Merge branch 'uniq-phinode'

* phi-sources can only have a single user (or none)c

Documentation/IR.rst

@@ -381,7 +381,7 @@ Others
 	* .phi_src: operand (type must be compatible with .target, alias .src)
 	* .target: the "result" PSEUDO_PHI
 	* .type: type of .target
-	* .phi_users: list of phi instructions using the target pseudo
+	* .phi_node: the unique phi instruction using the target pseudo
 
 .. op:: OP_CALL
 	Function call.

flow.c

@@ -46,25 +46,6 @@ static int rewrite_branch(struct basic_block *bb,
 	return 1;
 }
 
-///
-// returns the phi-node corresponding to a phi-source
-static struct instruction *get_phinode(struct instruction *phisrc)
-{
-	struct pseudo_user *pu;
-
-	FOR_EACH_PTR(phisrc->target->users, pu) {
-		struct instruction *user;
-
-		if (!pu)
-			continue;
-		user = pu->insn;
-		assert(user->opcode == OP_PHI);
-		return user;
-	} END_FOR_EACH_PTR(pu);
-	assert(0);
-}
-
-
 /*
  * Return the known truth value of a pseudo, or -1 if
  * it's not known.
@@ -852,7 +833,7 @@ static int retarget_parents(struct basic_block *bb, struct basic_block *target)
 
 static void remove_merging_phisrc(struct basic_block *top, struct instruction *insn)
 {
-	struct instruction *user = get_phinode(insn);
+	struct instruction *user = insn->phi_node;
 	pseudo_t phi;
 
 	FOR_EACH_PTR(user->phi_list, phi) {

linearize.c

@@ -407,11 +407,7 @@ const char *show_instruction(struct instruction *insn)
 		break;
 
 	case OP_PHISOURCE: {
-		struct instruction *phi;
 		buf += sprintf(buf, "%s <- %s    ", show_pseudo(insn->target), show_pseudo(insn->phi_src));
-		FOR_EACH_PTR(insn->phi_users, phi) {
-			buf += sprintf(buf, " (%s)", show_pseudo(phi->target));
-		} END_FOR_EACH_PTR(phi);
 		break;
 	}
 
@@ -1683,8 +1679,8 @@ static pseudo_t add_join_conditional(struct entrypoint *ep, struct expression *e
 		return (phi1 == VOID) ? phi1 : phi1->def->src;
 
 	phi_node = alloc_typed_instruction(OP_PHI, expr->ctype);
-	use_pseudo(phi_node, phi1, add_pseudo(&phi_node->phi_list, phi1));
-	use_pseudo(phi_node, phi2, add_pseudo(&phi_node->phi_list, phi2));
+	link_phi(phi_node, phi1);
+	link_phi(phi_node, phi2);
 	phi_node->target = target = alloc_pseudo(phi_node);
 	add_one_insn(ep, phi_node);
 	return target;
@@ -1756,7 +1752,7 @@ static void insert_phis(struct basic_block *bb, pseudo_t src, struct symbol *cty
 		struct instruction *br = delete_last_instruction(&parent->insns);
 		pseudo_t phi = alloc_phi(parent, src, ctype);
 		add_instruction(&parent->insns, br);
-		use_pseudo(node, phi, add_pseudo(&node->phi_list, phi));
+		link_phi(node, phi);
 	} END_FOR_EACH_PTR(parent);
 }
 
@@ -1789,7 +1785,7 @@ static pseudo_t linearize_logical(struct entrypoint *ep, struct expression *expr
 	src2 = linearize_expression_to_bool(ep, expr->right);
 	src2 = cast_pseudo(ep, src2, &bool_ctype, ctype);
 	phi2 = alloc_phi(ep->active, src2, ctype);
-	use_pseudo(node, phi2, add_pseudo(&node->phi_list, phi2));
+	link_phi(node, phi2);
 
