r300/compiler: Allow merged instructions to be scheduled on demand

We no longer emit full instructions immediately after they have been
merged.  Instead merged instructions are added to the ready list and
the scheduler can commit them whenever it wants.

1 files changed, 99 insertions, 50 deletions

diff --git a/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c b/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c
index fb1b86163a6..1f589cdb98e 100644
--- a/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c
+++ b/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c
@@ -60,6 +60,11 @@ struct schedule_instruction {
 	 * "all readers"), even those outside the basic block this instruction
 	 * lives in. */
 	struct rc_reader_data GlobalReaders;
+
+	/** If the scheduler has paired an RGB and an Alpha instruction together,
+	 * PairedInst references the alpha insturction's dependency information.
+	 */
+	struct schedule_instruction * PairedInst;
 };
 
 
@@ -142,6 +147,25 @@ static struct reg_value ** get_reg_valuep(struct schedule_state * s,
 	return &s->Temporary[index].Values[chan];
 }
 
+static void remove_inst_from_list(struct schedule_instruction ** list,
+					struct schedule_instruction * inst)
+{
+	struct schedule_instruction * prev = NULL;
+	struct schedule_instruction * list_ptr;
+	for (list_ptr = *list; list_ptr; prev = list_ptr,
+					list_ptr = list_ptr->NextReady) {
+		if (list_ptr == inst) {
+			if (prev) {
+				prev->NextReady = inst->NextReady;
+			} else {
+				*list = inst->NextReady;
+			}
+			inst->NextReady = NULL;
+			break;
+		}
+	}
+}
+
 static void add_inst_to_list(struct schedule_instruction ** list, struct schedule_instruction * inst)
 {
 	inst->NextReady = *list;
@@ -202,6 +226,9 @@ static void commit_update_reads(struct schedule_state * s,
 				decrease_dependencies(s, v->Next->Writer);
 		}
 	}
+	if (sinst->PairedInst) {
+		commit_update_reads(s, sinst->PairedInst);
+	}
 }
 
 static void commit_update_writes(struct schedule_state * s,
@@ -224,6 +251,9 @@ static void commit_update_writes(struct schedule_state * s,
 				decrease_dependencies(s, v->Next->Writer);
 		}
 	}
+	if (sinst->PairedInst) {
+		commit_update_writes(s, sinst->PairedInst);
+	}
 }
 
 static void commit_alu_instruction(struct schedule_state * s, struct schedule_instruction * sinst)
@@ -480,6 +510,7 @@ static int merge_instructions(struct rc_pair_instruction * rgb, struct rc_pair_i
 		|| (rgb->RGB.OutputWriteMask && alpha->WriteALUResult)) {
 		return 0;
 	}
+
 	memcpy(&backup, rgb, sizeof(struct rc_pair_instruction));
 
 	if (destructive_merge_instructions(rgb, alpha))
@@ -748,6 +779,71 @@ static int convert_rgb_to_alpha(
 }
 
 /**
+ * This function attempts to merge RGB and Alpha instructions together.
+ */
+static void pair_instructions(struct schedule_state * s)
+{
+	struct schedule_instruction *rgb_ptr;
+	struct schedule_instruction *alpha_ptr;
+
+	/* Some pairings might fail because they require too
+	 * many source slots; try all possible pairings if necessary */
+	rgb_ptr = s->ReadyRGB;
+	while(rgb_ptr) {
+		struct schedule_instruction * rgb_next = rgb_ptr->NextReady;
+		alpha_ptr = s->ReadyAlpha;
+		while(alpha_ptr) {
+			struct schedule_instruction * alpha_next = alpha_ptr->NextReady;
+			if (merge_instructions(&rgb_ptr->Instruction->U.P, &alpha_ptr->Instruction->U.P)) {
+				/* Remove RGB and Alpha from their ready lists.
+				 */
+				remove_inst_from_list(&s->ReadyRGB, rgb_ptr);
+				remove_inst_from_list(&s->ReadyAlpha, alpha_ptr);
+				rgb_ptr->PairedInst = alpha_ptr;
+				add_inst_to_list(&s->ReadyFullALU, rgb_ptr);
+				break;
+			}
+			alpha_ptr = alpha_next;
+		}
+		rgb_ptr = rgb_next;
+	}
+
+	/* Try to convert some of the RGB instructions to Alpha and
+	 * try to pair it with another RGB. */
+	rgb_ptr = s->ReadyRGB;
+	while (rgb_ptr && s->ReadyRGB && s->ReadyRGB->NextReady) {
+		int paired = 0;
+		if (rgb_ptr->NumWriteValues == 1
+					&& convert_rgb_to_alpha(s, rgb_ptr)) {
+
+			struct schedule_instruction * pair_ptr;
+			for (pair_ptr = s->ReadyRGB; pair_ptr;
+					pair_ptr = pair_ptr->NextReady) {
+				if (pair_ptr == rgb_ptr) {
+					continue;
+				}
+				if (merge_instructions(&pair_ptr->Instruction->U.P,
+						&rgb_ptr->Instruction->U.P)) {
+					remove_inst_from_list(&s->ReadyRGB, rgb_ptr);
+					remove_inst_from_list(&s->ReadyRGB, pair_ptr);
+					pair_ptr->PairedInst = rgb_ptr;
+
+					add_inst_to_list(&s->ReadyFullALU, pair_ptr);
+					rgb_ptr = s->ReadyRGB;
+					paired = 1;
+					break;
+				}
+
+			}
+		}
+		if (!paired) {
+			rgb_ptr = rgb_ptr->NextReady;
+		}
+	}
+}
+
+
+/**
  * Find a good ALU instruction or pair of ALU instruction and emit it.
  *
  * Prefer emitting full ALU instructions, so that when we reach a point
@@ -758,61 +854,15 @@ static void emit_one_alu(struct schedule_state *s, struct rc_instruction * befor
 {
 	struct schedule_instruction * sinst;
 
