[RS6000] cost SLOW_UNALIGNED_ACCESS

	* config/rs6000/rs6000.c (rs6000_rtx_costs): Make unaligned mem
	cost more.

From-SVN: r239012

gcc/ChangeLog

 2016-08-03  Alan Modra  <amodra@gmail.com>
 
+	* config/rs6000/rs6000.c (rs6000_rtx_costs): Make unaligned mem
+	cost more.
+
+2016-08-03  Alan Modra  <amodra@gmail.com>
+
 	* config/rs6000/rs6000.md (fix_trunc<mode>si2): Force source operand
 	to a reg.  Localize vars.
 

gcc/config/rs6000/rs6000.c

@@ -34336,11 +34336,16 @@ rs6000_rtx_costs (rtx x, machine_mode mode, int outer_code,
     case CONST:
     case HIGH:
     case SYMBOL_REF:
+      *total = !speed ? COSTS_N_INSNS (1) + 1 : COSTS_N_INSNS (2);
+      return true;
+
     case MEM:
       /* When optimizing for size, MEM should be slightly more expensive
 	 than generating address, e.g., (plus (reg) (const)).
 	 L1 cache latency is about two instructions.  */
       *total = !speed ? COSTS_N_INSNS (1) + 1 : COSTS_N_INSNS (2);
+      if (SLOW_UNALIGNED_ACCESS (mode, MEM_ALIGN (x)))
+	*total += COSTS_N_INSNS (100);
       return true;
 
     case LABEL_REF: