Prevent out of bounds indices accessing arrays

Change-Id: Ic20b7314fc3a61738f2089d393f672d801037dda

av1/encoder/rd.c

@@ -173,18 +173,20 @@ void av1_fill_mode_rates(AV1_COMMON *const cm, MACROBLOCK *x,
   int sign_cost[CFL_JOINT_SIGNS];
   av1_cost_tokens_from_cdf(sign_cost, fc->cfl_sign_cdf, NULL);
   for (int joint_sign = 0; joint_sign < CFL_JOINT_SIGNS; joint_sign++) {
-    const aom_cdf_prob *cdf_u = fc->cfl_alpha_cdf[CFL_CONTEXT_U(joint_sign)];
-    const aom_cdf_prob *cdf_v = fc->cfl_alpha_cdf[CFL_CONTEXT_V(joint_sign)];
     int *cost_u = x->cfl_cost[joint_sign][CFL_PRED_U];
     int *cost_v = x->cfl_cost[joint_sign][CFL_PRED_V];
-    if (CFL_SIGN_U(joint_sign) == CFL_SIGN_ZERO)
+    if (CFL_SIGN_U(joint_sign) == CFL_SIGN_ZERO) {
       memset(cost_u, 0, CFL_ALPHABET_SIZE * sizeof(*cost_u));
-    else
+    } else {
+      const aom_cdf_prob *cdf_u = fc->cfl_alpha_cdf[CFL_CONTEXT_U(joint_sign)];
       av1_cost_tokens_from_cdf(cost_u, cdf_u, NULL);
-    if (CFL_SIGN_V(joint_sign) == CFL_SIGN_ZERO)
+    }
+    if (CFL_SIGN_V(joint_sign) == CFL_SIGN_ZERO) {
       memset(cost_v, 0, CFL_ALPHABET_SIZE * sizeof(*cost_v));
-    else
+    } else {
+      const aom_cdf_prob *cdf_v = fc->cfl_alpha_cdf[CFL_CONTEXT_V(joint_sign)];
       av1_cost_tokens_from_cdf(cost_v, cdf_v, NULL);
+    }
     for (int u = 0; u < CFL_ALPHABET_SIZE; u++)
       cost_u[u] += sign_cost[joint_sign];
   }