cgen: in [] optimization

vlib/time/parse.v

@@ -42,7 +42,7 @@ pub fn parse_rfc2822(s string) ?Time {
 	mm := pos / 3 + 1
 	mut tmstr := byteptr(0)
 	unsafe { tmstr = malloc(s.len * 2) }
-	count := C.sprintf(charptr(tmstr), '%s-%02d-%s %s'.str, fields[3].str, mm,
+	count := C.sprintf(charptr(tmstr), '%s-%02d-%s %s', fields[3].str, mm,
 		fields[1].str, fields[4].str)
 
 	t := parse(tos(tmstr, count)) or {

vlib/v/gen/cgen.v

@@ -944,6 +944,16 @@ fn (g mut Gen) infix_expr(node ast.InfixExpr) {
 	else if node.op == .key_in {
 		right_sym := g.table.get_type_symbol(node.right_type)
 		if right_sym.kind == .array {
+			match node.right {
+				ast.ArrayInit {
+					// `a in [1,2,3]` optimization => `a == 1 || a == 2 || a == 3`
+					// avoids an allocation
+					// g.write('/*in opt*/')
+					g.in_optimization(node.left, it)
+					return
+				}
+				else {}
+	}
 			styp := g.typ(node.left_type)
 			g.write('_IN($styp, ')
 			g.expr(node.left)
@@ -1634,6 +1644,30 @@ fn (g mut Gen) gen_filter(node ast.MethodCallExpr) {
 	g.write(tmp)
 }
 
+// `a in [1,2,3]` => `a == 1 || a == 2 || a == 3`
+fn (g mut Gen) in_optimization(left ast.Expr, right ast.ArrayInit) {
+	is_str := right.elem_type == table.string_type
+	for i, array_expr in right.exprs {
+		if is_str {
+			g.write('string_eq(')
+		}
+		g.expr(left)
+		if is_str {
+			g.write(', ')
+		}
+		else {
+			g.write(' == ')
+		}
+		g.expr(array_expr)
+		if is_str {
+			g.write(')')
+		}
+		if i < right.exprs.len - 1 {
+			g.write(' || ')
+		}
+	}
+}
+
 fn op_to_fn_name(name string) string {
 	return match name {
 		'+'{

vlib/v/gen/cheaders.v

@@ -40,6 +40,8 @@ const (
 #endif
 #endif
 
+#define V_COMMIT_HASH "TODO"
+
 '
 	c_headers = '
 

vlib/v/gen/tests/3.c

@@ -33,6 +33,10 @@ void User_foo(User* u) {
 	array_string zzz = array_repeat(new_array_from_c_array(1, 1, sizeof(string), (string[]){
 tos3(""),
 }), u->age);
+	int a = 10;
+	if (a == 10 || a == 20 || a == 30) {
+		int b = 10;
+	}
 }
 
 void println(string s) {

vlib/v/gen/tests/3.vv

@@ -26,6 +26,10 @@ fn get_user_opt() ?User {
 fn (u &User) foo() {
 	age := u.age
 	zzz := [''].repeat(u.age)
+	a := 10
+	if a in [10, 20, 30] {
+		b := 10
+	}
 }
 
 fn println(s string) {}