 	// join
 	set_activeblock(ep, merge);
@@ -2049,7 +2045,7 @@ static void add_return(struct entrypoint *ep, struct basic_block *bb, struct sym
 	}
 	phi = alloc_phi(ep->active, src, ctype);
 	phi->ident = &return_ident;
-	use_pseudo(phi_node, phi, add_pseudo(&phi_node->phi_list, phi));
+	link_phi(phi_node, phi);
 }
 
 static pseudo_t linearize_fn_statement(struct entrypoint *ep, struct statement *stmt)

linearize.h

@@ -109,7 +109,7 @@ struct instruction {
 		};
 		struct /* phi source */ {
 			pseudo_t phi_src;
-			struct instruction_list *phi_users;
+			struct instruction *phi_node;
 		};
 		struct /* unops */ {
 			pseudo_t src;
@@ -291,6 +291,12 @@ static inline void use_pseudo(struct instruction *insn, pseudo_t p, pseudo_t *pp
 		add_pseudo_user_ptr(alloc_pseudo_user(insn, pp), &p->users);
 }
 
+static inline void link_phi(struct instruction *node, pseudo_t phi)
+{
+	use_pseudo(node, phi, add_pseudo(&node->phi_list, phi));
+	phi->def->phi_node = node;
+}
+
 static inline void remove_bb_from_list(struct basic_block_list **list, struct basic_block *entry, int count)
 {
 	delete_ptr_list_entry((struct ptr_list **)list, entry, count);

liveness.c

@@ -257,7 +257,6 @@ static void track_phi_uses(struct instruction *insn)
 			continue;
 		def = phi->def;
 		assert(def->opcode == OP_PHISOURCE);
-		add_ptr_list(&def->phi_users, insn);
 	} END_FOR_EACH_PTR(phi);
 }
 

memops.c

@@ -100,6 +100,7 @@ static int find_dominating_parents(pseudo_t pseudo, struct instruction *insn,
 		phi->ident = phi->ident ? : one->target->ident;
 		add_instruction(&parent->insns, br);
 		use_pseudo(insn, phi, add_pseudo(dominators, phi));
+		phi->def->phi_node = insn;
 	} END_FOR_EACH_PTR(parent);
 	return 1;
 }		

sparse-llvm.c

@@ -1342,8 +1342,6 @@ int main(int argc, char **argv)
 
 	compile(module, symlist);
 
-	/* need ->phi_users */
-	dbg_dead = 1;
 	FOR_EACH_PTR(filelist, file) {
 		symlist = sparse(file);
 		if (die_if_error)

ssa.c

@@ -350,7 +350,7 @@ static void ssa_rename_phi(struct instruction *insn)
 		pseudo_t phi = alloc_phi(par, val, var);
 		phi->ident = var->ident;
 		add_instruction(&par->insns, term);
-		use_pseudo(insn, phi, add_pseudo(&insn->phi_list, phi));
+		link_phi(insn, phi);
 		mark_phi_used(val);
 	} END_FOR_EACH_PTR(par);
 }

storage.c

@@ -261,35 +261,6 @@ static void set_up_argument_storage(struct entrypoint *ep, struct basic_block *b
 	} END_FOR_EACH_PTR(arg);
 }
 
-/*
- * One phi-source may feed multiple phi nodes. If so, combine
- * the storage output for this bb into one entry to reduce
- * storage pressure.
- */
-static void combine_phi_storage(struct basic_block *bb)
-{
-	struct instruction *insn;
-	FOR_EACH_PTR(bb->insns, insn) {
-		struct instruction *phi;
-		struct storage *last;
-
-		if (!insn->bb || insn->opcode != OP_PHISOURCE)
-			continue;
-		last = NULL;
-		FOR_EACH_PTR(insn->phi_users, phi) {
-			struct storage *storage = lookup_storage(bb, phi->target, STOR_OUT);
-			if (!storage) {
-				DELETE_CURRENT_PTR(phi);
-				continue;
-			}
-			if (last && storage != last)
-				storage = combine_storage(storage, last);
-			last = storage;
-		} END_FOR_EACH_PTR(phi);
-		PACK_PTR_LIST(&insn->phi_users);
-	} END_FOR_EACH_PTR(insn);
-}
-
 void set_up_storage(struct entrypoint *ep)
 {
 	struct basic_block *bb;
@@ -300,7 +271,6 @@ void set_up_storage(struct entrypoint *ep)
 	/* Then do a list of all the inter-bb storage */
 	FOR_EACH_PTR(ep->bbs, bb) {
 		set_up_bb_storage(bb);
-		combine_phi_storage(bb);
 	} END_FOR_EACH_PTR(bb);
 
 	name_storage();