Increase MOVE_RATIO to 17 for Lakemont

Larger MOVE_RATIO will always make code faster.  17 is the number with
smaller code sizes for Lakemont.

gcc/

	PR target/72839
	* config/i386/i386.c (lakemont_cost): Set MOVE_RATIO to 17.

gcc/testsuite/

	PR target/72839
	* gcc.target/i386/pr72839.c: New test.

From-SVN: r239578

gcc/ChangeLog

+2015-08-18  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/72839
+	* config/i386/i386.c (lakemont_cost): Set MOVE_RATIO to 17.
+
 2016-08-18  Chung-Lin Tang  <cltang@codesourcery.com>
 
 	PR middle-end/70895

gcc/config/i386/i386.c

@@ -426,7 +426,7 @@ struct processor_costs lakemont_cost = {
   COSTS_N_INSNS (3),			/* cost of movsx */
   COSTS_N_INSNS (2),			/* cost of movzx */
   8,					/* "large" insn */
-  9,					/* MOVE_RATIO */
+  17,					/* MOVE_RATIO */
   6,				     /* cost for loading QImode using movzbl */
   {2, 4, 2},				/* cost of loading integer registers
 					   in QImode, HImode and SImode.

gcc/testsuite/ChangeLog

+2015-08-18  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/72839
+	* gcc.target/i386/pr72839.c: New test.
+
 2016-08-18  Chung-Lin Tang  <cltang@codesourcery.com>
 
 	PR middle-end/70895

gcc/testsuite/gcc.target/i386/pr72839.c

+/* { dg-do compile } */
+/* { dg-require-effective-target ia32 } */
+/* { dg-options "-O2 -mtune=lakemont" } */
+
+extern char *strcpy (char *, const char *);
+
+void
+foo (char *s)
+{
+  strcpy (s,
+	  "12345678123456781234567812345678123456781234567812345678"
+	  "1234567");
+}
+
+/* { dg-final { scan-assembler-times "movl\[ \\t\]+\\$\[0-9\]+, \[0-9\]*\\(%\[^,\]+\\)" 16 } } */
+/* { dg-final { scan-assembler-not "rep movsl" } } */
+/* { dg-final { scan-assembler-not "rep movsb" } } */