+	/* Try to merge RGB and Alpha instructions together. */
+	pair_instructions(s);
+
 	if (s->ReadyFullALU) {
 		sinst = s->ReadyFullALU;
 		s->ReadyFullALU = s->ReadyFullALU->NextReady;
 		rc_insert_instruction(before->Prev, sinst->Instruction);
 		commit_alu_instruction(s, sinst);
 	} else {
-		struct schedule_instruction **prgb;
-		struct schedule_instruction **palpha;
-		struct schedule_instruction *prev;
-pair:
-		/* Some pairings might fail because they require too
-		 * many source slots; try all possible pairings if necessary */
-		for(prgb = &s->ReadyRGB; *prgb; prgb = &(*prgb)->NextReady) {
-			for(palpha = &s->ReadyAlpha; *palpha; palpha = &(*palpha)->NextReady) {
-				struct schedule_instruction * psirgb = *prgb;
-				struct schedule_instruction * psialpha = *palpha;
-
-				if (!merge_instructions(&psirgb->Instruction->U.P, &psialpha->Instruction->U.P))
-					continue;
-
-				*prgb = (*prgb)->NextReady;
-				*palpha = (*palpha)->NextReady;
-				rc_insert_instruction(before->Prev, psirgb->Instruction);
-				commit_alu_instruction(s, psirgb);
-				commit_alu_instruction(s, psialpha);
-				goto success;
-			}
-		}
-		prev = NULL;
-		/* No success in pairing, now try to convert one of the RGB
-		 * instructions to an Alpha so we can pair it with another RGB.
-		 */
-		if (s->ReadyRGB && s->ReadyRGB->NextReady) {
-		for(prgb = &s->ReadyRGB; *prgb; prgb = &(*prgb)->NextReady) {
-			if ((*prgb)->NumWriteValues == 1) {
-				struct schedule_instruction * prgb_next;
-				if (!convert_rgb_to_alpha(s, *prgb))
-					goto cont_loop;
-				prgb_next = (*prgb)->NextReady;
-				/* Add instruction to the Alpha ready list. */
-				(*prgb)->NextReady = s->ReadyAlpha;
-				s->ReadyAlpha = *prgb;
-				/* Remove instruction from the RGB ready list.*/
-				if (prev)
-					prev->NextReady = prgb_next;
-				else
-					s->ReadyRGB = prgb_next;
-				goto pair;
-			}
-cont_loop:
-			prev = *prgb;
-		}
-		}
-		/* Still no success in pairing, just take the first RGB
-		 * or alpha instruction. */
 		if (s->ReadyRGB) {
 			sinst = s->ReadyRGB;
 			s->ReadyRGB = s->ReadyRGB->NextReady;
@@ -826,7 +876,6 @@ cont_loop:
 
 		rc_insert_instruction(before->Prev, sinst->Instruction);
 		commit_alu_instruction(s, sinst);
-	success: ;
 	}
 	/* If the instruction we just emitted uses a presubtract value, and
 	 * the presubtract sources were written by the previous intstruction,