Port optimization to E(Fp²) too.

src/epx/relic_ep2_mul.c

@@ -41,7 +41,7 @@
 #if EP_MUL == LWNAF || !defined(STRIP)
 
 static void ep2_mul_gls_imp(ep2_t r, const ep2_t p, const bn_t k) {
-	size_t l, _l[4];
+	size_t l, _l[4], w = RLC_WIDTH;
 	bn_t n, _k[4], u;
 	int8_t naf[4][RLC_FP_BITS + 1];
 	ep2_t q, t[4][1 << (RLC_WIDTH - 2)];
@@ -68,19 +68,27 @@ static void ep2_mul_gls_imp(ep2_t r, const ep2_t p, const bn_t k) {
 		bn_mod(_k[0], k, n);
 		bn_rec_frb(_k, 4, _k[0], u, n, ep_curve_is_pairf() == EP_BN);
 
+		l = 0;
+		for (size_t i = 0; i < 4; i++) {
+			l = RLC_MAX(l, bn_bits(_k[i]));
+		}
+		if (l < bn_bits(u) / 2) {
+			w = 2;
+		}
+
 		l = 0;
 		for (size_t i = 0; i < 4; i++) {
 			_l[i] = RLC_FP_BITS + 1;
-			bn_rec_naf(naf[i], &_l[i], _k[i], RLC_WIDTH);
+			bn_rec_naf(naf[i], &_l[i], _k[i], w);
 			l = RLC_MAX(l, _l[i]);
 			if (i == 0) {
 				ep2_norm(q, p);
 				if (bn_sign(_k[0]) == RLC_NEG) {
 					ep2_neg(q, q);
 				}
-				ep2_tab(t[0], q, RLC_WIDTH);
+				ep2_tab(t[0], q, w);
 			} else {
-				for (size_t j = 0; j < (1 << (RLC_WIDTH - 2)); j++) {
+				for (size_t j = 0; j < (1 << (w - 2)); j++) {
 					ep2_frb(t[i][j], t[i - 1][j], 1);
 					if (bn_sign(_k[i]) != bn_sign(_k[i - 1])) {
 						ep2_neg(t[i][j], t[i][j]);