rs6000: Implement insn_cost for mfcr, mfcrf

This gives mfcrf a cost of three integer insns, just like we do for sync
and load-with-reservation already.


	* config/rs6000/rs6000.c (rs6000_insn_cost): Handle TYPE_MFCR and
	TYPE_MFCRF.

From-SVN: r254439

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2017-11-06  Segher Boessenkool  <segher@kernel.crashing.org>
+
+	* config/rs6000/rs6000.c (rs6000_insn_cost): Handle TYPE_MFCR and
+	TYPE_MFCRF.
+
 2017-11-06  Richard Sandiford  <richard.sandiford@linaro.org>
 
 	* tree-vrp.c (vrp_int_const_binop): Return true on success and

gcc/config/rs6000/rs6000.c

@@ -35038,6 +35038,8 @@ rs6000_insn_cost (rtx_insn *insn, bool speed)
 
     case TYPE_SYNC:
     case TYPE_LOAD_L:
+    case TYPE_MFCR:
+    case TYPE_MFCRF:
       cost = COSTS_N_INSNS (n + 2);
       break;