {
+				for (j = 0 ; j < 4; j++) {
+					struct r600_bytecode_alu alu;
+					memset(&alu, 0, sizeof(struct r600_bytecode_alu));
+					alu.inst = BC_INST(ctx.bc, V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_RECIP_IEEE);
+					alu.src[0].sel = shader->input[ctx.fragcoord_input].gpr;
+					alu.src[0].chan = 3;
+
+					alu.dst.sel = shader->input[ctx.fragcoord_input].gpr;
+					alu.dst.chan = j;
+					alu.dst.write = (j == 3);
+					alu.last = 1;
+					if ((r = r600_bytecode_add_alu(ctx.bc, &alu)))
+						return r;
+				}
+			} else {
 				struct r600_bytecode_alu alu;
 				memset(&alu, 0, sizeof(struct r600_bytecode_alu));
 				alu.inst = BC_INST(ctx.bc, V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_RECIP_IEEE);
@@ -1452,65 +1469,49 @@ static int r600_shader_from_tgsi(struct r600_screen *rscreen,
 				alu.src[0].chan = 3;
 
 				alu.dst.sel = shader->input[ctx.fragcoord_input].gpr;
-				alu.dst.chan = j;
-				alu.dst.write = (j == 3);
+				alu.dst.chan = 3;
+				alu.dst.write = 1;
 				alu.last = 1;
 				if ((r = r600_bytecode_add_alu(ctx.bc, &alu)))
 					return r;
 			}
-		} else {
-			struct r600_bytecode_alu alu;
-			memset(&alu, 0, sizeof(struct r600_bytecode_alu));
-			alu.inst = BC_INST(ctx.bc, V_SQ_ALU_WORD1_OP2_SQ_OP2_INST_RECIP_IEEE);
-			alu.src[0].sel = shader->input[ctx.fragcoord_input].gpr;
-			alu.src[0].chan = 3;
+		}
 
-			alu.dst.sel = shader->input[ctx.fragcoord_input].gpr;
-			alu.dst.chan = 3;
-			alu.dst.write = 1;
-			alu.last = 1;
-			if ((r = r600_bytecode_add_alu(ctx.bc, &alu)))
+		if (shader->two_side && ctx.colors_used) {
+			if ((r = process_twoside_color_inputs(&ctx)))
 				return r;
 		}
-	}
-
-	if (shader->two_side && ctx.colors_used) {
-		if ((r = process_twoside_color_inputs(&ctx)))
-			return r;
-	}
 
-	tgsi_parse_init(&ctx.parse, tokens);
-	while (!tgsi_parse_end_of_tokens(&ctx.parse)) {
-		tgsi_parse_token(&ctx.parse);
-		switch (ctx.parse.FullToken.Token.Type) {
-		case TGSI_TOKEN_TYPE_INSTRUCTION:
-			if (use_llvm) {
-				continue;
+		tgsi_parse_init(&ctx.parse, tokens);
+		while (!tgsi_parse_end_of_tokens(&ctx.parse)) {
+			tgsi_parse_token(&ctx.parse);
+			switch (ctx.parse.FullToken.Token.Type) {
+			case TGSI_TOKEN_TYPE_INSTRUCTION:
+				r = tgsi_is_supported(&ctx);
+				if (r)
+					goto out_err;
+				ctx.max_driver_temp_used = 0;
+				/* reserve first tmp for everyone */
+				r600_get_temp(&ctx);
+
+				opcode = ctx.parse.FullToken.FullInstruction.Instruction.Opcode;
+				if ((r = tgsi_split_constant(&ctx)))
+					goto out_err;
+				if ((r = tgsi_split_literal_constant(&ctx)))
+					goto out_err;
+				if (ctx.bc->chip_class == CAYMAN)
+					ctx.inst_info = &cm_shader_tgsi_instruction[opcode];
+				else if (ctx.bc->chip_class >= EVERGREEN)
+					ctx.inst_info = &eg_shader_tgsi_instruction[opcode];
+				else
+					ctx.inst_info = &r600_shader_tgsi_instruction[opcode];
+				r = ctx.inst_info->process(&ctx);
+				if (r)
+					goto out_err;
+				break;
+			default:
+				break;
 			}
-			r = tgsi_is_supported(&ctx);
-			if (r)
-				goto out_err;
-			ctx.max_driver_temp_used = 0;
-			/* reserve first tmp for everyone */
-			r600_get_temp(&ctx);
-
-			opcode = ctx.parse.FullToken.FullInstruction.Instruction.Opcode;
-			if ((r = tgsi_split_constant(&ctx)))
-				goto out_err;
-			if ((r = tgsi_split_literal_constant(&ctx)))
-				goto out_err;
-			if (ctx.bc->chip_class == CAYMAN)
-				ctx.inst_info = &cm_shader_tgsi_instruction[opcode];
-			else if (ctx.bc->chip_class >= EVERGREEN)
-				ctx.inst_info = &eg_shader_tgsi_instruction[opcode];
-			else
-				ctx.inst_info = &r600_shader_tgsi_instruction[opcode];
-			r = ctx.inst_info->process(&ctx);
-			if (r)
-				goto out_err;
-			break;
-		default:
-			break;
 		}
 	}
 
diff --git a/src/gallium/drivers/r600/r600_shader.h b/src/gallium/drivers/r600/r600_shader.h
index d61efcb1a72..f55e002aea6 100644
--- a/src/gallium/drivers/r600/r600_shader.h
+++ b/src/gallium/drivers/r600/r600_shader.h
@@ -32,9 +32,10 @@ struct r600_shader_io {
 	int			sid;
 	int			spi_sid;
 	unsigned		interpolate;
+	unsigned		ij_index;
 	boolean                 centroid;
 	unsigned		lds_pos; /* for evergreen */
-	unsigned		potential_back_facing_reg;
+	unsigned		back_color_input;
 	unsigned		write_mask;
 };