make NodeInputs statically sized, peephole a + ~a and a ^ ~a

3 files changed, 26 insertions, 3 deletions

diff --git a/ir.c b/ir.c
index 2e1fe8e..a35c80c 100644
--- a/ir.c
+++ b/ir.c
@@ -174,7 +174,8 @@ void node_add_out(Proc *p, Node *a, Node *b) {
 }
 
 void node_add_in(Proc *p, Node *a, Node *b) {
-	ZDA_PUSH(&a->in, b, &p->arena);
+	assert(a->in.len < NODE_INPUT_MAX);
+	a->in.data[a->in.len++] = b;
 	b->refs++;
 }
 
@@ -517,6 +518,13 @@ Node *node_idealize(Node *n, Proc *p, Lexer *l) {
 		break;
 	case N_OP_ADD:
 		if (same) return NODE(N_OP_MUL, CAR(n), node_new_lit_i64(p, 2));
+		if (CAR(n)->val.type.t == T_INT) {
+			/* a + ~a = -1 */
+			if (T(CAR(n), N_OP_NOT) && node_equiv(CAAR(n), CDR(n))) return node_new_lit_i64(p, -1);
+			if (T(CDR(n), N_OP_NOT) && node_equiv(CDAR(n), CAR(n))) return node_new_lit_i64(p, -1);
+		}
+		if (T(CAR(n), N_OP_NEG)) return NODE(N_OP_SUB, CDR(n), CAAR(n));
+		if (T(CDR(n), N_OP_NEG)) return NODE(N_OP_SUB, CAR(n), CDAR(n));
 		goto zero_no_effect;
 	case N_OP_SUB:
 		if (same) return node_new_lit_i64(p, 0);
@@ -561,6 +569,11 @@ Node *node_idealize(Node *n, Proc *p, Lexer *l) {
 		if (node_cmp_opposite(CAR(n)->type, CDR(n)->type) && node_equiv_input(CAR(n), CDR(n))) {
 			return node_new_lit_bool(p, 1);
 		}
+		if (CAR(n)->val.type.t == T_INT) {
+			/* a ^ ~a = -1 */
+			if (T(CAR(n), N_OP_NOT) && node_equiv(CAAR(n), CDR(n))) return node_new_lit_i64(p, -1);
+			if (T(CDR(n), N_OP_NOT) && node_equiv(CDAR(n), CAR(n))) return node_new_lit_i64(p, -1);
+		}
 zero_no_effect:	if (node_eql_i64(CAR(n), 0)) return CDR(n);
 		if (node_eql_i64(CDR(n), 0)) return CAR(n);
 		break;
diff --git a/ir.h b/ir.h
index 1cb3def..112ab8e 100644
--- a/ir.h
+++ b/ir.h
@@ -62,6 +62,15 @@ typedef enum {
 
 const char *node_type_name(NodeType t);
 
+#define NODE_INPUT_MAX 2
+
+typedef struct {
+	struct Node *data[NODE_INPUT_MAX];
+	ptrdiff_t len;
+} NodeInputs;
+
+typedef DYNARR(struct Node *) NodeOutputs;
+
 typedef struct Node {
 	union {
 		struct Node *prev_free;
@@ -70,7 +79,8 @@ typedef struct Node {
 			int walked;
 			NodeType type;
 			LexSpan src_pos;
-			DYNARR(struct Node *) in, out;
+			NodeInputs in;
+			NodeOutputs out;
 			Value val;
 		};
 	};
diff --git a/test.lang b/test.lang
index 9e9dd9b..2277fc3 100644
--- a/test.lang
+++ b/test.lang
@@ -9,6 +9,6 @@
 // also single-line now
 
 proc main(a i64) {
-	return a xor ~a
+	return a + -a
 	// (true = 0) = (a xor b)
 }