nv50: record last access to temp and attr regs

We now inspect the TGSI instructions in tx_prep to determine where
temps and FP attrs are last accessed.
This will enable us to reclaim some temporaries early and we also
use it to omit pre-loading FP attributes that aren't used.

1 files changed, 127 insertions, 0 deletions

diff --git a/src/gallium/drivers/nv50/nv50_program.c b/src/gallium/drivers/nv50/nv50_program.c
index 40d2384c3e2..c73ed08a559 100644
--- a/src/gallium/drivers/nv50/nv50_program.c
+++ b/src/gallium/drivers/nv50/nv50_program.c
@@ -85,6 +85,8 @@ struct nv50_reg {
 
 	int hw;
 	int neg;
+
+	int acc; /* instruction where this reg is last read (first insn == 1) */
 };
 
 struct nv50_pc {
@@ -108,6 +110,10 @@ struct nv50_pc {
 
 	struct nv50_reg *temp_temp[16];
 	unsigned temp_temp_nr;
+
+	/* current instruction and total number of insns */
+	unsigned insn_cur;
+	unsigned insn_nr;
 };
 
 static void
@@ -1323,6 +1329,112 @@ nv50_program_tx_insn(struct nv50_pc *pc, const union tgsi_full_token *tok)
 	return TRUE;
 }
 
+/* Adjust a bitmask that indicates what components of a source are used,
+ * we use this in tx_prep so we only load interpolants that are needed.
+ */
+static void
+insn_adjust_mask(const struct tgsi_full_instruction *insn, unsigned *mask)
+{
+	const struct tgsi_instruction_ext_texture *tex;
+
+	switch (insn->Instruction.Opcode) {
+	case TGSI_OPCODE_DP3:
+		*mask = 0x7;
+		break;
+	case TGSI_OPCODE_DP4:
+	case TGSI_OPCODE_DPH:
+		*mask = 0xF;
+		break;
+	case TGSI_OPCODE_LIT:
+		*mask = 0xB;
+		break;
+	case TGSI_OPCODE_RCP:
+	case TGSI_OPCODE_RSQ:
+		*mask = 0x1;
+		break;
+	case TGSI_OPCODE_TEX:
+	case TGSI_OPCODE_TXP:
+		assert(insn->Instruction.Extended);
+		tex = &insn->InstructionExtTexture;
+
+		*mask = 0x7;
+		if (tex->Texture == TGSI_TEXTURE_1D)
+			*mask = 0x1;
+		else
+		if (tex->Texture == TGSI_TEXTURE_2D)
+			*mask = 0x3;
+
+		if (insn->Instruction.Opcode == TGSI_OPCODE_TXP)
+			*mask |= 0x8;
+		break;
+	default:
+		break;
+	}
+}
+
+static void
+prep_inspect_insn(struct nv50_pc *pc, const union tgsi_full_token *tok,
+		  unsigned *r_usage[2])
+{
+	const struct tgsi_full_instruction *insn;
+	const struct tgsi_full_src_register *src;
+	const struct tgsi_dst_register *dst;
+
+	unsigned i, c, k, n, mask, *acc_p;
+
+	insn = &tok->FullInstruction;
+	dst = &insn->FullDstRegisters[0].DstRegister;
+	mask = dst->WriteMask;
+
+	if (!r_usage[0])
+		r_usage[0] = CALLOC(pc->temp_nr * 4, sizeof(unsigned));
+	if (!r_usage[1])
+		r_usage[1] = CALLOC(pc->attr_nr * 4, sizeof(unsigned));
+
+	if (dst->File == TGSI_FILE_TEMPORARY) {
+		for (c = 0; c < 4; c++) {
+			if (!(mask & (1 << c)))
+				continue;
+			r_usage[0][dst->Index * 4 + c] = pc->insn_nr;
+		}
+	}
+
+	for (i = 0; i < insn->Instruction.NumSrcRegs; i++) {
+		src = &insn->FullSrcRegisters[i];
+
+		switch (src->SrcRegister.File) {
+		case TGSI_FILE_TEMPORARY:
+			acc_p = r_usage[0];
+			break;
+		case TGSI_FILE_INPUT:
+			acc_p = r_usage[1];
+			break;
+		default:
+			continue;
+		}
+
+		insn_adjust_mask(insn, &mask);
+
+		for (c = 0; c < 4; c++) {
+			if (!(mask & (1 << c)))
+				continue;
+
+			k = tgsi_util_get_full_src_register_extswizzle(src, c);
+			switch (k) {
+			case TGSI_EXTSWIZZLE_X:
+			case TGSI_EXTSWIZZLE_Y:
+			case TGSI_EXTSWIZZLE_Z:
+			case TGSI_EXTSWIZZLE_W:
+				n = src->SrcRegister.Index * 4 + k;
+				acc_p[n] = pc->insn_nr;
+				break;
+			default:
+				break;
+			}
+		}
+	}
+}
+
 static boolean
 nv50_program_tx_prep(struct nv50_pc *pc)
 {
@@ -1330,6 +1442,11 @@ nv50_program_tx_prep(struct nv50_pc *pc)
 	boolean ret = FALSE;
 	unsigned i, c;
 
+	/* track register access for temps and attrs */
+	unsigned *r_usage[2];
+	r_usage[0] = NULL;
+	r_usage[1] = NULL;
+
 	tgsi_parse_init(&p, pc->p->pipe.tokens);
 	while (!tgsi_parse_end_of_tokens(&p)) {
 		const union tgsi_full_token *tok = &p.FullToken;
@@ -1382,6 +1499,8 @@ nv50_program_tx_prep(struct nv50_pc *pc)
 		}
 			break;
 		case TGSI_TOKEN_TYPE_INSTRUCTION:
+			pc->insn_nr++;
+			prep_inspect_insn(pc, tok, r_usage);
 			break;
 		default:
 			break;
@@ -1398,6 +1517,7 @@ nv50_program_tx_prep(struct nv50_pc *pc)
 				pc->temp[i*4+c].type = P_TEMP;
 				pc->temp[i*4+c].hw = -1;
 				pc->temp[i*4+c].index = i;
+				pc->temp[i*4+c].acc = r_usage[0][i*4+c];
 			}
 		}
 	}
@@ -1427,6 +1547,7 @@ nv50_program_tx_prep(struct nv50_pc *pc)
 					pc->attr[i*4+c].type = at->type;
 					pc->attr[i*4+c].hw = at->hw;
 					pc->attr[i*4+c].index = at->index;
+					pc->attr[i*4+c].acc = r_usage[1][i*4+c];
 				} else {
 					pc->p->cfg.vp.attr[aid/32] |=
 						(1 << (aid % 32));
@@ -1504,6 +1625,11 @@ nv50_program_tx_prep(struct nv50_pc *pc)
 
 	ret = TRUE;
 out_err:
+	if (r_usage[0])
+		FREE(r_usage[0]);
+	if (r_usage[1])
+		FREE(r_usage[1]);
+
 	tgsi_parse_free(&p);
 	return ret;
 }
@@ -1558,6 +1684,7 @@ nv50_program_tx(struct nv50_program *p)
 
 		switch (tok->Token.Type) {
 		case TGSI_TOKEN_TYPE_INSTRUCTION:
+			++pc->insn_cur;
 			ret = nv50_program_tx_insn(pc, tok);
 			if (ret == FALSE)
 				goto out_err;