diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 616dae35bae..34c4edae20e 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -1055,7 +1055,7 @@ struct processor_costs power8_cost = {
   COSTS_N_INSNS (17),	/* ddiv */
   128,			/* cache line size */
   32,			/* l1 cache */
-  256,			/* l2 cache */
+  512,			/* l2 cache */
   12,			/* prefetch streams */
   COSTS_N_INSNS (3),	/* SF->DF convert */
 };